Meeting Abstract
Nearly 1% of all bird species are obligate brood parasites. Obligate brood parasites do not build their own nests, incubate their own eggs or provision their own young. Recent results from our lab reveal that a critical maternal care-related brain region exhibits prolactin transcriptome insensitivity. Here, we further examine the effects of prolactin on brain and behavior of brood parasites. Adult female brown-headed cowbirds (Molothrus ater), a brood parasite ubiquitous across North America, were treated with either estrogen, estrogen + prolactin or saline as a control. We measured behavioral response of females in these treatment groups in a dichotomous choice test in which random tones and nestling begging sounds were broadcast. Immediately following behavioral measures, female subjects were placed in soundproof auditory chambers and exposed to random tones or nestling begging sounds to examine neural responses to these auditory stimuli among the treatment groups. Behavioral result revealed no significant difference across treatment groups in time spent near nest, time spent on nestling begging side or time spent on nest/control cup. In addition, no significant difference was observed within each treatment group in the time females performed these behaviors simulated nestling/nest side of the chamber as compared to the random tone/control cup side of the chamber. Examination of neural responses to random tones or nestling begging in treated and non-hormone treated females will determine whether a combination of auditory stimuli and hormone treatments also exhibits prolactin insensitivity. We are repeating these same tests in a closely related non-parasitic species (i.e. red-winged blackbird; Agelaius phoeniceus) to determine if these same measures do exhibit prolactin sensitivity in a maternal species.
