Individual variation is an inherent aspect of animal populations and understanding the mechanisms shaping resource use patterns within populations is crucial to comprehend how individuals partition resources. Theory predicts that differences in prey preferences among consumers and/or differences in the likelihood of adding new resources to their diets are key mechanisms underlying intrapopulation variation in resource use. We developed network models based on optimal diet theory that simulate how individuals consume resources under varying scenarios of individual variation in prey preferences and in the willingness of consuming alternate resources. We then investigated how the structure of individual–resource networks generated under each model compared to the structure of observed networks representing five classical examples of individual diet variation. Our results support the notion that, for the studied populations, individual variation in prey preferences is the major factor explaining patterns in individual–resource networks. In contrast, variation in the willingness of adding prey does not seem to play an important role in shaping patterns of resource use. Individual differences in prey preferences in the studied populations may be generated by complex behavioral rules related to cognitive constraints and experience. Our approach provides a pathway for mapping foraging models into network patterns, which may allow determining the possible mechanisms leading to variation in resource use within populations.
Individual networks of resource use from five animal populations
The dataset includes five interaction networks from three animal species. The data comprises qualitative information on individual patterns of resource use from each animal species. Individuals are depicted in rows and resources in columns. Pinaroloxias inornata (Passeriformes, Thraupidae) is a finch from the Coco Island, Costa Rica. This data was originally published by Werner and Sherry (1987). The Pinaroloxias network comprised 21 sampled individuals that used 7 different feeding strategies to acquire resources. Feeding strategies are described in the spreadsheet. The second and third sheets comprise information on feeding interaction from the marine snail Nucella emarginata (Neogastropoda, Muricidae) from two different localities in central California. These two data sets were originally published by West (1986). In site A, 20 individuals were sampled and consumed 7 resources. In site B, 31 individuals were sampled and consumed 3 resources. The fourth and fifth sheets describe the feeding interactions from two populations of the marine snail Vasula melones from Panama. These dataset was originally published by West (1988). In site A, 42 individuals were sampled and consumed 8 resources, whereas in site B, 21 individuals were sampled and consumed 14 resources. Resources are described within each spreadsheet. For further information regarding data collection from any of the study systems we refer readers to the original articles.
References:
Werner, T. K. and Sherry, T. W. 1987. Behavioral feeding specialization in Pinaroloxias inornata, the “Darwin’s finch” of Cocos Island, Costa Rica. – Proceedings of the National Academy of Sciences 84: 5506–5510;
West, L. 1986. Interindividual Variation in Prey Selection by the Snail Nucella (= Thais) Emarginata. - Ecology 67: 798;
West, L. 1988. Prey Selection by the Tropical Snail Thais Melones: A Study of Interindividual Variation. - Ecology 69: 1839;
Binary_Networks_resource_use_Oikos.xlsx
