Sensory and Neural Mechanisms of Parent-Offspring Recognition

Parental care is present across animal taxa, has arisen independently several times, and is often critical for offspring success. By providing care behaviors like feeding or protection, parents increase their offsprings’ chance for survival and future reproduction. However, parental care is a costly behavior, and parents should avoid providing care to unrelated young. This makes parent-offspring recognition important so that parents can correctly identify their own young and provide care only to those that are related. Infanticide and infant directed aggression are often displayed by species that provide care, further highlighting the importance of parent-offspring recognition. Parents should typically avoid displaying aggression toward their own young, and young should recognize their parents to avoid unfriendly adults.\nUsing the maternal mouthbrooding cichlid fish, Astatotilapia burtoni, I investigated the sensory and neural mechanisms that drive parent-offspring recognition. I compared neuronal activation during the mouthbrooding, maternal care, and infanticide stages of the female reproductive cycle and during the pre-release and post-release stages of fry development. I identified differences in neuronal activation at each of these stages. In females, neuronal activation during the mouthbrooding and maternal care stages were similar, suggesting there may be similar maternal circuits used during these periods. I then exposed mothers to either no information from their fry, only visual information, only chemosensory information, or both chemosensory and visual information from their fry. Behavioral data suggests that combined chemosensory and visual information promotes fry avoidance, but no differences in neuronal activation were identified in brain regions associated with maternal care and sensory processing. I conducted a similar experiment with fry, exposing them to either no information, only visual information, only chemosensory information, or both chemosensory and visual information from their mother. I found no differences in behavior or neuronal activation in fry exposed to different sensory stimuli, suggesting A. burtoni fry may not recognize their mothers during the infanticide stage. Together, these experiments confirm the utility of A. burtoni as a system to study parental care behaviors and provide important comparative data on the evolution of parental care and parent-offspring recognition.