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A comparative study of larval cannibalism in three species of ladybird
Abstract
1. Cannibalism was studied under laboratory conditions in three species of Coccinellidae (Coleoptera): Cycloneda sanguinea, Olla v-nigrum, and Harmonia axyridis. Larval cannibalism varied among species, C. sanguinea > H. axyridis ≥ O. v-nigrum.
2. Larvae of all species cannibalised more in response to reduced food availability (14 h starvation daily) than in response to reduced food quality (dry Ephestia eggs).
3. Larvae of H. axyridis cannibalised siblings at lower rates than non-siblings, but larvae of C. sanguinea and O. v-nigrum did not. Rates of cannibalism increased significantly with increasing size disparity among larvae of all three species.
4. Cannibalism in C. sanguinea and H. axyridis, but not in O. v-nigrum, increased with larval density, suggesting that not all attacks on conspecifics are driven by hunger.
5. Costs, not benefits, were the predominant effects of exclusively and partially cannibalistic diets. A diet of conspecific eggs yielded survival equivalent to the Ephestia egg diet for H. axyridis and O. v-nigrum, but developmental time was extended and adults were smaller. Larvae of C. sanguinea had superior survival and faster development on conspecific eggs than on the Ephestia egg diet. Only H. axyridis larvae survived as well on diets comprised exclusively or partially of conspecific larvae as on Ephestia eggs, although they developed more slowly.
... In any instance of cannibalism, the individual cannibalising is likely to receive some degree of nutritional benefit. Evidence suggesting this has come from studies that have observed decreased developmental time (Michaud, 2003), longer survival times (Yahsuda & Ohnuma, 1999;Michaud, 2003) and increased fecundity in cannibalistic individuals (Barry et al., 2008;Schwartz et al., 2016). In addition, cannibalism rates are often negatively associated with the supply of alternative food sources, implying that cannibalism can be used as a mechanism for gaining nutrition when nutrients are rare (Folkvord, 1991;Barry et al., 2008;Vijendravarma et al., 2013). ...
... In any instance of cannibalism, the individual cannibalising is likely to receive some degree of nutritional benefit. Evidence suggesting this has come from studies that have observed decreased developmental time (Michaud, 2003), longer survival times (Yahsuda & Ohnuma, 1999;Michaud, 2003) and increased fecundity in cannibalistic individuals (Barry et al., 2008;Schwartz et al., 2016). In addition, cannibalism rates are often negatively associated with the supply of alternative food sources, implying that cannibalism can be used as a mechanism for gaining nutrition when nutrients are rare (Folkvord, 1991;Barry et al., 2008;Vijendravarma et al., 2013). ...
... In any instance of cannibalism, the predator is likely to receive some amount of nutritional benefit, which may be particularly true when individuals are starved. For some species, cannibalism can significantly increase fitness by reducing development time (Michaud, 2003), increasing survival (Yashuda & Ohnuma, 1999) and/or increasing fecundity (Schwartz et al., 2016). In the current study, we found that vials in which a higher proportion of larvae reached the third instar were associated with higher rates of cannibalism. ...
The original idea for this thesis was conceived whilst I was working (voluntarily) in the behavioural ecology lab at Macquarie University, Sydney. My initial thoughts for the project centred around investigating the ways in which the environment might change such that sexual cannibalism increased population extinction risk. Whilst this is the running theme throughout the work presented here, I also, in various places, allude to the notion that there may be many reproductive behaviours that could very quickly become maladaptive in response to rapid environmental change. As I am keen to publish most, if not all of the data chapters in this thesis, each chapter is written independently of the others and structured in the style of a paper.
... Since aphids are notably only temporary food sources for aphidophagous ladybirds, the predatory larvae of those beetles are frequently driven to cannibalism and intraguild predation in order to obtain resources to complete their development (Noppe et al. 2012). The outcome of inter-larval encounters likely depends on the species involved, their distribution within a plant, the availability of prey, and other conditions such as the relative size and aggressiveness of the larvae and their instar stage (Polis et al. 1989, Lucas et al. 1998, Michaud 2002, 2003, Félix & Soares 2004, Yasuda et al. 2004. ...
... Accordingly, the collapse of an aphid population is seen to result in an increasing competition for food that drives coccinellid larvae to conspecific and heterospecific predation in order to complete their development. The increase in larval hunger enhances aggression between conspecifics (Agarwala 1991, Michaud 2003. Conversely, Agarwala & Dixon (1992) reported that starvation increased the vulnerability of Adalia bipunctata (L.) larvae to predation by other coccinellid larvae. ...
... In the present experiments, when the extraguild prey was available, all the intraguild interactions became relaxed, except for the combination of E. connexa-L4 and of C. sanguinea-L2 larvae. Furthermore, Michaud (2003) found that larval cannibalism in three species of ladybirds increased with the rate of encounter between conspecific larvae, independently of the food supply. ...
Antagonistic interactions among predators have the potential to dampen top-down impacts on a shared pest. Strong cannibalism by adults and larvae on eggs along with a stronger intraguild predation by Eriopis connexa on Cycloneda sanguinea (Coccinellidae) than vice versa had been documented. The intensity and direction of these interactions could vary with the larval instar. We calculated aggressiveness, attack, and predation rates between larvae in the laboratory and studied both larval mortality and within-plant distribution in plants. Despite high attack rates, larvae of both species usually escaped from predation, except for the fourth vs. second–instar combinations, where the smaller larvae were more vulnerable to predation than the larger. Successful predation by E. connexa fourth-instars on C. sanguinea second-instars frequently occurred. All interactions between larvae became relaxed when extraguild prey were present. The larval mortality within the plants was influenced by the availability of extraguild prey only. Larvae of both species promptly dispersed outside the plant when prey became unavailable. With the extraguild prey present, the larvae of both species initially preferred the plant upper stratum in both combinations, but then dispersed. This study suggests that the defensive capability and larval dispersal could prevent cannibalism and intraguild-predation interactions.
... Therefore it can be expected that the rate of inter-larval aggressiveness is controlled by natural selection at a certain level. Indeed, some studies have demonstrated inter-and intra-specific genetic variability in the tendency for cannibalism (Wagner et al. 1999, Yasuda et al. 2001, Michaud 2002, 2003, Burgio et al. 2005, Pervez et al. 2006, Tayeh et al. 2014). In addition, the probability that larval contact would lead to cannibalism depends on a number of factors: hunger state, instars and sizes of the two larvae, etc. (Agarwala & Dixon 1992, Wagner et al. 1999, Yasuda et al. 2001, Michaud 2003, Pervez et al. 2006, Dixon & Kindlmann 2012, Bayoumy & Michaud 2015. ...
... Indeed, some studies have demonstrated inter-and intra-specific genetic variability in the tendency for cannibalism (Wagner et al. 1999, Yasuda et al. 2001, Michaud 2002, 2003, Burgio et al. 2005, Pervez et al. 2006, Tayeh et al. 2014). In addition, the probability that larval contact would lead to cannibalism depends on a number of factors: hunger state, instars and sizes of the two larvae, etc. (Agarwala & Dixon 1992, Wagner et al. 1999, Yasuda et al. 2001, Michaud 2003, Pervez et al. 2006, Dixon & Kindlmann 2012, Bayoumy & Michaud 2015. ...
... These inter-population differences have to be revealed on the background of much stronger factors that should be standardized (pretest diet, hunger level, population density) or at least precisely measured (larval size). As regards larval size, in the earlier studies on H. axyridis it was approximated by instar (Yasuda et al. 2001, Michaud 2002, 2003, Bayoumy & Michaud 2015, Rocca et al. 2017). In the present study, larval size was planned to be more precisely estimated by larval weight. ...
The frequency of interlarval cannibalism between individuals from native (Siberian) and invasive (Caucasian) populations of the multicolored Asian ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) was investigated under laboratory conditions by placing two individuals without any food in a Petri dish for 24 h. Combinations of all larval instars were used and each larva was weighed before the test. Interlarval cannibalism frequency significantly increased with the size (weight) of the potential predator and decreased with the size of the potential prey. The threshold of this dependence (50% frequency of cannibalism) was observed when the large larva was about three times heavier than the small one. Ladybird larvae that fed on the green peach aphid Myzus persicae (Sulz.) (Hemiptera: Aphididae) before the test began showed higher propensity for cannibalism than those fed on frozen eggs of the grain moth Sitotroga cerealella Oliv. (Lepidoptera: Gelechiidae). The diameter of the Petri dish (from 4 to 9 cm) had no effect on cannibalism. Previous experience of cannibalism did not increase further cannibalism frequency. With all other conditions being the same, individuals from the invasive population showed significantly higher propensity for interlarval cannibalism than individuals from the native population. The vulnerability to cannibalism, however, did not differ between the two populations. The results of the study can be used for the analysis of biological invasions, for the modeling of population dynamics, and for the development of the methods of mass rearing of H. axyridis and other predatory ladybirds. © 2019 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany.
... Cannibalism was traditionally seen as a behavioral abnormality and, as a result, was largely neglected as a viable feeding strategy until the 1970s (Chapman et al. 1999a;Richardson et al. 2010). Over the past several decades, however, we have discovered that cannibalism is a taxonomically widespread feeding strategy that can be induced by environmental factors such as high population density and low food availability (Kakimoto et al. 2003;Michaud 2003;Richardson et al. 2010;Vijendravarma et al. 2013). The consumption of conspecifics is particularly common in predatory arthropods where it is considered a natural extension of their diet due to the fact they possess the physical and physiological adaptations for killing and consuming live prey. ...
... Some of the complexity in observed fitness can be understood by considering the benefits and costs of cannibalistic feeding strategies in greater detail. A major fitness cost is the risk of injury or death, which is a significant additional danger for herbivores whose other food sources pose little to no direct threat (Michaud 2003). In ladybird beetles, for example, the risk of death increases when individuals choose to consume aphids over pollen and again when they choose conspecifics over aphids (Michaud 2003;Dixon 2000). ...
... A major fitness cost is the risk of injury or death, which is a significant additional danger for herbivores whose other food sources pose little to no direct threat (Michaud 2003). In ladybird beetles, for example, the risk of death increases when individuals choose to consume aphids over pollen and again when they choose conspecifics over aphids (Michaud 2003;Dixon 2000). Cannibalistic individuals are also at a greater risk of contracting a virus or pathogen than carnivores because disease transmission rates are often higher between members of the same species (Pfennig et al. 1998;Chapman et al. 2000). ...
Cannibalism is relatively common in herbaceous insects, but studies looking at life-history traits on conspecific versus herbaceous diets reveal a mix of outcomes. In some taxa, fitness is highest on a conspecific diet, but in others, fitness is highest on an herbaceous diet. Identifying factors that maintain the cannibalistic feeding strategy has been complicated by the interaction between the direct effect of consuming conspecifics and the indirect effect of releasing future competition. Here, we isolate and study the direct fitness consequences of consuming conspecifics in the tea tortrix (Adoxophyes honmai) by comparing a flexible choice diet against three fixed-composition diets (0, 50, and 100% conspecific). While overall rates of cannibalism were low in the flexible choice treatment (17%), these cannibalistic individuals ingested a greater amount of resources than any other treatment. Increased ingestion is strongly correlated with greater pupae mass suggesting that these trait changes are a relatively straightforward consequence of resource acquisition. In contrast, development time was only weakly correlated with ingestion suggesting a more complex relationship with resource quantity and quality. Interestingly, individuals feeding on either pure conspecific or pure herbaceous diet revealed a trade-off between pupae mass and development rate, whereas the trade-off disappeared for individuals consuming mixed diets. Combining all life-history traits, fitness was maximal on the flexible choice diet compared to all three fixed-composition diets. Our manipulations reveal that only low levels of cannibalism confer a direct fitness advantage. The direct fitness benefit likely emerges from the balance of ingestion rate and nutritional value for each food type.
Significance statement
Cannibalism is common in herbaceous insects, but there is contradictory evidence as to whether the feeding strategy has a higher fitness than pure herbivory. Identifying the direct effects of cannibalism on fitness is challenging as most common experimental approaches do not disentangle these effects from the indirect effect of releasing future competition. Here, we study the direct effect of cannibalism on fitness in a tea tortrix moth and show that low levels of cannibalism have the highest fitness compared to either pure herbivory or pure cannibalism. By measuring ingestion rates, we show that benefits to life-history traits come about from a combination of increased ingestion under low levels of cannibalism and relaxation of the trade-off between development time and pupae mass. As a result, our study investigates the proximate mechanisms that explain the maintenance of low levels of cannibalism in an herbaceous insect.
... Earlier studies have demonstrated that both under the shortage of prey and at the excess of food, H. axyridis larvae and adults show more inclination to intraguild predation and cannibalism than many other aphidophagous ladybirds. This feature is possibly one of the mechanisms of competitive displacement of autochthonous predators by the invader (Kajita et al., 2000;Michaud, 2003;Felix and Soares, 2004;Ware et al., 2009; Raak-van den Berg et al., 2012; Katsanis et al., 2013). As regards intraspecific (inter-population) variation in cannibalism of H. axyridis, we have found only one study (Tayeh et al., 2014) that concerned the consumption of eggs by females and larvae of the first instar and demonstrated that larvae of invasive populations are more inclined to cannibalism than larvae of autochthonous populations. ...
... However, in combination with the literature data (Tayeh et al., 2014), our results suggest that invaders show higher aggressiveness and inclination for intraguild predation. These features contribute to successful interspecific competition (Burgio et al., 2002;Michaud, 2003 (Tayeh et al., 2014). It should be noted, however, that, based on the results of our study, it is not clear whether the observed differences were prerequisites of invasion (i.e. ...
... Bars of the same group (individuals from the same population developing on the same food) labeled with different letters correspond to significantly (P < 0.05 by the Tukey test) different values. The absence of letters means the absence of significant differences. of the studied Coccinellidae species(Michaud, 2003;Pervez et al., 2006; Hodek and Evans, 2012;Bayoumy and Michaud, 2015). ...
Effects of the number of larvae per Petri dish (1, 5, and 10) on the preimaginal development of individuals of the native (Irkutsk, southern Siberia) and invasive (Sochi, the Northern Caucasus) populations of the multicolored Asian ladybird Harmonia axyridis were investigated in the laboratory. The experiments were conducted under short (12 h) and long (18 h) day conditions; the larvae were fed on the green peach aphid Myzus persicae or on the eggs of the grain moth Sitotroga cerealella. An increase in the number of larvae developed in one Petri dish resulted in a significant decrease in the rate of development in individuals from both populations which fed on aphids. Survival decreased with an increase in the number of larvae developed in one Petri dish fed on both prey species, but only in larvae from the invasive population of H. axyridis. The weight of emerging adults decreased with the number of larvae per dish in individuals from both study populations, but only when fed on aphids. These data suggest that the influence of density-dependent factors on the development of H. axyridis depends significantly on larval prey species. In addition, larvae from the invasive population have somewhat more aggressive interactions with competitors, this possibly having been one of the prerequisites for invasion.
... The object of our study, the harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is well known as a noxious invasive species (Brown et al., 2011;Roy et al., 2016;Sloggett, 2012). Interspecific intraguild predation is typical of H. axyridis, its adaptive significance is clear and, in particular, it was possibly one of the mechanisms of replacement of autochthonous predators by this ladybird (Felix & Soares, 2004;Kajita, Takano, Yasuda, & Agarwala, 2000;Katsanis, Babendreier, Nentwig, & Kenis, 2013;Michaud, 2003;Raak-van den Berg, De Lange, & Van Lenteren, 2012;Sato, Shinya, Yasuda, Kindlmann, & Dixon, 2009a;Thomas et al., 2013;Ware, Yguel, & Majerus, 2009). As regards intraspecific cannibalism, its adaptive value requires special detailed consideration. ...
... Similar conclusions were suggested by the studies conducted on some other coccinellids (Bayoumy & Michaud, 2015;Hodek & Evans, 2012;Michaud & Grant, 2004;Nedvěd & Honěk, 2012;Osawa & Ohashi, 2008;Pervez et al., 2006). Cannibalism between larvae was less investigated, although it was shown that inclination to interlarval cannibalism increased in the absence or scarcity of natural prey and that the relative vulnerability to cannibalism and intraguild predation depends on larval species and size (Bayoumy & Michaud, 2015;Dixon & Kindlmann, 2012;Felix & Soares, 2004;Michaud, 2003;Omkar, Gupta, & Pervez, 2005;Pervez et al., 2006;Rondoni, Onofri, & Ricci, 2012;Sato et al., 2009a;Snyder, Joseph, Preziosi, & Moore, 2000;Wagner et al., 1999). ...
... Thus, the main aim of our study was to estimate the impact of cannibalism (and, most probably, other density-dependent factors) on survival and pupation of starved H. axyridis larvae of the fourth instar. It is known that the inclination to cannibalism strongly depends on feeding (Burgio et al., 2002;Dixon & Kindlmann, 2012;Hodek & Evans, 2012;Michaud, 2003;Pervez et al., 2006;Rondoni et al., 2012;Sato et al., 2009a;Snyder et al., 2000;Wagner et al., 1999). Therefore, to reveal the effects of cannibalism on various backgrounds, we used two different diets before the experiment and, in addition, experimental treatments differed in availability of water. ...
Cannibalism, which is rather common in ladybirds, has been usually studied at the individual level: benefits of cannibalism for cannibals were estimated. Our study was conducted at the group level: we evaluated the overall effect of interlarval cannibalism on a group of Harmonia axyridis larvae of the fourth instar deprived of food, including both cannibals and their victims. Experiments showed that the probability of pupation in larvae which were kept individually was significantly higher than in larvae kept in groups of five, other conditions being the same. The proportion of samples in which at least one of five individuals pupated among the larvae kept individually was also higher than among those kept in groups suggesting that the eventual benefit of cannibalism was outweighed by the negative impact of aggressive interlarval interactions. The mean and minimum survival time in samples where none of five larvae pupated were longer when larvae were kept individually than when larvae were kept in groups. However, the maximum survival time (the survival time of the last larva in a sample) increased when larvae were kept in groups, which was the only one benefit of cannibalism found in our study. Under natural conditions, the possible adaptive value of this effect is that in the absence of natural prey, longer larval survival time proportionally increases the possibility of finding a new prey patch thereby ensuring survival of the population.
... These interactions are advantageous to the species, as they reduce competition and protect depleting food resource, provide immediate nutritional gain and thereby protect the gene pool (Dixon, 2000;Snyder et al., 2000). The possible costs associated with these interactions among predators are that the predators could become the victim (Elgar and Crespi, 1992), a loss of inclusive fitness (Agarwala and Dixon, 1993;Joseph et al., 1999), risk of injury, toxicity or disease transmission (Pfenning, 1997;Hurst and Majerus, 1993) and delayed development and dwarfism in emerging adults (Michaud, 2003). Larval cannibalism represents a survival strategy of the larvae under prey scarce conditions (Dixon, 2000;Kindlmann and Dixon, 1993;Yasuda and Shinya, 1997). ...
... Cannibalism of eggs, lower and same stage larvae, pre-pupae and pupae by ladybird larvae is frequent in the laboratory as well as the fields (Dixon, 2000). Larval cannibalism is a function of relative vulnerability and frequency of encounters (Agarwala and Dixon, 1993); and is largely dependent on: (i) the species, (ii) food availability, (iii) degree of relatedness, (iv) size disparity, (v) larval density, and (vi) habitat complexity (Michaud, 2003;Ingels and De Clercq, 2011). Michaud (2003) found high costs of larval cannibalism in terms of decreased survival, prolonged development time and reduced biomass in larvae of Cycloneda sanguinea Linnaeus and Olla v-nigrum (Mulsant) when these were reared on exclusive diet of conspecific larvae. ...
... Larval cannibalism is a function of relative vulnerability and frequency of encounters (Agarwala and Dixon, 1993); and is largely dependent on: (i) the species, (ii) food availability, (iii) degree of relatedness, (iv) size disparity, (v) larval density, and (vi) habitat complexity (Michaud, 2003;Ingels and De Clercq, 2011). Michaud (2003) found high costs of larval cannibalism in terms of decreased survival, prolonged development time and reduced biomass in larvae of Cycloneda sanguinea Linnaeus and Olla v-nigrum (Mulsant) when these were reared on exclusive diet of conspecific larvae. While studying the influence of food availability, food quality, size disparity and density on larval cannibalism in two aphidophagous ladybirds, Propylea dissecta (Mulsant) and Coccinella transversalis Fab., Pervez et al. (2006) found that both species were cannibalistic and the rate of cannibalism was greater in the former species. ...
The present study assesses certain predation parameters, viz. consumption rate, conversion efficiency,
and growth rate of two congeneric ladybird beetles, Coccinella septempunctata L. and Coccinella
transversalis Fab., on aphids versus con- and heterospecific larval diets. Results revealed significant
influence of ladybird species, different diets and their interaction on the consumption rate, conversion
efficiency and growth rate of fourth instars. The fourth instars of both the ladybird species showed
highest consumption rate on aphid diet, followed by conspecific larval diet and lowest on a diet
of heterospecific larvae. Similarly, the conversion efficiency of fourth instars of C. septempunctata
and C. transversalis was highest when fed on aphid diet, and lowest when fed on heterospecific
larval diet. Moreover, the growth rate of larvae of both the ladybird species was recorded highest on
aphid diet; while lowest growth rate was recorded on a diet of heterospecific larvae. Present findings
therefore, suggest that the larval cannibalism or intraguild predation can provide individual benefits
to the surviving larvae in terms of reduced intra-/ interspecific competition and survival under prey
scarce conditions. However, aphid diet is more suitable than the diet of conspecific or heterospecific
larvae for the immature stages of both ladybird species.
... Larval cannibalism is a prevalent behavior in insects, particularly ladybirds (Coleoptera: Coccinellidae) (Michaud 2003;Pervez et al. 2006), as it is a plastic response to cope with developmental constraints caused by food scarcity (Khodaei and Long 2020). The behavior allows for instant energy gain and reduces intraspecific competition (Schausberger 2003). ...
... Higher instars of predaceous coccinellids are highly potent in suppressing numerous phytophagous insects and acarine pests (Hodek et al. 2012). These larvae may resort to cannibalism during prey scarcity (Michaud 2003;Pervez et al. 2006). Agarwala and Dixon (1993) stated that adult females and second instars of Adalia bipunctata L. were reluctant to eat their eggs and inferred the possibility of kin-recognition. ...
The study examined the kin-recognition ability in the third and fourth instars of two predatory ladybirds, Hippodamia variegata (Goeze) and Menochilus sexmaculatus (Fabricius), by investigating the impact of relatedness, food quality and hunger on the avoidance of kin-cannibalism. Higher instars of both species cannibalized more non-relative first instars than the relative ones, suggesting that they can distinguish kin and abstain from cannibalizing them. The frequency of cannibalism among these larvae increased when victims were fed on dissimilar and unsuitable diets compared to those fed on the same diet as the cannibals. Cannibalistic tendencies were delayed when victims were fed on the same and appropriate diet. Fourth instars of both species had greater encounters with victims whose diets differed. Hungrier larvae of both species had more encounters and incidences of cannibalism with a shorter latency period than their satiated counterparts. It is inferred that hunger, lack of access to natural food, and challenges during molting or pupation instigate ladybird instars to engage in cannibalism. Nevertheless, when relatives are presented as food, the frequency of larval cannibalism decreases. The rate of cannibalism was higher in M. sexmaculatus compared to H. variegata, as the former is a more aggressive predator.
... Reduced cannibalism in introduced species facilitates species establishment and provides a competitive advantage over native species. Cannibalism is observed in both native and introduced ladybirds, and rates of cannibalism differ between native and introduced species (Michaud 2003). Some studies show that the differences in the rate of cannibalism between native and introduced ladybirds did not change in absence or reduced prey densities (Michaud 2003), but contrastingly some native ladybird species showed higher levels of cannibalism compared to introduced ladybird species in the absence of prey (e.g., the native species Coccinella novemnotata Herbst, 1793 and the introduced species C. septempunctata [Cottrell 2005;Turnipseed et al. 2015]). ...
... Cannibalism is observed in both native and introduced ladybirds, and rates of cannibalism differ between native and introduced species (Michaud 2003). Some studies show that the differences in the rate of cannibalism between native and introduced ladybirds did not change in absence or reduced prey densities (Michaud 2003), but contrastingly some native ladybird species showed higher levels of cannibalism compared to introduced ladybird species in the absence of prey (e.g., the native species Coccinella novemnotata Herbst, 1793 and the introduced species C. septempunctata [Cottrell 2005;Turnipseed et al. 2015]). However, a recent study comparing cannibalism between H. axyridis larvae kept in isolation and in groups shows that the survival time of the last larva in a sample was increased in the larvae kept in groups in the presence of cannibalism (Reznik et al. 2018). ...
... The intensity of sibling cannibalism on eggs was density independent, while nonsibling cannibalism on eggs was density dependent (Osawa, 1993) and most intense near aphid colonies (Osawa, 1989). Larval cannibalism increased as a function of conspecific larval density (Michaud, 2003a). Cannibalism by one larva on another was shown to provide nutritional benefits when other prey were scarce (Wagner et al., 1999), nutrient deficient, or toxic (Snyder et al., 2000). ...
... Cannibalism by one larva on another was shown to provide nutritional benefits when other prey were scarce (Wagner et al., 1999), nutrient deficient, or toxic (Snyder et al., 2000). However, H. axyridis displays kin recognition, and is less likely to cannibalize a sibling than a non-sibling (Joseph et al., 1999, Michaud, 2003a. Mortality within the fourth instar (93.3 percent) was the highest of all stages, due to food shortages after aphid densities crash (Osawa, 1992b). ...
Throughout the last century, the multicolored Asian lady beetle, Harmonia axyridis (Pallas) has been studied quite extensively, with topics ranging from genetics and evolution to population dynamics and applied biological control being covered. Much of the early work on H. axyridis was conducted in the native Asian range. From the 1980's to the present, numerous European and North American studies have added to the body of literature on H. axyridis. H. axyridis has recently gained attention in North America both as a biological control agent and as a pest. This literature review was compiled for two reasons. First, to assist other researchers as a reference, summarizing most of the voluminous body of literature on H. axyridis pertaining to its biology, life history, uses in biological control, and potential non-target impacts. Secondly, to be a case study on the impacts of an exotic generalist predator.
... Cannibalism may occur in different growth stages of aphidophagous ladybird beetles, including egg, larva, prepupa, and pupa (e.g., Dixon, 2000;Osawa, 1989Osawa, , 1992bOsawa, 2002;Takahashi, 1989). It may also occur between sibling and nonsibling species (Kawauchi, 1985;Mills, 1982;Osawa, 1989;Pervez, Gupta, & Omkar., 2005), depending on a host of factors including differences in body size, population density and food availability (e.g., Michaud, 2003). The high incidence of cannibalism among ladybird beetles suggests that there may be considerable benefits of the behavior in terms of survival, providing energy, and eliminating potential competitors (e.g., Getto, Diekmann, & Roos, 2005;Martini, Garrigues, & Hemptinne, 2015;Osawa, 1992aOsawa, , 1992bOsawa, , 2002. ...
... axyridis, encompassing a wide variety of aphids, additional insect prey, and other types of food (Berkvens et al., 2008;Hodek, 1996;Koch, 2003), means that this species comes into contact with, and appears to be able to tolerate, a very wide diversity of prey defensive chemistry in its diet. Michaud (2003) Figure 3). The short development period is extremely important when tracking aphid density in H. axyridis (e.g., Osawa, 1992bOsawa, , 2000. ...
In this study, we focused on the direct (i.e., predation) and indirect (i.e., potential threat from coexisting with a larger individual) effects of cannibalism and intraguild predation (IGP) during larval stages of two sibling ladybird beetles. These effects play an important role in the coexistence of the generalist–common Harmonia axyridis and specialist–rare H. yedoensis (Coleoptera: Coccinellidae). Direct predation effect of cannibalism and IGP was asymmetric in the two sibling ladybird beetles; the fourth instar larvae of H . axyridis were better intraguild predators than cannibals, while the reverse was true in the larvae of H. yedoensis . Neither cannibalism nor IGP significantly affected female body weight in either species. Larval H . axyridis surviving exposure to cannibalism or IGP had a reduced number of ovarioles as adults, whereas adult H. yedoensis ovarioles were not affected. For the indirect effects, longer developmental times in males and females and a lower total number of ovarioles in females were detected in H . axyridis . In H. yedoensis , shorter developmental time of males, lighter adult weight and fewer total ovarioles in females were observed. Olfactometer choice experiments clarified that the fourth instar larvae of H . axyridis avoided the first instar conspecific larvae, while those of H. yedoensis were attracted to the odors from H . axyridis and conspecifics. Thus, H . axyridis has an avoidance mechanism only for cannibalism but not for IGP, whereas H. yedoensis does not have any avoidance mechanism. These different behaviors in the direct and indirect effects of cannibalism and IGP observed in the laboratory may play important roles in the coexistence of generalist–common H . axyridis and specialist–rare H. yedoensis in natural conditions, compensating for the large handicap of H. yedoensis at reproductive interference from H . axyridis .
... Cannibalism in N. pseudoferus, as commented on before, is very important and seems to be closely related to the absence of prey, as well as to size differences between the victim and the predator, as can be observed in the mortality percentages ( Figure A1a) and survival times for the different developmental stages studied ( Figure A1b). The importance of size differences in cannibalism has been cited and widely documented for scorpions [5,82], spiders [8,79,82,83] and predatory coccinellids [84,85], as well as for other invertebrate and vertebrate species [86,87]; however, it has seldom been studied in insects, with the exception of the work by Laycock et al. [88]. ...
... In contrast to the III-instars, the species shows greater zoophagy [91]; this is contrary to the results that showed reduced cannibalism at that stage and at subsequent stages. Perhaps in the first three instars, cannibalism is not caused by the need to eliminate potential competitors, as cited for other species [4,5,14,85,94]. ...
Cannibalism in insects plays an important role in ecological relationships. Nonetheless, it has not been studied as extensively as in other arthropods groups (e.g., Arachnida). From a theoretical point of view, cannibalism has an impact on the development of more realistic stage-structure mathematical models. Additionally, it has a practical application for biological pest control, both in mass-rearing and out in the field through inoculative releases. In this paper, the cannibalistic behavior of two species of predatory bugs was studied under laboratory conditions-one of them a generalist predator (strictly carnivorous), Nabis pseudoferus, and the other a true omnivore (zoophytophagous), Nesidiocoris tenuis-and compared with the intraguild predation (IGP) behavior. The results showed that cannibalism in N. pseudoferus was prevalent in all the developmental stages studied, whereas in N. tenuis, cannibalism was rarely observed, and it was restricted mainly to the first three nymphal stages. Cannibalism and intraguild predation had no linear relationship with the different cannibal-prey size ratios, as evaluated by the mortality rates and survival times, although there were variations in cannibalism between stages, especially for N. pseudoferus. The mathematical model's implications are presented and discussed.
... Cannibalism in ladybirds has been demonstrated to be a function of relative vulnerability and frequency of encounters (Agarwala and Dixon, 1993). Studies on different components of cannibalism in ladybirds have revealed that it is largely dependent on the species, food availability (Agarwala and Dixon, 1992;Devee et al., 2018), degree of relatedness (Pervez et al., 2013), size disparity and larval density (Michaud, 2003;Pervez et al., 2006). Even in the presence of a sufficient amount of essential prey, ladybirds are known to preferably consume conspecific eggs (Santi et al., 2003;Omkar et al., 2006). ...
... We also presented eggs either as frozen or fresh and in scattered or clustered pattern to assess ladybird preference for prey. It has earlier been observed that ladybirds cannot detect frozen aphids (Stubbs, 1980).While suitability of an egg versus conspecific and heterospecific diet has been assessed pre-viously in ladybirds (Michaud, 2003;Felix and Soares, 2004;Omkar et al., 2004) there is, to the best of our knowledge, none on frozen versus fresh eggs. It is our hypothesis that scattered eggs would be preferred more as a prey as they would not give out aposematic signals as suggested by Agarwala and Dixon (1993). ...
Egg cannibalism is very common among predaceous ladybirds. Studies have been done on coccinellids using egg as a diet but information on the influence of egg freshness and egg pattern on life history attributes of aphidophagous ladybird, Menochilus sexmaculatus (F.) (Coleoptera Coccinellidae) under laboratory conditions are scarce. In our experiment, the first instars were reared on fresh or frozen conspecific eggs in both clustered and scattered patterns. Incidence of cannibalism was not affected by either egg freshness or clustering pattern. However, percent consumption by instars differed significantly with first and fourth in-star consuming more of frozen clustered and fresh scattered conspecific eggs, respectively. F2 generation offspring had similar development on frozen and fresh conspecific eggs. Females reared on frozen eggs had higher fecundity and percent egg viability whereas longevity followed the reverse trend. However, overall fitness was similar on both diets, indicating that egg freshness did not affect nutritional status.
... While egg cannibalism is a more prevalent phenomenon, being an easy source of energy (Takahashi 1987;Agarwala and Dixon 1992), larval cannibalism has been investigated more in ladybirds (Michaud 2003;Pervez et al. 2006). In larval cannibalism, the role of size disparity (Yasuda et al. 2001), species specific context (Yasuda and Ohnuma 1999;Snyder et al. 2000), as well as kinship or relatedness (Michaud 2003;Pervez et al. 2005) have been observed. ...
... While egg cannibalism is a more prevalent phenomenon, being an easy source of energy (Takahashi 1987;Agarwala and Dixon 1992), larval cannibalism has been investigated more in ladybirds (Michaud 2003;Pervez et al. 2006). In larval cannibalism, the role of size disparity (Yasuda et al. 2001), species specific context (Yasuda and Ohnuma 1999;Snyder et al. 2000), as well as kinship or relatedness (Michaud 2003;Pervez et al. 2005) have been observed. Results of these studies indicate a proclivity of smaller sized individuals and conspecifics to being cannibalized in prey-scarce conditions (Hodek et al. 2012). ...
Oviposition site selection in ladybirds is a dynamic process influenced by a number of abiotic and biotic factors. In this study we investigated whether prey quantity and egg presence (varying in relatedness and age) influence oviposition behavior in the zigzag ladybird, Menochilus sexmaculatus (Fabricius). Influence of these factors on cannibalism by females was also investigated and we tried to observe whether cannibalism was a modifying mechanism during oviposition site selection. Females were placed in prey abundant or scarce conditions in presence of related or unrelated eggs of varying ages, and their oviposition (for 24 h), egg viability and cannibalism were recorded. Prey-scarce conditions significantly decreased oviposition but had no influence on egg viability. Prey scarcity also increased the incidence of cannibalism by females. Females avoided laying eggs in the presence of related eggs regardless of their age. On the other hand, cannibalism was more in related eggs that were older in age. This increased cannibalism in presence of older related eggs, may be a comprehensive way of eliminating potential competition threats from a potential oviposition site already having eggs. All the independent factors (prey quantity, egg relatedness and egg age) did not affect egg viability, is the suggestive of male nutritional status rather than female.
... Intra-guild predation could be one mechanism utilised by H. axyridis to displace indigenous species such as E. flavipes (Hautier et al. 2009). Evans (1991, Cottrell & Yeargan (1999), Yasuda & Ohnuma (1999) and Michaud (2003) also suggested that intra-guild predation might be facilitating the dominant invasion by H. axyridis. Studies done by Sakuratani et al. (2000), Kajita et al. (2000), Yasuda et al. (2001) and Koch et al. (2003) indicate that H. axyridis can effectively utilise other members of the aphidophagous guild as a food source. ...
... It was shown that the intensity of predation by H. axyridis on other guild members is inversely related to aphid density (Hironori & Katsuhiro 1997;Burgio et al. 2002). Joseph et al. (1999) and Michaud (2003) found that H. axyridis has the innate ability to display kin recognition and is thus less likely to cannibalise a sibling than a non-sibling. ...
Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an exotic ladybird, first recorded in South Africa in 2004, where it was introduced factitiously. In this study the seasonal occurrence of H. axiridis and other coccinellids were monitored in four vineyards and the adjacent windbreaks over three growing seasons in the Western Cape Province, South Africa. Harmonia axyridis made up the highest mean number of coccinellids collected per site over the collecting period, followed by Hippodamia variegata, Cheilomenes lunata, Exochomus flavipes and Micraspis sp. No indigenous parasitoids were observed attacking H. axyridis. The numbers of H. axyridis on the vines were negatively correlated with temperature but positively with rainfall. In view of the migration of H. axyridis from the vines in December, they appear not to pose any risk of contaminating grapes during harvest and tainting wine as most wine grapes are harvested from January onwards.
... The intensity of sibling cannibalism of larvae on eggs does not depend on the aphid population density (unlike nonsibling cannibalism) but varies in different lineages (Osawa, 1989(Osawa, , 1993. Nonsibling cannibalism on larvae increases as the aphid population decreases (Hironori and Katsuhiro, 1997) or the population density of larvae of the same species increases (Michaud, 2003). At the same time, H. axyridis demonstrates family recognition and is less willing to eat relatives than nonrelatives (Kawai, 1978). ...
... Most of the described specific ecological and biological traits of H. axyridis are traditionally considered beneficial for successful invasions: large size, high fertility, short development time from egg to imago (Michaud, 2002;Félix and Soares, 2004;Labrie et al., 2006;Hemptinne et al., 2012); polyphagy , cannibalism (Michaud, 2003), and high aggressiveness towards other species (Ware and Majerus, 2008). Broad ecological plasticity is also considered beneficial for successful invasions of the species Berkvens et al., 2008Berkvens et al., , 2010, as well as the high cold resistance and low sensitivity to natural enemies provided by its well-developed immunity and powerful chemical and physical protection (Cottrell and Shapiro-Ilan, 2008; Ware and Majerus, 2008;Nedvĕd et al., 2010). ...
The initial distribution and the global invasion of the ladybird H. axyridis are discussed. Some biological characteristics of the species are considered in view of its possible impact on the formation of evolutionary preadaptations promoting invasion.
... The spatial and temporal co-occurrence of aphidophagous ladybird species creates opportunities for CANN and IGP, especially when aphids become scarce (Schellhorn & Andow, 1999;Burgio et al., 2002;Michaud, 2002). Cannibalism propensity varies among aphidophagous species and can be influenced by food availability and quality, developmental stage, and encounter rates among individuals (Michaud, 2003;Bayoumy & Michaud, 2015). Intraguild predation interactions among ladybirds are usually bidirectional and asymmetric (Michaud & Grant, 2003). ...
... Various studies have reported that CANN on eggs and larvae by ladybirds became more frequent when aphid populations crash (Osawa, 1989;Agarwala & Dixon, 1992;Schellhorn & Andow, 1999;Burgio et al., 2002;Cottrell, 2005;Takizawa & Snyder, 2011;Rondoni et al., 2012). The collapse of an aphid population results in increasing competition for food and drives larvae to CANN and IGP in order to complete their development (Agarwala, 1991;Michaud, 2003), with the added advantage of eliminating competitors (Agarwala & Dixon, 1992). ...
... Ladybird beetles are known globally for their biological potential. During mass rearing, it is not uncommon for larvae to incur non-lethal injuries including appendage loss owing to strong cannibalism exhibited by these beetles 14 . Hence, Cheilomenes sexmaculata (Fabricius) was selected for the present study because it exhibits limb regeneration 6 and is widely distributed in the local agricultural fields of India. ...
Larval systems are de-differentiated and reorganized in insects undergoing complete metamorphosis, and body plan of adults are established during pupal stage. In ladybirds, limbs amputated in larval stages are regenerated during pupation. Given that changes in pupa are akin to embryogenesis, does the lost limbs are redeveloped as a part of metamorphosis or has some pre-patterning initiated prior pupation? To test this, we exposed third larval instars of Cheilomenes sexmaculata to amputation and scraped off the epidermal tissues from the amputation site every 24 h post amputation. We observed that the limb regeneration did not occur in the treatment where scrapping was done. Thus, the present study highlights the critical role of epidermal tissues at the wound site in limb regeneration, emphasizing that these tissues probably contain essential pre-regenerating cues
... Under mass rearing in crowded and resource-poor conditions, it is common for coccinellids larvae to cannibalise each other, which imparts a risk of injury to larval cannibals (Michaud, 2003;Schellhorn & Andow, 1999). Therefore, ladybirds are a potential model for regeneration studies as well as their related trade-offs, such as transgenerational (Abdelwahab et al., 2018;, developmental , functional recovery (Wu, Ma, et al., 2019;Yang et al., 2016) and sexual selection (Wang et al., 2015). ...
Regeneration has been a topic of interest across a range of taxa for centuries, and arthropods are no exception. Trade‐offs associated with regeneration are likely to involve the reallocation of resources away from other metabolic activities such as growth, development or reproduction. This might be reflected in costs to some developmental traits of the organism, despite regeneration being advantageous. These associated costs might also differ with the stage of injury or amputation. Here, we hypothesise that the extent of regeneration and trade‐offs associated with it may be stage‐specific. To test this hypothesis, the right forelimb of four larval stages of the ladybird beetle Cheilomenes sexmaculata (Fabricius) (Coleoptera: Coccinellidae) was amputated. Amputated individuals were reared until adulthood, and all developmental transitions were recorded. Regenerated legs in all the treatments were smaller than the controls, which did not experience the amputation, and the regenerative potency of early larval stages was higher than that of late larval stages. Limb regeneration caused delays in post‐amputation developmental duration in all the treatments, increasing their total developmental period. The length of the unamputated left foreleg as well as the wing and antenna size were also reduced in regenerated beetles, showing some internal trade‐off. However, there were no significant differences observed between regenerated and control adults in their fresh body weight and body size. Thus, limb regeneration depends upon the stage of larval development at which the amputation was performed. Amputation also affects the development of other appendages. The delay in normal beetle development might have been observed because of extra resource requirement, their allocation as well as reprogramming of the expression of some genes during regeneration.
... Ladybirds have brilliant defense mechanisms against the disturbance caused by any other insect or predator. In addition to wriggling and biting, ladybird larvae may defend themselves by attacking with their dorsal and lateral spines (Michaud, 2003). When disturbed, certain ladybird pupae flip, which might cause the attackers' antennae to be ripped off (Lucas et al., 2000). ...
Exotic ladybirds have been widely utilized to control economically significant herbivorous insects since the late 19th century. Since people became aware of the possible side effects of introductions, the introduction of non-native biocontrol agents has been significantly curtailed. However, recent instances of biological invasions of commercially significant pests have highlighted the need to carefully assess whether the anticipated advantages of pest management outweigh any potential environmental dangers of introduction. The most effective models to address issues with ecology and evolution are ladybirds. Therefore, there is a wide variety of information regarding the ecological and evolutionary aspects of ladybirds.
This chapter deals with the potential of the ladybird as a biocontrol agent and discusses its feeding habits, life cycle, position in the guild, use in classical and augmentative biological control, and impact on the prey.
... Due to a higher attacking rate, cannibalism prevails more in C7 larvae between the third and fourth instars, as reported by Khan and Yoldas [26] . Food scarcity and size disparity between the cannibal and the victim are the main causes of larval cannibalism [37,38] . High intensity of cannibalism by the fourth instars was largely due to their greater body-weights. ...
... Due to a higher attacking rate, cannibalism prevails more in C7 larvae between the third and fourth instars, as reported by Khan and Yoldas [26] . Food scarcity and size disparity between the cannibal and the victim are the main causes of larval cannibalism [37,38] . High intensity of cannibalism by the fourth instars was largely due to their greater body-weights. ...
Coccinella septempunctata L. (C7) and Menochilus sexmaculatus (Fabricius) (Ms) are aphidophagous ladybirds (Coleoptera: Coccinellidae), which dominates the ladybird fauna of Oriental region. Since these species co-occur and are highly predaceous on various aphids, it was hypothesized that in the scarcity or absence of aphids, i.e., extraguild prey, one ladybird species will start attacking and killing the other one, which will endanger their co-occurrence. Thus, we aim to determine, which ladybirds' larvae will subdue the other; their attack rates (rate at which a superior individual attacks the inferior one), escape rates (rate at which an inferior individual escapes from the attack of superior one) and predation rates (rate at which a superior individual eats the inferior one) were investigated, as they indulged in cannibalism and intraguild predation. Larvae of C7 were slightly bigger and heavier than those of Ms, thereby they gained a slight competitive advantage. This enabled C7 a better attacker and an escapist when confronted with larvae of Ms in a predatory guild, which resulted in lesser larval mortality due to intraguild predation by Ms larvae. However, C7 successfully preyed upon the larvae of Ms. The highest rate of cannibalism and intraguild predation was executed by C7 which made it a potent cannibal and an intraguild predator. Despite being outplayed by C7, the inferior Ms larvae didn't suffer much loss during the intraguild combat due to their armoured morphological features in the form of spines and rough texture. This is the reason why Ms still exists as the second most commonly occurring ladybird in the field.
... The hybrid offspring represented by females continued to mate with A. bipunctata males again, which eventually (after several generations) led to the loss of chromosomal genes of the unknown ladybird Adalia sp. in descendants from interspecific crossing. The genetic distance between haplotype H1 and haplotype H10 is 0.067 (Table 3), which 2003; Boakes et al. 2007); (3) the possibility of providing females from infected lines at the stage of the first instar larvae with additional resources due to cannibalism (larvae hatched from eggs, eating eggs from which males have not hatched, are better provided with food than larvae of uninfected lines, which have full or almost complete hatching) and reduced competition when searching for food (Michaud 2003); (4) increased ability to resist aggressive environmental conditions (it is possible that infected females tolerate unfavorable conditions better, which has been shown for a number of other insect species) (Xie et al. 2010;Jaenike 2012;Mathé-Hubert et al. 2019). ...
Adalia bipunctata (Coleoptera: Coccinellidae) is the host of three different symbiotic bacteria: Spiroplasma, Rickettsia, and Wolbachia. This paper presents an overview of data on the distribution of these bacteria in populations of the two-spot ladybird from different parts of the area: Sweden (Stockholm), Russia – from Karelia to Transbaikalia, and Kyrgyzstan. It is noted that in Moscow and St. Petersburg, the symbiosis of bacteria with A. bipunctata has been observed for almost 30 years, that is, it persists steadily. Since both symbiotic bacteria and mitochondrial DNA are inherited cytoplasmatically, the long-term existence of symbionts in the population can lead to a change in the frequency ratio of haplotypes. Spiroplasma, Rickettsia, and Wolbachia usually affect the reproduction of A. bipunctata, causing the male killing, however, sometimes there are strains of Wolbachia that do not cause the male killing. Adalia bipunctata has a parasitoid Aprostocetus sp. (Hymenoptera: Eulophidae), which also has a Wolbachia symbiont. However, the Wolbachia strains from the parasitoid are not related to the bacterial strains from A. bipunctata, which indicates the absence of horizontal transfer between the host beetle and the larvae of the parasitoid. The carriers of the symbionts may be Coccipolipus hippodamiae (Acarina: Podapolipidae) mites that parasitize ladybirds.
... Ladybird beetles are known globally for their biological potential. During mass rearing, it is not uncommon for larvae to incur nonlethal injuries including appendage loss owing to fierce cannibalism exhibited by these beetles (Michaud 2003). The loss of limbs put constraints on the morphology of beetles and alters their biomechanics. ...
Holometabolous insects undergoes metamorphosis which involves an intercalated pupa stage between larva and adult. The body plan of the adult is established during pupa stage and larval systems are de-differentiated and reorganized in insects undergoing complete metamorphosis. In ladybird beetles, the limbs amputated in the larval stages are regenerated in the adults. This occurs during pupation. Given that changes in the pupa are akin to embryogenesis, does the lost limbs are redeveloped as a part of metamorphosis or has some pre-patterning initiated prior pupation? To study this we hypothesised that limb regeneration in a holometabolous ladybird beetles, Cheilomenes sexmaculata is the result of the recapitulation of the embryonic gene programs in the pupa. To test this, we exposed the third larval stages of Cheilomenes sexmaculata (Fabricius) to amputation and prior to amputation the tissues on the amputated site was scraped off every 24hrs. It was found that limb regeneration does not occur in the treatment where scrapping was done. Assuming that these epidermal cells correspond to blastema, for limb regeneration in ladybird beetles blastema is essential and does not occur in its absence.
... Cannibalism in ladybirds is known to accelerate growth rate (Osawa, 2002), prolong survival (Roy et al., 2007), reduce the developmental time (Bayoumy et al., 2016;Gagne et al., 2002;Roy et al., 2007), and increase fertility (Bayoumy & Michaud, 2015a), size and weight (Osawa, 2002). In contrast, delayed development, lowered survival, and reduced reproduction because of cannibalism have also been reported in Coccinellidae (Michaud, 2003;Pervez et al., 2006;Ware et al., 2009). The heritability of cannibalism in the ladybird beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in low food environments has been reported earlier (Wagner et al., 1999). ...
Menochilus sexmaculatus, a generalist aphidophagous ladybird beetle, is one of the potential biocontrol agents of multiple aphid species. This beetle exhibits cannibalism among different life stages. A laboratory experiment was conducted by conditioning the larvae and adults on their natural prey that is aphids, or the conspecific eggs for five generations to assess whether cannibalism was affected by prior cannibalistic experiences or not. Adults of the fifth generation were provided with a choice of aphids and eggs. The time of first prey encounter and prey first encountered along with latency to consume prey and prey first consumed were recorded. Non‐cannibalistic individuals preferred aphids over eggs, while cannibalistic individuals showed no preference. The time of first prey encounter and consumption were similar for aphids and eggs irrespective of the diet they were reared on. To assess the long‐term effects, offspring developmental duration and body weight were recorded across generations. Similar developmental duration of immature stages was recorded in the first and second generations of cannibalistic and non‐cannibalistic lines; however, prolonged developmental duration was recorded in cannibalistic lines when compared with non‐cannibalistic ones of later generations. Offspring of later generations developed faster in both lines. The offspring body weight of the second and fourth generations of both lines was found to be similar. However, a decline in body weight was recorded in cannibalistic offspring of the first, third and fifth generations when compared with non‐cannibalistic ones. A decline in the body weight of offspring across generations was observed in both lines. The findings suggest that M. sexmaculatus rearing diet influences its preference for prey and that long‐term dietary conditioning can affect different fitness components. This could potentially reduce their effectiveness in biocontrol.
... (iii) Mortality caused by predation, f(R), follows the respective Holling's functional response; and in the case of h(R, C) = e f R, we assumed a Holling's type II functional response. (iv) A quadratic mortality for the ladybeetle, d(C) = mC 2 , which represents negative intraspecific interactions (e.g., cannibalism) commonly found in C. sanguinea (Michaud, 2003;Michaud and Grant, 2004;Rocca et al., 2017). For this type of quadratic mortality, see (Edwards and Yool, 2000). ...
The significance of the relationship between data and models in ecology cannot be overstated. Over the past few decades, numerous techniques have been developed and applied in the study of ecological systems. One such technique is the Bayesian calibration of model parameters, which draws from Bayes' theorem to incorporate prior knowledge in estimating parameter values and quantifying their uncertainty. In this study, we establish a Bayesian framework for analysing ecological time series and apply it to a specific case of aphid-ladybeetle predation. To accomplish this, we construct and assess six mathematical models consisting of ordinary differential equations. These models encompass three phenomenological models and three data-driven models. To gain insights into the behaviour of the models concerning a specific quantity of interest, namely aphid abundance, we conduct a sensitivity analysis of the parameters. Subsequently, we compare the outputs of the models by employing model selection techniques. Based on our analysis, the best-performing model is a phenomenological one that incorporates a Holling's type II functional response. We believe that this framework has the potential for application and extension to other ecological systems, thereby enhancing our understanding of these intricate systems.
... Under mass rearing in crowded and resource-poor conditions, it is common for 84 coccinellids larvae to cannibalise each other, which imparts a risk of injury to larval cannibals 85 (Schellhorn and Andow, 1999;Michaud, 2003). Around 16 different species of ladybird beetles 86 have been scored on limb regeneration based on their survival, proportion of regenerating leg, 87 5 and developmental costs associated with limb amputation (Michaud et al., 2020). ...
Regeneration is a topic of interest for centuries and arthropods are no exception. Trade-offs associated with regeneration are likely to indicate the reallocation of resources from other metabolic activities such as growth, development, or reproduction to regrowth of the lost body part. This may confer negative selection to some of the developmental traits of the organism despite regeneration being overall advantageous. Our hypothesis for the study was that the extent of regeneration and trade-offs associated with it may be stage-specific. To test this hypothesis, the right forelimb of all four larval stages of the ladybird beetle (Cheilomenes sexmaculata) was amputated. The amputated stages were reared till adulthood and all developmental transitions were recorded. Leg size was measured and compared with control. The result showed that the regenerated legs of all the treatments were smaller than the control and the regenerative potency of early larval stage was higher than late larval stages. Regeneration causes delay in post-amputation duration in all the treatments, increasing their total development period. However, insignificant difference was observed between the fresh body weight of regenerated and control adults. The length of unamputated left foreleg was reduced in regenerated beetles, showing some internal trade-off.
... It was found that the unregenerated and incompletely regenerated adults in P. dissecta took more time to commence mating and mated for shorter duration compared to the regenerated and normal adults. This can probably be attributed to the rejection behaviour of the females postassessment of the physical condition of males [18][19][20] . Another reason for the lower performance of unregenerated and incomplete adults could be incomplete physical contact with their mates due to the missing limb 16 . ...
In holometabolous insects, adult develops through larval and pupal stages. Limb regeneration has an impact on different life traits of organisms. In the present study, we found that limb regeneration of two ladybird species of different body size affected their life attributes. The fourth instar of Propylea dissecta and ladybird Cocci-nella septempunctata were taken from laboratory stock and ablated. Larvae were observed until adult emergence. Emerged adults were kept in different mating treatments. Unregenerated adults of ladybirds took more time to commence mating with shorter copulation and reduced fecundity and per cent viability. Thus, it can be concluded that regeneration ability modulates life attributes of ladybirds, irrespective of body size. REGENERATION is beneficial to insects in terms of physical fitness. It also modulates life attributes. Males have been known to regulate the courtship, copulation duration, quality and quantity of ejaculates depending upon the surrounding environment and their physical fitness 1-3. Poorly regenerated or physically disabled males are known to affect mobility, mating success and reproduction 4. Besides, it has been reported that the missing or regenerated limbs are known to affect the outcome of various ecological interactions, such as prey-predator interactions and intraspecific competition 5,6. In wolf spider Schizocosa ocreata, it has been reported that the prey capturing efficiency decreased due to a missing or regenerating limb. In field cricket Gryllus bimacu-latus, it has been reported that in females, loss of limb has resulted in significantly reduced mating ability, while in males it has resulted in reduced longevity. Under promiscuous conditions, poor quality males were overpowered by healthy males 7,8. In terms of reproductive performance in spiders, it has been reported that loss of forelegs can lead to reduced reproductive success by fewer sperm transfers 9. Studies on Harmonia axyridis showed that the unregenerated adults were poor in mating and reproductive parameters than the regenerated and non-ablated individuals 10. Ladybirds are polyandrous 11,12 and display mate choice 13,14. In Menochilus sexmaculatus Fabricius, it has been shown that regenera-tion occurs in the adult stage and not from instar to instar, and unregenerated adults were poor performers in mating and reproductive parameters 15. Another study on M. sexma-culatus reported that when the adult legs were ablated from three different joints, there was a difference in their mating performance and reproductive output 16. Here, we aim to study the effects of limb regeneration on two ladybird species, i.e. Coccinella septempunctata (L.) and Propylea dissecta (Mulsant). In this study, we have hypothesized that regeneration may have some costs in terms of reproductive attributes. This was examined using fourth instar individuals of P. dissecta and C. septempunc-tata that were amputated for their forelimb from the base of the coxa. Regenerated, normal and unregenerated adults of the two ladybird species were used in different mating treatments , and the impact on mating and reproductive attributes of both beetles was recorded. Live adults of medium-sized P. dissecta (average fresh wt: 13.04 ± 0.15 mg, n = 50) and large sized C. septempun-ctata (average fresh wt: 21.70 ± 0.15 mg, n = 50) were collected from the agricultural fields of Lucknow, Uttar Pradesh, India (26°50′N, 80°54′E). These beetles were selected for experimentation due to their predominance in local fields, wide prey range 17 and high reproductive output. Males and females were paired in plastic petri dishes (9.0 × 2.0 cm) and provided with an ad libitum supply of cowpea aphid Aphis craccivora Koch (Hemiptera: Aphididae) raised on cowpea Vigna unguiculata L. in a glasshouse at 25° ± 2°C, 65 ± 5% relative humidity (RH). Petri dishes with mating pairs were placed in BOD incubators (Yorco Super Deluxe, YSI-440, New Delhi) at 27° ± 1°C, 65 ± 5% RH, 14L : 10D. They were inspected twice daily (1000 and 1500 h) for oviposition. The eggs were separated and reared individually in petri dishes until the emergence of the fourth instar individuals. Fourth instar larvae (24-hold post-moulting) of P. dis-secta and C. septempunctata were divided into two groups of 100 individuals each. One group was reared as control (termed as normal hereafter) and chilled for 5 min with no amputation treatment. The other group was also chilled for 5 min to ease the ablation process. Amputation of forelimb from base of coxa of right side was done under a stereosco-pic binocular microscope (Magnus) at 16× magnification with the help of a micro-scalpel. Post-amputation, larvae were reared individually in petri dishes until adult emergence. All the adults were isolated and reared on the ad libitum supply of A. craccivora. Ten-day-old unmated adults of both species were selected for the amputation treatment and assessed for limb regene-ration. The ones with limb regeneration were called regenerated (in P. dissecta the limbs were incompletely regenerated, so here we used the term 'incompletely regenerated adults') and those without regeneration were called unregenerated. These and the normal adults were allowed to mate in the following combinations (1) regenerated♂ × regenerated♀ (♂ R × ♀ R), (2) regenerated♂ × normal♀ (♂ R × ♀ N),
... Cannibalism is common in ladybirds in natural systems (Michaud, 2003;Omkar et al., 2005Omkar et al., , 2006. Several studies have reported an increase in cannibalistic behaviour in ladybirds in the absence or scarcity of prey populations since aphid populations are ephemeral (Majerus, 1994;Perry & Roitberg, 2005;Wagner et al., 1999). ...
Cannibalism and its role in population dynamics, along with various factors influencing the rate of cannibalism, have been widely studied across taxa.
The effects of predatory cue concentrations and starvation on cannibalistic tendencies and other life‐history traits in cannibalistic and non‐cannibalistic adults of Menochilus sexmaculatus were investigated.
Egg cannibalism increased with increasing predatory cue concentration and was maximum in high predatory cue treatment; increased with starvation irrespective of their diet history.
Latency to cannibalise eggs was shorter for cannibalistic adults as compared to non‐cannibalistic adults irrespective of their hunger status and concentration of conspecific cues.
Non‐cannibalistic females have higher fecundity than cannibalistic females.
In conclusion, both cannibalistic and non‐cannibalistic individuals respond differently to intrinsic (hunger) and extrinsic cues (predatory cue concentrations). Cannibalistic individuals cannibalise more than non‐cannibalistic ones at low levels of starvation and predatory cues.
Our finding suggests that cannibalistic individuals are better at assessing the risk and removing future competitors, which might favour these individuals over non‐cannibalistic ones in adverse conditions and increased competition.
... With respect to predatory beetles, Banks (1956) showed that cannibalism was a significant source of mortality in the egg stage in coccinellids; emerging larvae consumed the unhatched eggs of their siblings, even at low population density. Common costs associated with larval cannibalism of eggs rather than feeding on moth (Ephestia) eggs were longer development time and reduced adult size in at least two coccinellids, H. axyridis and Olla v-nigrum (Mulsant) (Michaud, 2003). Adult coccinellids cannibalized their own eggs and unrelated eggs, especially when natural prey was in low supply (Cottrell, 2005). ...
Coleopteran predators have been used to manage pest populations in natural and managed landscapes for centuries. In some instances, predators must be mass-produced to generate the quantities necessary for augmentation biological control. The research literature reveals moderate advances in technology to mass-produce coleopteran predators, especially lady beetles. Several factitious prey/foods and artificial diets for polyphagous species are available. Recent advances demonstrate the potential of developing artificial diets for oligophagous species. More research is necessary to determine effective methods to manipulate rearing (population) densities, relative to food quality/quantity, cage size, oviposition, and mating, to reduce the negative effects of crowding and cannibalism in colonies. Temperature could be adjusted to regulate the metabolic rate of coleopteran predators to adjust colony size during periods of high or low demand. More research is necessary to establish measures of “quality control” for mass-produced coleopteran predators through regular monitoring for acceptable fitness and unwanted pathogens pre- and postshipment to customers.
... Основные выводы этих исследований заключаются в том, что интенсивность родственного каннибализма личинок на яйцах не зависит от плотности тли (в отличие от не родственного каннибализма), и варьирует в разных семейных линиях [Osawa, 1989[Osawa, , 1993. Неродственный каннибализм на личинках возрастает при уменьшении плотности тли [Hironori, Katsuhiro, 1997], а также при увеличении плотности личинок своего вида [Michaud, 2003]. При этом H. axyridis демонстрирует семейное распознавание и менее охотно поедает родственников, чем не родственников. ...
В книге описаны биологические особенности азиатской божьей коровки Harmonia axyridis и ее распространение по четырем континентам за последние 35 лет. Инвазия этого вида имеет ряд отрицательных последствий как для местной энтомофауны, так и для человека, с чем связано большое уделяемое H. axyridis внимание биологов. Азиатская божья коровка стала модельным объектом для изучения механизмов и последствий инвазий видов на новые территории. В книге представлены результаты многолетних исследований авторов и дан обзор мировой литературы. В первой главе охарактеризована изменчивость H. axyridis. Вторая и третья главы посвящены описанию нативных и инвазивных популяций H. axyridis. В этих главах представлены исторические данные об этапах расширения ареала вида. В главах 4 и 5 подробно охарактеризованы симбиотические бактерии, паразитоиды и паразиты H. axyridis.
Книга рассчитана на биологов, изучающих инвазии чужеродных видов, энтомологов, генетиков.
... Consistently, Bilde and Lubin (2001) observed that in the subsocial spider Stegodyphus lineatus (Latreille, 1817), there was a higher frequency of cannibalism between non-kin compared with kin spiders at higher densities and in the absence of food, thereby indicating that the recognition of siblings was enhanced under these conditions. On the other hand, sibling recognition has not been proven in the larvae of ladybird beetle Harmonia axyridis (Pallas, 1773); however, the rate of cannibalism by siblings was also lower than by non-siblings (Michaud 2003). Our results revealed that an absence of food was the strongest factor promoting cannibalism and illustrate that compared with L. laeta, lower energy reserves would favor the earlier dispersal of L. intermedia. ...
Cannibalism is a behavioral characteristic found in a wide variety of animal groups. Although the rates of cannibalism can vary from one group to another, studies indicate that the main factors contributing to an increase in the frequency of such behavior are the availability of food, population density, the behavior and availability of victims, and environmental stress. We carried out different laboratory experiments to assess whether different factors such as the presence or absence of food among siblings and non-siblings, and at different densities among conspecific and heterospecific individuals, affect longevity of recently emerged Brazilian brown recluse (Loxosceles intermedia Mello-Leitão, 1934) and Chilean recluse (Loxosceles laeta (Nicolet, 1849)) spiderlings during periods of starvation. The results revealed that the survivorship of L. laeta during starvation was significantly higher than that of L. intermedia and that the addition of conspecific individuals increased survival rates by 1.5- and 1.6-fold, respectively. The tolerance of conspecifics differed between the two species, and generally, cannibalism was not observed, probably due to the risk of predation and limited consumption by weakened spiders, which coincided with the continued availability of endogenous vitelline reserves, thus indicating that the use of these spiderlings as a food resource may act to regulate starvation in more resistant spiders. The greater longevity and conspecific tolerance of L. laeta may be important factors contributing to the establishment of large populations of this spider in restricted areas, whereas for L. intermedia, hunger probably functions as a trigger for dispersal.
... Consistently, Bilde and Lubin (2001) observed that in the subsocial spider Stegodyphus lineatus (Latreille, 1817), there was a higher frequency of cannibalism between non-kin compared with kin spiders at higher densities and in the absence of food, thereby indicating that the recognition of siblings was enhanced under these conditions. On the other hand, sibling recognition has not been proven in the larvae of ladybird beetle Harmonia axyridis (Pallas, 1773); however, the rate of cannibalism by siblings was also lower than by non-siblings (Michaud 2003). Our results revealed that an absence of food was the strongest factor promoting cannibalism and illustrate that compared with L. laeta, lower energy reserves would favor the earlier dispersal of L. intermedia. ...
Body coloration of orb-web spiders was previously hypothesized to be attractive to insects, luring potential prey, or associated with protection against visually oriented predators. We combined manipulative experiments with spectral reflectance analyses to test the prey attraction hypothesis, using the araneid spider Gasteracantha cancriformis as a model. The study was conducted in a shaded environment, within a forest fragment of the Atlantic forest located in Southeastern Brazil. Insect interception on web surfaces displaying the dorsal section of G. cancriformis opisthosoma, which emits blue fluorescence and reflects light in the ultraviolet wavelength region, was higher than on surfaces displaying the spider's ventral section, or in webs without spiders. This study supports the prey attraction hypothesis by providing evidence that the color patterns of G. cancriformis dorsum improve prey interception by their webs. Fluorescence and achromatic cues are probably important to lure and attract potential prey.
... Many studies have shown that IGP was frequently occurring among predatory ladybirds, both among conspecific (intraspecific IGP) or between species (interspecific IGP) and especially under insufficient food supply (Fedriani et al. 2000;Ware and Majerus 2008;Pervez and Gupta 2010). IGP has been described in ladybirds between larvae, or by larvae on eggs, by adults on larvae, or between adults (Michaud 2010;Osawa 2015;Ovchinnikov et al. 2019). ...
Intraguild predation (IGP)–the predation of a natural enemy species upon another one sharing a prey species–is relatively frequent in both natural and agroecosystems. This may reduce pest control and the establishment of predator populations during mass release of biological control agents or in multi-predator systems due to increased mortality of predators. IGP is exacerbated in isolated and space-limited systems such as greenhouses, due to reduced food resources and movement. Therefore, adding food resources as an alternative to the main prey, such as floral resources, could reduce IGP between natural enemies in these systems. In the present study we investigated the role of supplemental floral resources to help reduce intra- and interspecific IGP involving Harmonia axyridis and Propylea japonica (Coleoptera: Coccinellidae) in laboratory conditions, and we tested its application in a greenhouse setup. We found a significant reduction in intra- and interspecific IGP in laboratory conditions when floral resources were abundant. At a greenhouse scale, abundances of both ladybird species increased when floral resources were abundant, potentially through a combination of enhanced fertility and reduced IGP. This resulted in reduced abundances of aphid pest populations on tomato crops. Our study demonstrates that companion plants in greenhouses can improve pest control in systems with multi-species biological control agent releases.
... Earlier studies demonstrated that H. axyridis larvae had a stronger cannibalism behavior than many other aphidophagous ladybirds and was independent from prey abundance (Reznik et al. 2017) but increased with larval density (Michaud 2003). In field, the mortality of 4th instar larvae (93.30%) was higher than those of the other stages (less than 50.51%) ...
Background
Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an important biocontrol agent in native region of Asia, while its high propensity for cannibalism causes great obstacles in mass production. Provisioning obstructs in rearing containers could decrease the cannibalism of ladybird beetles. In this study, three different patterns of obstructs (Con-A, Con-B, and Con-C) were designed and equipped in plastic Petri dishes (95.38 cm ³ ) as rearing units, and their efficiency for H. axyridis larval survival was tested. The potential of the high-density rearing was then evaluated using the optimal units with 16, 24, or 32 larvae per unit (named 16-L, 24-L, or 32-L, respectively).
Results
Larval survivals in obstructs-equipped units were generally higher than those in control, and significantly increased with the Con-C units (39.8% versus 74.2% at adult stage). With the Con-C units, the survivals were significantly higher at 16-L density (82.5%) than those at 24-L density (62.5%), but both were non-significantly different from those at 32-L density (70.0%). The weights of newly emerged adults (fit with the expected sex ratio of 1:1) at the higher densities were lower than those at 16-L density.
Conclusions
The results demonstrate that H. axyridis can be reared at a higher density (≈ 0.336 larvae/cm ³ ) in a constrained unit and highlight the effects of obstructs in reducing cannibalism and improving insect survivals.
... Cannibalism -preying on conspecifics -is a key factor that can cause heavy losses during artificial rearing of insects (Kuriwada et al., 2009;Michaud, 2003). The vice is common among tettigoniids (Gangwere, 1967;Hartley, 1967;Lehtovaara et al., 2019;Mbata, 1992;Richardson et al., 2010;Ros-Santaella et al., 2015;Senthilkumar, 2006;Simpson et al., 2006). ...
Reliance on seasonal wild harvests of the edible long-horned grasshopper Ruspolia differens needs to be broken through developing efficient mass rearing protocols. This study aimed at boosting productivity of laboratory colonies of R. differens through understanding ways of minimising cannibalism, selecting suitable oviposition substrates and enhancing egg development and hatchability. Firstly, we investigated the extent of cannibalism in a colony of R. differens relative to total mortality, sex, diurnality, growth stage, body parts eaten and visual barriers (presence/absence of cardboard egg trays). R. differens cadavers recovered from cages with/without the egg trays were scored for cause of death (cannibalism/other), time of death (night/day), sex, growth stage and body part devoured. Secondly, cotton wool and leaf sheaths of Pennisetum sp., maize and Panicum sp. were evaluated for preference for oviposition by R. difference. Eggs oviposited in each substrate were incubated to determine developmental duration and hatchability. Thirdly, we tested effect of moistening R. differens eggs on incubation period and hatchability in intact and opened leaf sheaths against unmoistened eggs in intact sheaths as a control. We found that cannibalism accounted for 49% of R. differens deaths with 83% of victims being adults. Males and females were equally susceptible to cannibalism. Over 97% of cannibalism occurred at night and presence of egg trays almost doubled incidence of cannibalism. The thorax was the most preferred body part, which was consumed in 77% of cannibalised individuals. Maize and Panicum sp. were preferred for oviposition over Pennisetum sp. and cotton wool. Opening of egg laden leaf sheaths reduced incubation period by 0.4 days. Unmoistened eggs didn’t hatch after incubation for 25 days, but 65% of them hatched within 11 days upon moistening. These findings offer guidelines for improvement of protocols for mass rearing of R. differens for human consumption and other uses.
... Schellhorn and Andow (1999). Michaud (2003) was, studied a comparative of larval cannibalism in three species of ladybird,( Cycloneda sanguinea (Linnaeus), Harmonia axyridis (Pallas) and ...
... Cannibalism, the process of killing and consuming a part or all of a conspecifi c occurs in a wide range of carnivorous as well as in phytophagous arthropods (Fox, 1975;Polis, 1981;Woodward & Hildrew, 2002;Richardson et al., 2010;Booth et al., 2017). This behaviour may enhance fi tness of cannibals in periods of food scarcity by providing them access to high quality nutrients, reducing competition or decreasing the risk of predation and/or parasitism (Fox, 1975;Polis, 1981;Gabriel, 1985;Van den Bosch et al., 1988;Agarwala & Dixon, 1992;Elgar & Crespi, 1992;Henson, 1997;Gagné et al., 2002;Michaud, 2003;Claessen et al., 2004;Booth et al., 2017). Nevertheless, cannibalism may incur costs, including the risk of injuries from conspecifi cs that fi ght back or the transmission of pathogens and parasites present in the victim attacked (Elgar & Crespi, 1992). ...
Cannibalism, the act of eating an individual of the same species has been little studied in omnivorous insect predators.
Dicyphus errans (Wolff) (Hemiptera: Miridae) is a generalist omnivorous predator that commonly occurs in tomato greenhouses
and fi eld crops in the Mediterranean basin. In this work cannibalism among same-aged neonate nymphs of D. errans was studied
when 1, 2, 4, 8 or 16 individuals were placed in a Petri dish along with or without heterospecifi c prey. Although nymphs were unable
to complete their development in the absence of prey they survived longer when there were initially 2 individuals per dish
than in any other treatment including a single individual. This may indicate that cannibalism in this predator has positive effect on
nymphal survival, which however was not the case at higher densities. The presence of heterospecifi c prey increased nymphal
survival and individuals were as equally successful in completing their development as when kept singly. Developmental time in all
the treatments was very similar. Adult weight of both females and males was signifi cantly greater when a nymph was reared alone
and similar in all the other treatments. The results indicate that cannibalism occurs among neonates of D. errans if heterospecifi c
prey is scarce and has a negative effect on adult weight when heterospecifi c prey is abundant. This should be considered in studies
on enhancing the biocontrol effi ciency or mass rearing of this predator.
... However, many insects that play important roles in ecosystems are declining worldwide (Fox, 2013;Goulson, Lye, & Darvill, 2008;Hallmann et al., 2017;Potts et al., 2010), such as pollinators (Gallai, Salles, Settele, & Vaissiere, 2009;Greenleaf & Kremen, 2006;Klein et al., 2007). Many studies that explore performance among taxa, particularly in insects, only compare performance in relation to one metric, such as reproduction (Braby, 2002;Jervis et al., 2007) or larval growth and survival (Davies & Gilbert, 1985;Michaud, 2003;Morey & Reznick, 2000). However, this approach is problematic for comparing among species since the relative allocation of resources to one life stage for a species might be different for another species. ...
Life history trade‐offs are ubiquitous in nature. Life history theory posits that these trade‐offs arise from individuals having limited resources to allocate toward all vital functions, such as survival, growth and reproduction. These trade‐offs position most species along a slow‐fast life history continuum, where individuals with slow life histories often have higher survival at the cost of delayed reproduction and individuals with fast life histories often live faster and die younger. However, these trade‐offs are sometimes less obvious for invasive species. Here, we constructed age‐based population models to compare life history strategies and trade‐offs between the noninvasive, native mustard white and invasive, exotic cabbage white (Pieris spp.) butterflies. We found that the cabbage white has faster larval growth and higher fecundity at younger ages, suggesting it has a fast life history compared to the mustard white. However, cabbage white also has higher adult survival at younger ages, suggesting that it experiences weaker trade‐offs among vital rates than its native counterpart. Our study illustrates the importance of demographic studies in evaluating life history strategies among congener species with different population histories, and emphasizes the many advantages experienced by invasive species in their novel environments. Invasive species have many advantages over native species in their novel environments. Here, we found that the invasive cabbage white butterfly has weakened life history trade‐offs compared to its native counterpart, which challenges fundamental life history theory that organisms should exhibit trade‐offs among vital functions.
... Cannibalism, the process of killing and consuming a part or all of a conspecifi c occurs in a wide range of carnivorous as well as in phytophagous arthropods (Fox, 1975;Polis, 1981;Woodward & Hildrew, 2002;Richardson et al., 2010;Booth et al., 2017). This behaviour may enhance fi tness of cannibals in periods of food scarcity by providing them access to high quality nutrients, reducing competition or decreasing the risk of predation and/or parasitism (Fox, 1975;Polis, 1981;Gabriel, 1985;Van den Bosch et al., 1988;Agarwala & Dixon, 1992;Elgar & Crespi, 1992;Henson, 1997;Gagné et al., 2002;Michaud, 2003;Claessen et al., 2004;Booth et al., 2017). Nevertheless, cannibalism may incur costs, including the risk of injuries from conspecifi cs that fi ght back or the transmission of pathogens and parasites present in the victim attacked (Elgar & Crespi, 1992). ...
Cannibalism, the act of eating an individual of the same species has been little studied in omnivorous insect predators. Dicyphus errans (Wolff) (Hemiptera: Miridae) is a generalist omnivorous predator that commonly occurs in tomato greenhouses and field crops in the Mediterranean basin. In this work cannibalism among same-aged neonate nymphs of D. errans was studied when 1, 2, 4, 8 or 16 individuals were placed in a Petri dish along with or without heterospecific prey. Although nymphs were unable to complete their development in the absence of prey they survived longer when there were initially 2 individuals per dish than in any other treatment including a single individual. This may indicate that cannibalism in this predator has positive effect on nymphal survival, which however was not the case at higher densities. The presence of heterospecific prey increased nymphal survival and individuals were as equally successful in completing their development as when kept singly. Developmental time in all the treatments was very similar. Adult weight of both females and males was significantly greater when a nymph was reared alone and similar in all the other treatments. The results indicate that cannibalism occurs among neonates of D. errans if heterospecific prey is scarce and has a negative effect on adult weight when heterospecific prey is abundant. This should be considered in studies on enhancing the biocontrol efficiency or mass rearing of this predator.
... Similarly, the decreasing survival rate with increasing rearing density could be linked to the lower space and food available per individual. At higher predator density, nutrition may become scare due high population pressure and hence, to avoid starvation, cannibalism apparently occurs (Michaud, 2003). The higher density could have increased the competition of food and space, which affected the survival rate of different developmental stages in the current study. ...
... The performance of the larvae of predatory ladybird beetles is often affected by the species of aphid they eat (Blackman, 1967;Hukushima and Kamei, 1970;Hamalainen and Markkula, 1972;Pasteels, 1978). This finding is similar to that of Michaud (2003), where the rate of cannibalism in H. axyridis, Olla v-nigrum (Mulsant) and Cycloneda sanguinea L. significantly increased with reduction in the quantity of food supplied. Schellhorn and Andow (1999 b) observed high rates of cannibalism in three co-occurring ladybirds when aphid populations crashed. ...
Influence of predator and prey densities on larval cannibalism in aphidophagous, Coccinella undecimpunctata L. was studied under laboratory conditions. Cannibalism increased with reduced food availability. In the absence of prey, there was a significant differences of larval cannibalism and recorded the highest rate of cannibalism. Cannibalism rate also increased with an increase in larval density of predator. The high rate of cannibalism was recorded at high larval density. Third and fourth levels of density of predator(9 and 12 larvae/ unit) had the highest cannibalism rate in the first instar at the first aphid density (25aphids/unit). There were significant differences between larval densities of the four larval instars of C. undecimpunctata.
... Further, H. axyridis eats Heteroptera (Tillman 2013), Thysanoptera (Zhang et al. 2014), Coleoptera (Stuart et al. 2002), Lepidoptera (Schanderl et al. 1988, Chen et al. 2012, and mites (Lucas et al. 1997). Intraguild predation and cannibalism (Michaud 2003, Cottrell 2004, Pell et al. 2008 are well documented. Also, accepted are pollen and fruits (Koch et al. 2004, Lundgren et al. 2004). ...
Production of feces (PF) is a useful proxy indicating quantity of ingested food. Although influenced by many uncontrolled factors PF provides insight into food consumption under natural conditions. In Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) variation in PF was investigated in populations of various hostplants at localities of central Bohemia (50N, 14E), throughout the season of 2016. The adults collected from these hostplants were starved for 48 h at standard conditions, and dry mass of feces produced during this period was measured. Despite enormous differences in PF among individuals, significant variation over the season occurred in average PF of both males and females. PF increased with abundance of aphids and was significantly greater in females than males. Gravidity, as manifested through oviposition within 48 h after capture, was associated with increased PF, while hostplant and color morph did not affect variation in PF among individuals. From PF as measured in this study, it can be estimated that at sites hosting abundant aphid populations H. axyridis (as an adult male or female) may consume 19 (male) to 45 (female) aphids per day (assumed body length 1mm). In the absence of aphids, adults may consume one to nine individuals of alternative prey per day (body length 1–2 mm).
... axyridis (Osawa, 1993), a phenomenon the intensity of which seems to be inversely related to aphid density (Burgio et al., 2002). When other prey were scarce, cannibalism of one larva to another provided nutritional benefits (Wagner et al., 1999), but the species is less likely to cannibalize a sibling than a non-sibling displaying a kin recognition (Joseph et al., 1999;Michaud, 2003a). (Korschefsky, 1932;Dobzhansky, 1933;Chapin, 1956;Sasaji, 1977;Kuznetsov, 1997). ...
Harmonia axyridis (Pallas) (Coleoptera Coccinellidae) is an active predator of aphids and other insect pests. Over the last few decades concerns have been raised about its invasiveness in those areas where it has been introduced as a biological control agent. In a first test, we investigated the ability of H. axyridis to survive, grow and reproduce at higher temperature (30 °C) than the recorded optimum of 25 °C. In a second test, we examined the effects of a pyrethroid insecticide (λ-Cyhalothrin) on H. axyridis in comparison with Adalia bipunctata (L.), a species commonly found in Europe.
This chapter is concerned with approaches and techniques used in studying those aspects of parasitoid and predator life-cycles that are relevant to the topics covered by other chapters in this book.
Banker plants increase biological pest control by supporting populations of non-pest arthropod species used as alternative hosts or prey by natural enemies. Due to the specificity of trophic interactions, banker plants may not efficiently promote natural enemies with different ecologies. Yet in most cropping systems different pest species are present together and require different biocontrol agents to efficiently control them. In the present study, we tested the combined use of two banker plants and their associated prey / host to enhance populations of the specialist parasitoid Encarsia formosa targeting the main tomato pest Bemisia tabaci , and a polyphagous ladybird Propylea japonica targeting the secondary pest Myzus persicae in tomato crops. In a laboratory and a greenhouse experiment, we measured the abundances of these four species using the Ricinus communis – Trialeurodes ricini banker plant system alone, in combination with the Glycines max – Megoura japonica system, or in absence of banker plants. We found that the first banker plant system enhanced populations of E. formosa, resulting in higher control of B. tabaci populations and the suppression of their outbreak in both our laboratory and greenhouse experiment. Conversely, abundances of P. japonica were not affected by this first system, but were significantly increased when the second was present. This resulted in high control of M. persicae populations and the suppression of their early and late outbreaks. Our study demonstrates the potential for combined banker plants to provide long-term, sustainable control of multiple pests by their target natural enemies in complex agroecosystems.
Background
Since larval cannibalism is frequently observed in intensive rearing systems, the regeneration of lost legs is common for the beneficial species Coccinella septempunctata (Coccinella: Coccinellidae) to adapt to the competitive environment, but whether functional recovery occurs in the leg‐regenerated coccinellids remains unknown. To evaluate the functional recovery of regenerated right foreleg after being damaged, the behaviors of leg‐regenerated ladybugs containing predation, attachment, intraspecific competition, prey preference and fecundity were studied in the laboratory.
Results
The prey consumption and searching rate of leg‐regenerated ladybugs decreased, and their handling time extended. A significantly reduced attachment coefficient was detected in leg‐regenerated coccinellids. Because of the competitive inferiority, leg‐regenerated ladybugs were greatly hampered in competition with normal opponents, and this inferiority led to a switch of prey preference from big‐sized adults to small‐sized first–second instar nymphs of Paratrioza sinica. However, although reduced functional abilities were examined, the leg‐regenerated paternity had a higher reproductive output compared to the normal paternity.
Conclusion
Leg‐regenerated ladybugs caused by cannibalism may make an investment tradeoff between egg fecundity and functional recovery. Thus, larval cannibalism potentially improves the offspring production of the biological control agent in complex environments. © 2018 Society of Chemical Industry
The population genetic structure, possible causes, sources, and routes of global invasion of the ladybird Harmonia axyridis are discussed. Infection with the reproductive endosymbionts is considered in the light of possible influence on the formation of evolutionary preadaptations that contributed to the invasion.
New distributional data are given for four Old World aphidophagous lady beetles (Coccinellidae) occurring in the Maritime Provinces of Canada, some of which represent new provincial records. Records are cited for Scymnus (Pullus) suturalis from Nova Scotia, for Harmonia axyridis from New Brunswick and Nova Scotia, and for Propylea quatuordecimpunctata and Hippodamia variegata from New Brunswick, Nova Scotia, and Prince Edward Island. New eastern U S records are also given for the immigrant Harmonia quadripunctata.
We examined environmental (food levels) and genetic (heritability and evolvability) influences on the expression of cannibalism in larvae of the ladybird beetle Harmonia axyridis Pallas (Coleoptera-Coccinellidae). In conjunction, we examined potential fitness consequences of cannibalism under different levels of food availability by measuring time of larval development and size at adult. Using a full-sib design, we split broods into food environments that differed by five-fold and measured rates of cannibalism by third instar larvae on first instar conspecifics. Surprisingly there was significant genetic variation in the expression of cannibalism in response to increased prey levels. Some families exhibited a decrease in cannibalistic behaviour, some an increase, while some families did not alter their cannibalistic rate in response to different food levels. In the low food environment, there was a strong genetic basis for the expression of cannibalism with a heritability significantly different from zero. In the higher food environment, heritability was not significantly different from zero. However, evolvabilities for cannibalism were similarly high for both food level environments. Fitness consequences also depended on food levels. Larvae from the low food environments reduced their development time by approximately 1 day when they cannibalized an average of one first-instar conspecific larva. Although in the higher food environment rates of cannibalism did not decrease significantly, development times remained unaffected. Our results suggest significant genetic variation in the expression of cannibalism within a natural population of H. axyridis and selection favouring cannibalism under low food environments but not when prey levels are high.
Cannibalism, a widespread phenomenon in nature, can both reduce competitors and introduce a high-quality food into the cannibal's diet. We investigated the dietary benefits of cannibalism for larvae of the multicolored Asian lady beetle, Harmonia axyridis (Pallas). Cannibalism might benefit the larvae by allowing cannibals to take advantage of prey-detoxification already completed by the victim or the different, and perhaps more diverse, feeding history of the victim. In two laboratory experiments we reared H. axyridis larvae with aphid prey, and with or without conspecifics to consume, and recorded larval development and survivorship. In the first experiment, we fed groups of H. axyridis larvae an aphid species of intermediate quality, Aphis nerii (Boyer deFonscolombe), and prevented or permitted consumption of conspecifics of varied quality—conspecific victims had either fed upon the same intermediate quality food as the focal individual or had fed upon a high quality food. Cannibalism increased survivorship and shortened development time, and eating conspecifics that had fed upon higher-quality food further shortened early development. In a second experiment, we reared groups of H. axyridis larvae with one or both of two aphid species of poor (Uroleucon spp.) or intermediate [Aphis fabae (Scopoli)] quality, and either permitted or prevented cannibalism. Larvae could complete development when fed both conspecifics and the intermediate quality aphid, but not on any other diet. Overall, when mixed with other foods, cannibalism allowed H. axyridis larvae to develop on prey that were otherwise nutrient deficient or toxic.
Coccinellid larvae are known to prey upon conspecific and heterospecific eggs, larvae, prepupae, and pupae. This behavior may depend on both the aggregation and intensive search of potential cannibals and predators near aphid colonies and the disappearance of aphids before coccinellid larvae have completed their development. We examined how coccinellid density and prey availability influence cannibalism and interspecific predation of larvae and pupae of 4 species of coccinellids. We determined whether coccinellid mortality and dispersal were density-dependent when prey become scarce, and estimated the leaving rates of Coleomegilla maculata (DeGeer), Adalia bipunctata (L.), and Hippodamia convergens (Guerin) larvae from plants with aphids and plants without aphids. Our results show that larval and pupal cannibalism and interspecific predation occur more frequently when aphid populations crash, but we found no evidence of coccinellid density-dependent mortality or density-dependent larval dispersal among species. However, A. bipunctata and H. convergens were significantly more aggressive and more likely to leave a plant without aphids than was C. maculata. These results suggest that the decision to stay on a plant is not strongly aphid- or pollen-mediated for C. maculata, but the decision to stay or leave does appear to be aphid-mediated for H. convergens and to some extent A. bipunctata. Whether a coccinellid larva stays or leaves and its tendency to cannibalize can affect larval and pupal survival and the population dynamics of each species.
Larvae of the lacewing Chrysoperla plorabunda (Fitch) were evaluated in laboratory and field tests for potential to control the brown citrus aphid, Toxoptera citricida (Kirkaldy) in inundative releases. Larvae surviving to pupation consumed an average of 1676, 1297, 392, 165 and 130 1st–4th instar T. citricida nymphs and apterous adults, respectively, and the mean developmental time was 27.0, 23.0, 16.5, 13.8 and 18.3 days, respectively. The average pupation rate was 37.5%, but only 6.3% of pupae yielded adults. Developmental time and survival to pupation varied with the life stage of aphids fed to larvae, 4th instars yielding the highest survival and shortest developmental time. Development of C. plorabunda was compared on diets of T. citricida and Aphis spiraecola. Only 6.3% of larvae completed development on T. citricida, whereas 37.5% yielded adults on A. spiraecola. Larvae consumed more of the brown T. citricida than the green A. spiraecola in a choice test on a white background, but no preference was evident when aphids were offered on a black background. Two separate field trials were performed in citrus groves with T. citricida infestations in which an average of 275 and 116 C. plorabunda larvae/tree were released, respectively. The rate of T. citricida colony maturation (= survival to alate production) was very low in the first trial, and relatively high in the second trial, but did not differ between control and release trees in either trial. The most apparent cause of aphid colony mortality was predation by the coccinellids Cycloneda sanguinea L. and Harmonia axyridis Pallas. Despite acceptance of T. citricida in the laboratory, very few C. plorabunda larvae were observed feeding on aphid colonies on release trees.
In the absence of aphids, adult females of Adalia bipunctata (L.) showed a greater reluctance to eat eggs than males.
Eggs and young larvae were more vulnerable to cannibalism than older larvae and starved larvae were more vulnerable than well‐fed larvae.
Both egg and larval cannibalism is inversely related to the abundance of aphids.
Eggs are a better food, in terms of larval growth and survival, than aphids.
In the absence of aphids interspecific predation occurred, but not equally, between the coccinellids A.bipunctata, A.decempunctata (L.), Coccinella septempunctata L. and C.undecempunctata L.
Larvae and adults of A. bipunctata and C.septempunctata were reluctant to eat conspecific eggs painted with a water extract of the other species' eggs and larvae of C. septempunctata were more likely to die after eating a few eggs of A.bipunctata than vice versa.
These results indicate that cannibalism occurs mainly when aphid prey is scarce and is adaptive in that it improves the chances of survival, and coccinellids, to varying degrees, are defended against interspecific predation.
Sibling (cannibalism among siblings) and non‐sibling cannibalism (cannibalism among non‐siblings) were studied in a natural population of a lady beetle, Harmonia axyridis Pallas .
Of all the eggs laid ( n =2269), 24.76% ( n =562) were killed by sibling cannibalism and 36.10% ( n =819) were killed by non‐sibling cannibalism. Sibling cannibalism occurred constantly and intensively in most egg batches throughout the entire oviposition period. On the other hand, non‐sibling cannibalism was more intense in the middle and late oviposition periods, and when the egg batches were close to an aphid colony. This may be due to the high density of H. axyridis larvae relative to aphid density in the middle and late oviposition periods and also the larvae searching intensively near an aphid colony.
1. A field study was conducted in which colonies of Toxoptera citricida (Kirkaldy) were initiated with different numbers of foundresses on ungrafted citrus trees var. ‘Carrizo’ within an existing citrus grove in central Florida.
2. The growth rate, longevity, and final size of T. citricida colonies were all positively correlated with number of foundresses.
3. Colonies initiated by many foundresses produced alatae earlier than those initiated by fewer foundresses.
4. Nymphal developmental time was reduced in colonies initiated by more foundresses but the mean number of grand-progeny per foundress was lower when only surviving colonies were compared.
5. The longevity of foundresses was unaffected by their number but foundress fecundity and nymphal survival decreased as foundress number increased.
6. The most abundant natural enemies were Diptera: Syrphidae, primarily Pseudodorus clavatus (F.), and Chamaemiidae (Leucopis sp.), followed by Coleoptera: Coccinellidae, primarily Cycloneda sanguinea (L).
7. Colonies initiated with more foundresses attracted more oviposition by dipteran predators than did colonies initiated with fewer foundresses.
Coccinellids have been widely used in biological control for over a century, and the methods for using these predators have remained virtually unchanged. The causes for the relatively low rates of establishment of coccinellids in importation biological control have not been examined for most species. Augmentative releases of several coccinellid species are well documented and effective; however, ineffective species continue to be used because of ease of collection. For most agricultural systems, conservation techniques for coccinellids are lacking, even though they are abundant in these habitats. Evaluation techniques are available, but quantitative assessments of the efficacy of coccinellids have not been done for most species in most agricultural crops. Greater emphasis is needed on evaluation, predator specificity, understanding colonization of new environments, and assessment of community-level interactions to maximize the use of coccinellids in biological control.
For many species, cannibalism can strongly affect population dynamics and mortality rates. However, it is less clear if and how it can stablize population size. If cannibalism is density-dependent, as has been shown for over 40 studies (see Fox 1975; Polis 1981 for reviews), it can potentially regulate population size (Polis 1981; Judeet al.1987; Sailaet al.1987). However, other models (Ricker 1962; Hastings and Constantino 1987) and empirical studies (Radovich 1962; Mertz 1969; Mertz 1972; Barber 1979a; Barber 1979b; DeAngeliset al.1979; Higgins 1990; Orret al.1990) show that cannibalism may also destabilize populations, often by causing cycles.
Covering the contextual and taxonomic diversity of cannibalism, this book explains its costs, benefits, and consequences for a taxonomically broad distribution of species from lower eukaryotes to higher primates. The authors, all experts in their taxon of interest, use theory developed for the analysis of foraging, sociality, demography, and genetics to assess the ecological and evolutionary causes and effects of cannibalism. The emerging picture from recent research challenges the view that cannibalism is either abnormal behaviour or an infrequent addition to the predator's usual diet.
Twenty-five species of Coccinellidae were found on apple in eastern West Virginia from 1983 to 1996. From 1989 through 1994, the exotic coccinellid, Coccinella septempunctata (first collected in 1983), has dominated the farina of the tribe Coccinellini. Another adventive species, Harmonia axyridis (first collected in 1994), became the dominant species in the tribe Coccinellini in 1995, and continues to dominate the coccinelline guild on apple. Harmonia axyridis has displaced C. septempunctata and is providing better biological control of Aphis spiraecola on apple in eastern West Virginia.
The introduction of the multicolored Asian lady beetle, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), to the United States has led to its interaction with native coccinellid species. Harmonia axyridis adults and larvae co-occur temporally and spatially with adults and larvae of the native species, Coleomegilla maculata (DeGeer), which is the most abundant coccinellid species on sweet corn in Kentucky. We tested the capability of H. axyridis to develop on a diet of only C. maculata eggs and the propensity for either species to prey upon the other. We found that H. axyridis larvae can complete development on a diet of only C. maculata eggs and that predation between H. axyridis and C. maculata larvae usually results in H. axyridis eating C. maculata.
Data are presented on the relative abundance of the coccinellid Olla v-nigrum (Mulsant) in Florida citrus, before and after invasion by the Asian citrus psyllid, Diaphorina citri Kuwayama. Adults and larvae of O. v-nigrum were observed preying on immature psyllids throughout their range in Florida. Immature psyllids were eliminated by predation from many flushed citrus terminals that exhibited damage symptoms; pupae of O. v-nigrum and Harmonia axyridis Pallas were recovered from adjacent leaves. Olla v-nigrum, a relatively rare species before the invasion by D. citri, is now a dominant species throughout Florida in citrus groves where the psyllid is present, but remains rare in regions where D. citri is absent. The strong numerical response of this native ladybeetle to D. citri populations indicates that it is assuming a key role in biological control of the psyllid. /// Se presentan datos sobre la abundancia relativa del coccinélido Olla v-nigrum (Mulsant) en cítricos en la Florida, antes y después de la invasión del psílido Asiático, Diphorina citri Kuwayama. Adultos y larvas de Olla v-nigrum fueron observados alimentándose de las formas inmaduras del psílido a través de la Florida. Se observaron muchos brotes terminales en los cítrcos con daños del psílido, pero estos fueron eliminados por depredación; pupas de O. v-nigrum y Harmonia axyridis Pallas fueron coleccionadas en hojas adyacentes. Olla v-nigrum, una especie relativamente escasa antes de la invasión de D. citri, ahora es dominante en los cítricos de Florida donde está presente el psílido, pero sigue siendo escasa donde D. citri está ausente. La fuerte respuesta numérica de este coccinélido en comparación con las poblaciones de D. citri indica que está asumiendo un papel clave en el control biológico del psílido.
A lady beetle native to Asia,Harmonia axyridisPallas, is established in the Pacific Northwest of North America. Ten years occurred between the intentional release of beetles and the first observation of an individual on July 18, 1991, in Kings County, Washington. The beetle was extremely abundant in western Washington and Oregon throughout 1993–1994, where the species ranged from mideastern Washington, south to just north of the California/Oregon border, east to an elevation of 1371 m in the Cascade Mountains and west to the Pacific Coast. Field sampling confirmed the habits and habitats ofH. axyridisas a generalist, semiarboreal, aphidophagous predator. Our records associateH. axyridiswith 17 aphid prey species on 17 plant hosts. In western Oregon,H. axyridisco-occurs with 11 species of native and 2 species of exotic aphidophagous coccinellids on trees and shrubs. In arboreal habitats, 70% of individual lady beetles and 82% of live adult coccinellid mass were represented byH. axyridis,while constituting only 4% of the coccinellids in alfalfa, clover, and peppermint. AdultH. axyridisdispersed to feeding sites from overwintering aggregations, which formed the preceding October, during March. At least two generations, with a partial to complete third generation, occur per year. Parasitism of field-collected adult beetles byDinocampus coccinellae(Schrank) was less than 1%.
A monitoring system established within an array of cultivated and uncultivated habitats was used to characterize the first 5 yr of establishment of the exotic multicolored Asian lady beetle, Harmonia axyridis (Pallas), in an agricultural landscape of southwestern Michigan. Population trends over time were summarized for 11 species of resident coccinellids before and after the arrival of H. axyridis. In addition, annual population increase, habitat utilization patterns, and within-season population fluctuation for H. axyridis were analyzed. H. axyridis became a dominant coccinellid species in the landscape 4 yr after its arrival. Adults of this species were found in all habitats monitored, including early secondary succession, poplar plantation, alfalfa, soybean, corn, and winter wheat. Significant population peaks were observed early and late in the season, depending on the habitat. Resident species that appear affected by the establishment of H. axyridis are Brachiacantha ursina (F.), Cycloneda munda (Say), and Chilocorus stigma (Say). However, to attribute the decline on the numbers of those species to H. axyridis will require further assessment.
Field data collected from the major citrus-producing regions of Florida over the past 5 yr indicate that the introduction of the multicolored Asian lady beetle, Harmonia axyridis (Pallas), has increased in abundance while the formerly dominant Cycloneda sanguinea (L.) has declined. What is known of the diet breadth, habitat preferences, and thermal thresholds for development of these two species indicates considerable niche overlap. The larger H. axyridis has many intrinsic advantages over C. sanguinea, including higher fecundity and fertility, and a lower rate of larval cannibalism. In laboratory tests, adults and larvae of H. axyridis consumed eggs of C. sanguinea more readily than vice versa. All H. axyridis adults provided with either a conspecific or a heterospecific second-instar larva killed and ate it, whereas only 15% of C. sanguinea adults consumed a second-instar larva of H. axyridis over a 24-h period. Larvae of H. axyridis were more aggressive against larvae of C. sanguinea in laboratory tests than vice versa; even when H. axyridis larvae were paired with a C. sanguinea larva 2 d older and two to three times as large, they won 67% of contests. In choice tests, larvae of both species preferred to feed on dead C. sanguinea larvae than on dead H. axyridis larvae. Larvae of H. axyridis were capable of completing development exclusively as intraguild predators on C. sanguinea larvae, whereas the reverse was not true. The data suggest that H. axyridis is a highly evolved interspecific competitor, whereas C. sanguinea is adapted more to intraspecific competition and has few defenses against H. axyridis. Competitive displacement of C. sanguinea by H. axyridis appears to be in progress in the citrus ecosystem in Florida.
Factors affecting the mortality of Coleomegilla maculata lengi Timberlake were investigated at Guelph, Ontario from 1976 through 1978. It was found that most of the overwintering mortality of caged beetles occurred at the end of the winter. Parasitism by Perilitus coccinellae Shrank reduced survivorship of overwintering beetles. There was no significant difference found in overwintering mortality of beetles caged at three different densities. Predation of eggs of C. m. lengi was 44.8 and 48.6% in 1976 and 1977, respectively. Stage-specific mortality for the coccinellids of the first generation in corn (primarily C. m. lengi) at Guelph calculated for the period from egg to pupa was 93.8% in 1977. In 1978, mortality from egg to pupa of C. m. lengi was 95.4%. C. m. lengi displays a type IV survivorship curve of Slobodkin.
In field-collected egg masses more than 21% of the eggs were destroyed by first-instar larvae from the same egg mass. Since 39.8% of these were estimated to be nonviable, the effective reduction in number of larvae owing to egg cannibalism by undispersed first-instar larvae was 12.7%. Cannibalistic behavior has been stated to have survival value, since this food supply lengthens the life and increases the chance of finding prey by otherwise nonfed larvae. Laboratory experiments showed that cannibalism lengthens the life span, but results also in larvae which disperse from the egg mass later and are less active than noncannibalistic larvae, so their chances of finding prey are reduced. Cannibalism might still be an advantage under low-prey-density situations were it not for the known fact that this species can maintain itself and mature on substances other than prey. Therefore, this behavior may not be advantageous to the role of larvae as natural control agents.
Cannibalism is widespread among many different organisms, and can have both negative and positive fitness consequences. Avoiding eating relatives can minimize negative fitness consequences of cannibalism. Such avoidance requires kin discrimination, but evidence for this ability among cannibals is limited with little data that address the cues used in such discrimination. We examined whether larvae of the ladybird beetle Harmonia axyridis avoid eating their relatives. We further manipulated environmental factors to create individuals that had similar or dissimilar rearing environments to begin to test for endogenous versus exogenous recognition cues. In our experiments, third-instar larvae were much less likely to cannibalize if they were interacting with a relative. Larvae that did cannibalize kin required more encounters, and significantly delayed cannibalism, compared to larvae cannibalizing unrelated individuals. Acquired cues were less important. Even though the different rearing environment resulted in significantly different phenotypic effects, similarity or dissimilarity of rearing environment had no effect on cannibalism, and there was no interaction between environments and relatedness in cannibalism. We suggest that H. axyridis has a well-developed kin discrimination system, and that kin recognition in this ladybird beetle is based on endogenous rather than exogenous cues. We also argue that these cues reflect either direct or indirect genetic effects on larval phenotypes.
The relative impact of cannibalism and predation on the development and survival of fourth instar larvae was assessed in two species of aphidophagous ladybird beetles, Coccinella septempunctata and Harmonia axyridis. The effect of eating aphids, conspecific larvae or heterospecific larvae on larval performance differed in the two species: aphids were the best food for C.septempunctata and survival of C.septempunctata larvae was significantly lower when offered heterospecific larvae rather than conspecific larvae or aphids as food, indicating that H.axyridis larvae were not suitable food for C.septempunctata. However, as the different foods did not affect the larval performance of H.axyridis, this species appears to be more polyphagous. Both intraguild predation by the aggressive larvae of H.axyridis and the polyphagous food habit of this species may account for its dominance in ladybird assemblages and its displacing other ladybird beetles in several places in the world.
When eggs ofAdalia bipunctata L. are offered to larvae of their own species, these larvae are able to develop to adults. Reducing the daily egg supply
results in decreased larval survival and pupal weight and especially fecundity of the adult females. The duration of larval
development is significantly increased, the longevity of adults is shortened.
Les larves d'Adalia bipunctata (L.), qui ont été alimentées avec des œufs de la même espèce, peuvent se développer normalement jusqu'au stade imaginal.
La mortalité et la durée de développement des larves augmentent lorsque le nombre d'œufs offerts chaque jour comme aliment
décroît, le poids des nymphes diminue mais la durée du stade nymphal reste inchangée. L'influence d'une offre de nourriture
inférieure à l'optimum au cours de la vie larvaire, est particulièrement forte sur la fécondité et la longévité des adultes.
Une réduction de l'alimentation ayant une influence faible sur la durée des stades larvaires et sur le poids des nymphes,
provoque une diminution très importante de la fécondité des femelles. Après une réduction plus grande de l'alimentation des
larves, les femelles meurent avant le début de la période de reproduction. Après un approvisionnement alimentaire plus riche
en œufs, la durée de vie des coccinelles est un peu plus longue, mais leur fécondité est un peu plus faible que celle obtenue
avec des adultes provenant d'un élevage conduit avec une offre d'acariens en excès.
Seven species of Coccinellidae inhabiting citrus groves in Florida were evaluated for ability to develop and reproduce on the citrus aphids Toxoptera citricida (Kirkaldy) and Aphis spiraecola Patch. Choice tests performed with adults and larvae indicated that both aphid species were generally acceptable prey. Coccinella septempunctata L., Coleomegilla maculata fuscilabris (Mulsant), Coelophora inaequalis F., and Olla v-nigrum Mulsant were unable to complete development on either aphid. Hippodamia convergens Guerin larvae completed development on A. spiraecola with 68% survival; none survived on T. citricida. Only Cycloneda sanguinea (L.) and Harmonia axyridis Pallas completed development on both A. spiraecola (60 and 70% survival, respectively) and T. citricida (100 and 95% survival, respectively). Larval developmental time was shorter on T. citricida than on A. spiraecola, and resulting adults were heavier, differences being more pronounced in H. axyridis. Females of C. septempunctata, C. inaequalis, and O. v-nigrum produced viable eggs on T. citricida. O. v-nigrum did not produce eggs on A. spiraecola. Females of C. m. fuscilabris and H. axyridis produced no eggs on A. spiraecola and mostly infertile eggs on T. citricida. Female H. convergens laid twice as many eggs feeding on T. citricida as on A. spiraecola and egg viability was similar. C. sanguinea females laid similar numbers of eggs on both aphids, but eggs produced on A. spiraecola had higher fertility. Pollen added to the T. citricida diet temporarily improved the fertility of H. axyridis females, but not that of C. sanguinea females. C. sanguinea was judged the best candidate for augmentative biocontrol of T. citricida, the primary vector of citrus tristeza virus.
Insect Predator-prey Dynamics: Ladybird Beetles and Biological Control The dynamics of cannibalistic populations: a foraging perspective. Cannibalism: Ecology and Evolution among Diverse Taxa
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Cannibalism in beetles. Cannibalism: Ecology and Evolution among Diverse Taxa
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Effect of cannibalism and predation on the larval performance of two ladybird beetles
- Yasuda
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predation on the larval performance of two ladybird beetles.
Entomologia experimentalis et applicata, 93, 63±67.
Accepted 6 October 2002
SPSS 8.0 for Windows
SPSS (1998) SPSS 8.0 for Windows. SPSS Inc., Chicago, Illinois.