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Central Place Foragers (central + place_forager)
Selected AbstractsFactors influencing food collection behaviour of Brants' whistling rat (Parotomys brantsii): a central place foragerJOURNAL OF ZOOLOGY, Issue 1 2001T. P. Jackson Abstract The hypothesis that Brants' whistling rat Parotomys brantsii is a central place forager, whose foraging decisions are modified by (a) predation risk, (b) time of day, and (c) food choice, was tested. Field observations showed that whistling rats followed central place foraging rules for a single-prey loader and much of their food material was brought back to burrow entrances to feed on, with larger food items being carried back greater distances than small ones. Small food items were consumed in situ more often than large ones, suggesting that predation risk may also play a role in their foraging behaviour. Larger food items were preferentially stored at burrow entrances or carried underground, whilst smaller items tended to be consumed immediately. Individuals foraged more actively in the afternoon than in the morning and, although there was no tendency for individuals to eat more food at this time, far more food was stored or taken underground during the afternoon. Different foraging strategies were used for different plant species with some species preferentially eaten, and others stored or taken below ground more frequently. This study shows that the foraging behaviour of Brants' whistling rats is complex, and whilst they may follow simple central place foraging strategies, other factors such as the time of day and food plant species also influence their foraging behaviour. [source] An economic model of the limits to foraging range in central place foragers with numerical solutions for bumblebeesECOLOGICAL ENTOMOLOGY, Issue 3 2000James E. Cresswell Summary 1. A model is described that evaluates the maximum economic foraging range in central place foragers by using optimality criteria to discriminate between foraging sites at different distances from the forager's central place. 2. The basic model can be varied to suit foragers that optimise either their rate of net energy uptake or their foraging efficiency. 3. The model requires specification of the time and energy budgets of travel and foraging, and of the rewards obtainable at potential foraging sites. 4. The specific case of bumblebees, whose foraging ranges are poorly known, is considered. 5. Numerical solutions of the model for parameter values that represent bumblebees and their forage predict economic foraging ranges exceeding several kilometres. The model demonstrates that economics alone can explain extensive flight ranges in bees. [source] Ant nest location, soil nutrients and nutrient uptake by ant-associated plants: does extrafloral nectar attract ant nests and thereby enhance plant nutrition?JOURNAL OF ECOLOGY, Issue 3 2010Diane Wagner Summary 1. As central place foragers, ants accumulate organic debris near their nests. Consequently, soil nutrient stocks are often enriched near the nest site. We investigated the hypothesis that plant-derived food sources, such as extrafloral nectar (EFN), can encourage soil-dwelling ant colonies to nest near the plant, thereby inadvertently providing the plant with an additional source of mineral nutrients. The study focused on a population of Acacia constricta, a North American shrub bearing EFNs. 2. Several lines of evidence supported the notion that food rewards drew ant nests close to A. constricta plants. Firstly, ant species that visit EFNs nested significantly closer to A. constricta plants than would be expected by chance, whereas this was not the case for two ant species that do not visit EFNs. Secondly, A. constricta plants with an ant nest occurring naturally underneath the canopy had greater foliar volume, more EFNs per leaf and more EFNs per cm of leaf rachis than plants lacking an ant nest under the canopy. Thirdly, experimental supplementation of the nectar resources on acacias led to the establishment of significantly more new nests near the plant, relative to controls. However, nectar supplementation did not affect acacia seed production within the year of the study. 3. Soil from the nests of three, EFN-visiting ant species contained higher average stocks of most mineral nutrients than nearby soils outside the influence of the nest. 4. To test whether A. constricta can assimilate the nutrients in ant nests, we fed 15N-labelled food to Dorymyrmex sp. (smithi complex) workers nesting near acacias. Twenty-four days later, the leaves of acacias with an experimentally fed ant colony under the canopy contained significantly higher 15N and %N than acacias without a nest under the canopy, indicating that acacias assimilated and benefited from nutrients derived from ants. 5.Synthesis. The results indicate that nectar resources can attract the nests of some ant species, and that plants may benefit from access to soil nutrients derived from ant nests. Our data support the hypothesis that EFNs may confer nutritive, as well as protective, benefits. [source] | ||||||||||