Natal origin affects host preference and larval performance relationships in a tritrophic system (original) (raw)
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Insects allocate eggs adaptively across their native host plants
Arthropod-Plant Interactions, 2019
Finding plants for their eggs is the only parental care shown by many winged insects. Hatched juveniles often feed on one individual plant until gaining the power of flight as adults. Females are therefore predicted to lay more eggs on plants supporting high offspring survival. Many experiments comparing egg-laying and offspring survival across plant species refute this, leading to alternative concepts including 'enemy free space', 'optimal bad motherhood' and 'neural constraints'. Whether tested plants have the same geographic origin as the insect is often overlooked. Using 178 oviposition-performance studies, we found when insects and plants share a native range, 83% of insect species associated their eggs with plants conferring highest offspring survival. This was broadly true across insect taxa and for generalists and specialists. Only 57% did so with non-native plants. That females are attracted to hosts with high offspring survival is a well-supported theory that does not necessarily apply to exotic host plants.
Oecologia, 2012
Insect preferences for particular plant species might be subjected to trade-oVs among several selective forces. Here, we evaluated, through laboratory and Weld experiments, the feeding and ovipositing preferences of the polyphagous leafminer Liriomyza huidobrensis (Diptera: Agromyzidae) in relation to adult and oVspring performance and enemy-free space. Female leafminers preferred laying their eggs on Vicia faba (Fabaceae) over Beta vulgaris var. cicla (Chenopodiaceae), in both laboratory and Weld choice experiments, although no oviposition preference was observed in no-choice tests. Females fed more often on B. v. var. cicla (no-choice test) or showed no feeding preference (choice test), even when their realized fecundity was remarkably higher on V. faba. OVspring developed faster, tended to survive better, and attained bigger adult size on the preferred host plant. Also, a Weld experiment showed higher overall parasitism rates for leafminers developing on B. v. var. cicla, with a nonsigniWcant similar tendency in Weld surveys. According to these results, host plant selection by L. huidobrensis appears to be driven mainly by variation in host quality. Moreover, the consistent oviposition choices for the best host and the labile feeding preferences observed here, suggest that host plant selection might be driven by maximization of oVspring Wtness even without a conXict of interest between parents and oVspring. Overall, these results highlight the complexity of decisions performed by phytophagous insects regarding their host plants, and the importance of simultaneous evaluation of the various driving forces involved, in order to unravel the adaptive signiWcance of female choices.
The induction of larval resource preference in heterogeneous habitats
Ecological Entomology, 2018
Animals often have to evaluate and choose between multiple food sources in their habitat, and these potentially complex decisions can have a large impact on their fitness. Among other factors, previous experience with an alternative resource can significantly increase subsequent preference for the resource ("induction of preference"). Such induction of resource preference is particularly relevant in spatially or temporally heterogeneous habitats. Although most mobile species-especially generalists-probably frequently encounter habitat heterogeneity, the impact of preference induction on individual behaviour and fitness in heterogeneous habitats is poorly understood. We analysed larval preference induction in wheat-adapted generalist red flour beetles (Tribolium castaneum) under three types of habitat heterogeneity. We first analysed the induction of larval preference for novel resources (other cereal flours) under temporal heterogeneity, exposing larvae to new resources during development. We found that larvae preferred a new resource if they experienced it recently, but that the magnitude of induction varied across resources. Interestingly, we also observed specific induction for a homogenous mix of wheat and a novel resource, with larvae preferring the mix over either pure resource. To analyse induction under spatial heterogeneity, we placed beetle eggs in one of two alternative resource patches and tested the preference of emerged larvae. Unexpectedly, hatching into a novel resource did not always induce preference. Finally, we found that induction of preference for new resources could be maladaptive for larval development. Together, our work demonstrates that experience-based plasticity of larval resource choice may strongly impact larval preference and fitness in heterogeneous habitats.
Insect Science, 2013
In most phytophagous insects, the larval diet strongly affects future fitness and in species that do not feed on plant parts as adults, larval diet is the main source of nitrogen. In many of these insect-host plant systems, the immature larvae are considered to be fully dependent on the choice of the mothers, who, in turn, possess a highly developed host recognition system. This circumstance allows for a potential mother-offspring conflict, resulting in the female maximizing her fecundity at the expense of larval performance on suboptimal hosts. In two experiments, we aimed to investigate this relationship in the polyphagous comma butterfly, Polygonia c-album, by comparing the relative acceptance of low-and medium-ranked hosts between females and neonate larvae both within individuals between life stages, and between mothers and their offspring. The study shows a variation between females in oviposition acceptance of low-ranked hosts, and that the degree of acceptance in the mothers correlates with the probability of acceptance of the same host in the larvae. We also found a negative relationship between stages within individuals as there was a higher acceptance of lower ranked hosts in females who had abandoned said host as a larva. Notably, however, neonate larvae of the comma butterfly did not unconditionally accept to feed from the least favorable host species even when it was the only food source. Our results suggest the possibility that the disadvantages associated with a generalist oviposition strategy can be decreased by larval participation in host plant choice.
Insects, 2019
Early experience of olfactory stimuli associated with their host–plant complex (HPC) is an important driver of parasitoid foraging choices, notably leading to host fidelity. Mechanisms involved, such as peripheral or central modulation, and the impact of a complex olfactory environment are unknown. Using olfactometer assays, we compared HPC preference of Aphidius ervi Haliday (Hymenoptera:Braconidae) females originating from two different HPCs, either with the other HPC in close vicinity (complex environment) or without (simple environment). We also investigated antennal responses to volatiles differentially emitted by the two respective HPCs. In a simple environment, HPC of origin had an influence on olfactory choice, but the preferences observed were asymmetric according to parasitoid origin. Electroantennographic recordings revealed significant sensitivity differences for some of the tested individual volatiles, which are emitted differentially by the two HPCs. Besides, presence ...
Behavioral Ecology and Sociobiology, 2007
The reproductive success of insect parasitoids depends on two activities, searching for hosts to obtain immediate fitness rewards (offspring) and searching for food to extend life span and enhance future reproductive opportunities. Models suggest that to deal with this tradeoff and to cope with the variability of the resources they depend on, parasitoids should simultaneously integrate information originating from three distinct sources: host and food availabilities in the environment (environmental information) and the metabolic reserves of the parasitoid (internal information). We tested whether, in the parasitic wasp Venturia canescens, these three types of information are perceived simultaneously and interact during host-patch exploitation. Experiments were performed with strains originating from two different geographical locations and with individuals of the two reproductive modes, arrhenotoky and thelytoky. We hypothesised that there would be differences between modes of reproduction as they thrive in different ecological conditions. Our results show that metabolic state, food availability and the number of ovipositions performed simultaneously modulate patch residence time in V. canescens of both populations and reproductive modes. Unfed wasps left their host patch earlier than fed ones. The tendency to leave the patch increased with an increasing probability of finding food. Our study confirms that globally, each oviposition increases the patch-leaving tendency (decremental mechanism). This effect was modulated by both the metabolic reserves and food availability, and the relationship depended on the geographic origin of populations. Individuals of one of the populations switched from a decremental to an incremental patch-leaving mechanism depending on the presence or absence of food in the vicinity. Differences between reproductive modes in the responses to environmental cues can be explained by the different ecological conditions they live in.
Host preference and larval performance suggest host race formation in Galerucella nymphaeae
Oecologia, 2002
In this study we investigated the possibilities for host race formation in Galerucella nymphaeae. This is a chrysomelid beetle feeding on four different hosts, belonging to two different plant families, the Nymphaeaceae and Polygonaceae. Previous results showed that beetles living on the two different host families differ in morphology, i.e., body length, mandibular width, and color of the elytra. In the current study, the preference of G. nymphaeae for four hosts was investigated, together with larval performance on these hosts. In a multichoice experiment, both parents and offspring showed a strong feeding preference for their natal host plant family: between 88-98% of the total consumption consisted of the natal host plant family. Females preferred to lay eggs on their natal host family: 81-100% of the egg clutches were laid on the natal host family. Host preference was accompanied by differences in offspring performance. Offspring survival was 1.2-25 times as high on the host family from which their parents originated than on the hosts of the other plant family. Furthermore, larval development tended to progress faster on the natal than on the other host family. Since the beetles use their host plant as a mating place, positive assortative mating is a likely consequence of the beetles' host preference. Together, these results suggest that there are two host races of G. nymphaeae: one living on Nymphaeaceae and the other on Polygonaceae.
foraging efficiency of C. glomerata, it did not reduce the negative influence of natural background vegetation. At the same time, however, females foraging in natural vegetation attacked more host patches on host-plant species on which they previously had a positive oviposition experience. We conclude that, even though the presence of natural vegetation reduces the foraging efficiency of C. glomerata, it does not prevent experienced female wasps from specifically orienting towards the host-plant species from which they had learned the HIPVs.