Meeting Abstract
Parental care is a widespread phenomenon observed in many diverse taxa. Neuroendocrine systems have long been thought to play an important role in stimulating the onset of parental care behavior. In most birds with altricial young, circulating prolactin (PRL) levels are low during non-breeding times and significantly increase during late incubation and early post-hatch chick care. Because of this pattern, PRL has been suggested to be involved in the initiation of parental care in birds, but rarely has this hypothesis been causally tested. In order to begin testing the hypothesis, we inhibited the release of endogenous PRL on the three days prior to hatching in incubating parents and the first two days of post-hatch parental care, when PRL was found to be highest during the breeding cycle in zebra finches. Zebra finches are socially monogamous and biparental, which allows both males and females to be tested. Breeding pairs were randomly assigned to receive either 5 daily treatments of bromocriptine (BR; n=20), a proven inhibitor of PRL release, or vehicle control (n=20). BR was suspended in peanut oil and all treatments were administered orally via a pipette. During treatment, nest temperatures were recorded. On the last two days of treatment, parental behavior was recorded inside the nest with chicks. In addition to hormonal systems, reproductive experience may also influence parental care. Therefore, we tested age-matched inexperienced and experienced pairs in each both treatments, yielding a 2×3 design (sex X treatment X experience). We predict that there will be no sex differences and that BR-treated birds will show less parental care and have lower nest temperatures than controls. In addition, we predict inexperienced birds will show less behavior and have lower nest temperatures than experienced birds. Results will be presented and discussed.
