Meeting Abstract
Life history theory predicts that there is a trade-off between investment in current reproductive success and future reproductive opportunities. Therefore, for iteroparous species with maternal care, older mothers should expend more energy in ensuring the survival of her current clutch than younger mothers that likely have future reproductive opportunities. To test this hypothesis, we measured aggression of female red-backed salamanders (Plethodon cinereus) toward intruding conspecifics in relation to maternal age. Red-backed salamanders guard their eggs for approximately two months until hatching. In the presence of an intruder, a female can engage in aggressive behaviors to increase the likelihood of clutch survival at the risk of injury to the female that may cost future reproductive opportunities. To test for an association between maternal aggression and age, we exposed female salamanders with broods that were 5, 20, or 45 days old to a non-reproductive, conspecific female intruder and recorded all behaviors for 3 hours. We also observed females 24 hrs prior to the trial to assess baseline behaviors at each time point. At the end of the trial, we sacrificed females to measure circulating corticosterone and testosterone, and we used skeletochronology to estimate female age. We predicted that older females will spend more time with their eggs and display greater aggression when faced with an intruder, and if these behaviors are mediated by corticosterone or testosterone, we expect that age will be correlated with circulating hormone levels. These data will shed light on how age may affect behavioral patterns during the maternal care period.
