The Economics of Seed Handling

Kaufman, Lynn W.; Collier, George

doi:10.1086/283800

Cited by 33 publications

(16 citation statements)

References 22 publications

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“…This selectivity does not appear to be correlated with any obvious morphological characters of the seeds. Wind-dispersed species, with papery seed coats, were not consistently preferred over the harder bird-dispersed species as would be predicted based on handing times (Kaufman and Collier 1981 ). Seed preference was also not significantly related to seed size in either habitat over the range of seed masses Table I.…”

mentioning

confidence: 78%

“…Seed predators often show selective predation on a subset of the species available within a community. This selectivity may be based on characteristics such as seed size (energy content), nutritional content, handling time, and local abundance (Kaufman and Collier 1981;Price 1983;Kelrick et al 1986). The result of such selective predation is a change in the relative species abundances of seeds which survive to germinate and establish.…”

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confidence: 99%

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Selective Predation on the Seeds of Woody Plants

Meiners¹,

Stiles²

1997

Journal of the Torrey Botanical Society

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confidence: 78%

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confidence: 99%

Selective Predation on the Seeds of Woody Plants

Meiners¹,

Stiles²

1997

Journal of the Torrey Botanical Society

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“…Two‐hour trials were conducted using animals that had been starved for 24 h. In addition to providing two thermal regimes (high = T a +; low = T a –), handling time was manipulated by using husked ( H –) and entire (i.e. unhusked, H +) sunflower seeds (see Kaufman & Collier 1981); previous experiments demonstrated that Degus do not consume sunflower seed husks (R. A. Vásquez, unpublished data). Search time was also manipulated by placing seeds in one of two configurations: grouped seeds ( G +) occupied an area of ≈ 100 × 100 mm 2 on the surface in the middle of the patch, whereas ungrouped seeds ( G –) were randomly distributed in the patch with half of the seeds on the surface and the other half mixed with the sand.…”

Section: Methodsmentioning

confidence: 99%

Patch use in a diurnal rodent: handling and searching under thermoregulatory costs

Bozinovic

Vásquez

1999

Functional Ecology

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1. The role of physiological complexity in animal foraging ecology was investigated through experiments to determine how animals manage time and energy during patch use under thermoregulatory costs. The Degu Octodon degus (Molina 1782), a diurnal rodent inhabiting the semiarid environments of central Chile, was studied. 2. Previous studies reported that Degus are constrained to specific foraging areas mainly by limits to thermal tolerance and food quality. Predation risk may also be important. Because new evidence shows that physiological processes are important in shaping foraging ecology, it was hypothesized that Degu foraging behaviour is influenced by the risk of hyperthermia as well as by the advantages of gathering food efficiently. 3. Feeding trials were conducted in an experimental arena with food offered in an experimental patch containing sand and placed under a heater. Using video cameras, the overall time budget was measured, including frequency and duration of patch visits, and events of food gathering. Besides ambient temperature (high or low), handling time was manipulated by using husked and unhusked sunflower seeds, and searching time by using two seed distributions. 4. Ambient temperature and husk state as well as ambient temperature and seed distribution interacted in their influence on both handling time and searching efficiency. These results imply that a thermally risky patch affects both parameters associated with patch use and diet selection and that this effect disappears when animals are not risking hyperthermia. 5. Degus decreased the frequency of patch visits under thermoregulatory costs. This behaviour resulted exclusively from the effect of ambient temperature. Data on time use suggest that direct exposure to higher environmental temperatures is avoided through changes in the duration of patch visits. Degus harvested food items in shorter foraging bouts when food was under a stressful thermal patch. 6. In conclusion, a time‐minimizing foraging behaviour, in face of Degus’ thermoregulatory physiology and related risks, was observed.

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“…Krebs et al 1977, elner & Hughes 1978, Jaeger & Barnard 1981, Kaufman & Collier 1981, Moermond & Denslow 1983 generally support such models, at least qualitatively (but see Hughes & elner 1979, Rapport 1980, Barnard & Brown 1981.…”

Section: Laboratory Studiesmentioning

confidence: 97%