Isogroup Selection to Optimize Biocontrol Increases Cannibalism in Omnivorous (Zoophytophagous) Bugs (original) (raw)
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Insects, 2020
Cannibalism in insects plays an important role in ecological relationships. Nonetheless, it has not been studied as extensively as in other arthropods groups (e.g., Arachnida). From a theoretical point of view, cannibalism has an impact on the development of more realistic stage-structure mathematical models. Additionally, it has a practical application for biological pest control, both in mass-rearing and out in the field through inoculative releases. In this paper, the cannibalistic behavior of two species of predatory bugs was studied under laboratory conditions—one of them a generalist predator (strictly carnivorous), Nabis pseudoferus, and the other a true omnivore (zoophytophagous), Nesidiocoris tenuis—and compared with the intraguild predation (IGP) behavior. The results showed that cannibalism in N. pseudoferus was prevalent in all the developmental stages studied, whereas in N. tenuis, cannibalism was rarely observed, and it was restricted mainly to the first three nymphal ...
PloS one, 2017
Abstract. Zoophytophagous predators can substitute zoophagy for phytophagy to complete their development and reproduction. In such predators, variation in feeding behaviour is observed both across and within populations. This may be caused by genetic variation in diet specialization, some genotypes specializing on plant resources, whereas others rely mostly on prey to meet their energy and nutriment requirements. We tested the hypothesis that genotypes specialize either on prey or plant resources in the zoophytophagous mullein bug Campylomma verbasci. In the laboratory, we reared 11 isogroup lines of the mullein bug and recorded feeding behaviour on two diets. The first diet was composed of two-spotted spider mites and leaves, and in the second we added pollen, a high-quality vegetal resource. Overall differences in zoophagy among isogroup lines remained consistent regardless of the presence or absence of pollen. While some lines were insensitive to changes in trophic resource composition oth...
Cannibalism in Two Subtropical Lady Beetles.pdf
Cannibalism is an important factor influencing both immature survival and adult reproductive success in aphidophagous lady beetles. This study employed three series of laboratory experiments to characterize life stage-specific cannibalism responses of Coccinella undecimpunctata L. and Cydonia vicina nilotica Mulsant to 1) different conspecific densities, with and without prey, 2) other life stages, and 3) various densities of prey, Myzus persicae Sulzer. All larval instars of both species cannibalized more in the absence of prey than in its presence at all conspecific densities, but in general, cannibalism increased with conspecific density only in the absence of prey, and more strongly for third and fourth instar C. undecimpunctata than for their C. vicina nilotica counterparts. Adults contributed the most cannibalism of any life stage, and eggs were the most vulnerable. In addition to cannibalizing their own and earlier instars, second and third instar C. undecimpunctata sometimes cannibalized third and fourth instars, respectively, and fourth instars occasionally ate pupae. Larvae of C. vicina nilotica were only preyed upon by the same or later stages and pupae, by adults, not fourth instars. A relative vulnerability index was calculated for each life stage based on its net vulnerability to cannibalism by all life stages and plotting these indices revealed species-specific patterns of diminishing vulnerability to cannibalism as a function of life stage. Relative species vulnerability to cannibalism, considering all life stages, was higher for C. undecimpunctata (0.55) than for C. vicina nilotica (0.45). Finally, linear regression was used to characterize the change in propensity for cannibalism between same-instar larval pairs as a function of prey density, which enabled determination of a theoretical upper prey threshold for each larval instar, i.e., the prey J Insect Behav (2015) 28:387-402 density beyond which no cannibalism would be expected. In both species, regressions for third and fourth instars did not intercept the X-axis, suggesting that some cannibalism by these stages was inevitable within the range of prey densities tested.
Costs and benefits of prey specialization in a generalist insect predator
Journal of Animal Ecology, 2002
Summary There are very few studies on prey specialization in predatory insects. Of the prey that the larvae of the generalist ladybird beetle Adalia bipunctata regularly feed on in the field, some are more suitable as food than others. A laboratory experiment was undertaken to determine whether it is possible to select for improved performance of this insect predator on a ‘poor quality’ prey, and the cost, if any, of such specialization. The ladybird performed better when reared on the pea aphid Acyrthosiphon pisum than on the black bean aphid Aphis fabae. Over the course of six generations of selection there was a significant increase in performance on both species of aphid, especially the black bean aphid. Ladybirds previously selected for five generations for better performance on the black bean aphid performed significantly worse when reared on pea aphid compared with those reared continuously for six generations on pea aphids, and vice versa. That is, specialization on one spec...
A meta-analysis of preference-performance relationships in phytophagous insects
Ecology Letters, 2010
Ecology Letters (2010) 13: 383–393Ecology Letters (2010) 13: 383–393AbstractThe extent to which behavioural choices reflect fine-tuned evolutionary adaptation remains an open debate. For herbivorous insects, the preference–performance hypothesis (PPH) states that female insects will evolve to oviposit on hosts on which their offspring fare best. In this study, we use meta-analysis to assess the balance of evidence for and against the PPH, and to evaluate the role of individual factors proposed to influence host selection by female insects. We do so in an explicitly bitrophic context (herbivores versus plants). Overall, our analyses offer clear support for the PPH: Offspring survive better on preferred plant types, and females lay more eggs on plant types conducive to offspring performance. We also found evidence for an effect of diet breadth on host choice: female preference for ‘good quality plants’ was stronger in oligophagous insects than in polyphagous insects. Nonetheless, despite the large numbers of preference–performance studies conducted to date, sample sizes in our meta-analysis are low due to the inconsistent format used by authors to present their results. To improve the situation, we invite authors to contribute to the data base emerging from this work, with the aim of reaching a strengthened synthesis of the subject field.The extent to which behavioural choices reflect fine-tuned evolutionary adaptation remains an open debate. For herbivorous insects, the preference–performance hypothesis (PPH) states that female insects will evolve to oviposit on hosts on which their offspring fare best. In this study, we use meta-analysis to assess the balance of evidence for and against the PPH, and to evaluate the role of individual factors proposed to influence host selection by female insects. We do so in an explicitly bitrophic context (herbivores versus plants). Overall, our analyses offer clear support for the PPH: Offspring survive better on preferred plant types, and females lay more eggs on plant types conducive to offspring performance. We also found evidence for an effect of diet breadth on host choice: female preference for ‘good quality plants’ was stronger in oligophagous insects than in polyphagous insects. Nonetheless, despite the large numbers of preference–performance studies conducted to date, sample sizes in our meta-analysis are low due to the inconsistent format used by authors to present their results. To improve the situation, we invite authors to contribute to the data base emerging from this work, with the aim of reaching a strengthened synthesis of the subject field.
Evolution, 2007
Physiological causes of genetic differences in cannibalism were examined to gain a better understanding of constraints on behavior evolution. Cannibalism has complex population level consequences in Tribolium confusum, including dramatic effects on population size. Laboratory strains with low and high cannibalism rates, obtained through inbreeding, have maintained distinct levels of cannibalism for over two decades even in the absence of artificial selection to maintain the differences. Why strains differ in their cannibalism rates was examined by measuring: (1) the nutritional benefit from cannibalism in both nutritionally good and poor environments, and (2) the possibility that eggs are an important source of water. How strains achieve differences in cannibalism was examined by testing for differences between strains in their ability to find eggs and in their tendency to eat eggs.
Host-plant genotype mediates supply and demand of animal food in an omnivorous insect
Ecological Entomology, 2011
1. Omnivorous predators can protect plants from herbivores, but may also consume plant material themselves. Omnivores and their purely herbivorous prey have previously been thought to respond similarly to host-plant quality. However, different responses of omnivores and herbivores to their shared host plants may influence the fitness, trophic identity, and population dynamics of the omnivores.
Environmental Entomology, 2000
Cannibalism, a widespread phenomenon in nature, can both reduce competitors and introduce a high-quality food into the cannibalÕs diet. We investigated the dietary beneÞts of cannibalism for larvae of the multicolored Asian lady beetle, Harmonia axyridis (Pallas). Cannibalism might beneÞt the larvae by allowing cannibals to take advantage of prey-detoxiÞcation already completed by the victim or the different, and perhaps more diverse, feeding history of the victim. In two laboratory experiments we reared H. axyridis larvae with aphid prey, and with or without conspeciÞcs to consume, and recorded larval development and survivorship. In the Þrst experiment, we fed groups of H. axyridis larvae an aphid species of intermediate quality, Aphis nerii (Boyer deFonscolombe), and prevented or permitted consumption of conspeciÞcs of varied qualityÑ conspeciÞc victims had either fed upon the same intermediate quality food as the focal individual or had fed upon a high quality food. Cannibalism increased survivorship and shortened development time, and eating conspeciÞcs that had fed upon higher-quality food further shortened early development. In a second experiment, we reared groups of H. axyridis larvae with one or both of two aphid species of poor (Uroleucon spp.) or intermediate [Aphis fabae (Scopoli)] quality, and either permitted or prevented cannibalism. Larvae could complete development when fed both conspe-ciÞcs and the intermediate quality aphid, but not on any other diet. Overall, when mixed with other foods, cannibalism allowed H. axyridis larvae to develop on prey that were otherwise nutrient deÞcient or toxic.
Cannibalism in Two Subtropical Lady Beetles Coleoptera Coccinellidae.pdf
Cannibalism is an important factor influencing both immature survival and adult reproductive success in aphidophagous lady beetles. This study employed three series of laboratory experiments to characterize life stage-specific cannibalism responses of Coccinella undecimpunctata L. and Cydonia vicina nilotica Mulsant to 1) different conspecific densities, with and without prey, 2) other life stages, and 3) various densities of prey, Myzus persicae Sulzer. All larval instars of both species cannibalized more in the absence of prey than in its presence at all conspecific densities, but in general, cannibalism increased with conspecific density only in the absence of prey, and more strongly for third and fourth instar C. undecimpunctata than for their C. vicina nilotica counterparts. Adults contributed the most cannibalism of any life stage, and eggs were the most vulnerable. In addition to cannibalizing their own and earlier instars, second and third instar C. undecimpunctata sometimes cannibalized third and fourth instars, respectively, and fourth instars occasionally ate pupae. Larvae of C. vicina nilotica were only preyed upon by the same or later stages and pupae, by adults, not fourth instars. A relative vulnerability index was calculated for each life stage based on its net vulnerability to cannibalism by all life stages and plotting these indices revealed species-specific patterns of diminishing vulnerability to cannibalism as a function of life stage. Relative species vulnerability to cannibalism, considering all life stages, was higher for C. undecimpunctata (0.55) than for C. vicina nilotica (0.45). Finally, linear regression was used to characterize the change in propensity for cannibalism between same-instar larval pairs as a function of prey density, which enabled determination of a theoretical upper prey threshold for each larval instar, i.e., the prey J Insect Behav (2015) 28:387-402 density beyond which no cannibalism would be expected. In both species, regressions for third and fourth instars did not intercept the X-axis, suggesting that some cannibalism by these stages was inevitable within the range of prey densities tested.
Heritability and fitness consequences of cannibalism in Harmonia axyridis
Evolutionary Ecology Research, 1999
We examined environmental (food levels) and genetic (heritability and evolvability) influences on the expression of cannibalism in larvae of the ladybird beetle Harmonia axyridis Pallas (Coleoptera: Coccinellidae). In conjunction, we examined potential fitness consequences of cannibalism under different levels of food availability by measuring time of larval development and size at adult. Using a full-sib design, we split broods into food environments that differed by five-fold and measured rates of cannibalism by third instar larvae on first instar conspecifics. Surprisingly, there was significant genetic variation in the expression of cannibalism in response to increased prey levels. Some families exhibited a decrease in cannibalistic behaviour, some an increase, while some families did not alter their cannibalistic rate in response to different food levels. In the low food environment, there was a strong genetic basis for the expression of cannibalism with a heritability significantly different from zero. In the higher food environment, heritability was not significantly different from zero. However, evolvabilities for cannibalism were similarly high for both food level environments. Fitness consequences also depended on food levels. Larvae from the low food environments reduced their development time by approximately 1 day when they cannibalized an average of one first-instar conspecific larva. Although in the higher food environment rates of cannibalism did not decrease significantly, development times remained unaffected. Our results suggest significant genetic variation in the expression of cannibalism within a natural population of H. axyridis and selection favouring cannibalism under low food environments but not when prey levels are high.