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Manipulation of Host Plant Quality: Herbivores Keep Leaves in the Dark

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Abstract

1. Environmentally induced variation in plant defences may partially account for variation in herbivory rates among plants. 2. Some herbivores alter the microenvironment within a host to promote favourable changes in plant tissues. Caterpillars from the families Pyralidae and Ctenuchidae form a roll of leaves around an expanding bud which reduces light availability by 95%. 3. In the neotropical shrub, Psychotria horizontalis, shading by the roll of leaves decreased the toughness of the expanding leaves by 31% and leaf tannin concentration by 15%, while having no effect on two measures of nutritional quality, nitrogen concentration and water content. Moreover, herbivores preferred leaves that had grown within a leaf roll over control leaves (P<0.001). 4. This behavioural mechanism may allow the herbivore to disable an otherwise well-defended plant.

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... First, the effects of plant species on arthropods may depend on plant biomass production in the ecosystem and plant quantity (Kirchner, 1977). Second, the observed effects may reflect the influence of specific leaf traits of the plant species on arthropods, that is, the 'plant quality' hypothesis (Sagers, 1992). However, the independent roles of plant quantity and quality in driving the diversity of arthropod communities and multiple arthropod groups remain poorly understood. ...
... Therefore, the response of total arthropod taxon richness and abundance to the increases in plant nutrient content could be nonlinear due to diverse responses of arthropod species. In addition, leaf structural traits, including leaf lignin content and SLA, are also important indicators of plant nutrient content or food quality for arthropods (Peeters et al., 2007;Sagers, 1992). For instance, several chewing leaf beetles (Order: Coleoptera) consume leaves with high lignin content, independent of leaf nutritional content, to maintain their richness and abundance (Peeters et al., 2007). ...
... Several reports have indicated that the increased plant production strongly influenced the taxon richness and abundance of terrestrial arthropod communities (Siemann, 1998;Wimp et al., 2010). In contrast, other reports have shown that plant leaf traits, rather than plant productivity, greatly influenced insect richness and abundance by affecting the insects' ability to locate, consume and persist on their hosts (Forbes et al., 2017;Joern et al., 2012;Sagers, 1992). The incomplete knowledge of how plant quality and quantity affect arthropod diversity may be a consequence of the following aspects. ...
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The quantity (e.g. biomass production) and quality (e.g. leaf nutrient content) of plants can strongly influence arthropod diversity, but few studies have tried to disentangle such effects. In this study, we examined the independent effects of plant productivity and leaf traits on the taxon richness and abundance of entire arthropod communities and multiple arthropod orders in replicated monocultures of 15 herbaceous species in the Inner Mongolian grassland. Total taxon richness of arthropod communities increased with plant productivity and an increase in a high nutrient content indicator (PC1) of plant leaf traits (e.g. high leaf nitrogen, phosphorus and water contents), but decreased with an increase in a poor nutrient content indicator (PC2) of plant leaf traits (e.g. high leaf lignin content but low specific leaf area). Total abundance of arthropod communities increased with increasing plant productivity but decreased with increasing PC2. Many common, rather than rare arthropod orders, exhibited strong responses to the changes in plant quantity or quality. Taxon richness of Diptera, Neuroptera and Coleoptera responded positively to the increase in plant productivity and PC1, while taxon richness of Hemiptera and Coleoptera responded negatively to the increase in PC2. Abundances of Diptera and Coleoptera responded positively to the increased plant productivity, whereas abundances of Hymenoptera and Hemiptera responded negatively to the increased PC2. The order‐specific responses of arthropod richness and abundance to plant quantity or quality reflected the different food requirements and feeding behaviors of arthropods. Our findings demonstrate that plant quantity and quality can independently control richness and abundance of arthropod communities. The changes in plant productivity and nutrient content of different plant species may alter arthropod diversity and community structure, and these changes in turn may have strong cascading effects on multiple functions (e.g. prey, decomposers, pollinators and predators) in terrestrial ecosystems.
... The use of a host plant as food source and refuge against natural enemies is a common feature of small arthropod grazers, both terrestrial (e.g., caterpillars: Sagers, 1992;Weiss et al., 2003) and marine (e.g., amphipods: Duffy and Hay, 1991;Poore and Steinberg, 1999). These mesoherbivores construct their nests by rolling up the selected leaf or blade into a tube (Barnard et al., 1991;Fukui, 2001), which might reduce the probability of being eaten by large predators. ...
... The change of the normal leaf or blade structure can lead to a concomitant modification in some important tissue attributes of the host plant, such as growth rate or chemical and physical defensive traits (e.g., tannin concentration and tissue toughness, respectively). An increase in the quality of tissues in the nest, due to reduced chemical defenses or higher levels of nitrogen, has shown positive effects on terrestrial leaf-rolling caterpillars (e.g., enhanced growth: Sandberg and Berenbaum, 1989;Sagers, 1992;Fukui et al., 2002). ...
... On the basis of this suggestion, we expected that ovigerous females of herbivorous amphipods would exhibit prolonged occupancy within the nest, which might provoke reactions by the host algae and in turn influence amphipod behavior. For example, it could be expected that blade tissues within a nest would quickly start to deteriorate due to shading or grazing (as observed in terrestrial plants-e.g., Sagers, 1992), thereby shortening residence times of the amphipod. ...
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Many small arthropod herbivores from terrestrial and marine environments construct tubicolous nest-like domiciles on their host plants or algae by rolling up selected portions of the leaf or blade. Nests serve as both shelter and food, which results in conflicting needs for the grazers because feeding activity continuously destroys parts of the nests. While the nesting habit of ampithoid amphipods and other peracarid crustaceans is widely known, very little is known about the nest dynamics and how the conflict between shelter and food requirements is resolved. Herein we examined the nest-building behavior and nest occupancy of the kelp-dwelling amphipod Peramphithoe femorata on the giant kelp Macrocystis pyrifera. Domiciles on the distal-most part of the blades were occupied by amphipods and were steadily advanced toward the blade base. Since the blades grow from a basal growth meristem, blades and nests develop in opposite directions. Thus, the amphipods exploit the kelp growth pattern to maintain their nests in the medium-distal part of the blades. During a 2-week-long experiment, we observed that blade elongation equaled nest advancement during the first 8 days after nest construction. Thereafter, blade growth slowed down and was surpassed by nest advancement rates, possibly forcing amphipods to seek out new blades. Nest occupancy was generally short (1–4 days), but some amphipods resided longer (>4 days) in their nests. The sophisticated nest-building behavior of P. femorata and other ampithoids maximizes nest persistence, offers optimal protection against predators, and promotes feeding on nutritive or, alternatively, on less defended tissues.
... Because leaves maturing under different light levels produce different levels of foliar chemicals including phenolics (e.g., Barber & Marquis, 2011a), the main defensive compound type in Quercus (e.g., Feeny, 1970;Barbehenn et al., 2005;Murakami et al., 2005;Adams et al., 2009;Barber & Marquis, 2011b;Pearse & Hipp, 2012;Stoepler & Rehill, 2012), leaf ties could alter foliar phenolic contents and their effects on herbivory. For example, Sagers (1992) demonstrated that leaf rolls constructed by caterpillars on a Neotropical shrub decreased the phenolic concentration of expanding leaves through shading (see also Fukui et al., 2002). Furthermore, leaf ties could decrease leaf toughness via lowered fibre content by reducing light and carbon fixation, and increase leaf water content by lowering evapotranspiration. ...
... We found some evidence that leaf ties improve leaf quality from the perspective of the shelter builder and secondary inhabitants. Leaf shelters constructed by caterpillars are known to alter the leaf quality in other systems, influencing either the preference (Sagers, 1992) or growth rate of caterpillars on experimental versus control leaves (Fukui et al., 2002). In our study in 2012, leaves within experimental ties had lower phenolic concentration compared to single, non-tied leaves for four of seven oak species. ...
Article
Leaf shelter construction by herbivorous insects can improve leaf quality, sometimes changing resultant herbivory. In two experiments in a Missouri (USA) deciduous forest we quantified the impact of leaf tie construction and changes to leaf quality on subsequent leaf damage. First, using eight Quercus species, we compared damage to single leaves versus experimental leaf ties that had been stocked with either Pseudotelphusa quercinigracella (Gelechiidae) or Psilocorsis cryptolechiella (Depressariidae) to determine how initial leaf quality (total phenolics) influenced damage caused by shelter inhabitants. Skeletonization by leaf tying caterpillars and leaf edge chewing by free feeding species were 12.2× and 1.3× greater on tied than on non‐tied leaves, respectively. July and September leaf phenolic content had a slight positive effect on the probability of skeletonization, none on the probability of edge damage, and a weakly positive or negative effect on the intensity of skeletonization and edge damage, depending on leaf position. Second, we created experimental leaf ties, protected from herbivores, on the same Quercus species to determine whether tie formation changes leaf quality (total phenolics, nitrogen, water, toughness). Tie formation decreased phenolics, but this change was predicted to add only 0.8% leaf area loss. Synthesis. Herbivory increased dramatically when leaves were in ties, with the effect mostly due to the tie itself rather than a change in leaf quality. We predict that the advantages of building and using leaf ties in this system are more likely to be escape from natural enemies and changes in abiotic factors. Leaf tie formation increases leaf area loss to leaf tying caterpillars (Psilocorsis cryptolechiella and Pseudotelphusa quercinigracella) by 12.2X and to free feeders by 1.3X across eight species of Quercus The amount of leaf area loss is only weakly affected by differences in total phenolics among individuals within species and between Quercus species There is little evidence that tie formation increases leaf quality; rather escape from natural enemies or amelioration of the abiotic environment may explain the advantage of tie formation
... Similar results were reported for other insect herbivores, including the larva of a Desmia sp. (Lepidoptera: Pyralidae) on Psychotria horizontalis Swartz (Rubiaceae) (Sagers 1992). ...
... The "shade habitat hypothesis" has been explained in terms of changes in plant attributes such as increased nitrogen content, which enhance the nutritive value of the plant (Iason andHester 1993, Moon et al. 2000), decreased content of mainly phenolics that act as secondary metabolites used for defense (Newbery and Foresta 1985, Bryant et al. 1987, Iason and Hester 1993, Dudt and Shure 1994, and increased palatability by reducing tissue toughness (Bryant et al. 1987, Sagers 1992, Guerra et al. 2010. Less attention has been given to morphological traits such as trichome density, and results often were not deÞnitive (Bentz 2003, Guerra et al. 2010. ...
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Plant morphological changes mediated by growth conditions are linked to changes in host preference of herbivores. Understanding how these morphological changes influence herbivore feeding is critical in the interpretation of results of host evaluation of candidate weed biocontrol agents in quarantine and improvement of the evaluation system. We determined the effect of plant growth conditions on leaf trichomes and host choice of Conchyloctenia hybrida Boheman, an insect adapted to the removal of trichomes before feeding. The study included four Solanum species: Solanum lichtensteinii Willdenow (natural host of C. hybrida ), Solanum mauritianum Scopoli, Solanum melongena L., and Solanum tuberosum L.. Plants were grown in either full sun, shade, a glasshouse, or in a growth-chamber. Plants grown in full sun had a higher leaf trichome density than those in shade or controlled environments. S. mauritianum had the highest trichome density and thickness of trichome layer. In a multiple-choice test using excised leaves, feeding by C. hybrida was higher on Solanum plants grown in the controlled environment as compared with full sun. Trichome removal from leaf surfaces of plants grown in full sun, using adhesive tape, was effective for S. lichtensteinii , S. mauritianum , and S. melongena , but not S. tuberosum . Leaf consumption by C. hybrida increased significantly where manual trichome removal using adhesive tape was effective. Structurally, leaves of S. tuberosum have simple trichomes with basal cells sunken into the mesophyll tissue. When using forceps to remove trichomes of S. tuberosum , mesophyll and vascular tissue remained attached to the trichomes. Generally, the type, density, and mat-thickness of leaf trichomes determined feeding by C. hybrida , but varied with plant species and growth conditions.
... Em B. intermedia, a ocorrência dessas lagartas coincide com o aparecimento dos primórdios foliares, no final da estação seca (agosto e setembro), utilizados na construção de abrigos. Segundo Sagers (1992) esses abrigos criam um microambiente que induz condições favoráveis para uma melhor qualidade nutricional das folhas de seu interior para as lagartas. A presença de mais de uma lagarta dessa espécie nesses abrigos é comum em B. intermedia, o que pode trazer algumas desvantagens, como o aumento da competição por alimento e o acúmulo de fezes (Capuccino, 1993) (vide Capítulo 15). ...
... from natural enemies and abiotic stresses (Kudo 1994;Larsson et al 1997;Fukui 2001;Danks 2002;Crawford et al. 2007). Insect ecosystem engineers are also known to manipulate plant metabolism for their own benefit (Sagers 1992;Sandberg & Berenbaum 1989;Marini-filho & Fernandes 2012). But how such alteration of plant metabolic quality affects the behaviour and performance of subsequent shelter-users has rarely been investigated (Cornelissen et al 2015; but see Crawford et al 2007). ...
Article
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Herbivores that modify plant morphology, such as gall-forming insects, can disproportionately impact arthropod community on their host plants by providing novel habitats and shelters from biotic and abiotic stresses. These ecosystem engineers could also modify plant chemical properties, but how such changes in plant quality affect the behaviour of subsequent colonizers has rarely been investigated. We explored how an initial infestation of the tall goldenrod (Solidago altissima) by an ecosystem engineer, the rosette gall-midge (Rhopalomyia solidaginis), affects colonization behaviour of a shelter-using beetle (Microrhopala vittata) through plant-induced responses in the field. Beetles preferentially colonized plants with galls and exhibited a clumped distribution on those plants, which suggested a possible advantage for aggregating on galled plants. Accordingly, we found that beetles remained longer on galled plants with previous beetle damage than those without beetle damage. No such effect of beetle damage was found on plants without a gall. Similar interactions between galler infestation and beetle damage were found in beetle's feeding choice, leaf diterpene and serine protease inhibitor production, and volatile organic compound (VOC) emission. These plant metabolic induction and herbivore response patterns indicated that the gall-midge can alter how plants respond to the beetle damage and that gall presence coupled with beetle damage improves leaf palatability for the beetle. Finally, we found reciprocal effects of beetles on gall-midge performance to be neutral to slightly positive, suggesting that the observed field association of the two herbivores could be formed by plant-mediated facilitation. Synthesis. Our study suggests that an ecosystem engineer could have significant impact on herbivore community not only by changing plant morphology, but also by altering host quality and modifying plant-induced responses to subsequent herbivory. As such, R. solidaginis also functions as a keystone herbivore that has disproportionate effects on community dynamics and composition meditated by induced plant growth and metabolic responses. © 2016 The Authors. Journal of Ecology
... Loeffler (1996) demonstrated that the main advantage of leaf tie construction by Dichomeris larvae on Solidago is reduced dislodgment from physical forces. Leaf constructs can be lower in defensive compounds (Berenbaum 1978, Lewis 1979, Sandberg and Berenbaum 1989, Sagers 1992, Oki 2000, Fukui et al. 2002 or leaf toughness (Lewis 1979, Fukui et al. 2002. In contrast, Costa and Varanda (2002) found no differences in leaf quality between those in shelters and not. ...
Article
Introduction Insect herbivores and other arthropods create a variety of constructs on their host plants: silk webs, leaf shelters, galls, and stem cavities. This state change, often modifying resource availability for species other than the construct-builder (constructor, hereafter), is an example of allogenic physical ecosystem engineering. Physical ecosystem engineers are “organisms that directly or indirectly control the availability of resources to other organisms by causing physical state changes in biotic or abiotic materials” (Jones et al. 1994, 1997). In the case of allogenic engineering (in contrast to autogenic engineering), the physical state change is caused by the engineer, but the engineer is not part of the new physical state. The presence of constructs can impact the species richness, food web structure, and trophic interactions of the community of arthropods associated with engineered plants. The impact of engineering will depend on the responses of individual species to the presence of the constructs and the resulting interactions with all other species. One approach to understanding the nature of these responses is to view the engineered plant as a mosaic of engineered and nonengineered habitats. The response of a particular animal species to a plant that has been colonized by a constructor will depend on the relative value of the engineered versus nonengineered habitat to that animal. This value will be a function of differences between the two habitat types in the intensity of abiotic stress, the relative quality of food resources, competitive and mutualistic interactions (with other species in nonengineered habitats and with other secondary inhabitants in engineered habitats), and responses of natural enemies to engineering. © Cambridge University Press 2007 and Cambridge University Press, 2009.
... Certaines larves de Tortricidae peuvent ainsi consommer des feuilles normalement toxiques en empêchant la photo-activation de composés de défense comme l'hypericine (Sandberg & Berenbaum ~ 52 ~ 1989). Certaines larves de Pyralidae diminuent la dureté et les concentrations en tanins sans affecter les teneurs en azote et en eau des feuilles (Sagers 1992). Le Lépidoptère Rhopobota naevana (Hübner) (Tortricidae) est capable d'induire en plus une augmentation de la teneur en azote des feuilles (Fukui et al. 2002). ...
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Phloeomyzus passerinii est un important ravageur des peupleraies en Europe. Ce puceron se développe sur les troncs de peuplier, avec un mode nutrition mal connu, et présente des performances variables selon les génotypes de peuplier. Dans une optique de gestion de cet insecte, il était nécessaire de clarifier la nature de ses interactions trophiques avec son hôte. En complément, nous avons étudié comment la résistance de l’hôte et des facteurs environnementaux, comme la fertilisation et une contrainte hydrique, pouvaient affecter ces interactions. Des approches histologiques et biochimiques ont permis de mettre en évidence l’induction par l’insecte d’un tissu organise dans l’écorce d’un génotype sensible (I-214), qualifiable de pseudo-galle, où les composés phénoliques solubles disparaissent mais ou des acides aminés s’accumulent. Des approches complémentaires ont montré que le comportement de nutrition du puceron était optimisé sur ces tissus modifiés, et son développement larvaire amélioré. Concernant les mécanismes de résistance, dans un génotype très résistant (Brenta), la formation de la pseudogalle était totalement inhibée, suite à une lignification intense et étendue des tissus, empêchant l’installation du puceron. Dans un génotype de résistance intermédiaire (I-45/51), la formation était seulement partiellement inhibée, diminuant les performances démographiques et comportementales de l’insecte, et la capacité du tissu modifié à accumuler des acides aminés. Pour étudier l’impact environnemental, nous avons considéré les effets de trois niveaux de fertilisation et de trois niveaux d’irrigation du sol. La fertilisation n’a pas modifié les performances du puceron, probablement à cause d’une accumulation d’acides aminés par la pseudogalle d’autant plus forte que la fertilisation était faible. Le déficit hydrique a affecté les interactions, notamment au travers d’un effet génotype dépendant, favorisant le développement de l’insecte lors d’une contrainte intermédiaire chez le génotype résistant seulement et affectant négativement le développement chez les génotypes sensible et résistant lors d’une contrainte élevée.
... Many insects actively modify local environments to their own advantage instead of choosing more advantageous places among the existing ones (Danks 2002). Although some studies have demonstrated active manipulation of plant quality by shelter-building insects (e.g., Sandberg & Berenbaum 1989, Sagers 1992, others have shown that many caterpillars often choose leaves of lower nutritional quality indicating that choice of suboptimal leaves for shelter construction is offset by other advantages provided by the foliage (Lill & Marquis 2007). Costa & Varanda (2002), for example, showed that leaf ties built by the caterpillar Stenoma scitiorella Walker (Lepidoptera: Elachistidae) using leaves of Xylopia aromatica (Annonaceae) did not affect the concentration of chemical defenses or the feeding preference of these insects. ...
Article
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Amelioration of harsh conditions, manipulation of host plant quality, and protection from natural enemies have all been suggested as potential forces in the evolution and maintenance of concealed feeding in insects. The construction of shelters-either in the form of mines, galls, and leaf rolls-are expected to increase larval survivorship and might influence other organisms of the community through non-trophic direct and indirect effects when shelters are co-occupied or occupied after abandonment, placing leaf and stem shelter-builders within the context of ecosystem engineering. In this review, we evaluate the potential of shelter built by insects to reduce pressure exerted by natural enemies, increase tissue quality, and provide shelter against abiotic conditions experienced during insect development. Through a quantitative analysis, we also examined the effects of insect shelters on patterns of richness and abundance of local communities, reviewing the data published in the last 15 years. We demonstrate strong effects of shelters on several arthropods, with increased richness and abundance when shelters are present in the host plants. These results reinforce the importance of the physical structures created by insects that although subtle, might have important roles in facilitative interactions.
... In a number of cases, we observed that some larvae refused to feed during the trial. We were not able to explain this particular behaviour, although, in some cases, larvae have been reported not to feed for unknown reasons in laboratory trials (Sagers 1992). ...
Article
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In a three-hour bioassay, we tested the palatability and feeding preferences of Uresiphita maorialis (kōwhai moth) for Sophora tetraptera, Sophora microphylla and Sophora prostrata. Palatability tests showed no differences among the Sophora species. Feeding preferences, on the other hand, showed that S. tetraptera and S. microphylla leaves are preferred over S. prostrata leaves. Our results support our field observations in Wellington city parks and gardens showing that S. tetraptera and S. microphylla plants frequently have higher densities of larvae than S. prostrata
... Costs and benefits of shelter-building behaviors have been studied in several species of lepidopterans Marquis and Lill 2007). Benefits include light shielding (Sandberg and Berenbaum 1989), microclimate enhancement (Hunter and Willmer 1989;Larsson et al. 1997), protection from predators (Damman 1987;Eubanks et al. 1997), and increase in plant quality (Sandberg and Berenbaum 1989;Sagers 1992). In the present study, the shelters that were found provided defense against predators and, to a lesser extent, nutritional benefits, which change with shelter occupation time (Abarca and Boege 2011). ...
Article
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Shelter-building behavior by caterpillars provides a mechanism of defense against predators, microenvironment enhancement, and in some cases nutritional benefits. This study provides a detailed description of the life cycle and shelter-building process of caterpillars, and identifies constraints and factors influencing this adaptive behavior in Lepidomys n. sp. near proclea Druce (Pyralidae: Chrysauginae), a tropical dry forest pyralid. Five macroscopic larval instars were detected during the life cycle, and activities performed during shelter-building were categorized and timed. Caterpillar predators were identified, and 20% of all collected larvae died due to attack by parasitoid wasps. Shelter-building behavior was found to be constrained by the ontogenetic stage of caterpillars and influenced by leaf size of the host plant, Piper stipulaceum Opiz (Piperales: Piperaceae) . A similar pattern of shelter-building behavior exhibited by Tosale n. sp. near cuprealis larvae that coexisted in the same host plant is also described. Larvae of the second species were significantly less abundant than those of Lepidomys and hatched one month later in the rainy season, which could indicate some competitive interactions between these two pyralid species.
... We chose these masses because an earlier pilot experiment provided evidence that larvae collected from the field in the 35-50 mg range varied in their parasitism rate depending on whether they had been fed shelter material or pinnae with no evidence of herbivory. We switched the food between no-herbivory and shelter-adjacent pinnae as opposed to between no-herbivory and within-shelter pinnae in these treatments to maximize the probability of detecting the effects of induced plant defenses in case these defenses were partially inactivated by shading or some other aspect of shelter construction [23]. When larvae approached maximum size, we monitored them each day to determine their exact date of pupation and eclosion (median larval duration = 19 days, median pupal duration = 12 days). ...
Article
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Plant chemical defenses can negatively affect insect herbivore fitness, but they can also decrease herbivore palatability to predators or decrease parasitoid fitness, potentially changing selective pressures on both plant investment in production of chemical defenses and host feeding behavior. Larvae of the fern moth Herpetogramma theseusalis live in and feed upon leaf shelters of their own construction, and their most abundant parasitoid Alabagrus texanus oviposits in early instar larvae, where parasitoid larvae lay dormant for most of host development before rapidly developing and emerging just prior to host pupation. As such, both might be expected to live in a relatively constant chemical environment. Instead, we find that a correlated set of phenolic compounds shows strong seasonal variation both within shelters and in undamaged fern tissue, and the relative level of these compounds in these two different fern tissue types switches across the summer. Using experimental feeding treatments, in which we exposed fern moth larvae to different chemical trajectories across their development, we show that exposure to this set of phenolic compounds reduces the survival of larvae in early development. However, exposure to this set of compounds just before the beginning of explosive parasitoid growth increased parasitoid survival. Exposure during the period of rapid parasitoid growth and feeding decreased parasitoid survival. These results highlight the spatial and temporal complexity of leaf shelter chemistry, and demonstrate the developmental contingency of associated effects on both host and parasitoid, implying the existence of complex selective pressures on plant investment in chemical defenses, host feeding behavior, and parasitoid life history.
... While many functions have been proposed for shelter building by larval lepidopterans (e.g. Damman, 1987;Henson, 1958;Loeffler, 1996;Sagers, 1992;Sandberg & Berenbaum, 1989), we still understand little about the relationship between function and shelter architecture. As evidenced by the diversity of lepidopterans which build larval shelters (DeVries, 1987(DeVries, , 1997Greeney & Jones, 2003;Scoble, 1992;Stehr, 1987), these retreats surely serve important functions. ...
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Little has been published on the natural history of the strictly Neotropical nymphalid genus Hypanartia. We describe, for the first time, the early stages of Hypanartia dione dione from rearings in eastern Ecuador. Plants from two genera, Cecropia (Cecropiaceae) and Boehmeria (Urticaceae), are used as larval food plants. Larvae construct and inhabit shelters on the food plant leaves which are similar in many respects to those built by some members of the family Hesperiidae. Larval coloration and general morphology are similar to H. d. arcaei from Costa Rica.
... Shelters can also enhance food plant quality because they involve physical changes in leaves that may alter their chemical composition (Sagers, 1992). Furthermore, when herbivores trench the leaves before building a shelter, as in the case of the lepidopteran investigated in the present study ( Fig. 1), this may prevent induction of plant responses, which can reduce food quality by decreasing water and nitrogen concentration and increasing secondary metabolite production (Agrawal, 1999). ...
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1. Shelter building and petiole trenching in the Lepidoptera is a behaviour that mediates ecological pressures including those exerted by both food plants and natural enemies. 2. Fitness costs and benefits of trenching and shelter-building behaviour related to predation and larval performance were investigated in a pyralid species that inhabits and feeds on leaf shelters. 3. Assays comparing the performance of caterpillars feeding on trenched versus non-trenched foliage and fresh versus dry leaves were conducted. Whereas pupal weight was positively affected by petiole trenching, larval development was delayed when caterpillars fed on dry leaves. 4. A field experiment comparing predation on caterpillars inside and outside shelters demonstrated that predation was significantly higher for exposed caterpillars. 5. No physiological costs associated with shelter building were found given that caterpillars performed equally regardless of the number of shelters they built. 6. The effect sizes of top-down and bottom-up forces on pupal weight, development time, and predation risk indicated that the major effect of shelters is through the reduction of predation risk. The integration of experiments and natural history observations showed that fitness benefits provided by shelters change across ontogeny.
... Despite the abundance and diversity of shelter-building caterpillars, little is known about the function of the shelter-building behavior. Two of the proposed benefits of shelters are protection from natural enemies and protection from desiccation (Loeffler 1996; Eubanks et al. 1997; Fukui 2001; Jones et al. 2002), though several other possibilities have been suggested (e.g., defense against caterpillar removal, food quality maintenance) (Sandberg and Berenbaum 1989; Sagers 1992; Fukui 2001). Ants are regarded as important predators that can affect both insect species composition and the abundance of insects on plants (Fowler and Macgarvin 1985; Bentley and Benson 1988; Floren et al. 2002). ...
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Caterpillar shelters provide protection against desiccation and natural enemies, whereas extra-floral nectaries (EFNs) may be an anti-herbivore adaptation that reduces herbivore abundance by attracting predators and parasites. We used a large, long-term dataset for caterpillars found in the Brazilian cerrado to examine temporal variations in the relative abundance of shelter-building caterpillars and exposed caterpillars, and to determine how much variation depends on the season and the presence of EFNs on host plants. We also compared the patterns of parasitism between sheltered and exposed caterpillars, between seasons, and between different host plants. The cerrado has a marked dry season, and its vegetation is a mixture of mostly deciduous shrubs and trees. Leaf production occurs mainly during the rainy season, and many plant species bear EFNs. Our results show that 60 % of cerrado caterpillars build shelters. These caterpillars were found to be proportionally more abundant during the dry season and less parasitized than exposed ones. The proportion of caterpillars building shelters was highest on plants with new leaves (functional EFNs), and parasitism of caterpillars on these plants was higher. Even though our study includes a taxonomically diverse suite of caterpillars that build many different types of shelter and a diverse set of plants and EFN types, our results suggest that EFNs play an important role in structuring caterpillar assemblages in the cerrado, and that the prolific use of shelters by caterpillars may be a result of their effectiveness in protecting caterpillars from natural enemies and desiccation.
... Shelter architecture varies from loosely curled leaves to intricately cut and folded patterns or even large, silken shelters built by many individuals and enveloping many hostplant leaves (Stamp 1982Stamp , 1984 Fitzgerald and Willer, 1983; Fitzgerald et al., 1991; Fitzgerald and Clark, 1994; Fitzgerald 1995; Greeney, 2009; Ide, 2004; Weiss et al., 2003). Although here we focus on shelter construction as a defensive tactic, shelters are also thought to serve a variety of additional functions such as preventing dislodgement and desiccation, or increasing host tissue quality (Damman, 1987; Hunter and Willmer, 1989; Sagers, 1992; Loeffler 1993 Loeffler , 1996 Larsson et al., 1997). In fact, shelter-building lepidopterans are well known to suffer from heavier parasitism than non-shelter building caterpillars in the same community (Hawkins and Sheehan, 1994; Dyer and Gentry, 1999; Gentry and Dyer, 2002). ...
Article
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Larval lepidopterans (hereafter, caterpillars) protect themselves from natural enemies with a diverse suite of defenses which are employed before, during, or after encounters with enemies. Some strategies help caterpillars avoid detection, while others function to repel or escape attackers. Postattack strategies attempt to remove or destroy the eggs or larvae of parasitoids. In this review we focus on some of the best documented chemical, physiological, morphological, and behavioral characters which protect caterpillars from predators, parasitoids, and pathogens.
... The optical density of the solution was then measured at 760 nm using a known concentration of tannic acid as a standard. These properties are correlated with the performance of herbivorous insects: water and nitrogen contents are positively correlated with insect performance, while carbon and polyphenol contents are negatively correlated (e.g., Sagers 1992;Hartley 1998;Fukui et al. 2001). ...
Article
Seven species of parasitoids and two species of moths emerged from bud galls induced by two species of gall midges (Asteralobia soyogo (Kikuti) and A. sasakii (Monzen)) (Diptera: Cecidomyiidae) on four species of trees of the genus Ilex (I. pedunculosa Miq., I. crenata Thunb., I. chinensis Sims, and I. integra Thunb.) (Aquifoliaceae). Larvae of the moth Rhopobota ustomaculana (Curtis) (Lepidoptera: Tortricidae) bored into bud galls induced by A. soyogo and A. sasakii on I. pedunculosa and I. crenata, respectively. Rhopobota ustomaculana larvae fed on leaves as well as gall tissues of I. pedunculosa, suggesting that R. ustomaculana is a facultative cecidophage. To clarify consequences of gall tissues as a food resource for cecidophagous moths, we compared the chemical properties of galls with those of normal plant tissues (leaves) of I. pedunculosa. Bud galls of I. pedunculosa had higher water content and lower nitrogen, carbon, and polyphenol (a chemical associated with plant insect defenses) contents than leaves. Therefore, bud galls may be a richer food resource for R. ustomaculana larvae because of the higher water content and lower carbon and polyphenol contents, although they are a poorer resource in terms of nitrogen content.
... obs.). Rolling or tying leaves may also increase leaf nutritional quality (Sagers 1992), allow larvae to feed on phototoxic plants (Sandberg & Berenbaum 1989), and protect caterpillars from dislodgment (Loeffler 1996). Additional modifications to the basic structure, such as channels or perforations (Figs. ...
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The majority of larvae in the family Hesperiidae build and inhabit shelters on or near the host plant. A review of hesperiid natural history publications from all regions, in combination with extensive field observations on New World skippers shows that larval shelters fall into at least ten separate categories. The functions, plasticity, and ontogenetic variation of skipper shelters are discussed. Terms useful in shelter description are defined and a classification system for shelter types is suggested. A dichotomous key to these types is provided.
... A number of studies indicate that arthropods occupying leaf shelters have enhanced access to high-quality food resources. The nutritional benefi ts of concealed feeding may result from reduced exposure to light, which can alter tissue quality (e.g., decreased leaf toughness and phenolic concentrations in rolled leaves; Sagers 1992, Oki and Varanda 2000, Fukui et al. 2002 or from the toxic effects (both pre-and post-ingestive) of foliage consumption in the presence of light (Berenbaum 1978;Sandberg and Berenbaum 1989;Champagne et al. 1996). The direct infl uence of foliage manipulation on structural defenses (e.g., lignins and leaf toughness) and other quantitative carbon-based defenses with low turnover or mobility (e.g., polyphenolics; Feeny 1970) is likely to be greatest for shelters constructed with young, expanding foliage, because the light environment in which these tissues develop can affect the accumulation of these compounds (Coley et al. 1985, Dudt and Shure 1994, Ruohomaki et al. 1996, but see Costa and Varanda 2002 for a counterexample). ...
... Finally, the retreats might also interfere with the plants chemical defence against herbivores. One of the documented advantages of the leaf-rolling habit is to prevent the induction of photoactive chemicals by the host plant (Sandberg and Berenbaun, 1989;Sagers, 1992). The phytochemistry of Dipterocarpus tuberculatus is very poorly known (Gibbs, 1974) and until more information is available on the defensive responses of dipterocarps to herbivory, this will remain as an intriguing possibility. ...
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The final- instar larva of Calindoea trifascialisis described and illustrated for the first time, includ- ing chaetotaxy. All instars have paired fleshy lateral protuberances associated with large exocrine glands on the first abdominal segment. When disturbed, the larvae secrete defensive allomones that deter ants. The larvae construct tent-like feeding retreats and skeletonize the leaves of Dipterocar- pus tuberculatus while concealed within the retreat; retreats of increasing size are constructed throughout larval development. When feeding is completed, the final-instar larva constructs a pupation retreat. This leaf roll falls from the plant and is capable of movement prior to pupation. The morphology and larval retreats of an unidentified species of thyridid from Queensland, Austra- lia are also illustrated and discussed in the context of the new information concerning C. trifascia- lis.
... This result suggests that an increase in cellulose does not represent a barrier against insect herbivory. Indeed, there are cases in which leaf-tying insects have been shown to have the ability to reduce the anti-herbivore defences of their host plants (Sagers 1992;Fukui et al. 2002), thus allowing them to consume leaves with high cellulose content or a higher toughness. According to the literature, the main food source for P. arda is L. alpina seeds (Cerda et al. 1982;Carrillo & Cerda 1987). ...
Article
Phytophagous insects choose their feeding resources according to their own requirements in addition to properties of the host plants, such as biomechanical defences. The feeding preferences of the native folivorous insects of the Andean-Patagonian forest (Argentina) have rarely been studied. These environments present a wide diversity and abundance of insects associated with trees of the Nothofagus and Lophozonia (Nothofagaceae) genera, which represent the main tree species of the forests of the southern hemisphere. In particular, Lophozonia alpina and Lophozonia obliqua are of great interest because they have a wide distribution, a high capacity for hybridization and exhibit great phenotypic plasticity. This versatility causes substantial variation in the biomechanical properties of leaves, affecting the feeding preferences of insects. The purpose of this work was to study the food selection behaviour of three leaf-chewing insects (Polydrusus nothofagii, Polydrusus roseaus (Coleoptera: Curculionidae) and Perzelia arda (Lepidoptera: Oecophoridae)) associated with L. alpina and L. obliqua as host plants. Based on their choices, our aim was to determine a preference scale for each insect species and the variables on which these preferences were based. Therefore, we selected trees of L. alpina and L. obliqua, measured several properties such as cellulose content and recorded which leaves were eaten. As a result, we determined that the three species of insects feed on both host plants but prefer the leaves of L. obliqua, with cellulose content being the main determining factor for their decisions. However, in the case of P. arda, there was a positive relationship between cellulose and host plant preference, whereas there was an opposite relationship for the weevils. We conclude that during feeding selection, there are some properties of the leaves that have a more important role than others and that the same property does not exert the same behavioural response in all folivorous insects.
... Shelter builders actively manipulate plant parts of their hosts, which was shown to improve resource quality by lowering physical and chemical plant defenses (Sagers, 1992). Exposed feeders, by contrast, are capable to forage selectively due to their higher mobility. ...
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1. Assemblages of insect herbivores are structured by plant traits such as nutrient content, secondary metabolites, physical traits, and phenology. Many of these traits are phylogenetically conserved, implying a decrease in trait similarity with increasing phylogenetic distance of the host plant taxa. Thus, a metric of phylogenetic distances and relationships can be considered a proxy for phylogenetically conserved plant traits and used to predict variation in herbivorous insect assemblages among co-occurring plant species. 2. Using a Holarctic dataset of exposed-feeding and shelter-building caterpillars, we aimed at showing how phylogenetic relationships among host plants explain compositional changes and characteristics of herbivore assemblages. 3. Our plant–caterpillar network data derived from plot-based samplings at three different continents included >28,000 individual caterpillar–plant interactions. We tested whether increasing phylogenetic distance of the host plants leads to a decrease in caterpillar assemblage overlap. We further investigated to what degree phylogenetic isolation of a host tree species within the local community explains abundance, density, richness, and mean specialization of its associated caterpillar assemblage. 4. The overlap of caterpillar assemblages decreased with increasing phylogenetic distance among the host tree species. Phylogenetic isolation of a host plant within the local plant community was correlated with lower richness and mean specialization of the associated caterpillar assemblages. Phylogenetic isolation had no effect on caterpillar abundance or density. The effects of plant phylogeny were consistent across exposed-feeding and shelter-building caterpillars. 5. Our study reveals that distance metrics obtained from host plant phylogeny are useful predictors to explain compositional turnover among hosts and host-specific variations in richness and mean specialization of associated insect herbivore assemblages in temperate broadleaf forests. As phylogenetic information of plant communities is becoming increasingly available, further large-scale studies are needed to investigate to what degree plant phylogeny structures herbivore as- semblages in other biomes and ecosystems.
... Therefore, changes in plant biomass were often tightly linked with concomitant shifts in host leaf traits, confounding investigators' ability to isolate the effects of plant quantity and quality on the richness of arthropod communities (Wimp & Murphy, 2021). Second, many previous studies examined the effects of plant production and/or host plant traits only on a subset of taxonomic or functional groups (Peeters et al., 2007;Sagers, 1992). Nonetheless, multiple trophic groups of arthropods such as herbivores and predators are mainly regulated by vegetation and are critical for ecosystem function as pollinators and pest control (Joern & Laws, 2013). ...
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Plant quantity and quality can independently affect the diversity of the entire arthropod communities and multiple arthropod taxa in grassland ecosystems. However, it remains unclear how these effects on arthropod taxa at one trophic level propagate through food web to influence the diversity of higher trophic levels. We performed a monoculture experiment with 15 herbaceous species in the Inner Mongolian grassland to investigate how natural variations in plant productivity and host leaf traits affect herbivore taxon richness, which in turn affects predator taxon richness. For herbivores, plant productivity indirectly promoted herbivore taxon richness by increasing herbivore biomass, which was attributed to the increases in the richness of dominant sucking herbivores and endophytes with high food requirements. However, the high plant quality indicator (e.g. high leaf protein, phosphorus and water contents, and high leaf protein to carbohydrate ratio) directly increased, whereas the low plant quality indicator (e.g. high leaf lignin content) directly decreased herbivore taxon richness. Taxon richness of chewing and sucking herbivores with specific feeding modes (tearing or sucking mouthparts) showed strong positive responses to increasing plant quality. For predators, herbivore taxon richness, rather than herbivore biomass, mainly mediated the positive effects of plant productivity and the high plant quality indicator, but the negative effect of the low plant quality indicator, on predator taxon richness. At the feeding guild level, the taxon richness of parasitoids, other predators and spiders exhibited positive responses to different herbivores, which was attributed to their different diet preferences. Predator diversity could be promoted by prey partitioning among predator guilds facilitating species coexistence. At the family level, the taxon richness of most predator families was positively correlated with that of more than one herbivore family, suggesting that high predator diversity may be caused by balanced diets owing to high prey diversity. Synthesis. Natural variations in plant quantity and quality can substantially affect the diversity of herbivores and cascade up the food web to affect predators. Specificity and mechanisms of feeding have a large impact on the responses of arthropod guilds at each trophic level.
... Several species of Lepidoptera larvae use substrate-borne vibrations in territorial contests over a resource, such as a feeding site or leaf shelter. Leaf shelters are commonly observed in larval Lepidoptera, providing benefits such as protection from enemies, improved microclimate, and feeding sites (e.g., Hunter and Willmer 1989;Sagers 1992;Berenbaum et al. 1993;Eubanks et al. 1997;Fukui 2001;Lill and Marquis 2007;Abarca et al. 2014). Given the benefits and energetic costs associated with shelters, caterpillars exhibit competition to defend them from intruders (Sigmon 2015). ...
Chapter
Over the past few decades, scientists have discovered that insects live in complex vibratory environments that they both create and exploit for their survival. Yet, this growing body of literature is focused predominantly on adults, leaving a significant knowledge gap on vibratory sensing and communication in juveniles. There is burgeoning yet scattered evidence indicating that juveniles use vibrations in a wide range of contexts. In this chapter, we endeavored to synthesize the literature on vibratory sensing and communication in caterpillars (larval Lepidoptera). Caterpillars are obligate substrate-bound insects that are exposed to a wide range of vibrations generated by biotic and abiotic sources. This chapter shows that caterpillars across diverse taxonomic groups use vibrations in a variety of contexts, including predator detection and risk assessment, detection of abiotic events such as wind and rain, recruitment and spacing, territorial defense, and maintaining relationships with ants. While it is clear that many caterpillars are capable of detecting and discriminating between vibration sources, vibration receptors have not yet been identified in caterpillars, or any other holometabolous insect larvae. We discuss potential vibration receptors in larvae based on our knowledge of adult receptors and larval morphology and physiology. The vibratory landscapes of juvenile insects, including eggs, larvae, nymphs, and pupae, remain poorly understood. Yet, most juveniles are substrate-bound, and therefore, it is likely that vibrations play an important role in their survival. We recommend further investigations on vibratory sensing and communication in juveniles, from documenting the species using vibrations to discovering the sensory organs involved in detecting and processing vibratory information.
... One place to look to identify these traits is the list of proposed adaptive reasons caterpillars build constructs in the first place, as those benefits might also accrue to colonists. The main proposed adaptive reasons for building a construct on a plant are amelioration of a harsh environment (Connor andTaverner 1997, Fukui 2001), including protection against UV radiation (Connor and Taverner 1997;Vieira and Romero 2013), improved host plant quality (Sagers 1992), reduced competition (Green et al. 1998), and escape from natural enemies (e.g., Ito andHigashi 1991, Sendoya andOliveira 2017;Baer and Marquis 2020) and pathogens (Green et al. 1998), including easier access to leaves than when hiding off plants to escape predation (Minno 1994). Each might be relevant to colonists. ...
Chapter
Construct (“shelter”)-building caterpillars are those that build structures on or in plants. When these constructs are colonized by other arthropods, the caterpillars act as ecosystem engineers. Here we describe the known and predicted impacts of caterpillars on their associated arthropod faunas, and how such impacts might change with increasing influence of humans on the global ecosystem. First, we provide evidence that the presence of constructs built by caterpillars influences community composition of arthropods on plants, encourages the initial invasion and abundance of exotic arthropod species, and influences the amount of damage inflicted on the plant. Second, we describe a qualitative model of the influence of construct traits (openness, presence of frass, and volume) on colonization by other arthropods. We predict that constructs with one or more openings, those that contain frass, and those with larger internal volumes will attract more colonists. Third, available data suggest increasing drought and temperature will reduce the abundance of constructs and increase the use of those constructs by predators, while increasing rainfall and higher predation will increase the use of constructs by herbivorous insects. Altogether, studies are needed that quantify current environmental impacts on both construct building by caterpillars and the use of those constructs by other arthropods. Such studies will necessitate a tritrophic approach, i.e., understanding the role of host plant variation, the responses of caterpillars and associated arthropods to each other and to the host plant, and the role of natural enemies in shaping the use of caterpillar constructs.KeywordsLeaf sheltersSilkPlant defensePlant architecturePredationEcosystem engineeringCommensalismParasitismDroughtRainfallFrassInvasive speciesPhylogenyStem boringLeaf tiesLeaf rollsGallsClimate changeFunctional traitsExtrafloral nectariesLeaf minesArthropod community structureLeaf qualityTritrophic interactionsNatural history
... Plant material of each Passiflora species was randomly collected from five leaves that were healthy and of the relatively same age. Third instar caterpillars fasted for 6 hours before the plant choice experiment began (Sagers 1992) when they were gently placed at the centre of each Petri dish using a fine camel-hair brush. Petri dishes inside the BODs rotated every five hours to avoid any ambient influence on larval plant choice. ...
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Host plant quality is determinant for herbivorous insects performance and survival. While on larval stages, insects select their host plants based on factors such as leaf nitrogen and water content, digestibility, and defences. Of great interest is the coevolutionary relationship between the Heliconiini insects and the Passiflora plants. In this study we experimentally evaluated Dryas iulia (Nymphalidae) larval preference to four sympatric Passiflora (Passifloraceae) and subsequently, the larval performance on the two most consumed species. We tested the hypothesis that D. iulia larvae prefer the Passiflora species with higher nutritional quality and lower defence, which supports the greatest larval performance. Dryas iulia larvae preferred P. misera (60.5% leaf consumption) over P. pohlii (28.9%), P. suberosa (15.5%), and P. edulis (not consumed). Passiflora misera presented the highest N concentration, third in water content, second in tector trichomes, and no glandular trichomes (only P. suberosa did). Nitrogen best explained D. iulia larvae leaf consumption; which further explains the greatest larval performance in P. misera than in P. suberosa: i.e. higher survival (23.1%), conversion efficiency of ingested food (32.8%), relative growth rate (14.8%), heavier pupae (15.2%), and lower relative consumption rate (13.8%). This study creates the opportunity to further investigate the Heliconiini-Passiflora system and showed that D. iulia larvae can assess and choose the host plant (even among sympatric species) that supports the greatest performance.
... En contraste, la población ruderal obtuvo el mayor porcentaje de componentes que dan estructura, soporte y protección física a las plantas: celulosa, lignina y sílice (Tabla 4). De modo que, hojas con gran cantidad de estos elementos sugieren una mayor dureza, pues conforman tanto las paredes celulares como los tricomas, y junto con el bajo contenido de compuestos nitrogenados, representan un sustrato poco nutritivo, menos digestible e indeseable para el consumo humano y para los herbívoros (Damman 1987, Sagers 1992, Gonzáles et al. 2001, Lill & Marquis 2001. ...
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Antecedentes: La selección humana favorece rasgos de interés, pero también implica cambios en otros correlacionados. En especies con domesticación incipiente, la variación en la intensidad de selección genera una diferenciación entre sus poblaciones que permite analizar estos cambios. Pregunta: ¿Cómo son los cambios entre rasgos seleccionados y correlacionados en poblaciones con diferente forma de manejo de A. cristata? Especie de estudio: Anoda cristata es una especie con domesticación incipiente, aprovechada como quelite en la región centro-sur de México. Sitio y años de estudio: Región Montaña de Guerrero entre 2008 y 2009. Métodos: Se estableció un jardín común con plantas de tres poblaciones: arvense fomentada, arvense agreste y ruderal. Se realizaron cuatro censos para registrar cambios en los rasgos seleccionados y correlacionados. Resultados: La mayoría de las correlaciones fenotípicas entre rasgos a nivel de especie fueron significativas. Para las poblaciones arvenses existen trade-offs entre área foliar-densidad de tricomas y reproducción. Las estructuras sexuales reproductivas aparecieron primero en la población ruderal. La especie muestra una tendencia de resistencia a la herbivoría a través de la cantidad de tricomas. La población arvense agreste tiene una estrategia de tolerancia ante la defoliación. El análisis bromatológico indica que existe variación en la composición nutrimental. Conclusión: Los resultados sugieren que la intensidad de selección ha generado divergencia entre poblaciones. Las correlaciones y los síndromes de domesticación observados parecen estar asociados con compromisos de asignación de recursos, a través de las diferentes formas de manejo e intensidades de selección que ejerce la gente.
... The secretory products of the salivary glands of Lepidoptera include silk and watery saliva. Silk serves different functions including dispersion and escape from natural enemies (ballooning) [10], protection and improvement of food quality (leaf rolling) [11], and communication [12]. Recently, it has been recognized that watery saliva also plays an important role in Lepidoptera-host plant interactions. ...
Article
Lepidoptera herbivores deposit copious amounts of saliva when feeding. Their saliva is produced by the paired mandibular and labial glands and evidence indicates that it may play an important role in allowing an herbivore to establish on its host plant. Genomic studies of Lepidoptera saliva are beginning to reveal the role of saliva in herbivory. Molecules involved in digestion, detoxification, immunity, defense against plant secondary chemicals, chemoreception, etc. have been identified using high throughput genomic tools. These genomic tools have also revealed changes that occur in Lepidoptera saliva when caterpillars feed on different host plants. However, there are other factors either biotic or abiotic (e.g. larval stage, larval health, temperature, water stress, etc.) that might also affect its composition. Though further functional and ecological studies are still necessary to fully understand the role of Lepidoptera saliva on herbivory, here we review current trends.
... Shelter builders actively manipulate plant parts of their hosts, which was shown to improve resource quality by lowering physical and chemical plant defenses (Sagers, 1992). Exposed feeders, by contrast, are capable to forage selectively due to their higher mobility. ...
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1. Assemblages of insect herbivores are structured by plant traits such as nutrient content, secondary metabolites, physical traits, and phenology.
... While we would expect that long-term associations between small herbivores and their algal hosts would accelerate the deterioration of plant tissue inside their domiciles [28], extended occupancy may provoke specific responses by the alga [29]. Accordingly, predicting damage by mesograzers on large kelps requires an understanding of the sequence of domicile development following infestation of the host alga, the structure of the grazer assemblages inside the domiciles, as well as the algal responses to damage. ...
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Large herbivores such as sea urchins and fish consume a high proportion of benthic primary production and frequently control the biomass of marine macrophytes. By contrast, small mesograzers, including gastropods and peracarid crustaceans, are abundant on seaweeds but have low per capita feeding rates and their impacts on marine macrophytes are difficult to predict. To quantify how mesograzers can affect macrophytes, we examined feeding damage by the herbivorous amphipods Sunamphitoe lessoniophila and Bircenna sp., which construct burrows in the stipes of subtidal individuals of the kelp Lessonia berteroana in northern-central Chile, southeast Pacific. Infested stipes showed a characteristic sequence of progressive tissue degeneration. The composition of the amphipod assemblages inside the burrows varied between the different stages of infestation of the burrows. Aggregations of grazers within burrows and microhabitat preference of the amphipods result in localized feeding, leading to stipe breakage and loss of substantial algal biomass. The estimated loss of biomass of single stipes varied between 1 and 77%. For the local kelp population, the amphipods caused an estimated loss of biomass of 24-44%. Consequently, small herbivores can cause considerable damage to large kelp species if their feeding activity is concentrated on structurally valuable algal tissue.
... For tropical understory plants, variation in light availability is one of the most important determinants of changes in phytochemical profiles, and many secondary compounds increase in concentration with greater light availability (Dyer & Palmer 2004;Dyer et al. 2004;Richards et al. 2015;Glassmire et al. 2016). Furthermore, light heterogeneity directly affects herbivore reproduction (Kuhlmann & M€ uller 2010a,b) and feeding behaviour (Sagers 1992) as well as overall plant resistance to herbivores (Mazza et al. 2000). These effects can be enhanced when changes in light affect photoactive metabolites, such as furanocoumarins and chromenes, which can be toxic to herbivores (Berenbaum 1978). ...
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Phytochemical traits are a key component of plant defense theory. Chemical ecology has been biased towards studying effects of individual metabolites even though effective plant defenses are comprised of diverse mixtures of metabolites. We tested the phytochemical landscape hypothesis, positing that trophic interactions are contingent upon their spatial location across a phytochemically diverse landscape. Specifically, intraspecific phytochemical changes associated with vertical strata in forests were hypothesised to affect herbivore communities of the neotropical shrub Piper kelleyi Tepe (Piperaceae). Using a field experiment, we found that phytochemical diversity increased with canopy height, and higher levels of phytochemical diversity located near the canopy were characterised by tradeoffs between photoactive and non‐photoactive biosynthetic pathways. For understory plants closer to the ground, phytochemical diversity increased as direct light transmittance decreased, and these plants were characterised by up to 37% reductions in herbivory. Our results suggest that intraspecific phytochemical diversity structures herbivore communities across the landscape, affecting total herbivory.
... For example, a carnivorous flatworm (Turbellaria: Seriata) was observed entering a larval tunnel through the webbing, potentially hunting the large larva inside. However, structures built by other invertebrates were found to increase the quality of host tissue, reduce desiccation and prevent dislodgment during feeding (Sagers 1992, Loeffler 1996, Larsson et al. 1997. In particular, prey species often choose to feed in concealed locations so their movements do not attract predators (Danks 2002, Abarca and Boege 2011, Greeney et al. 2012. ...
Article
Prey are often difficult to locate visually, which may help them avoid predators. However, an animal's appearance might also evolve in response to the abiotic environment. Here, we investigate the processes that determine the appearance of silk webbing built by New Zealand's largest endemic moth Aenetus virescens (Lepidoptera: Hepialidae), whose larvae burrow into the trunks of native trees. Larvae cover tunnel entrances with silk webbing, detritus and epiphytes, giving them a similar appearance to tree bark. First, we conducted spectral analyses of webbing and background bark in avian tetrahedral colour space to test whether webbing made larvae less visible to predatory parrots. Next, we manipulated the spectral contrast of webbing and background bark and assessed its effect on predation by parrots for over 2 years. Last, we measured the effect of webbing on tunnel temperatures and quantified how temperatures within tunnels affected larval growth. Results indicate that webbing made larvae less visible to predatory parrots. However, webbing contrast to background bark did not affect predation by parrots. Instead, webbing increased temperatures within tunnels and facilitated more rapid larval growth. Overall results indicate that the appearance of organisms that are difficult to locate visually may not always result from selection by predators. This article is protected by copyright. All rights reserved.
Chapter
Current trends in population growth suggest that global food production is unlikely to meet future demands under projected climate change scenarios unless the pace of plant improvement is accelerated. Plant production is facing many challenges due to changing environmental conditions and the growing demand for new plant-derived materials. These challenges come at a time when plant science is making significant progress in understanding the basic processes of plant growth and development. Major abiotic stresses like drought, heat, cold and salinity often cause a range of morphological, physiological, biochemical , and molecular changes affecting plant growth, development, and productivity; so sustainable food production poses a serious challenge to much of the world, particularly in emerging countries. This underscores the urgent need to find better ways to translate new advances in plant science into concrete successes in agricultural production. In order to overcome the negative effects of abiotic stress and to maintain food security in the face of these challenges, new, improved, and resilient plant varieties, contemporary breeding techniques, and a deep understanding of the mechanisms for offsetting harmful climate change are undoubtedly necessary. In this context, Improvement of Plant Production in the Era of Climate Change is a guide to the most advanced techniques that help in understanding plant response to abiotic stress, leading to new horizons and the strategy for the current translation studies application to overall solution to create a powerful production and crop improvement in such an adverse environment. FEATURES • Provides a state-of-the-art description of the physiological, biochemical, and molecular-level understanding of abiotic stress in plants. • Courses taught in universities from basics to advanced level in field of plant physiology, molecular genetics, and bioinformatics will use this book. • Focuses on climatic extremes and their management for plant protection and production, which is great threat to future generation and food security. • Understanding of new techniques pointed out in this book will open the possibility of genetic engineering in crop plants with the concomitant improved stress tolerance. • Addressing factors that are threatening future food production and providing potential solutions to these factors. • Written by a diverse group of internationally famed scholars, this book adds new horizons in the field of abiotic stress tolerance.
Chapter
Legumes are grown in more than 120 countries across all the continents. 90% of the global production of legume are produced in small group of countries such as India, Turkey, Pakistan, Bangladesh, Nepal, Iran, Mexico, Myanmar, Ethiopia, Australia, Spain, Canada, Syria, Morocco and Egypt. Legume are vegetarian sources of proteins and are an integral part of daily diet in several forms universally. Legume crops are great worth crops and play a dynamic role in crop diversification and economic sustainability of legume farming systems in dry areas. Most of the legume crops are grown under rainfed agroecosystem with poor level of input use which has resulted in low production. In this chapter we focus on (i) ecology and adaptation of legumes crop (ii)physiological responses of grain legumes to stress environments (ii) agronomic approaches to stress management.
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Caterpillars of Cerconota achatina (Zeller, 1855) feed on lhe leaves of Byrsonima Rich in cerrado (savanna) of Brasília (Distrito Federal). They build shelters by tying leaves together with silk and frass. Within the leaf shelters the caterpillars form a tube of silk in which they feed. develop and pupate. In the laboratory the pupal stage is 14,4 days (sd=8,6: n=46). It was not possible to determine the age or numbers of instars of caterpillars in the wild. Of 93 caterpillars collected. 60% were feeding on B. cocclohifolia (Spr.) Kunth, 25% on B. crassa Nied. and 15% on B. verbascifolia [Rich. ex] Adr. & Juss. These numbers suggest a preference for B. coccolobifolia. Caterpillars of all size were found in every month of the year which suggest ovelapping generations and multivoltinism. They did not show a preference for new foliage and 75% of them were found on host-plants on wich less than 25% of leaves were young.
Chapter
Maintenance of nutritional quality in crops is vital to provide quality human food as well as animal feed under stressful environmental conditions. The aim of the present review is to assess the effects of heat stress on qualitative traits of field crops. Environmental stresses significantly affect the nutritional properties and quality traits of crops through physiological and biochemical alterations occurring at different growth stages. Among environmental stresses, heat stress is the most pertinent especially under the current changing climate. Heat stress generally affects the grain quality depending upon crop cultivars. Several studies have proposed different management approaches for enhancing the grain quality of crops under heat stress environments. For managing heat stress, the grain quality may serve as a critical parameter for discriminating the crop genotypes having a higher potential to grow under heat stress conditions. Among heat stress mitigating strategies, seed priming and application of osmoprotectants, organic acids, and other antioxidants have the potential to increase the grain quality of many field crops.
Article
Many caterpillars construct shelters by folding leaves and feeding from within. Many shelter-constructing species suffer high rates of parasitism as larvae or pupae. In spite of the likely significance, the effects of these shelters on the survival of pupae and the trade-off between feeding and constructing shelters have attracted little experimental attention. In both field and laboratory experiments, fern-feeding caterpillars [Herpetogramma theseusalis (Walker) (Lepidoptera: Crambidae)] invested heavily in shelters, losing weight and significantly delaying pupation rather than feeding or pupating in exposed locations. Experimentally thinning the walls of shelters in the field doubled the parasitism rate. Parasitism of pupae exceeded predation by an order of magnitude or more in both seasons of this study. Caterpillars constructed similarly sized shelters regardless of availability of fern fronds, resulting in incomplete shelters on especially small fronds, putting pupae at increased risk of parasitism. We suggest that similar interactions are common and merit more attention.
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Insect-food-plant associations have been shown to be influenced by the chemical, physical and nutritional characteristics of plants. We suggest that among insect larvae that use leaf material to build shelters, food-plant use may be constrained by differences in host leaf structure, illuminating a rarely investigated aspect of insect-plant interactions. To explore the potential effects of leaf structure on shelter building behavior in a Neotropical skipper butterfly, we investigated shelter building patterns on two congeneric food-plants that varied in leaf thickness. Shelter architecture varied significantly between hosts, with thicker leaves requiring longer cuts to construct shelters. The relationship between shelter building behavior and leaf structure is discussed in relation to selection pressures on larval shelters and food-plant choice.
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I have analyzed seedlings the growth of Cedrela odorata (Meliaceae) comparing those that grow in a gap of 50 x 25 m with an area of natural regeneration of the same size. I registered the growth of the seedlings during 450 days determining that the proportion of growth in height is higher in seedlings in the gap. Other variables as to be number of branches, length of branches, and leaf area also presented significative higher values in seedlings in the gap than those in the area in process of regeneration. Though, these results are preliminaries for the comparison of the growth of C. odorata due I realized only in one place of study. The work is a contribution to the knowledge of some characteristics of the growth of this species in a Bolivian montane humid forest where has existed on exploitation due to its high economic value.
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Plant leaves are utilized by various shelter-building insects. Some insects are constrained in their host plant use by the difficulty in modifying leaves into shelters, while others may cope through different construction methods. Here, we show that the leaf-rolling weevil Phymatapoderus pavens (Coleoptera, Attelabidae) constructs two types of leaf rolⅼ on Boehmeria silvestrii (Urticaceae) according to the shape of the leaf. Female weevils make leaf rolls using the whole leaf when the leaf is small and weakly lobed, whereas they use only one of the lateral lobes when the leaf is large and deeply lobed. Both types were found within a population and each functioned as a site for the growth of offspring. Weevils bite the leaf veins differently when constructing each of these leaf rolls, suggesting that the leaf roll type is determined before the leaf is rolled. Compared with another leaf-rolling weevil species, Apoderus praecellens (Coleoptera, Attelabidae), which makes leaf rolls on similarly lobed leaves of Isodon umbrosus var. hakusanensis (Lamiaceae), P. pavens utilizes a wider range of leaf shapes because these weevils are able to construct leaf rolls on the lateral lobes of the leaves. Differences in leaf-rolling behaviour, leaf venation pattern, and the relative size of weevils and leaves are factors affecting the results.
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Weevils are one of the dominant taxonomic groups in terrestrial ecosystem, diversifying to more than 60,000 described species. Although the most derived weevil group, Curculionidae, has adapted to and is utilising almost all parts of plant, basal groups show relatively limited larval feeding habits, such as pollen, seed, or fungus-infested wood feeders. Thus, it seems that ancestral larval infesting plant parts of weevils were restricted to N-rich, induced-defenseless, and temporal resources. Among the basal weevils, Attelabidae obtained such resources for their larvae by evolving unique maternal plant-manipulations: attelabid females manipulate specific young plant tissues of their host plants in a species-specific manner, e.g. cutting a shoot or a leaf, rolling a leaf, or constructing sophisticated wrapped leaf rolls, before and after oviposition presumably to secure the survivorship of eggs or larvae. Molecular phylogenetic analyses based on the nuclear 18S and 28S ribosomal DNA and the mitochondrial COI genes indicated that the maternal plant-cutting behaviour originated in a common ancestor of Attelabidae, but was subsequently lost in the several lineages. The monophyly was recovered for the subfamily Attelabinae with high support, but not for the subfamily Rhynchitinae. By employing maximum likelihood-based ancestral state reconstructions, the larval leaf-blade feeding was inferred to have evolved from the boring of cut shoots/petioles. Moreover, the maternal leaf-rolling behaviour might have originated independently in the Attelabinae, Byctiscini, and also in several Deporaini lineages. Since the sophisticated behaviour of Attelabinae, i.e. constructing wrapped leaf rolls, have originated only once and not been lost in the lineage, these complex and innovative behaviours may have contributed to the success of the lineage diversification.
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To test the resource availability hypothesis we compared the leaf content in carbon-and nitrogen-based allelochemicals between heavily and lightly shaded plants of Adenostyles alliariae and A. alpina (Asteraceae). Both species contain pyrrolizidine alkaloids (PAs) but only A. alpina also contains sesquiterpenes in its leaves. In A. alliariae we found no difference in leaf alkaloid content between the two treatments. In A. alpina alkaloid content tended to be higher in the heavily shaded treatment. One sesquiterpene, cacalol-trimer, was present in higher concentrations in the heavily shaded leaves, whereas concentrations of the other sesquiterpene, cacalol, were reduced. Under light-(carbon)limiting conditions the resource availability hypothesis predicts an increase in nitrogen-based defenses and a decrease in carbon-based defenses; these predictions were met in A. alpina with the exception of the carbon-based cacalol-trimer. Leaf nitrogen content was strongly increased in heavily shaded plants of both species. We found significant genetic variation in PA content in one out of four populations of A. alliariae. For PA content in A. alpina we found significant genetic variation in two out of four populations and for cacalol content in three populations. We therefore conclude that selection on allelochemical content is possible in some populations, whereas in other populations evolutionary processes must have fixed the level of allelochemical content in the two species.
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The eastern foothills of the Cascade Range in Washington State, United States of America are west of the State's major fruit-producing region. Alders (Alnus Hill (Betulaceae)), an important floristic component of riparian communities in the Cascade Range foothills, were surveyed for leafrolling caterpillars (Lepidoptera: Tortricidae) that might serve as alternate hosts for parasitoids of orchard pest leafrollers, particularly the nonnative wasp Colpoclypeus florus (Walker) (Hymenoptera: Eulophidae). Tortricid leafrollers were abundant on alder, but reared parasitoids did not include C. florus. Survey results also revealed that rolled leaves were secondarily colonised by a wide variety of predatory and phytophagous arthropods. Rolled leaves were almost 10-fold more likely to be occupied by predatory arthropods than adjacent, roll-free leaves. Phytophagous thrips and mites showed a similar preference for rolled leaves. The most abundant predaceous arthropods in the leafrolls were Anthocoris antevolens White (Hemiptera: Anthocoridae), found in 4.4% of leafrolls, and the spider Clubiona pacifica Banks (Araneae: Clubionidae), found in 8.3% of leafrolls. Both species, and several other predatory insect and spider species found in the rolled leaves, also occur in eastern Washington orchards where they contribute to biological control. Because of its frequent colonisation by beneficial arthropods, alder may prove useful in conservation biological control programs.
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Introduction Much of the emphasis in studying mutualisms has been placed on defining the strength of these associations and the conditions that cause their collapse (Bronstein 1994, 1998). Yet, very few studies of aphid-ant mutualisms have linked the importance of host plant traits with the establishment and persistence of these mutualisms. Aphid performance, as well as the quality and quantity of their honeydew, may be affected by differences in host plant genetics or through environmentally induced effects on host plant quality. Differences among host plants that influence the attractiveness of aphids to tending ants can therefore alter the nature and strength of this association. The importance of host plants in determining the establishment and persistence of aphid-ant mutualisms could have consequences for biodiversity if these aphid-ant mutualisms play an important role in the structure and diversity of ecological communities. The idea that mutualisms are important components of ecological communities arose 130 years ago (van Beneden 1875, French paper cited in Boucher 1985). However, much of the theoretical and empirical work in ecology for the past 70 years has supported the view that antagonistic interactions among species are more important than positive interactions in determining community organization. Yet, empirical data on an array of different mutualisms has shown that they can be important to community structure and diversity. © Cambridge University Press 2007 and Cambridge University Press, 2009.
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Altica deserticola (Coleoptera: Chrysomelidae) is a monophagous insect that feeds on, and is thus a harmful pest of, liquorice. Both adults and larvae feed on leaves, causing serious damage to leaf blades. It will even lead to the extinction of liquorice, resulting in significant economic losses. Leaf-disc tests were used to determine the feeding preference of A. deserticola on leaves of Glycyrrhiza uralensis and G. glabra and explore the underlying mechanism of liquorice feeding resistance to A. deserticola by comparing leaf hardness and thickness, cuticle thickness, and nitrogen and tannin content in the two plants. The results showed that larvae and adults have the same feeding preferences, i.e., both preferably fed on G. uralensis, indicating a higher resistance in this species. The hardness, thickness, and the thickness of the stratum corneum of the leaves of G. glabra were significantly greater than those of G. uralensis. Nitrogen content was higher in G. uralensis, while total tannin, tannic acid, and catechin content were higher in G. glabra. The thick cuticle and hard texture of G. glabra leaves may be an important physical trait for effectively resisting A. deserticola feeding, while high tannin and low nitrogen content may also be important.
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Damage to leaves by herbivores can have a significant and extensive impact on growth and reproduction of plants (Marquis, 1984, 1992a, b; Marquis & Braker, 1993), which in turn can influence competitive outcomes and community composition (Janzen, 1970; Dirzo, 1984; Clark & Clark, 1985; Dirzo & Miranda, 1991). In tropical forests, approximately 11% of the annual leaf area produced is consumed by herbivores and pathogens (Coley & Aide, 1991), a resource loss equivalent to investments in reproduction (Bazzaz et al., 1987). This loss would be substantially higher except for the fact that plants allocate considerable resources to physical, chemical, and phenological defenses. Most of our understanding of the costs and benefits of defenses and of the interplay between defenses and herbivores is based on research on mature leaves. However, young expanding leaves are the most vulnerable stage during the life of a leaf. In tropical shade-tolerant species of plants, expanding leaves suffer 5–100 times the rates of damage from pathogens and herbivores as mature leaves (Coley & Aide, 1991). Seventy percent of the lifetime damage can occur during this small window of vulnerability. Many leaf developmental traits may therefore be the result of selection by herbivores and pathogens.
Article
Herbivorous insects rarely directly compete over food resources, except in the case of concealed feeders when the food source also serves as shelter and territory. The objective of this study was to characterize the competitive behaviors of four common, co-occurring caterpillar species that tie together overlapping leaves on white oak – Psilocorsis quercicella (Oecophoridae), P. cryptolechiella, P. reflexella, and Pseudotelphusa quercinigracella (Gelechiidae). Artificial leaf ties were created by clipping a piece of transparency paper to a white oak leaf. An ‘occupant’ caterpillar was allowed to build a shelter between the transparency paper and leaf, after which an ‘intruder’ caterpillar was introduced into the leaf tie. Caterpillars were observed pushing and hitting one another to gain or maintain access to the shelter. The occupant caterpillar maintained possession of the shelter in 52 % of the interactions, the intruder usurped the shelter from the occupant in 24 % of the interactions, and the caterpillars shared the shelter in 24 % of the interactions. The four species examined differed significantly in their behavior toward other caterpillars, and ordered most to least aggressive are P. reflexella, P. cryptolechiella, P. quercicella, and Pse. quercinigracella. There were also behavioral differences within and between species when acting as an occupant or an intruder. Psilocorsis cryptolechiella was more aggressive and Pse. quercinigracella was less aggressive when defending a shelter than when attempting to usurp a shelter. It was also found that the four focal caterpillar species, when collected from naturally colonized leaf ties, co-occur significantly less often than expected when compared to a null model. It appears that direct competition for shelters that serve as a territory as well as a food source is frequent and influences the composition of the leaf-tying caterpillar community.
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Shelter building by larvae of Phycita diaphana Staudinger, 1870 (Lepidoptera Pyralidae) using Ricinus communis L. in arid zone. In July 2017, in southeastern Tunisia, larvae of Phycita diaphana were observed on seedlings of castor bean. Infested pointed lobes of the leaves are characterized by the presence of shelters or nests ranging from one to six shelters per leaf. The shelter area ranged from 1.01 to 28.27 cm 2. In each shelter, we found from one to nine larvae. We conclude that Ph. diaphana spends the whole larval stage protected without changing its feeding habits. The leaf roll may reduce leaf toughness and lower levels of plant defensive chemicals, and hence provides a more easily and more safely eaten food. Larvae of Ph. diaphana use the pointed lobe to build its shelter. As Castor bean is used in several fields of economy, mainly the production of biodiesel fuel, the monitoring of this pest will be important and interesting. Thereby, studying the life cycle of pests constitute a significant element of phytosanitary control.
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