Meeting Abstract
To optimize breeding success, animals must coordinate availability of environmental resources with breeding behavior. Yet mechanisms by which resources alter neural systems to fine-tune breeding behavior remain relatively unknown. In female European starlings (Sturnus vulgaris), nest cavities are limited resources that are necessary for breeding. Females that explore nest cavities compared to those that do not readily perform sexually-motivated behaviors. This suggests that nest cavity exploration may alter neural systems to stimulate breeding behavior. The present study explored this possibility and examined contributions of additional supplementary cues indicative of the breeding season. We assigned female starlings to either aviaries with 1) standard lab amenities, 2) nest boxes, or 3) nest boxes, plants, flowing water, insects and berries. Aviary condition did not have a significant effect on behavior, physiology, or neural measures. Rather, compared to other females, females housed with nest boxes that explored those boxes had higher estradiol, larger ovarian follicles, higher relative preproenkephalin (PENK) and cannabinoid receptor 1 mRNA, and lower relative levels of D1 and D2 dopamine receptor mRNA in the medial preoptic area (mPOA), a region in which opioids, dopamine, and endocannabinoids act to modify female breeding behaviors. PENK and tyrosine hydroxylase mRNA in the mPOA also positively predicted variance in nest box exploration. These data suggest that for female starlings, nest cavity exploration causally alters breeding physiology and mRNA expression in the mPOA. Thus nest cavity exploration may be a form of self-stimulation required to alter neural systems to fine-tune breeding behavior.
