Digestion-Constrained Optimal Foraging in Generalist Mammalian Herbivores

Hirakawa, Hirofumi

doi:10.2307/3545798

Cited by 41 publications

(28 citation statements)

References 30 publications

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“…In particular, small species of vertebrate herbivores tend to feed on diets richer in nutrients than large species (Fleming, 1991;Hume et al, 1993;Hirakawa, 1997). Analogous trends are also found for conspecific individuals of different body size (Benavidess et al, 1994;Conradt et al, 1999;Agetsuma, 2001).…”

Section: Introductionmentioning

confidence: 85%

Diet composition and body size in insect herbivores: Why do small species prefer young leaves?

Čížek¹

2005

Eur. J. Entomol.

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Abstract. The hypothesis that small body size is correlated with preference for young leaves was tested in a community of leafchewing insect herbivores feeding on Ficus wassa in a humid tropical forest in Papua New Guinea. Feeding experiments on 48 species of herbivorous insects revealed a negative correlation between body size and a preference for feeding on young leaves. While small species preferred young leaves, large species showed no preferences, or preferred young leaves only slightly. This relationship was found for the entire leaf-chewing community, as well as for many of the constituent taxa on several taxonomic levels, from orders to genera. Taxonomic position of a species played little role in determining its preferences. It is proposed that higher toughness and lower nutrient content may act as complementary defences, which prevent small insects from feeding on mature foliage. While the low nutrient content of mature leaves may affect smaller herbivores due to their relatively higher metabolic rate and lower digestion efficiency, their toughness complicates feeding mechanically and may prevent the compensatory feeding necessary to offset the low nutritive value of mature leaves.

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Section: Introductionmentioning

confidence: 85%

Diet composition and body size in insect herbivores: Why do small species prefer young leaves?

Čížek¹

2005

Eur. J. Entomol.

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“…To compensate for poor nutritional rewards, herbivore food resources must be more abundant and easier to procure (Hirakawa 1997). For avian herbivores, food quality is considered to be very important because of the severe limits on their digestive processing capabilities (e.g.…”

Section: Introductionmentioning

confidence: 99%

Winter foraging strategy of the Chinese Grouse (Bonasa sewerzowi): ecological and physiological factors

et al. 2011

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Both the quality of food and the rate of food intake may influence an animal's food choice. We investigated the feeding choices of Chinese Grouse (Bonasa sewerzowi) among a group of trees/shrubs with similar morphologies but heterogeneous chemical compositions in a coniferous forest of the northeastern Qinghai-Tibet Plateau during two winters. The primary food was willow buds and twigs (foraging occurrence of 83%). The Kangding willow Salix paraplesia was most preferred, whereas the Sichuan willow S. hylonoma was most avoided, and feeding preference (foraging occurrence/ food abundance) among the six main willow species was negatively correlated with the tannin content of the plant consumed rather than the protein, lipid, phosphorus, calcium, ash, fibre, or energy contents. The intake rates of dried biomass, energy, protein, fibre and tannin in different willow species were closely related to the bud sizes of these species. However, neither rate of intake nor total biomass acquired from a particular willow was related to the feeding preference of the Chinese Grouse. Therefore, we conclude that, rather than rate of food intake, the major evolutionary determinant of Chinese Grouse diet has been to maximise the intake of nutrients while simultaneously minimising the intake of digestion inhibitors.

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“…Sih and Christensen argue that the prey model is a poor descriptor of the foraging behaviors of animals with mobile prey. However, even in herbivores (Hirakawa 1997a;Verlinden and Wiley 1989) and molluscivores (van Gils et al 2005;Quaintenne et al 2010) that have essentially immobile prey, optimal foraging theory fails to predict the observed diet preferences. In these cases, the digestive rate model (DRM; Verlinden and Wiley 1989;Hirakawa 1995Hirakawa , 1997b) is shown to better predict animal diet preference, but the DRM itself is the result of generalizing the prey model (i.e., rate maximization) to include the effect of digestive constraints.…”

Section: Consequentlymentioning

confidence: 99%

When rate maximization is impulsive

Pavlic

Passino

2010

Behav Ecol Sociobiol

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Although optimal foraging theory predicts that natural selection should favor animal behaviors that maximize long-term rate of gain, behaviors observed in the laboratory tend to be impulsive. In binary-choice experiments, despite the long-term gain of each alternative, animals favor short handling times. Most explanations of this behavior suggest that there is hidden rationality in impulsiveness. Instead, we suggest that simultaneous and mutually exclusive binary-choice encounters are often unnatural and thus immune to the effects of natural selection. Using a simulation of an imperfect forager, we show how a simple strategy (i.e., an intuitive model of animal behavior) that maximizes long-term rate of gain under natural conditions appears to be impulsive under operant laboratory conditions. We then show how the accuracy of this model can be verified in the laboratory by biasing subjects with a short pre-experiment ad libitum high-quality feeding period. We also show a similar behavioral mechanism results in diet preferences that are qualitatively consistent with the digestive rate model of foraging (i.e., foraging under digestive rate constraints).

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Digestion-Constrained Optimal Foraging in Generalist Mammalian Herbivores

Cited by 41 publications

References 30 publications

Diet composition and body size in insect herbivores: Why do small species prefer young leaves?

Diet composition and body size in insect herbivores: Why do small species prefer young leaves?

Winter foraging strategy of the Chinese Grouse (Bonasa sewerzowi): ecological and physiological factors

When rate maximization is impulsive

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