1. Convergence in gut microbiome after pairing in adult male and female marmosets, and sex-bias in microbe transmission.
In a diet-controlled longitudinal study, we demonstrated that males and females exhibit a significant convergence in the structure and composition of the gut microbiome in the first eight weeks of pairing. Further, we also show that males acquire more novel microbes from their female partners than the reverse. This may be related to higher rates of male-initiated social contact (grooming, anogenital investigation) during the first weeks after pairing. The first figure below presents the Unifrac distance score between mates before and after pairing, for which a smaller value indicates greater similarity between pairmates. The second figure illustrates individual and composite changes in the major taxonomic constituents in the gut microbiome pre- and post-pairing. Under review, mSystems.
2. OXT/OXTR and AVP/AVPR1a diversity across New World monkeys
NWMs offer an exciting opportunity to explore the relationship between neuropeptides and social behaviors. Only recently, it has been shown that NWMs show remarkable diversity in OXT/OXTR system. We have identified 5 OXT ligand variants in NWMs. Marmosets possess a modified OXT ligand with a substitution at the 8th AA from Leucine to Proline (see below). This OXT variant results in a significant change in structure, and these 5 OXT ligands across NWM genera have coevolved with their respective OXTR. We are currently evaluating how this Pro8-OXT modulates a wide range of social behavior in marmosets. Learn more.
3. Neuropeptides and social behavior
Oxytocin and maintainance of male-female relationships
Marmosets are one of the few primate species (other than humans) in which males and females form and maintain long-term social relationships, otherwise known as ‘pair bonds’. Our research aims to identify neuroendocrine mechanisms that regulate the behavioral processes that facilitate the preservation of long-term marmoset pairs.
We have shown that marmosets (just like humans) show some level of interest in opposite-sex strangers, which may threaten fidelity with a long-term partner. However, treatment with oxytocin reduced the time spent ‘checking out’ these strangers, and delayed the expression of sexual solicitation behaviors that constitute the marmoset equivalent of ‘flirting’ with strangers. The results also highlight that there are at least two mechanisms for maintaining social and sexual fidelity with a long-term partner: attraction to the partner, and avoidance of potential mates. In marmosets, oxytocin appears to affect the second mechanism, which nevertheless leads to good marmoset couples. Learn more.
4. Oxytocin, vasopressin, and parental behavior
Marmosets mothers, fathers, and siblings all participate in helping to care for dependent infants. We study the role that oxytocin and vasopressin play in modulating responses to infants, infant stimuli, and other individuals in the family. We have found that vasopressin enhances responsiveness to infant stimuli in female marmosets, and oxytocin enhances responsiveness to infant stimuli in male marmosets. Learn more.
5. Oxytocin and prosocial behavior
For marmosets to maintain long-term pair bonds and biparental care, marmosets behave cooperatively. We are interested in the relationship between oxytocin and the expression of spontaneous prosocial behaviors. To study this, we have trained marmosets to participate in tray pulling tasks to test ‘altruistic’ food sharing, inequity aversion, and cooperation between pairmates and strangers. We have found that marmosets readily behave prosocially. However, when treated with oxytocin, our marmosets reduce their ‘altruistic’ food sharing with opposite-sex strangers. Learn more.
6. Neuroendocrinology of parenting, social support, and infant development
Variation in steroid hormones in parents during rearing and the quality of parental care
The effects of oxytocin on social buffering during stressors