Optimal Diets under the Energy Maximization Premise: The Effects of Recognition Time and Learning

Hughes, Roger N.

doi:10.1086/283380

Cited by 375 publications

(180 citation statements)

References 18 publications

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“…Yet, the bird bypassed these individuals without seeming to recognize their presence and either pursued another grasshopper (of the same or another species) farther away or continued searching. Such results are consistent with the hypothesis that crypsis and associated microhabitat selection by prey are important in regulating encounter, detection and recognition rates by predators Hughes, 1979). However, I typically could not locate the positions of prey from my observation post independent of bird foraging behavior so I was unable to de- ).…”

Section: Resultssupporting

confidence: 84%

Foraging Behavior and Switching by the Grasshopper Sparrow Ammodramus savannarum Searching for Multiple Prey in a Heterogeneous Environment

Joern¹

1988

American Midland Naturalist

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ABSTRACT:Switching among four alternative grasshopper species by the grasshopper sparrow (Ammodramus savannarum) through frequency-dependent predation was examined. Grasshoppers were presented against a heterogeneous natural background in an outdoor aviary where total density was held constant but relative density of each grasshopper species varied. Switching among prey, primarily between two of the four species, and inter-bird variability in switching was observed. Species-specific preferences and interactions among the alternative grasshopper species affected the final diet choice as one grasshopper species was always preferentially selected and another disregarded independent of changes in relative density. Attributes of avian foraging behavior, including: (a) proportion of total time spent handling prey, searching for prey or engaging in nonforaging activity; (b) capture success; (c) time required to catch prey (relative to either total or search time), and (d) attack distance did not vary according to the relative abundance treatments. Results of this study are related to quantitative estimates of predation and relative densities of grasshopper species in a natural grassland setting.

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Section: Resultssupporting

confidence: 84%

Foraging Behavior and Switching by the Grasshopper Sparrow Ammodramus savannarum Searching for Multiple Prey in a Heterogeneous Environment

Joern¹

1988

American Midland Naturalist

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“…The optimal diet model described at the beginning of this paper assumed that handling time is a constraint, while more de- [Ardea 68 tailed observations showed that this is in fact not true, since handling time varies with hunger level. Similarly, discrimination time which was treated as a fixed constraint, may be modifiable through experience (Dawkins 1971), and this can be incorporated into an optimal diet model (Hughes 1979). In general, it might turn out many behavioural attributes which are treated as fixed constraints in simple optimal foraging models are actually variably, and can be altered according to environmental risks.…”

Section: Discussionmentioning

confidence: 99%

“…Since the dotted line lies above this, it will always pay to spend time handling a more profitable item when it is encountered. This model can be slightly modified to include the effects of crypsis (Charnov 1973, Hughes 1979, Erichsen et at. 1980 by considering that crypsis imposes a cost on the predator in the form of a "discrimination time": the time needed to distinguish the prey item from its background.…”

Section: Cryptic Preymentioning

confidence: 99%

Optimal Foraging, Predation Risk and Territory Defence

Krebs¹

2002

Ardea

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“…Hence, M individuals should be attractive to the predator, but the predator faces the problem that on initial encounter it cannot differentiate between evasive unprofitable E individuals and profitable mimetic M individuals. However, if it invests a time t s in 'sampling' an encountered individual (say by chasing it), then this sampling does allow differentiation into either species E or M. This sampling time is similar to the recognition time in the diet choice model of Hughes (1979). Clearly, if the individual is of species E then the predator should desist from further time investment in that individual and return to searching.…”

Section: (B) a Mathematical Treatment Of Evasive Batesian Mimicrymentioning

confidence: 99%

Evasive mimicry: when (if ever) could mimicry based on difficulty of capture evolve?

Ruxton

Speed

Sherratt

2004

Proc. R. Soc. Lond. B

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We elucidate the conditions under which an easy-to-catch edible prey species may evolve to resemble another edible species that is much more difficult to capture ('evasive Batesian mimicry'), and the conditions under which two or more edible but hard-to-catch species evolve a common resemblance ('evasive Mü llerian mimicry'). Using two complementary mathematical models, we argue that both phenomena are logically possible but that several factors will limit the prevalence of these forms of mimicry in nature. Evasive Batesian mimicry is most likely to arise when it is costly in time or energy for the predator species to pursue evasive prey, when mimics are encountered less frequently than evasive models and where there are abundant alternative prey. Evasive Mü llerian mimicry, by contrast, is most likely to arise when evasive prey species differ in abundance, predators are slow to learn to avoid evasive prey and evading capture is costly to the prey. Unequivocal evidence for evasive Batesian or Mü llerian mimicry has not yet been demonstrated in the field, and we argue that more empirical work is needed to test whether putative examples are indeed a result of selection to signal difficulty of capture.

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Optimal Diets under the Energy Maximization Premise: The Effects of Recognition Time and Learning

Cited by 375 publications

References 18 publications

Foraging Behavior and Switching by the Grasshopper Sparrow Ammodramus savannarum Searching for Multiple Prey in a Heterogeneous Environment

Foraging Behavior and Switching by the Grasshopper Sparrow Ammodramus savannarum Searching for Multiple Prey in a Heterogeneous Environment

Optimal Foraging, Predation Risk and Territory Defence

Evasive mimicry: when (if ever) could mimicry based on difficulty of capture evolve?

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