科研之友
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摘要
Comparing closely related species that live in different environments is a powerful way to understand selective pressures that influence life-history evolution. We examined a suite of life-history traits and parental care in neotropical buff-breasted wrens Cantorchilus leucotis and north-temperate Carolina wrens Thryothorus ludovicianus (Family Troglodytidae), to test hypotheses about life-history evolution. As expected, buff-breasted wrens exhibited smaller clutch sizes and higher annual adult survival than Carolina wrens. We found minimal support for the nest predation hypothesis, as nest survival and age-corrected provisioning rates to whole broods were similar between species, and number of breeding attempts and breeding season length were greater in temperate wrens. Critical predictions of the food limitation hypothesis were not supported; in particular age-corrected provisioning rates per nestling were higher in the tropical than temperate species. The adult survival and offspring quality hypothesis garnered the most support, as buff-breasted wrens exhibited greater age-corrected provisioning rates per nestling, a longer nestling period, longer re-nesting intervals following nest success, and lower annual fecundity than Carolina wrens. Despite similarly prolonged breeding seasons, reproductive strategies differ between species with buff-breasted wrens investing considerably in single broods to optimize first-year survival and Carolina wrens investing in multiple small broods to optimize annual fecundity.
- 出版日期2012-9
