What makes a predator specialize?

Bristow, Catherine M.

doi:10.1016/0169-5347(88)90070-5

Cited by 19 publications

(17 citation statements)

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“…Although similar diversity in feeding habits among phytophagous insects has stimulated much, intensive study (e.g., Schoonhoven et al 1998 and references therein), the ecological and evolutionary causes and consequences of diet breadth for predatory insects have been relatively little examined (e.g., Hassell and Southwood 1978;Evans 1982;Tauber and Tauber 1987;Bristow 1988;Milbrath et al 1993;Albuquerque et al 1997). Many predatory insects appear highly opportunistic in attacking various species and kinds of prey, but such behavior may be misleading as to prey suitability and to the nutritional requirements of the predator (e.g., Thompson 1951;Blackman 1967;Hodek 1973;New 1991;Strohmeyer et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Essential versus alternative foods of insect predators: benefits of a mixed diet

Evans¹,

Stevenson²,

Richards³

1999

Oecologia

137

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Although many predatory insects appear to be opportunistic generalists in their selection of prey, only a subset of prey species may in fact serve as "essential foods" capable of supporting immature growth and adult reproduction. It has been suggested that other, "alternative foods" serve only to maintain the predator when essential foods are not available, but little research has evaluated the significance of a mixed diet of essential and alternative foods for predator growth or reproduction. Here we test the general hypothesis that although alternative prey may be inadequate to support reproduction when consumed alone by adult predators, consumption of such prey may enhance the predator's reproductive output when the predator also has access to essential prey. We compared egg production by two aphidophagous lady beetles, Coccinella septempunctata and C. transversoguttata, provided with diets of aphids (essential prey) and weevils (alternative prey). As predicted, female predators produced greater numbers of eggs when a diet of pea aphids in limited number was supplemented by alfalfa weevil larvae. The predators laid no eggs when provided only with weevils or only with sugar. But once aphids were added to the diet, females of C. transversoguttata (but not C. septempunctata) laid eggs in greater numbers when they had fed previously on weevils than on sugar. Females of both species also produced eggs in modest numbers when provided with both weevils in excess and sugar, but this diet supported a lower rate of egg production than did a diet of weevils in excess plus a limited number of aphids. Although C. septempunctata has a longer history of association with the alfalfa weevil than does C. transversoguttata, the former species was not more effective in exploiting this alternative prey in support of reproduction. The tendency of generalist predators such as adult lady beetles to consume alternative as well as essential prey probably enhances considerably their ability to capitalize on short-lived and scattered opportunities as they seek out suitable sites in which to reproduce.

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Section: Introductionmentioning

confidence: 99%

Essential versus alternative foods of insect predators: benefits of a mixed diet

Evans¹,

Stevenson²,

Richards³

1999

Oecologia

137

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“…Furthermore, even predators with general feeding habits frequently have complex behavioral mechanisms for finding, choosing, and consuming their prey (e.g, Hagen 19 8 7, Dicke et al 19 8 9, Peckarsky and Wilcox 1989, Sabelis 1990, Scott and Barlow 1990, Provencher and Riechert 1991. For a variety of reasons, little is known about how these mechanisms vary among closely related species, and consequently both the evolution and the stability of predator-prey associations remain problematic (e.g., Tauber and Tauber 1987, Bristow 1988, Gilbert 1990.…”

Section: Introductionmentioning

confidence: 99%

Prey Specificity in Chrysopa: An Interspecific Comparison of Larval Feeding and Defensive Behavior

Milbrath¹,

Tauber²,

Tauber³

1993

Ecology

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To examine pathways in the evolution of prey specialization in insects, we conducted a comparative experimental analysis of larval behavior in two sympatric predacious sister-species (Chrysopa quadripunctata, a generalist, and C. slossonae, a specialist on the woolly alder aphid). Responses of the larvae to food (Myzus persicae) and camouflaging material (waxy secretions from woolly alder aphids or exuviae from M. persicae) were quantified during four discrete developmental periods. Our analysis revealed speciesspecific, ontogenetic, and environmentally induced variation in larval defensive and feeding behavior. The pattern of interspecific variation indicates that larval behavior could have subserved two processes in the evolution of prey specialization in the sister-species' progenitor: establishment on a specific prey and adaptation to the prey. First, the presence of the woolly alder aphid's secretions results in generalist larvae camouflaging themselves to a degree that rivals that of the specialist. Such phenotypic plasticity could have promoted the progenitor's initial adoption of the ant-tended woolly alder aphid as prey and its wool as a source of camouflaging material. Second, quantitative differences between the generalist's and specialist's behavior indicate that adaptation to the woolly alder aphid did not require the acquisition of novel behavioral traits in the larvae. It involved modifications in the expression of defensive behavior that existed in the generalist ancestor and alterations in the ability to attack and feed on robust prey.

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“…Some species are near-monophagous, such as Anisosticta novemdecimpunctata which feeds predominantly on Hyalopterus pruni in its specialist reed-bed habitat, while others such as Adalia bipunctata and Coccinella septempunctata feed and breed on tens or even hundreds of different aphid species (Majerus, 1994;Hodek, 1996;Klausnitzer & Klausnitzer, 1997). The evolutionary causes of dietary specialization have been extensively studied for a long time in phytophagous insects, but only relatively recently have we begun to study and understand the factors responsible for dietary specialization in predators including ladybirds (Bristow, 1988;Tauber et al, 1993;Sloggett, 2008).…”

Section: Specialization Trade-offs and Body Sizementioning

confidence: 99%

Weighty matters: Body size, diet and specialization in aphidophagous ladybird beetles (Coleoptera: Coccinellidae)

Sloggett¹

2008

Eur. J. Entomol.

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Abstract. Aphidophagous ladybirds exhibit a broad range of body sizes. Until now this has been thought to be a function of the different prey densities that they feed at, with smaller ladybirds feeding at lower prey densities. The size of the prey species they feed on has been considered to have no relationship with ladybird body size. However, these arguments possess a limited capacity to explain observed data from the field. I here demonstrate a more realistic, complex approach incorporating both prey density and the size of prey species. Small ladybirds can feed on small aphids at both low and high densities. However when the aphid species is large they cannot catch the older, bigger, more energy-rich aphid instars due to their small size. They are thus unable to feed on large aphid prey at low densities, although at higher densities numbers of the smaller instars may be sufficient to sustain them. By contrast large ladybirds can feed on large aphids at both low and high densities due to their superior ability to catch the bigger, more energyrich older aphids; however they cannot be sustained by low densities of small aphids due to food limitation consequent on their large size. This more complex association between ladybird size, prey size and prey density possesses a better explanatory power for earlier field data. Because of this relationship, ladybird body size also provides an important trade-off determining dietary breadth and specialization in the aphidophagous Coccinellidae. Dietary specialists more closely match the size of their limited prey species, have higher overall capture efficiencies and can thus continue to reproduce at lower aphid densities for longer. By contrast dietary generalists adopt a one-size-fits-all strategy, are medium-sized and have lower capture efficiencies of individual prey species, thus requiring higher aphid densities. The role of body-size in dietary specialization is supported by data from the British fauna. Rather than trade-offs related to prey chemistry, which have hitherto been the centre of attention, body size trade-offs are the likely most important universal factor underlying dietary specialization in aphidophagous coccinellids.

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What makes a predator specialize?

Cited by 19 publications

References 0 publications

Essential versus alternative foods of insect predators: benefits of a mixed diet

Essential versus alternative foods of insect predators: benefits of a mixed diet

Prey Specificity in Chrysopa: An Interspecific Comparison of Larval Feeding and Defensive Behavior

Weighty matters: Body size, diet and specialization in aphidophagous ladybird beetles (Coleoptera: Coccinellidae)

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