Variation in Behavioral Syndromes in Brood Parasites of the Genus Molothrus not Explained by Genetic Variation in DRD4 Fragment

NICOLÁS MEMELSDORFF; ARIEL E VAGNOZZI; ROMINA C SCARDAMAGLIA; MARÍA I CRAIG; MACARENA VÁZQUEZ; VALENTINA FERRETTI

Congreso; North American Ornithological Conference - Virtual Conference; 2020

Shiny cowbirds (Molothrus bonariensis) and Screaming cowbirds (M. rufoaxillaris) are brood parasites that differ in their use of hosts, the former being a generalist and the latter a specialist. Given this marked difference in parasitic behavior, we expect them to differ in other aspects of their personality, and to have a genetic basis for this difference. Here we look at whether there are genetic polymorphisms associated with a region of the DRD4 gene, a gene associated to differences in behavior, whether these polymorphisms are related to different personality traits, and whether these differences are in turn related to sex and species of the individuals studied. We captured individuals of both species in Buenos Aires Province. We took a blood sample from each individual for genetic analyses and tested them to measure different personality axes. We found that females exhibit, in general, greater exploratory behavior than males, and males are less fearful of novel situations in both species; but, we found no polymorphisms in the targeted region of the DRD4 gene for the samples analyzed. However, when we compared the sequence amplified to that of other non-parasitic species, we detected a deletion of three base pairs and two substitutions which generate differences in the aminoacidic sequence. Further work should explore the functional implications of these differences, and whether they are associated to adaptations to brood parasitic behavior.