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The biology of giant water bugs (Hemiptera: Belostomatidae) in Trinidad

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SynopsisAn account is given of the habitat, feeding habits, life history and dispersal of Belostoma malkini and Lethocerus maximus in Trinidad. Degeneration of the flight muscles is described, and the factors involved in its control are discussed.

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... They are found in freshwater habitats such as rice fields, marshes, ponds, lakes, and rivers (Cullen 1969;Menke 1979;Mukai et al. 2005). Their reproductive biology is unique and well-known (Clutton-Brock 1991;Shuster & Wade 2003;Arnqvist & Rowe 2005;Smiseth 2014), including female competition and male parental care (Ichikawa 1988(Ichikawa , 1990(Ichikawa , 1991Smith & Larsen 1993;Thrasher et al. 2015). ...
... Previous studies focused on the dietary items of Belostomatidae from the viewpoints of both applied and conservational aspects. Belostomatids prey upon a variety of aquatic animals such as insects, cladocerans, amphipods, tadpoles and small fish ( Fig. 1) (Hoffman 1924;Rankin 1935;Cullen 1969;Tawfik 1969;Menke 1979;Okada & Nakasuji 1993;Hirai & Hidaka 2002;Toledo 2003;Ohba & Nakasuji 2006;Zaracho 2012;Ouyang et al. 2017). Therefore, they are regarded as effective predators of medically important freshwater snails or mosquitoes (Table 1). ...
... Lethocerines, also called "electric light bugs," are frequently attracted to light in large numbers (Menke 1979;Ono 1995;Yoon et al. 2010;Nwosu & Nwosu 2012;Nagaba & Takeda 2013). It is known that the flight activity of belostomatids is highest during the wet season and around the full moon (Bowden 1964;Cullen 1969;Duvirad 1974). In K. deyrolli, migration was triggered by food shortage (Ohba & Takagi 2005) and air temperature higher than 15 C, irrespective of day length (Yoon et al. 2010). ...
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Giant water bugs (Heteroptera: Belostomatidae) are aquatic predators of freshwater habitats, and include ca. 150 species distributed throughout the world's subtropical and tropical areas. They have unique mating systems, which involve female competition, and exhibit paternal care, wherein males attend eggs laid by the females on emergent plants (Lethocerinae) or on their backs (Belostomatinae). I review here the studies on the predator–prey relationships, morphology, migration, mating behavior and conservation of this family of insects. Giant water bugs (Belostomatidae: Heteroptera) are known as aquatic predators in freshwater habitats and have unique mating systems concerning male parental care and female competition. I review the ecology in this family based on published works.
... n. sp. (this study), Lethocerus maximus ( Cullen, 1969), L. mazzai ( De Carlo, 1962), Hydrocyrius columbiae ( Miller, 1961), Belostoma flumineum ( Flosi, 1980), B. malkini ( Cullen, 1969), and Abedus breviceps ( Keffer and McPherson, 1988). T. solensis L. maximus L. mazzai H. columbiae B. flumineum B. malkini A. breviceps Instar 1 2.0 15.0 11.0 16.0 4.6 7.75 6.4 Instar 2 3.0 22.5 17.0 21.0 6.2 11.00 9.1 Instar 3 4.6 32.5 26.0 28.5 9.0 15.50 11.3 Instar 4 6.9 46.5 37.5 37.5 11.5 22.25 15.5 Instar 5 9.9 67.5 53.0 50.5 16.5 32.50 20.0 Table 3. ...
... n. sp. (this study), Lethocerus maximus ( Cullen, 1969), L. mazzai ( De Carlo, 1962), Hydrocyrius columbiae ( Miller, 1961), Belostoma flumineum ( Flosi, 1980), B. malkini ( Cullen, 1969), and Abedus breviceps ( Keffer and McPherson, 1988). T. solensis L. maximus L. mazzai H. columbiae B. flumineum B. malkini A. breviceps Instar 1 2.0 15.0 11.0 16.0 4.6 7.75 6.4 Instar 2 3.0 22.5 17.0 21.0 6.2 11.00 9.1 Instar 3 4.6 32.5 26.0 28.5 9.0 15.50 11.3 Instar 4 6.9 46.5 37.5 37.5 11.5 22.25 15.5 Instar 5 9.9 67.5 53.0 50.5 16.5 32.50 20.0 Table 3. ...
... n. sp. (this study), Lethocerus maximus ( Cullen, 1969), L. mazzai ( De Carlo, 1962), Hydrocyrius columbiae ( Miller, 1961), Belostoma flumineum ( Flosi, 1980), B. malkini ( Cullen, 1969), and Abedus breviceps ( Keffer and McPherson, 1988) (the same species as in Table 2), calculated by dividing instar length by length of the previous instar. T. solensis L. maximus L. mazzai H. columbiae B. flumineum B. malkini A. breviceps ...
Article
A new genus and species of predaceous water bugs, Triassonepa solensis n. gen. n. sp., is described from the Triassic Cow Branch Formation of Virginia and North Carolina (USA) based on ~36 adult specimens and 51 nymphs. This species is the oldest known member of the extant family Belostomatidae. It is placed in a new genus based on the unique structure of the raptorial foreleg, in which the tarsus is elongate and opposed to the tibia + femur. The fossil record of this family is reviewed and the paleoenvironmental implications of the species assemblage preserved in the Cow Branch Formation are discussed.
... Most species are recorded from the New World (Polhemus, 1995;Schuh and Slater, 1995;Perez-Goodwyn, 2006;Est evez and Ribeiro, 2011;Moreira et al., 2011;Ribeiro et al., 2018). They are predators that grab preys with their raptorial forelegs, injecting potent salivary secretions and venom, and siphoning out the liquified tissues of the prey (Cullen, 1969;Criscione and Grimaldi, 2017;Walker et al., 2018). Representatives of the genus Lethocerus Mayr, 1853 are known to capture a wide variety of prey, including fishes (Schuh and Slater, 1995), turtles (Ohba, 2011), water snakes (Wilson, 1958), and woodpeckers (Hungerford, 1919); in capturing their prey, Lethocerus species rely on being undetected, owing to their immobility and cryptic coloring (Cullen, 1969). ...
... They are predators that grab preys with their raptorial forelegs, injecting potent salivary secretions and venom, and siphoning out the liquified tissues of the prey (Cullen, 1969;Criscione and Grimaldi, 2017;Walker et al., 2018). Representatives of the genus Lethocerus Mayr, 1853 are known to capture a wide variety of prey, including fishes (Schuh and Slater, 1995), turtles (Ohba, 2011), water snakes (Wilson, 1958), and woodpeckers (Hungerford, 1919); in capturing their prey, Lethocerus species rely on being undetected, owing to their immobility and cryptic coloring (Cullen, 1969). Members of this family are also famous for the occurrence of elaborate paternal care, which plays roles in maintaining oxygen or humidity conditions of the egg masses, as well as in protection against predators (Ichikawa, 1988;Ohba et al., 2006;Matthews and Matthews, 2010;Ohba, 2018). ...
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In this paper we redescribe and illustrate the holotype of Paranoika placida Zamboni, Martins-Neto & Popov, 2002 from the Lower Cretaceous of Brazil (Crato Formation). We propose that the family Paranoikidae Zamboni et al., 2002 (type genus: Paranoika Zamboni et al., 2002) is a junior synonym of Belostomatidae Leach, 1815. Paranoika (type species: P. placida) is a junior synonym of Lethocerus Mayr, 1853. Thus Paranoika placida Zamboni, Martins-Neto & Popov, 2002 becomes Lethocerus placidus (Zamboni, Martins-Neto & Popov, 2002) comb. nov. We also propose that L. placidus comb. nov. is the senior synonym of Lethocerus vetus Nel & Waller, 2006, syn. nov. Multivariate statistical analyses including L. placidus comb. nov. and extant Lethocerus species were carried out with the aim of preliminarily discussing possible relationships between morphological similarities and patterns of geographical distribution of the genus.
... The belostomatids are predacious water bugs and contain Ϸ136 species belonging to seven genera (Smith 1997). They are general predators, attacking moving small creatures, including invertebrates, Þsh, and amphibians (Hoffman 1924, Rankin 1935, Cullen 1969, TawÞc 1969, Hirai and Hidaka 2002. The genus Lethocerus (Belostomatidae) is cosmopolitan and its species live in freshwater habitats, including ponds, lakes, and rivers (Cullen 1969, Menke 1979, DuBois and Rackouski 1992. ...
... They are general predators, attacking moving small creatures, including invertebrates, Þsh, and amphibians (Hoffman 1924, Rankin 1935, Cullen 1969, TawÞc 1969, Hirai and Hidaka 2002. The genus Lethocerus (Belostomatidae) is cosmopolitan and its species live in freshwater habitats, including ponds, lakes, and rivers (Cullen 1969, Menke 1979, DuBois and Rackouski 1992. ...
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Previous studies have suggested that the developmental pattern of insect body parts is influenced by food conditions during the nymphal stages. In this study, we compared the developmental patterns of five body parts (body length, fore-femur length, mid-femur length, hind-femur length, and angle of claw) in the predatory insect Lethocerus deyrolli Vuillefroy fed three diets (tadpoles, Odonata nymphs, and tadpole–Odonata nymph mixture) during the nymphal stages. Significant age by sex interactions were detected in body length, fore-femur length, mid-femur length, and hind-femur length, indicating developmental patterns of these traits varied between sexes. Significant age by food interactions were detected in body length and hind-femur length and were marginally significant in mid-femur length, showing developmental patterns of these traits varied among food types. None of the interactions were significant in angle of the claw. A predation experiment was performed using double-claw nymphs as a control and one-claw nymphs (adult type) as a treatment. Double-claw nymphs successfully caught both large and small tadpoles, whereas one-claw nymphs caught small tadpoles more frequently than large tadpoles. Our results suggest that the claw development, which is very likely related to predatory function, may be less affected by nutritional conditions, and that double claws during nymphal stages may be indispensable to increased predation success.
... Although the giant water bug, Lethocerus deyrollei, one of the top predators in the system, was also common in most regions of central Japan, it is now listed as a vulnerable species (Japan Environmental agency 2000). There are many studies on the life cycle (Ichikawa 1993a;Numata and Hashizume 1997;Hidaka 2000) and behavior (e.g.Hoffman 1924;Hungerford 1925;Cullen 1969;Menke 1979;Ichikawa 1988Ichikawa , 1989Ichikawa , 1990Ichikawa , 1991aIchikawa , 1991bIchikawa , 1993bIchikawa , 1995Smith and Larsen 1993;Hirai and Hidaka 2002) of this species and congeneric species in the field and laboratory. To conserve L. deyrollei and its habitats in rice cultivation areas, it was necessary that the population dynamics should be studied in the field in detail. ...
... In the Temporary Pool, however, no egg clusters and young nymphs were found through the study period, even though the water temperature was high enough for oviposition. It is known that oviposition substrata such as reed-like hygrophytes or similar structures are necessary for the reproduction of L. deyrollei and congeneric species (Hungerford 1925;Hoffman 1931;Rankin 1935;Cullen 1969;Ichikawa 1988;Smith and Larsen 1993;Hashizume 1994). In this study, egg clusters were found on wooden stakes and plant roots on the slope of a levee in the Permanent Pool, and culms of rice plants in the Paddy. ...
Article
The population dynamics of Lethocerus deyrollei, including the seasonal change in the habitat utilization, were studied in five types of waters, permanent and temporary pools, ditch, rice paddy and marsh in a Satoyama, the traditional landscape in Japan consisting of mixtures of coppice woodlands, farmlands, and settlements, in northern Osaka, from June, 1999 to December, 2001. A mark and recapture census was carried out with adults, and the stage and the number were recorded in nymphs. A total of 95 adults were numbered, and 48 (51%) were recaptured in all the five water types during the study period. Adults of the new generation appeared from late July, and disappeared before the winter in all types of waters. A total of three overwintered adults were recaptured in permanent and temporary pools, ditch, and paddy from between early April and early June. Densities of both L. deyrollei adults and their prey, tadpoles and frogs, were high in permanent and temporary pools, and ditch, in which water temperatures were high in the summer season. Third to fifth (final) instar nymphs were also observed in all water types with different densities in summer, while first and second instars were found only in permanent pool, ditch and paddy habitats in which water temperatures were high and oviposition substrata such as the rice plant, other hygrophytes and wooden stakes existed. These results show that the traditional water system of paddy in the Satoyama landscape as a whole provides an important habitat for L. deyrollei which is now under threat by changing agricultural practices like other native biota inhabiting the system.
... Les connaissances actuelles ne nous permettent pas d'identifier les facteurs influençant la migration (le vol) de ces insectes. Néanmoins, différents paramètres sont suspectés : la densité de proie, la période de reproduction, la phase lunaire et la température (34)(35)(36)(37). La corrélation entre les précipitations et l'activité de vol a été rapportée pour les Belostomatidae lors d'une étude réalisée en zone tropicale au Costa Rica (37,38). ...
... Despite being poorly documented, the life histories of the species of Belostomatini are quite variable, e.g., Weberiella is a kinon specialist taxon-an entire coenosis of the surface film of Amazon running water (Fittkau 1977), and with unknown flight ability. In Abedus, which are often recorded in perennial streams, flight is quite unusual (Menke 1977;Lytle 1999), whereas Belostoma, with notable flight ability, prefers ponds, lakes, flooded areas, or river banks (Cullen 1969;Menke 1979). In fact, the species of Belostoma with hemelytral membrane reduction (triangulum group + B. martinezi) and most species of Abedus have been recorded only in running waters habitats (Lauck 1964;Lytle 1999). ...
Article
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The new species Belostoma inusitatum is described and illustrated based on specimens from the west side of the Araguaia-Tocantins basin, in Mato Grosso state in central-western Brazil. This new species is assigned to the B. triangulum species group and compared with its congeners. A key and distribution map for the species of this group are included. The three-articulated antenna without lateral projections of B. inusitatum n. sp. is documented for the first time in Belostoma. Also, the uncommon shape of the prosternal keel, the distinct reduction of the hemelytral membrane, and the diverticulum of the phallosoma sharply incised at the posterior margin are reported for this new species. A discussion about the reduction in the number of antennal articles and the size of the hemelytral membrane in Belostoma and Abedus is presented.
... 150 species distributed throughout the world's subtropical and tropical areas (Lauck and Menke 1961), consisting of eight genera in the subfamily Belostomatinae (Horvathinia Montandon, Hydrocyrius Spinola, Limnogeton Mayr, Abedus Stål, Weberiella De Carlo, Belostoma Latreille, Appasus Amyot & Serville, and Diplonychus Laporte) and three genera in the subfamily Lethocerinae (Benacus Stål, Kirkaldyia Montandon, and Lethocerus Mayr) (Polhemus 1995;Perez-Goodwyn 2006;Estévez and Ribeiro 2011;Ribeiro et al. 2018). They are found in freshwater habitats such as rice fields, marsh, ponds, lakes, and slow-moving rivers (Cullen 1969;Menke 1979;Mukai et al. 2005). Besides their large bodies, their reproductive biology is unique and well known (Clutton-Brock 1991;Shuster and Wade 2003;Arnqvist and Rowe 2005;Smiseth 2014), which includes female competition and male parental care (Ichikawa 1988(Ichikawa , 1990(Ichikawa , 1991Smith and Larsen 1993;Thrasher et al. 2015). ...
Chapter
We describe general biology of giant water bugs (Heteroptera, Belostomatidae), exclusive paternal care (back-brooding behavior in Belostomatinae and emergent-brooding behavior in Lethocerinae), and recent topics in sexual selection in this family. In the general biology, we introduced phylogenetic relationships of Belostomatidae within Nepomorpha and among Belostomatidae genera, distribution, food, behavior, and general egg morphology. After Smith’s evolutionary hypothesis (Smith RL, The evolution of social behavior in insects and arachnids. Cambridge University Press, Cambridge, 1997), feeding habit of Belostomatidae was revealed and the result agreed with his hypothesis. In the exclusive paternal care, we reviewed the role of paternal care, oviposition site selection, and evolution of sexual size dimorphism and its relation to the presence of paternal care. After controlling for phylogenetic signal, it seems that the infanticide phenomenon does not necessarily explain the origin of sexual size dimorphism biased toward females in Belostomatidae, since the ancestor of all Belostomatidae was most likely a non-brooder. Finally, we show the future direction of the study in giant water bugs: coevolution between male and female genitalia in Belostomatidae, allometry for sexual size dimorphism and its disagreement with Rensch’s rule, and phylogenetic test of predictions provided by Smith’s evolutionary scenario assuming alternative conditions (Horvathinia is an emergent-brooder, a back-brooder, or a non-brooder).
... Instances of oogenesis-flight syndrome have not been studied in detail in aquatic insects but seem likely in the hydrophilid, Helophorus brevipalpis (Landin 1980), and dytiscids in the genus Graphoderus (Iversen et al. 2017). There is also good evidence for the syndrome in belostomatid bugs (Cullen 1969;Lytle and Smith 2004), and it is likely in Gerridae and probably numerous other taxa, although its hormonal control has not been shown definitively in either aquatic Hemiptera or Coleoptera. On the other hand, it certainly is absent, or present in abbreviated form, in some migrating dragonflies. ...
Chapter
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All habitats change over time, so most organisms must resist unfavorable conditions or disperse to more favorable localities. Typically, aquatic habitats are relatively short lived because of drying or infilling. Aquatic insects, then, often have adaptations for effective dispersal, sometimes over long distances and most often by flight. This chapter examines some of the environmental drivers and organismal responses that affect the nature of dispersal. These include consideration of how different habitats affect dispersal, especially some differences between lentic and lotic habitats. Dispersal characteristics may also have major effects on genetic structure of populations. Both selective forces and proximate cues affect when insects disperse and when and where they colonize new habitats; availability of space, presence of predators, and availability of food may all play a role, depending on species and circumstances. Adaptations for dispersal include, in addition to active flight, behaviors that promote passive movement by wind, dispersal polymorphism (i.e., changes in body structure, such as wing development, that enhance dispersal, usually hormonally controlled and incurring some cost in fecundity), increased body size, and timing of diapause and reproduction. In a few species dispersal extends to migrations of hundreds of kilometers and may have important seasonal effects on habitats of origin and of destination. Dispersal is also integral to the concept of metapopulations and in fact may be a major driver of community composition and dynamics. Simultaneous dispersal of very large insect populations can have an important effect on nutrient and energy flow to and from communities. Finally, dispersal may be a critical determinant of whether and how aquatic insects respond to climate warming.
... The bug then sucks the liquefied guts through its rostrum like a straw. Using this method, the giant water bug is able to capture and eat animals up to fifty times its own size [77][78][79][80][81][82][83][84] . Giant water bugs of the genus Lethocerus are traditionally used as human food in Southeast Asia. ...
Article
Freshwater ecosystems are colonized by a diverse array of aquatic organisms and often contribute the bulk of regional freshwater biodiversity. Aquatic insects are abundant in most freshwater habitats and often exhibit high diversity and play an important role in ecosystem functioning by virtue of their abundance, taxonomic diversity and trophic significance, besides, water quality monitoring as reliable indicators. Ponds are an excellent habitat for biodiversity studies of freshwater insects. The present paper focuses on the diversity of hemipteran fauna in Sengunam pond, Perambalur, Tiruchirappalli, Tamil Nadu, India. The hemipteran insects recorded from Sengunam lake were Aquarius and Limnogonus (water striders), Nepa (water scorpion), Ranatra (water scorpion/water stick insect), Hesperocorixa and Corixa (water boatman), Notonecta (backswimmer), Neoplea and Paraplea (pygmy backswimmers), Lethocerus (giant water bug) and Diplonychus (water bug). Therefore, it is imperative to make continuous investigation, census and research activities on the taxonomy and diversity of aquatic insects, so that knowledge regarding this important group can be utilized by future researchers as baseline data for further research and conservation planning of both the aquatic insects and water bodies.
... While the large-bodied members of the subfamily Lethocerinae feed on small snakes, anurans, and fish, the much smaller members of the subfamily Belostomatinae mainly feed on various invertebrates and anuran larvae, but do not regularly prey on fish (Cullen 1969;Babbitt and Jordan 1996;Swart and Felgenhauer 2003;Mori and Ohba 2004;Ohba and Nakasuji 2006;Swart et al. 2006;Ohba 2011). Prey selection in belostomatines has been thoroughly investigated in the predator-prey relationship between Belostoma cf. ...
Article
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A considerable body of the literature considers the potential impact of exotic predators on native prey organisms, while comparatively, few studies have asked whether and how native predators include novel prey types into their diet spectrum. Here, we asked whether the native aquatic heteropteran Diplonychus esakii preys on the highly invasive western mosquitofish (Gambusia affinis), which has been introduced to southern China and threatens native fish species through competition and predation on their fry. We conducted 48-h prey choice experiments under semi-natural conditions. In a ‘no-choice’ experiment (one predator and one potential prey; n = 200), we found the heteropterans to prey more on large-bodied fish, a pattern that was also described for other belostomatids, while prey sex had no effect on capture rates. Moreover, large-bodied heteropterans caught more fish than small-bodied individuals. However, overall capture rates in our study were low (11.5–30%) compared to studies on other belostomatids, which explains why subsequent binary prey choice experiments using one predator and two prey—either large and small females or male and female (with smaller sample sizes of n = 20 and 30, respectively)—did not confirm the results of our first experiment. Our study exemplifies how a pattern of body size-dependent predation can arise in a novel (not coevolved) predator–prey interaction. We tentatively argue that the observed pattern could be driven by intrinsic features of the predator, namely, altered prey preferences with increasing age coupled with a general preference for large-bodied prey, or changing nutritional needs at different developmental stages.
... The evolution of paternal care in hemipteran lineages has been driven by a complex of factors. It probably originated as a response to pressure from predators and parasitoids [43,[71][72][73][74][75][76], to prevent eggs from desiccation [77,78], to develop a more elaborate manipulation of tradeoffs between air exchange and desiccation in water bugs [79][80][81][82], or to represent an adaptation to unstable or ephemeral food resources in cydnid families [25,27,32,83,84]. In treehoppers, maternal care is associated with changes from a solitary to gregarious life history in connection with the acquisition of ant mutualism [2,74]. ...
Article
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Maternal care (egg-nymph guarding behavior) has been recorded in some genera of Acanthosomatidae. However, the origin of the maternal care in the family has remained unclear due to the lack of phylogenetic hypotheses. Another reproductive mode is found in non-caring species whose females smear their eggs before leaving them. They possess pairs of complex organs on the abdominal venter called Pendergrast’s organ (PO) and spread the secretion of this organ onto each egg with their hind legs, which is supposed to provide a protective function against enemies. Some authors claim that the absence of PO may be associated with the presence of maternal care. No study, however, has tested this hypothesis of a correlated evolution between the two traits. We reconstructed the molecular phylogeny of the subfamily Acanthosomatinae using five genetic markers sequenced from 44 species and one subspecies with and without maternal care. Eight additional species from the other two acanthosomatid subfamilies were included as outgroups. Our results indicated that maternal care has evolved independently at least three times within Acanthosomatinae and once in the outgroup species. Statistical tests for correlated evolution showed that the presence of maternal care is significantly correlated with the secondary loss or reduction of PO. Ancestral state reconstruction for the node of Acanthosoma denticaudum (a non-caring species in which egg smearing with developed POs occurs) and A. firmatum (a caring species with reduced POs) suggested egg smearing was still present in their most recent common ancestor and that maternal care in A. firmatum has evolved relatively recently. We showed that maternal care is an apomorphic trait that has arisen multiple times from the presence of PO within the subfamily Acanthosomatinae. The acquisition of maternal care is correlated with the reduction or loss of PO, which suggests an evolutionary trade-off between the two traits resulting from physiological costs. This prediction also implies that presence of maternal care can be highly expected for those groups lacking behavioral data, which invariably also lack the organ. No secondary loss of maternal care was detected in the present tree. We suggest that the loss of maternal care may be suppressed due to the vulnerability of the PO-free condition, which thus maintains maternal care.
... Lethocerus Mayr has frequently been observed feeding on animals many times larger than themselves: fi shes, frogs, salamanders, and freshwater snakes (Menke 1963 ). In the laboratory, adults of Lethocerus killed and digested a large Hydrophilus Geoffrey and those of Belostoma malkini Lauck, the freshwater shrimp Palaemonetes Heller, the large tree frog Hypsiboas crepitans (Wied-Neuwied), and the fi shes Poecilia Bloch & Schneider and Rivulus Poey (Cullen 1969 ). Individuals of Ranatra wait for their prey hiding between aquatic plants in a more vertical position, with the head directed downward (Nieser 1975 ). ...
Chapter
The infraorder Nepomorpha is one of the most specialized groups of heteropterans, with most of its species spending the entire life cycle within the water. True water bugs include ten families, 52 genera, and approximately 730 species in the Neotropical region, which shelters about 30 % of the global diversity of the group. Despite this fact, little is known about their biology, ecology, and geographical distribution in the Neotropics. Several genera need to be revised and many species remain with outdated descriptions. The systematics of the infraorder, although has received little attention in recent years, remains with various unresolved questions, and no phylogenetic study was conducted for any endemic group of this region.
... Species of the Belostomatidae subfamily Lethocerinae are cosmopolitan, and live in freshwater habitats such as ponds, lakes and rivers (Cullen, 1969; Menke, 1979b; Smith & Larsen, 1993; Perez Goodwyn, 2006). The giant water bug, Kirkaldyia deyrolli Vuillefroy, is distributed in Japan from central Honshu to the Ryukyu Islands. ...
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Residents of Vietnam living in areas with water shortages collect and store tap water when available in containers such as jars, for their daily activities. Although these water jars are important breeding sites of the mosquito, the use of chemical larvicides in such containers is legally prohibited in Vietnam. The effect of Olyset(®) Net on the abundance of mosquito larvae and predatory Heteroptera (Micronecta and Veliidae) in jars was evaluated in field experiments conducted at Tan Chanh, Long An, Vietnam. The number of Aedes larvae reduced if the jar was covered using Olyset(®) Net, while the numbers of non-Aedes mosquito larvae (Culex and Anopheles), as well as those of Micronecta and Veliidae did not change until the end of the experiment. However, the Micronecta population increased after removing the Olyset(®) Net from the jars and Aedes larvae decreased due to the increase in the Micronecta number, 3 weeks after the Olyset(®) Net was removed. Incomplete use of Olyset(®) Net failed to control mosquitoes in the jars because of the invasion of adult mosquitoes and water transfer by residents among the jars, transferring even the larvae. The results suggest that Micronecta, as well as Olyset(®) Net, can be considered as possible larval control agents.
... Upon capture, belostomatids inject toxins causing paralysis of prey and digestive enzymes causing necrosis of tissue (Swart and Felgenhauer, 2003;Swart et al., 2006). While the large-bodied species of the subfamily Lethocerinae have been widely reported to feed on large prey including small snakes, anurans, and most notably fish (Babbitt and Jordan, 1996;Mori and Ohba, 2004;Ohba and Nakasuji, 2006;Swart et al., 2006), the smaller-bodied species of the subfamily Belostomatinae prey on various terrestrial and aquatic invertebrates and anurans but usually avoid fish (Cullen, 1969;Swart and Felgenhauer, 2003;Ohba and Nakasuji, 2006;Swart et al., 2006). ...
Article
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In the southern Mexican Cueva del Azufre, a cave ecosystem with high concentrations of toxic hydrogen sulfide, one species of hemipteran (Belostoma cf. bakeri) has adopted a unique ecological function in that it acts as one of the top predators in the subterranean food web, preying on the abundant cavefish Poecilia mexicana. To date, several aspects of this predator-prey interaction have been explored, but basic questions related to the ecology of the waterbugs remained unstudied. We tested whether there is evidence for reproduction of waterbugs within the cave, which would indicate a self-sustaining population. Furthermore, we investigated the habitat affinities of different size-classes of waterbugs. We infer that waterbugs reproduce inside the cave despite the toxic properties of the water, as evidenced by the presence of nymphs of all sizes and males carrying developing zygotes. We also found size-dependent differences in use of habitat, and particularly small nymphs occupy different microhabitats than larger individuals. Adult waterbugs and large nymphs were most common at sites with cavefish. Small nymphs were rare at these locations, possibly to avoid cannibalism or exploit different resources in other locations. Furthermore, stable-isotope-analysis indicated that waterbugs likely derive their carbon from a combination of fish, dipteran larvae, and chemoautotropic bacteria.
... The male guards the eggs until hatching, keeping them moist and defending them from predators. " Biological observations of four American and two Oriental species are published, namely Lethocerus americanus (Leidy, 1847) (Hoffman 1924; Hungerford 1925), Lethocerus maximus De Carlo, 1938 (Cullen 1969), Lethocerus mazzai De Carlo, 1961 (De Carlo 1969), Lethocerus medius (Guérin-Méneville, 1857) (Smith & Larsen 1993) and Lethocerus indicus (Lepeletier & Serville 1825) (Hoffman 1933a,b). The behavior of Kirkaldyia deyrolli (Vuillefroy 1864) is the best known, and is one of the reference points for the post-embryonic paternal care in insects (Ohba 2011). ...
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Journal of Threatened Taxa: Abstract: Two species of giant water bugs Lethocerus were found in the Gangetic plains of northern India and Nepal. Lethocerus indicus is widespread, whereas a single record of Lethocerus patruelis confirms the eastern distribution range in Bihar. Four instars of aquatic nymphs occur exclusively in temporary shallow stagnant water bodies which harbor rich amphibian populations but lack permanent fish fauna. From mid-August to the first week of November adults fly. Later they live submerged in aquatic habitats of large rivers and permanent stagnant water bodies which harbor diverse fish fauna. Repeated findings of adults with ventrally attached egg-shaped pupae of aquatic mites (Hydracarina) suggest that these are host-specific ones of Lethocerus. Thus, the occurrence of protelean parasites on giant water bugs in the Gangetic plains is a previously unknown unique finding since apparently mites have been noticed only from other Nepomorpha families. Keywords: Aquatic insect, gangetic plains, giant water bug, hydracarina, host-specificity, India, life cycle, Nepal, protelean mites.
... Waterbug brooding behavior incurs both proximate and ultimate costs. Brooding males remain at the water surface to aerate the eggs (Cullen 1969), whereas unencumbered males remain well below the surface amid submerged vegetation. The added weight and drag of the egg pad also reduces swimming speed (Kight et al. 1995), which makes it difficult for the males to escape predators or capture prey (Crowl and Alexander 1989). ...
Article
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Reproductive effort and/or success sometimes increase with the age of a parent. We found that reproductive effort was greatest in older egg-brooding male giant waterbugs, Belostoma flumineum Say. Consistent with previous studies, males with large egg pads were unlikely to discard them unhatched under any condition. However, males with small egg pads were significantly more likely to discard the eggs unhatched in the autumn (when breeding adults are young) than in the spring. By brooding smaller pads, older males invested more heavily in each offspring. Males bearing small egg pads were also significantly less likely to discard them in the presence of females. Three kinds of hypotheses have previously been proposed to explain why reproductive investment and/or success might increase with age: selection hypotheses predict differential survival of better parents; experience hypotheses predict that more experienced parents achieve greater success without additional cost per offspring; and residual reproduction hypotheses predict that older parents invest more per offspring. It is difficult to experimentally untangle these hypotheses, but the results of this study provide cautious support for a residual reproduction hypothesis that older males with few remaining reproductive opportunities invest more heavily per offspring by retaining small egg pads.
... It has been suggested that these behaviours increase oxygen diffusion into the eggs males carry (Smith 1976a, 1976b, 1997), and thus maintain the oxygen and humidity levels required for egg viability (Smith 1976a, 1976b, 1997; Kraus et al. 1989). Egg pads removed from males and exposed to the air, submerged in water, or left at the air–water interface have lower hatching success than egg pads carried by males, which reach a high degree of hatching success (usually above 80%), although effects can vary across species (Cullen 1969; Smith 1976b; Venkatesan 1983; Kraus et al. 1989). ...
Article
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We carried out a capture–recapture multistate modelling approach to estimate survival and recapture probabilities and transition rates between parental and nonparental status in an adult wild population of the water bug Abedus breviceps Stål, 1862 (Hemiptera: Belostomatidae). The global model included the following parameters: sex, male parental status (brooding or not), and transience (individual’s permanent movement from the site after first capture). Models were selected by means of the information-theory paradigm. The best supported model shows no difference in survival between males and females regardless of male parental status. Thus, the frequently assumed cost of parental care in terms of survival is not supported by our data. Furthermore, during the study, male expected adult life span in the wild was lower than the time needed to brood a batch of eggs from oviposition to hatching. We discuss potential consequences of such a short male expected adult life span in terms of parental behaviour decision rules related to fitness maximization.
... A number of researchers have found that intensive moonlight does not reduce, in fact, in some cases, increases the catch by light-trap (Bogus [18], Pristavko [143], Cullen [39], Johnson [90], Duviard [54], Papp and Vojnits [135], Doiron and De Oliveira [50], Bowden and Jones [25], Járfás and Viola [86], Jeffrey and Dyor [87], Cook and Perfect [37], Shrivastava et al. [166], Saroja et al. [161], Linhares and Anderson [95], Ito et al. [83], Janousek and Olson [84]). Collecting two rice pests (Scotinophora coarctata F. and Scotinophora lurida Burmeister) with a 125 W mercury vapour lamp, Balasubramani et al. [8] observed a higher catch by the full, then by the new moon. ...
Article
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The present study discusses the light trapping of insects depending on the environmental illumination, twilight polarization phenomena and the moon phases. The trapping data were taken of Hungarian national light-trap network. The important results are the followings: The Babinet-point, a polarization free spot of the sky at twilight, can be a role of orientation of insects. The height of the Moon above the horizon is in negative correlation with the number of the caught insects. The maximum individual number of species was collected at various moon phases. Keywords: light-trap, collecting distance, Babinet-point, moon phases
... The flight of certain belostomatids (e.g. Diplonychus nepoides) has been shown to be influenced by the full moon, and has been noted principally during the few nights preceding or following the full moon (Cullen 1969;Duviard 1974). We, however, did not observe this phenomenon in our study. ...
Article
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The giant water bug, Lethocerus deyrolli, is an endangered wetland insect found throughout East Asia. In 2006, the light-attraction flight of L. deyrolli was studied in Gyodong Island, Korea, using artificial light. The flight of L. deyrolli was observed from early June to late October, and two peaks in the numbers of attracted insects were noted in the middle of June and September. L. deyrolli begins to exhibit flight behaviour at a daily mean air temperature of 15°C and above, but optimal flight temperatures for the insect are between 17°C and 19°C, with a wind speed of less than approximately 1.8 m/sec and a relative humidity of around 80%. The length of daylight did not substantially influence the flight pattern. Daily flight occurred principally between 9 pm and 10:30 pm. L. deyrolli individuals attracted by the artificial light were frequently consumed by magpies or house rats. It appears most probable that artificial lights, such as street lights and tennis court lights, constitute a critical factor in the local extinction of L.deyrolli.
... Members of the Lethocerinae have been reported to feed on prey as large as small birds, snakes, and adult anurans, but more commonly feed on small fish, aquatic and terrestrial invertebrates, and anuran larvae (Torre Bueno, 1906;Babbitt and Jordan, 1996;Hirai and Hidaka, 2002;Mori and Ohba, 2004;Ohba and Nakasuji, 2006). The Belostomatinae exploit a wide range of prey types including anuran larvae, snails, and terrestrial and aquatic invertebrates (Torre Bueno, 1906;Cullen, 1969;Gonsoulin, 1973;Chase, 1999;Mori and Ohba, 2004;Swart and Taylor, 2004;Ohba and Nakasuji, 2006). Fish are notably absent from the diets of these smaller belostomatids. ...
Article
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Belostoma lutarium (Stål) is semiaquatic predator common to vegetated ponds, lakes, and bayous throughout eastern North America. We used scanning electron microscopy and histological cross sections to show that the morphology of the feeding structures of B. lutarium agrees with the general hemipteran feeding plan. Slight deviations from the previously reported observations for other Nepomorpha include the structure of the triturating devices, feeding stylets, and the efferent salivary duct. Furthermore, interrupted feeding trials indicate that B. lutarium is able to feed on large prey for over 2 h and not deplete its supply of salivary enzymes. All three productive components of the salivary gland (main, lateral, and accessory glands) empty most of their salivary products during the first 2 h of feeding, and begin regenerating their secretions during the feeding process. Essentially, no latency period for saliva production exists in this species. The structure and function of the mouthparts and salivary gland are adapted for the predaceous feeding habits of Belostomatidae.
... Brooding involves remaining at the water surface, which exposes the eggs to atmospheric oxygen while simultaneously preventing desiccation (Smith 1976(Smith , 1997. Males also stroke the egg pad with their legs, presumably to increase aeration of eggs, prevent the establishment of fungi (Cullen 1969), and possibly to assess the status of egg development. Brooding continues until the eggs hatch, after which males remove and discard the pad of egg membranes with their legs. ...
Article
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We examined the effects of ambient temperature on the brooding behavior of male waterbugs, Belostoma flumineum Say. Male waterbugs are more likely to prematurely terminate care for small egg-pads than for larger egg-pads. Because embryogenesis and breeding season are both associated with ambient temperature, males in warmer environments may respond differently than those in cooler conditions. We studied the effects of temperature on male parental behavior by housing groups of completely and partially egg-encumbered males under different thermal regimes. Completely encumbered males rarely discarded egg-pads, regardless of ambient temperature. Partially encumbered males housed under warm ambient temperatures, however, were significantly more likely to discard the eggs than those housed under cooler conditions. These results are consistent with the hypothesis that cool ambient temperatures at the end of the breeding season elicit a terminal investment strategy.
... Giant water bugs such as Belostomatidae have raptorial forelegs that are used to prey upon a variety of aquatic animals, for example insects, cladocerans, amphibians and small fish (Cullen 1969; Smith 1997). The subfamily Lethocerinae, which has the largest body size among Belostomatidae, is known to be a vertebrate specialist that preys upon fish, amphibians and snakes (Smith 1997; Hirai & Hidaka 2002; Mori & Ohba 2004; Toledo 2005; Ohba & Nakasuji 2006; Swart et al. 2006; Ohba et al. 2008). ...
Article
The giant water bug, subfamily Lethocerinae, which has the largest body size among Belostomatidae, is known to be a vertebrate specialist that preys upon fish, amphibians and snakes. However, there have been no reports concerning predation on a turtle by Lethocerinae. Here, I report that a male giant water bug Kirkaldyia (Lethocerus) deyrolli (Heteroptera: Belostomatidae) (58.09 mm in total length) was catching hold of a turtle Chinemys reevesii (34.14 mm in carapace length) in a ditch adjoining a paddy rice field. This is a first report of K. deyrolli eating a turtle.
... These reductions in loach population density may influence the diets of higher order predators such as carnivorous birds inhabiting rice fields (e.g., Narusue and Uchida 1993; Lane and Fujioka 1998). Species of the Belostomatidae subfamily Lethocerinae are cosmopolitan, and live in freshwater habitats such as ponds, lakes, and rivers (Cullen 1969; Perez Goodwyn 2006). The giant water bug, Kirkaldyia deyrolli Vuillefroy (formerly Lethocerus deyrolli; see Perez Goodwyn 2006), is distributed throughout Japan from central Honshu to the Ryukyu Islands, southeastern Asia, China, Taiwan and Korea. ...
Article
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Rice fields provide major habitats for lentic aquatic insects including the giant water bug Kirkaldyia (=Lethocerus) deyrolli (Heteroptera: Belostomatidae) in Japan. Previous researchers have emphasized that con-serving populations of the frogs, Hyla japonicus and Rana nigromaculata, is very important for preserving K. deyrolli because these frogs were found to be a major component of the diet of K. deyrolli adults. However, these previous studies were carried out in rice fields with no loaches, Misgurnus anguillicaudatus, which were probably been inhabited by loaches in the past. A series of field surveys and laboratory experiments were conducted to determine the dietary preference of K. deyrolli adults for loaches, frogs, and aquatic insects; the reproductive effects of consuming these foods; and their protein content. In the rice fields, K. deyrolli adults ate loaches when they were available. When the three prey species (frog: R. nigro-maculata, loach: M. anguillicaudatus, and dragonfly: Orthetrum albistylum speciosum) were supplied in labo-ratory conditions, K. deyrolli adults ate more loaches than frogs or dragonflies. In addition, K. deyrolli adults provided with loaches or frogs laid more egg masses within the limited breeding season than when provided with dragon-flies. The edible parts of the loach bodies were the largest of the three prey types. It is possible that K. deyrolli adults have been forced to eat frogs due to reductions in the population density of loaches because modern rice culti-vation obstructs loach migration routes and reduces their spawning grounds.
... A previous study of an unidentified belostomatine in the genus Diplonychus showed that eggs in atmospheric conditions loose up to 50% of their mass in 24 h due to water loss (Venkatesan & Rao 1980). Similar differences in egg survival to those found between our treatments have been described in other belostomatines such as Diplonychus indicus (Venkatesan 1983), Abedus herberti (Smith 1976a), Belostoma flumineum (Smith 1976b) and Belostoma malkini (Cullen 1969). However, Kraus et al. (1989), working with A. indentatus, found high egg viability for clutches with no parental care placed at the airwater interface. ...
Article
Males of the subfamily Belostomatinae, within the giant waterbugs (Hemiptera: Belostomatidae), brood eggs on their backs from oviposition until egg-hatching. The eggs in the clutch must be kept moistened and exposed to enough oxygen flow for them to develop properly and maximize hatching success. When submerged, males regularly perform different behavioral patterns that promote oxygen flow to the eggs. One of these patterns, brood pumping, consists of ‘push-up’ like movements using their hind legs. In this study, we assessed if temperature, oxygen dissolved in the water and the developmental stage of the clutch influence brood pumping rate in Abedus breviceps. In the wild, we found that males covered with bigger eggs showed a higher brood pumping rate than that of males with smaller eggs. An analysis of egg growth curves under laboratory conditions demonstrated that males that did not perform brood pumping were carrying broods that were in the first third of their developmental period. We also found that non-brooded clutches had a much lower hatching success than those brooded by males, even when exposed to controlled and favorable environmental conditions. We discuss the persistence and modulation of paternal care intensity in belostomatines as an aptative character conditioned by environmental and anatomical features.
... Belostomatids are predacious water bugs and include approximately 140 species belonging to seven genera (Menke 1979). The genus Lethocerus (Belostomatidae) is cosmopolitan and lives in freshwater habitats such as ponds, lakes, and rivers (Cullen 1969; Menke 1979; DuBois and Rackouski 1992). ...
Article
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The endangered giant water bug Lethocerus deyrolli (Vuillefroy) is frequently attracted in large numbers to artificial lights in Japan. To examine factors enhancing flight migration for L. deyrolli, we carried out field work in western Hyogo Prefecture, central Japan, in September during the nonreproductive and prewintering season. The body weight of specimens collected under flight migration (flight bugs) was significantly less than that of those collected in ponds (pond bugs). A field experiment using open cages in a rice paddy field was carried out with two treatments, with and without a food supply. The remaining rate of L. deyrolli for the food present treatment was significantly higher than that for the food absent treatment for the first two days. These results suggest that L. deyrolli would fly in search of food when the food supply of the present habitat becomes unsuitable.
... Species of the Belostomatidae subfamily Lethocerinae are cosmopolitan, and live in freshwater habitats such as ponds, lakes and rivers (Cullen, 1969; Menke, 1979b; Smith & Larsen, 1993; Perez Goodwyn, 2006). The giant water bug, Kirkaldyia deyrolli Vuillefroy, is distributed in Japan from central Honshu to the Ryukyu Islands. ...
Article
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A field research was carried out in Hyogo Prefecture, Japan in order to establish the role of the water-scorpion, Laccotrephes japonensis Scott as predator of nymphs of the endangered giant water bug, Kirkaldyia (= Lethocerus) deyrolli. To assess the impact of this predator, a field experiment was set up with (Control) and without L. japonensis (Removed). The survival rate of K. deyrolli in Removed treatment was higher than in the Control. Our experimental results showed that L. japonensis is an important predator for K. deyrolli nymphs in the field.
... The family Belostomatidae Leach, 1815, comprises the largest heteropterans, where it is a group with a worldwide distribution and a high diversity in the tropical region (Merritt and Cummins, 1996;Ribeiro, 2007). These are animals with predatory habits, and their ecological importance lies in the role they play as biocontrol agents, where aquatic arthropods, fish, and amphibians are its main prey (Cullen et al., 1969;Saha et al., 2010). ...
Article
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Belostoma, a genus of the family Belostomatidae, includes species of great ecological importance as biocontrol agents. Few species of these species have been the subject of cytogenetic analyses. Karyotypic evolution in this genus involves agmatoploidy and simploidy; there are also different sex chromosome systems. We examined two Belostoma species (B. dilatatum and B. candidulum) collected from the Paranapanema River Basin (Brazil). Mitotic and meiotic analysis revealed 2n(♂) = 26 + X₁X₂X₃Y for B. dilatatum and 2n(♂) = 14 + XY for B. candidulum; both karyotypes have holokinetic chromosomes. Differences in heterochromatin distribution were also observed between the species, besides variation in the localization of CMA₃⁺/DAPI⁻ blocks. The existence of different types of sex chromosome systems in these species was confirmed based on arrangements of the chromosomes in different meiotic stages. We identified a new sex system in B. dilatatum, and make the first cytogenetic report on B. candidulum.
... In giant water bugs (Belostomatidae), for instance, aeration and moistening of the eggs by guarding males are crucial for offspring survival (Smith 1997). Even though it has been suggested that guarding males of giant water bugs might also protect their eggpads against predators (Cullen 1969; Kraus et al. 1989), no study so far has tested this hypothesis. Actually, there are only two studies that provided experimental demonstration of the effectiveness of male egg-guarding behaviour as a defence against natural enemies in arthropods. ...
Article
Although the benefits of maternal care have been investigated in many species, the caring role of males in species with exclusive paternal care has received less attention. We experimentally quantified the protective role of paternal care in the harvestman Iporangaia pustulosa. Additionally, we compared the effectiveness of paternal care against predation in this species with a syntopic harvestman with maternal care, Acutisoma proximum. We demonstrated that nearly one third of the unprotected Iporangaia clutches disappeared entirely in 13 days, while the other two thirds presented a mean reduction of 55% in egg number. Conversely, 50% of the control clutches did not suffer any reduction, and only one was entirely consumed by predators. We also demonstrated that the mucus coat that covers Iporangaia clutches has an important deterrent role against predation by conspecifics: 58.3% of the clutches without mucus were attacked and three of them were entirely consumed, whereas only three clutches with mucus were attacked, suffering a reduction of up to three eggs. Iporangaia males were as efficient as Acutisoma females in protecting eggs. However, unattended Acutisoma clutches were nearly 20% more attacked by predators than unattended Iporangaia clutches. Unattended Iporangaia eggs are more protected by a mucus coat that prevent or decrease predation rate, whereas Acutisoma eggs are more susceptible to predation, probably because they lack this mucus coat. Thus, besides the fact that Iporangaia males efficiently protect the offspring against egg predators, females also contribute to egg protection by providing a mucus coat that also deters egg predators.
... Les connaissances actuelles ne nous permettent pas d'identifier les facteurs influençant la migration (le vol) de ces insectes. Néanmoins, différents paramètres sont suspectés : la densité de proie, la période de reproduction, la phase lunaire et la température (34)(35)(36)(37). La corrélation entre les précipitations et l'activité de vol a été rapportée pour les Belostomatidae lors d'une étude réalisée en zone tropicale au Costa Rica (37,38). ...
Article
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Hosting of Mycobacterium ulcerans by water bugs is now well established and their vectoring role has been demonstrated experimentally. These findings were recently corroborated by detection of viable bacilli in the saliva of wild water bugs. However, the extent of water bug involvement in M. ulcerans ecology remains unclear and difficult to evaluate due to lack of understanding about water bug biology. The purpose of this study is to describe the first detection of M. ulcerans DNA in the tissue of water bugs captured outside the aquatic environment. This finding supports the hypothesis that water bug migratory behavior contributes not only to the spread of M. ulcerans but also to transmission outside the aquatic environment.
Thesis
Une des 17 maladies tropicales négligées déclarées par l’OMS, l’ulcère de Buruli constitue aujourd’hui un réel problème de santé publique en Afrique centrale et de l’Ouest où il sévit dans près de 30 pays. Cette maladie touchant principalement les populations des zones enclavées reste un mythe car l’on ne connaît pas aujourd’hui le mode de transmission exacte de la bactérie responsable, Mycobacterium ulcerans, à l’humain. Une meilleure connaissance de l’écologie de ce bacille constitue pourtant un levier important tant pour apporter des informations concernant sa transmission que pour lutter contre ce fléau. Fortement soupçonnés de jouer un rôle d’hôtes ou de vecteur de M. ulcerans, certains taxons de punaises aquatiques semblent être prédisposés de par leur écologie ou leur comportement à héberger le bacille voire à le transmettre. Les travaux que nous présentons ici visent dans un premier temps à identifier sur des bases anatomiques complétées par des approches moléculaires les différents taxons de punaises aquatiques présents au Cameroun. Au-delà de proposer une clé d’identification d’espèces et une classification des punaises aquatiques du Cameroun reposant sur des séquences nucléotidiques, nous discutons du rôle important joué par l’écologie de certaines espèces de punaises dans la transmission de M. ulcerans. Les différentes approches comparatives et biostatistiques développées dans ce travail de thèse étayent l’hypothèse que certains taxons de punaises aquatiques, et notamment issus des familles Belostomatidae et Naucoridae, acquièrent la mycobactérie à partir de l’environnement en partageant des habitats (fréquentation de la végétation aquatique émergée) où le bacille prolifère, et en se nourrissant de proies, comme des mollusques ou de petits poissons, eux-mêmes contaminés par la bactérie. La capacité de vol chez les punaises aquatiques n’apparaît pas faciliter l’acquisition de M. ulcerans mais semble impliquée dans la dissémination de ce dernier en contaminant de nouveaux environnements. Au terme de cette thèse, nous discutons de l’écologie des communautés de punaises aquatiques et de leur macroécologie au Cameroun, et examinons l’importance de l’échantillonnage comme élément important de tout travail de recherche en écologie et évolution des maladies infectieuses.
Conference Paper
We investigated the population dynamics of the giant water bug, Belostoma angustum, across highlands in the Pampas of southern Brazil. We evaluated genetic and morphological variation, as well as the demographic history of 18 populations. Genetic variation was assessed from mitochondrial and nuclear markers. The morphological variation was estimated using linear measurements and geometric morphometrics approaches. Our results from multiple analyses of molecular variance (AMOVA) show that Belostoma angustum structures as a large panmictic-like population across the Pampas highlands range. Every most frequent haplotype is shared by individuals from all three sampled areas in genetic markers from the mitochondrial as well as from the nuclear locus. Differentiation among haplotypes was very low, not greater than two mutation steps. Furthermore, there was no evidence for isolation-by-distance (IBD) based on the mitochondrial data. The pairwise Фst was low and not significant, indicating historical gene flow among populations of the giant water bug studied throughout Pampas. Our findings about the demographic history of panmictic population throughout Pampas highlands suggest it experienced recent and rapid population expansion that started in the Late Pleistocene period, approximately 15,000 years old after Last Glacial Maximum. We did not find morphological variation among populations of B. angustum throughout Pampas highlands reflected, except for some body dimensions. The overall phenotypic uniformity among populations becomes more likely if gene flow is hypothesized to homogenize populations. Our genetic findings suggest indirectly that individuals of B. angustum are strong fliers able to overcome the topographical barriers of the sampled area.
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The population dynamics of freshwater organisms are expected to be related to the connectivity among comparable streams, ponds, or rivers in a patchy habitat. Here, we investigated the population dynamics of the giant water bug, Belostoma angustum Lauck 1964 (Hemiptera: Belostomatidae), in a fine-scale spatial sampling, and evaluated which gene flow model previously described for freshwater organisms could explain the genetic-morphological variation in this species. For these purposes, we evaluated genetic and morphological variations, as well as the demographic history of this freshwater insect. Our genetic analyses showed a lack of geographical structure within B. angustum populations across the evaluated range, concordant with widespread gene flow model. Our findings of the demographic history of B. angustum suggest recent and rapid expansion beginning during the late Pleistocene after the Last Glacial Maximum. Likewise, we did not find geographically structured morphological variation in B. angustum, except for body size. The lack of structure of genetic-morphological variation in B. angustum could be explained by a stepping ponds system resulting in the widespread gene flow detected among populations of this species. The warmer and wetter climatic conditions after the last gla-cial period may have favored the demographic expansion of B. angustum populations due to the increasing of potential freshwater habitats and food resources. This favorable habitat probably allowed the stepping ponds dispersal mode resulting in the verified geographically unstructured genetic-morphological variation.
Article
Despite being one of the dominant groups in freshwater ecosystems, morphological and ontogenetic studies on aquatic Hemiptera have received little attention in the Oriental region. We present the ontogenetic trajectory and allometry of the widespread Oriental belostomatid species, Diplonychus rusticus (Fabricius) for the first time. We have measured nine different morphological variables throughout the growth of the bug using both field captured and laboratory reared specimens. Our results suggest that the developmental instars can be distinguished by the size variables, as seen in the Principal Component Analysis. On the basis of a CHAID (Chi-squared Automatic Interaction Detection) based regression tree, we also show that the characters - total length without head and maximum width prove to be adequate for effective instar identification. The multivariate allometric growth pattern shows that different body parts exhibit different types of allometry. This is apparent in the allometry exhibited by forelegs and mid and hind legs, which show allometry of opposite polarities. This may be due to the different functions attributed to these body parts. Our results show that the growth pattern in D. rusticus is comparable with the New World genus Belostoma, suggesting a conserved growth pattern in the family Belostomatidae.
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More than 2,100 adult, drifting giant water bugs (Lethocerus americanus) were collected from the upstream face of the uppermost raceway screens at a run-of-river trout hatchery on a Wisconsin tributary to Lake Superior during December 1991 - May 1997. This drift was greatest from mid-October through March at water temperatures lower than 4°C, and was rare during summer. Individuals that were collected from the screens, marked, and released above the hatchery were rarely recovered, hence the location of the source population and drift distances are speculative. The sex ratio overall was close to 1:1, with males dominating numerically in 1994 and 1997, and females in 1993 and 1996. Females averaged 56.5 mm in total length (range 51-63 mm), and males 50.7 mm (range 47-56 mm). There was significant interannual variation in the mean lengths of males, but not of females. No differences in mean lengths or sex ratios between early- and late-winter collections were evident for any year. We suggest that the drift of these insects is best explained as a dispersal mechanism following the final molt and that winter is selected for dispersal to minimize predation risks.
Chapter
Aquatic Hemiptera include the semi-aquatic bugs (Gerromorpha) which live primarily on the water's surface and the aquatic bugs (Nepomorpha) which live submerged beneath the water, along with several other mostly terrestrial groups that live near aquatic habitats. Over 4,800 described species of aquatic Hemiptera occur across all continents except Antarctica, and occupy a diversity of habitats ranging from lakes and streams to seasonal rain pools. Taxa can be large-bodied (up to 11 cm), and most are predatory on other insects or sometimes vertebrate prey. Aquatic Hemiptera evolved terrestrially and invaded aquatic habitats secondarily. This terrestrial groundplan has influenced the evolution of aquatic Hemiptera mating behavior, respiratory physiology, and ecology.
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Chinches acuáticas de la superfamilia Nepoidea (Hemiptera: Nepomorpha) de Colombia: nuevos registros para Suramérica y ampliación de su distribución en el país Resumen Debido a la escasa información de las chinches acuáticas de la superfamilia Nepoidea en Colombia, se recopiló información mediante la revisión de las principales colecciones entomológicas a nivel nacional y la bibliografía existente para este grupo. Se registra por primera vez el género Abedus para Colombia y Suramérica y se amplía la distribución departamental de los géneros Belostoma, Curicta, Lethocerus, Ranatra y Telmatotrephes. Se presentan los mapas de distribución para los géneros registrados y una clave taxonómica para su identificación. Los Nepoidea en Colombia están bien representados con respecto a la región neotropical, siendo Belostomatidae la familia mejor muestreada. El género Belostoma presentó la mayor distribución con un amplio intervalo altitudinal. Es necesario realizar colectas en áreas críticas para completar el inventario a nivel nacional. Abstract For the true aquatic bugs grouped under the Nepoidea superfamily, there is little information available about the genera and species present in Colombia. For this reason information was gathered from the main entomological Colombian collections and from literature of this group. The genus Abedus is reported for the first time for South America and Colombia, together with new generic state records of Belostoma, Curicta, Lethocerus, Ranatra and Telmatotrephes. The distribution maps for each genus and a taxonomic key for their identification is included. Nepoidea is well represented in Colombia in respect to the Neotropical region, being Belostomatidae more thoroughly sampled. Belostoma is more broadly distributed over a much wider altitude range. More studies in critical areas are needed in order to complete the national inventory.
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El 15 Octubre de 2012, a las 19:56 hs. en la Estancia Santo Domingo, Dpto. Paso de los Libres, provincia de Corrientes (29°36?2.10?S, 56°59?23.10?O) se observó un ejemplar hembra de L. annulipes (7,05 cm longitud total) depredando sobre un ejemplar macho de la especie Erythrolamprus poecilogyrus (Wied-Neuwied, 1825) (40,5 cm longitud total). El evento se registró en una charca temporaria de 10 m de largo por 1 m de ancho aproximadamente, con una profundidad de 30 cm. La temperatura del aire y del agua al momento de la captura fue de 21°C y 24°C respectivamente. Al momento de la observación la serpiente se encontraba sin vida.
Article
Limnogeton fieberi Mayr inhabits shallow regions of fresh or slightly brackish waterponds, canals and rice fields in Egypt where it preys, during the nymphal and imaginal stages, on aquatic snails including Planorbis biossyi and Bullinus truncatus which serve as intermediate hosts for Shistosoma haematobium that causes bilharzia in humans. The seasonal cycle of that predator is passed by one or two annual generations, and consists of an active period (June–October) followed by a sexual quiescent period (October–June). Eggs are laid in rafts glued to the backs of males until hatching. At mean temperatures of 27.2° C during the 1st generation and 25.6° C during the 2nd generation, the incubation period means were 13.9 and 14.1 days, respectively. Under the same temperatures, the nymphal period means were 45.6 and 47.4 days for female and male nymphs, respectively, during the 1st generation. The corresponding means during the 2nd generation were 53.4 and 55.6 days. The oviposition period took 11.0 days in females of 2nd generation which laid a mean number of 140.3 eggs/female. An oviposition period of 37.2 days and a mean number of 378.1 eggs/female were reported for females of 1st generation that laid all eggs in one active period. However, a long oviposition period of 286.1 days was reported for those that laid their eggs during two successive periods and the mean number of eggs, in this case, was 377.8 eggs/female. Longevity means reported for female and male adults of 1st generation were 286.0 and 316.6 days at 27.2° C, while those of 2nd generation lived for 244.5 and 260.5 days, respectively, at 25.6° C. Zur Lebensweise der Riesenwasserwanze, Limnogeton fieberi (Hemipt.: Belostomatidae), eines räuberischen Feindes von Krankheiten übertragenden Schnecken Die in seichtem Süß- oder Brackwasser von Teichen, Gräben und Kanälen in Ägypten vorkommende Wasserwanze, Limnogeton fieberi, frißt während ihres larvalen und imaginalen Lebens Wasserschnecken, die als Zwischenwirte für den die Bilharzia des Menschen übertragenden Saugwurmes Shistosoma haematobium fungieren. Der Lebenszyklus der Raubwanze umfaßt 1 oder 2 Generationen jährlich und besteht aus einer aktiven Periode (Juni–Okt.), auf die eine sexuelle Ruheperiode (Okt.–Juni) folgt. Die Eier werden in Platten auf den Rücken des ♀ geklebt, wo sie bis zum Larvenschlüpfen getragen werden. Bei mittleren Temperaturen von 27,2° C während der ersten und 25,6° C während der zweiten Generation betrug die Eidauer 13,9 und 14,1 Tage. Bei gleichen Temperaturen dauerte die Larvenentwicklung i. M. 45,6 (♀) und 47,4 (♂) Tage während der ersten Generation bzw. 53,4 und 55,6 Tage während der zweiten. Die ♀♀ der zweiten Generation legten i. M. 140,3 Eier in 11,0 Tagen. Bei der ersten Generation betrugen die Eilege-Periode 27,2 Tage und die Eizahl 378,1, sofern die ♀♀ ihre Eier in einer einzigen Aktivperiode ablegten. Bei Ablage in 2 aufeinanderfolgenden Perioden jedoch erreichte die Eilegezeit 286,1 Tage bei einer Eizahl von 377,8. Die mittlere Lebensdauer der Imagines bei 25,6° C betrug in der ersten Generation 286,0 (♀) und 316,6 (♂) Tage, in der zweiten Generation 244,5 und 260,5 Tage.
Article
Differential flight muscle regression was registered in Belostoma elegans (Mayr, 1871) and B. oxyurum (Dufour, 1863). A two year survey in contrasting habitats showed the preference for the more stable ones by B. oxyurum, and the more unstable ones by B. elegans. Fibrillar muscles were regressed in most of the B. oxyurum specimens, and developed for flight in most B. elegans. No positive correlation between egg production and muscle regression was found in any species. IVth and Vth instar larvae of both species were raised up in laboratory under unstable conditions. When moulting to adult stage none had their muscles developed, suggesting that the muscle development should be achieved later. B. oxyurum with its muscles regressed was found in quiescence during a dry-up of a sampled environment, thus this species would have to survive unexpected changes this way, and B. elegans would emigrate flying. The differential muscle development is associated with the ecological strategies of these two species.
Article
We examined the seasonal dietary patterns of the endangered giant water bug, Lethocerus deyrollei, in rice fields located at Sayo, Hyogo Prefecture, central Japan. The results showed that L. deyrollei underwent a shift in its major food item from breeding adults of Hyla japonica in spring (May and June) to newly metamorphosed juveniles of Rana nigromaculata in summer (July to September). Dietary shifts were shown to correspond with a seasonal fluctuation in the availability of anurans in the rice fields. Although adults of R. nigromaculata were relatively abundant throughout the active season they were infrequently exploited by L. deyrollei, possibly because of the difficulty in handling these large-sized frogs. Therefore, seasonal partitioning of the rice-field habitat by small-sized frogs, adult H. japonica and juvenile R. nigromaculata, would enable L. deyrollei to forage in the rice fields during the extensive active period. From these results, we suggest that the conservation of frog populations is very important for the preservation of this endangered insect and for the maintenance of biodiversity within these rice-field ecosystems.
Article
Although behaviors may remain highly conserved through evolutionary time, the ecological functions they serve can undergo surprising transformations. We used phylogenetic, correlational, and experimental evidence to show how a >150-million year-old behavior, which originally evolved to facilitate migration, has been co-opted for flash flood escape in two distantly related giant water bug species (Hemiptera: Belostomatidae). Using behavioral experiments with simulated rainfall, we showed that species from flash-flooding as well as non-flash-flooding environments are capable of rainfall response behavior (RRB), the ability to use rainfall as a cue to abandon an aquatic habitat. The results suggest that, in addition to allowing individuals to escape flash floods, RRB is the proximate mechanism generating a well-established ecological pattern: The correlation between rainfall and migration to seasonal breeding habitats that has been documented in 13 species throughout the family. Placing RRB in phylogenetic context reveals that for several taxa the behavior is an exaptation (a trait evolved for one function but later co-opted for another) for escaping flash floods. For Lethocerus medius, rainfall response behavior is an addition exaptation because the behavior is used to initiate migration to seasonal rain pools (ancestral function) as well as for flash flood escape (co-opted function). In the distantly related Abedus herberti, rainfall response behavior is a transfer exaptation because it has been co-opted exclusively for flash flood escape and the ancestral function has been lost. These findings emphasize that a phylogenetic framework is needed to fully understand the origins and ecological significance of behaviors.
Article
Five species of Belostomatids were caught in a light trap placed in a tree savanna 3 km distant from a small artificial lake in central Ivory Coast. Only Diplonychus nepoides Fabr. was fairly abundant. The flights of this species present a well-marked lunar rhytmicity: 79% of the catches occur during the fortnight around full moon. Rainfall does not seem to be an important factor. A highly significant, positive correlation has been found between the number of trapped bugs and nocturnal temperature.
Article
Full-text available
Unlike most aquatic invertebrate taxa in desert streams, adults and juveniles of the giant water bug Abedus herberti Hidalgo experience low mortality from flash floods (90%). One explanation is that A. herberti use periods of torrential rainfall (>15 cm hr –1 ) that often precede flash floods as a cue to abandon streams. Stream abandonment behavior consisted of exiting the stream after some threshold duration of torrential rainfall (8.0 min for adults, 29 min for juveniles), moving in a negatively geotactic direction away from the stream, and stopping in a sheltered area away from the active stream channel. Individuals crawled as far as 23 m from the stream, but returned within 24 h. Experiments with simulated rainfall demonstrated that the behavioral cue for stream abandonment behavior is probably related to the impact of rain on the stream surface, and not to other chemical or physical cues associated with inputs of rainwater (i.e., changes in pH, ion concentrations, water temperature, turbidity, or discharge) or approaching thunderstorms (i.e., pressure drops, thunder, lightning, or cloud cover). These other cues may play an auxiliary role in the behavior, however. Stream abandonment behavior can only account for part of the high survival rates observed for A. herberti during flash floods, since less than a third of observed individuals responded to either natural or simulated rainfall.
Article
Full-text available
Predatory insects that depend upon particular prey animals are commonly regulated by the prey animal’s abundance. Nymphs of the giant water bug Kirkaldyia (=Lethocerus) deyrolli (Heteroptera: Belostomatidae) are predators regarded as specialists in feeding on tadpoles. We studied the ontogenetic diet shift of aquatic nymphs by quantifying instar abundance and by analyzing captured prey and prey relative abundance during the period of rice irrigation in three localities. We also evaluated the contribution of major prey items (tadpoles, frogs, and Odonata nymphs) on specific growth rates of each nymphal stage in a rearing experiment. First to third-instar nymphs of K. deyrolli fed mainly on tadpoles, regardless of differences in prey availability. Nymphs of subsequent fourth and fifth instar stages shifted from tadpoles to other prey animals within each rice field. A rearing experiment demonstrated that giant water bug nymphs provided with tadpoles had greater specific growth rates at all nymphal stages, except for the final stage, than nymphs fed other prey (frogs and Odonata nymphs). The emergence of young K. deyrolli nymphs seemed to coincide with the period during which tadpoles became abundant in the rice fields. Consumption of tadpoles seems important to allow the nymph to complete its larval development in an unstable temporary habitat.
Article
Full-text available
Buruli ulcer is a debitliating human skin disease with an unknown transmission mode although epidemiological data link it with swampy areas. Data available suggest that aquatic insects play a role in the dissemination and/or transmission of this disease. However, their biodiversity and biology remain poorly documented. We conducted an entomological survey in Bankim, Cameroon, an area recently described as endemic for Buruli ulcer in order to identify the commonly occurring aquatic bugs and document their relative abundance, diversity, and spatial distribution. Collection of aquatic bugs was realized over a period of one month by daily direct capture in different aquatic environments (streams, ponds, and rivers) and through light traps at night. Globally, the data obtained showed the presence of five families (Belostomatidae, Naucoridae, Nepidae, Notonectidae, and Gerridae), their abundance, distribution and diversity varying according to the type of aquatic environments and light attraction.
Article
This review presents a systematic compilation of species in which only the male cares for the offspring. Such species occur rarely in the polychaetes, Hemiptera, Amphibia and birds and more often in the pycnogonids and fish. The facts are interpreted in the light of sexual selection theories. Care by only the male is more likely to occur if fertilization is external and might often be selected for as a consequence of site-attached behaviour by males. An explanation is suggested for the evolution of total role-reversal: it might result from the breakdown of a state of secondary equality of parental investment by the two sexes.
Article
Degeneration of indirect flight muscles takes place during the first gonotrophic cycle in females. Feeding and mating stimulate egg production and muscle histolysis. Starved virgin females do not histolyse the flight muscles. Mating has greater effect on muscle degeneration than feeding. Ovariectomy inhibits degeneration to a certain extent.
Article
Certain segmental units of the three main longitudinal muscle-bands in the abdomen of the larva of Galleria, Platysamia, Telea, Antheraea, and Samia (Philosamia) do not degenerate during the histolytic phase in the prepupa and early pupa. In the 3rd abdominal segment the amount of muscle that persists is variable; in the 4th, 5th, and 6th segments, invariable. Apart from single pairs of transverse muscles in the 2nd and 3rd segments and those of the gut and heart there are no other muscles in the pupa. Vestiges of degenerated muscles are often found in the pupa. The longitudinal muscles which survive the transformation of the pupa into the adult degenerate during the first 2 days of adult life. Experiments were made on larvae, prepupae, pupae, and adults in attempts to influence muscle-degeneration and muscle-persistence. Extirpation of ganglia or severance of nerves in larvae and prepupae of Galleria caused the normally persistent muscles to degenerate during pupation. Controls in which larvae were dissected before pupation revealed no degeneration of denervated muscles. In saturniids denervation also resulted in degeneration or atrophy but only after a much longer period, a matter of several weeks instead of several days. Muscles may be affected by extirpation of ganglia or severance of nerves in segments preceding their own segment. Previous workers have shown that the growth of the new adult muscles is dependent on the influence of the central nervous system. This is not so in the case of sheets of fine muscle-fibres lying under the epidermis of the adult. They develop in the absence of central innervation. Operations which had no effect on muscle-degeneration in the adult included extirpation of ganglia in pupa and adult, beheading and bleeding, extirpation of corpora allata plus corpora cardiaca, ligations, extirpation of pupal gonads, and isolation of adult abdomens. Substitution of blood from diapausing pupae or saline for the adult blood in isolated abdomens was effective in slowing the process of muscle-degeneration. This result shows that the blood composition is of importance in the process of histolysis in the adult. The previous work on the physiology of insect histolysis is briefly reviewed. The influence of the nervous system as described in this paper is discussed and related to similar findings in other arthropods and in vertebrates.
Article
The fine structure of the sieve-plates covering the spiracles of Hydrocyrius columbiae has been shown to consist of stout trabeculae bearing a system of minutely branching struts which ultimately form the boundaries of pores about 0·5 μ2 in area in spiracles 1, 2, and 4–10, and about 3 μ2 in spiracle 3. Measurements of the airflow through the spiracles under different pressures show it to be about a hundred times faster through spiracle 3 than through any other. Spiracle 3, facing posteriorly into the sub-hemelytral airstore, communicates with the principal tracheae to the flight muscles. While the intact bug can withstand pressures of at least 220 cm Hg without ill effect, after exposure of the spiracles by removing overlying cuticular structures, the sieve-plates permit water to enter the tracheae under about 150 cm Hg. The sieve-plates do not make any appreciable reduction in the rate of water loss when the bug is in air. A ventral hair-pile, consisting of small hooked hairs and long hairs terminating in flattened blades, functions mainly to allow the ventrally-placed abdominal spiracles to communicate with the sub-hemelytral airstore via three bridges. All but the first pair of spiracles are in contact with the airstore which communicates with the atmosphere through a pair of retractile siphons. The siphons are able to curve dorsally by means of muscles and are able to pierce the meniscus when the bug rests horizontally at the surface. Comparisons are made with some other Belostomatidae and with the larva in which a ventrally-placed airstore communicates with all the functional spiracles. Spiracle 3 of the larva does not differ in structure from the other spiracles.
Article
When alate aphids of several species were allowed to settle down on their host plants, their flight muscles began to break down within a few days. The onset of muscle degeneration could be delayed by preventing the aphids from settling down, either by denying them their host altogether or by leaving them on a poor host in darkness for several days.The reproductive capacity of alatae before they lost the ability to fly varied for different species. Embryo development was arrested in alatae of all the species that were studied after the end of the teneral condition following the final ecdysis, and was resumed when they settled down on a new host. Some species of aphids contained a number of fully formed embryos at the time embryo development was arrested, and these plus a few additional embryos whose development had been completed after the aphids settled down were born before the ability to fly was lost. In other species the young alatae contained only rudimentary embryos that required several days to develop to the stage at which they were normally born; in these species no larvae were born until the muscles had begun to degenerate and the ability to fly was lost. Other species fell between these two groups and in one species, Macrosiphum euphorbiae (Thomas), whether or not the aphids reproduced at all before losing the ability to fly depended upon their size.The ability of alatae of Aphis fabae Scop. to engage in long flights of 1 hr or more was retained for as long as the aphids retained the ability to fly.
Article
The ventral intersegmental muscles of the abdomen in Rhodnius undergo a cycle of development and involution during each larval stage. They are fully developed only at the time of moulting or hatching from the egg. Within 3 or 4 days after moulting the fibrils have disappeared; but the nuclei, with a little cytoplasm containing mitochondria, survive within the highly folded muscle-sheath. The formation of fibrils begins between 2 and 3 days after feeding. At first they are uniformly birefringent. The striations appear later, and the muscles will then contract after transection. The fibrils are 0.1-0.2 µ thick when first formed; they grow by intussusception and splitting to a thickness of about 0.8 µ. Succinoxidase first appears in quantity in the mitochondria at the time when striation and contractility develop. It disappears within 3 days after moulting, during the involution of the fibrils. The distribution of ribonucleic acid in the developing muscle is described. Involution results from autolysis which begins around the nuclei in the centre of the uscle. The phagocytic blood-cellsplay no part in the break-down. The rich nerve-supply to the muscles persists apparently unchanged throughout the cycle of involution; and the cycle of growth occurs normally after section of the nerves.
Article
The responses of whole insects, selected organs, and tissues to treatment with the saliva of an assassin bug Platymeris rhadamanthus are described. The excitability of muscle and nerve is rapidly abolished. In the general lysis that follows immobilization only cuticular and collagenous structures are spared. The disruption of lipid layers in the walls of nervous tissue is histologically demonstrable at an early stage. The saliva contains at least six proteins, and lacks mucoprotein or other mucoid substance. Three proteolytic fractions were recognized after starch-gel electrophoresis at pH 8·6, one of them forming the major component of the saliva. Attempts to locate a toxic fraction were unsuccessful. The alkaline endopeptidase activity of whole saliva characterized with an azocasein substrate closely resembles gut proteases of other insects examined with the same substrate. Hyaluronidase is present in the saliva and with protease acts as a spreading factor by breaking down the intercellular matrix. Lipase and esterase activity were not detected in the saliva, but gut-wall extracts were lipolytic. The saliva shows weak phospholipase activity. ATP-ase, and serotonin were not detected. The mode of action of assassin bug saliva as a venom and in external digestion is discussed. It is suggested that its toxicity is due to the disruption of phospholipid layers of the cell wall and is the first manifestation of general lysis during external digestion.
Article
When female blowflies are fed unlimited quantities of ‘protein’ (marmite and milk) and sugar solutions, their corpora allata (c.a.) volumes increase before and decrease during yolk formation in normal females but hypertrophy in ovariectomized flies. If fed sugar solution alone, the ovaries of the flies do not mature and the c.a. in both normal and ovariectomized females remain small. The interpretation and control of these variations in volume were investigated. When ovariectomized or normal females are fed ‘protein’, their c.a. volumes increase in proportion to the quantity consumed. When ‘protein’ is removed from the diet, the c.a. decrease in size. The c.a. respond similarly in both types of fly up to the stage at which yolk is normally deposited. If a further quantity of ‘protein’ is ingested at this stage, the c.a. of normal females increase slightly in volume and then decrease during yolk deposition. But the c.a. of ovariectomized females hypertrophy before decreasing in size. The decrease in c.a. volume during yolk formation may be virtually eliminated by forcing the flies to ingest excess quantities of ‘protein ‘during this phase. The graded response of the c.a. to ‘protein’ consumption suggests that fluctuations of c.a. volume represent variations in activity induced (proportionately) by ‘protein’ metabolites in the blood (there is no accumulation of ‘protein’ in the gut). The decrease in size during yolk formation is due to the removal of ‘protein’ metabolites by the ovaries for the purpose of yolk formation. In ovariectomized flies, these yolk precursors accumulate in the blood causing the c.a. to become hyper-active as indicated by hypertrophy. The responses of the c.a. to ‘protein’ consumption do not appear to be unduly affected by denervation, cutting of the nervi oesophagi or of the cardiac-recurrent nerve. There is slight evidence that the corpus cardiacum is able to store c.a. hormone.
Article
A circadian clock is shown to be involved in the control of macromolecular orientation of chitin by cells secreting and organizing insect endocuticle. Daily organization of locust endocuticle into alternating lamellate and non-lamellate layers persists in constant temperature (36° C) and constant darkness for at least 2 weeks; the freerunning period is then about 23 h, so that after a number of days the circadian clock is 180° out of phase with the astronomical clock, with which it is normally phased. The rhythm is almost independent of temperature, with a Q10 of 1.04, as contrasted with a Q10 of 2.0 for the actual rate of increase of endocuticular thickness. Locust epidermal cells differ in response to specific imposed environmental conditions according to their location in the integument. In some cells, constant low temperature uncouples chitin lamellogenesis from the circadian clock, provided that illumination (light or dark) is constant also: the result is continuously lamellate endocuticle. In other cells constant light acts as an uncoupling factor, provided that temperature (high or low) is constant also: the result in this case is continuously non-lamellate endocuticle. The circadian rhythm of chitin lamellogenesis persists in a cave cricket (Dolichopoda linderi). A similar circadian lamellogenesis rhythm occurs in the endocuticle of nymphs and adults of the cockroach Periplaneta americana. A crossed-fibre multiple-ply endocuticle in the legs and wings of giant toe-biter water bugs (Belosto-matidae) also displays circadian organization, the chitin macromolecules in any one layer lying in parallel fibres, at an angle of approximately 6o° to those in the next layer. It is suggested that daily organization of the skeleton may be a general feature of arthropods. Examples include the phenomena of timing of chitin lamellogenesis; chitin crossed-fibrillar organization; degree of fluorescence of the rubber-like protein resilin; and mineralization of crayfish gastroliths.
Article
operate to elicit the reflex ; flight ceases when the legs again make contact with the substrate. When giant water bugs were removed from substrate contact, they did not fly, but instead swam. If they stopped, they would begin again with direct tactile stimulation. In short, they appeared to swim in those situations in which terrestrial insects fly. Although a few of the water bugs eventually flew, they did so only after a considerable period ; during this time they were swimming. This study is an attempt to analyze the swimming and flight reflexes of these giant water bugs.
Article
Ten species are recognized for the area treated, namely L. atnericanus (Leidy), uhlcri (Montandon), annulipes (Herrich-Schäffer), medius (Guérin), delpontei De Carlo, colossicus (Stål), truxali Menke, angustipes (Mayr), maximus De Carlo, and griseus (Say). These are keyed, a synonymic bibliography is given for each species, and distribution maps are included. The biology of the genus is summarized, and there is a discussion of the general distribution picture with special emphasis on the West Indian fauna, which seems of twofold origin, derived partly from South America and partly from Central America.
Article
IN a paper published in 1927, Hora1 suggests that the swarming of some Ephemeroptera is related to the lunar cycle. Evidence has been obtained which suggests that Povilla adusta Navas, a mayfly widely distributed in Central and Southern Africa, shows such a rhythm of emergence in Uganda. The interest of this lies in the fact that very few examples are known of lunar rhythms in non-marine animals (see Gaspers2).
Article
In macropterous weevils of S. hispidula F. marked variation occurs in regard to the development of the muscles of flight, some insects being able to fly while others are permanently flightless. Both forms are widely distributed and may occur in the same locality.In the flightless insects the histology of the fibrous muscles is entirely different from that of the normal muscle; the discs of the fibrous muscles are reduced in size and the phragmata of the metatergum are suppressed. Forms intermediate betweeen the two extremes occur.A study has been made of the post-metamorphic development of the flight muscles in S. lineata, a species which is an excellent flier, and it has been found that in the newly emerged weevils the condition of the flight muscles and their chitinous supports closely resembles that of the abnormal form of S. hispidvla. In S. lineata, however, the normal condition is usually attained a short time after emergence.The flightless macropterous weevils of S. hispidula may therefore be regarded as individuals in which the normal post-metamorphic development of the flight muscles and their chitinous supports has been arrested.In the normal form of S. hispidula it has been found that the muscles of flight usually degenerate during the winter, but in S. lineata they are functional for a much longer period and weevils of this species fly readily in spring.Evidence obtained by breeding S. hispidula suggests that unfavourable environmental conditions during ontogenetic development may be responsible for the production of the flightless weevils.
Article
Flying swarms have been observed to vary in vertical extent from a few metres to several thousand metres, with the spacing of the locusts in them ranging from more than 10 locusts/m3 down to the order of 0·001/m3. Some characteristic effects seen, from ground and air, are described in qualitative terms. Two well-documented records of flying locusts in numbers at some 2,000 m above ground were both associated with lapse rates close to the dry adiabatic, from the ground up to at least the level of these locusts. On two other occasions detailed observations of vertical temperature distribution have been made in the immediate vicinity of large swarms flying up to 1,100–1,700 m above ground, and in both these cases the topmost locusts were within 150 m of the upper limit of superadiabatic or adiabatic lapse rates from the surface. Comparable observations on a swarm in which all flying locusts were below 6 m demonstrated isothermal conditions, with the air temperature at 50 m within 1/2°F of that at the surface. All adequately-documented records of swarm displacement so far available have been directly down-wind, at ground speeds which for the larger swarms studied have approximated to the speed of the corresponding wind. The smaller swarms, most of them less than 10 km2 in extent, have shown lower flying heights, relative to the corresponding vertical extent of dry adiabatic lapse rates, together with ground speeds which were also low, in relation to the wind speeds concerned and to the corresponding performance of the larger swarms. There is some evidence of an association between rain and low flying heights; and consideration of heat exchange at the ground surface indicates that the energy normally available for convection, in the arid regions frequented by swarms, is likely to be drastically reduced after rain. Quantitative evidence on the strength and distribution of the vertical components of air movement likely to be encountered by flying locusts has been provided by pilot-balloon and accelerometer data. Twin-theodolite pilot-balloon observations in central Somalia have shown that during much of the day some 10 per cent of uniformly-distributed locusts in flight at about 20 m at any one time could be expected to experience up-currents exceeding their gliding sinking-speed. Gust-spectra recorded by aircraft accelerometer within and around high-flying swarms have demonstrated up-gusts, exceeding a value equivalent to the sinking-speed of a gliding locust, at about fifty points per km2 among the higher-flying locusts at any one time. The possible use of locusts as indicators of air movements is discussed, with a summary of the evidence available on the contributions made by the active behaviour of the locusts themselves to the effects observed. Attention is directed to the importance of gregarious behaviour in the continued cohesion of individual swarms, observed over many days and hundreds of kilometres, despite the disruptive effects both of atmospheric turbulence and of the apparently random orientation of the flying locusts themselves. The order of magnitude of these potentially disruptive effects is estimated for a particular case, and shown to be large compared with the variations actually observed in the extent of the swarm concerned.
Article
In the hibernating (diapausing) Colorado potato beetle, Leptinotarsa decemlineata Say, the flight muscles show pronounced degeneration. The muscle fibrils are greatly reduced in diameter and the sarcosomes are virtually absent. Similar signs of degeneration could be produced by extirpation of the postcerebral complex of endocrine glands, the corpora cardiaca and corpora allata. Reimplantation of active postcerebral complexes resulted in a very rapid regeneration of the muscle fibrils and new formation of sarcosomes.
Article
Also published in Bulletin biologique de la France et de la Belgique. Plates interleaved with descriptive text. Thesis (doctoral)--Caen, 1924. Includes bibliographical references (p. [299]-305). Microfilm. s
Article
DURING July 1951 a number of specimens of gravid female mosquitoes, in which the flight muscles showed various degrees of autolysis, were collected in the vicinity of Churchill, Manitoba. The loss of scales and hairs renders identification of a mosquito of this group impossible by means of conventional characters. There is good circumstantial evidence, however, that all these specimens were either Aedes communis De Geer, or an as yet undescribed species indistinguishable from it on any single morphological character in the larval or adult stage1.
Biologia de Lethocerus mazzai
  • De Carlo
The biology and zoology of aquatic and semi-aquatic Hemiptera
  • Hungerford
Migration, an evolutionary necessity for denizens of temporary habitats Proc. XI int
  • T R E Soüthwood
Über einen geschlechtsspezifischen Duftstoffer der Wasserwanze Belostoma indica Vitalis
  • Bltenandt
The Giant Water Bugs (Belostomatidae, Hemiptera)
  • Cummings
Los Belostomatidos Americanos
  • De Carlo
An experimental study on the death feigning of Belostoma fluminea Say and Nepa epiculata Uhler
  • Severin
The relation of activity of two species of Belostomatidae to rainfall and moonlight in Ghana (Hemiptera; Heteroptera)
  • Bowden
L̂organe trachéo-parenchymateux de quelques Hémipteres aquatiques
  • Ferriere
Notes on the giant water bugs
  • Hungerford
A functional approach to insect migration and dispersal and its bearing on future study
  • C G Johnson
L̂atrophie des muscles du vol après la chute des ailes chez Lipoptena cervi L
  • Mercier
Der flugapparat der Käfer, Vorbedingung Verlauf seiner Rücksbildung
  • Rüschkamp
Belostomatidae and other fish destroying bugs
  • Dimmock
Contribution àl̂étude du Termite lucefuge
  • Feytaud
Life histories of N. American water bugs 1, Belostoma ftuminea Say
  • Torre-Biteno
  • Usinger