The Evolution of Coloniality in White-tailed and Black-tailed Prairie Dogs (Sciuridae: Cynomys Leucurus and C. Ludovicianus)

摘要: In a 6—yr study, I investigated possible selective bases for coloniality in two species of squirrels (Sciuridae): loosely colonial White—tailed Prairie Dogs (Cynomys leucurus) and densely Black—tailed (C. ludovicianus). White—tail study sites were Wyoming Colorado, USA; Black—tail Colorado South Dakota. examined three hypotheses that might explain the evolution coloniality: (a) shortage suitable habitat, (b) social facilitation foraging, (c) reduced predation. The apparent surplus unused habitat absence isolated individuals both indicated prairie dogs are not forced to live together because shortages. An analysis dog foraging patterns there is no terms either group hunting large or elusive prey, location large, scattered food supplies, modification soil order effect growth vegetation more favorable abundant than which would otherwise result, (d) defense grounds. Three lines evidence indicate predation may be most important benefit coloniality. First, simulated predatory attacks by badgers (Taxidea taxus) wards (subcolonies) detect predators quickly do smaller wards; further, Black—tails White—tails. Second, devote proportionately less time alertness (i.e., scanning predators) wards, vigilant Third, breeding synchronization center—edge differences individual importance self herd effects. Interspecific ward size density ultimately result habitats contain significantly protective cover habitats.