Stronger between-clan than within-clan contests and their ecological correlates in a non-territorial, fission-fusion species, the Asian elephantpreprint
Аннотация: Abstract Socioecological theory attributes variation in social organization of female-bonded species to differences in within- and between-group competition, shaped by food distribution. Strong between-group contests are expected over large, monopolisable resources, and are not generally expected in species that feed on low quality resources distributed across large, undefended home ranges. Within groups, frequent contests are expected over discrete feeding sites but not over low-quality, dispersed resources. We report on the first tests of socioecological theory, largely unexplored in non-primate species, in female Asian elephants. Asian elephants show graminivory, overlapping home ranges, and high fission-fusion dynamics, traits that are thought to be associated with infrequent contests. We studied agonistic interactions within and between female elephant clans with respect to food distribution, food abundance, and competitor density effects of group size and clan density, in a grassland habitat around the Kabini backwaters, southern India. We found that the Kabini grassland had three times the grass biomass as adjacent forests, and between-clan encounters were considerably higher than that known from a neighbouring forest. Individual-level agonism was also more frequent between clans than within clans. Thus, the food-rich habitat patch probably enabled strong between-clan contest competition under graminivory. Moreover, the rate of between-clan encounters increased when more clans were present, and the duration of encounters was positively related to grass biomass at the contested sites. Despite fission-fusion dynamics, within-clan agonism was also somewhat frequent, but not influenced by food distribution, in contradiction to classic socioecological predictions, possibly because of intensified competition due to high density. Interestingly, within-clan agonism increased with female group size until intermediate group sizes, suggesting that the tension between within-group and between-group competition might govern group size, since larger groups are advantageous in this strong between-clan contest regime. Our findings refine the current understanding of female elephant socioecology. Despite predominant graminivory and fission-fusion dynamics, within-group agonism can be frequent, especially when large groups face ecological constraints at high density. Further, frequent between-group contests may arise despite graminivory and non-territoriality when food becomes patchy and density is high. These changes may be effected by anthropogenic alteration of habitats.
Год издания: 2019
Авторы: Hansraj Gautam, T. N. C. Vidya
Издательство: Cold Spring Harbor Laboratory
Источник: bioRxiv (Cold Spring Harbor Laboratory)
Ключевые слова: Primate Behavior and Ecology, Wildlife Ecology and Conservation, Animal Behavior and Reproduction
Другие ссылки: bioRxiv (Cold Spring Harbor Laboratory) (PDF)
bioRxiv (Cold Spring Harbor Laboratory) (HTML)
bioRxiv (Cold Spring Harbor Laboratory) (HTML)
bioRxiv (Cold Spring Harbor Laboratory) (HTML)
bioRxiv (Cold Spring Harbor Laboratory) (HTML)
Открытый доступ: green