Josh Garner: Alloparental behavior in prairie voles ( Michrotus ochrogaster )

1. Josh Garner: Alloparental behavior in prairie voles (Michrotusochrogaster)

2. Does recognition of ones young affect alloparental behavior The purpose of this study is to examine the affect of manipulations of the olfaction and oxytocin expression with respect to alloparental behavior in mammals

3. Would a vole by any other name smell as sweet? • Prairie voles (Microtus ochrogaster) are socially monogamous and show biparental care (Keebaugh et al. 2011) • Oxytocin (OT) is a neuropeptide that promotes partner preference and alloparenting (Young et al 2004) • The vomeronasal organ detects pheromones and sends signals to olfactory bulb which is dense with OT receptors (OTR) (Ferguson et al 2000)

4. Literature review • Alloparental care is positively correlated to OTR density in nucleus accumbens (NAcc) (Keebaugh et al. 2011) • Increasing OTR expression in adulthood did not have an affect on alloparental behaviors (Keebaugh et al. 2011) • Pair bonding and parental behavior may be result of pheromone and dopamine facilitated conditioning (Young et al. 2004)

5. Literature review • When OTR expression was increased in virgin females they were more likely to exhibit alloparental behavior (Keebaugh et al. 2011) • Mothers in a single mother family unit spend the most time away from the nest and are most likely to attack juvenile offspring (Ahern et al. 2009)

6. Hypothesis An adult prairie vole’s parental behavior is selectively directed because olfactory recognition of their young can elicit parental behavior. By removing the vomeronasal organ and increasing oxytocin expression a social stimulus from an unrelated juvenile vole will be more likely to elicit alloparental behavior.

7. Picture taken from Young et al. 2004

8. Methods • Prairie voles will be housed in same-sex groups with 3-4 voles per cage after weaning at 21 days of age • Housing will be a 36x18x19 cm steel cage under a 12:12 h light/dark cycle at 22oC with access to water and food ad libitum • After weaning at 21 days of age the vomeronasal organ was removed orally from a group of voles (Wysocki et al. 1991)

9. Methods • After a recovery period the voles groups of voles will be given an infusion of oxytocin into the NAcc • After another recovery period the all voles will be tested for alloparental behavior • All voles will be tested in a large clean cage and first given 15 minutes to acclimate followed by a 15 minute alloparenting session

10. Methods • Once test begins two unrelated pups will be placed on one end of the cage and alloparental behaviors will be measured • If the test vole attacks the pup the test will be stopped immediately • If the test vole does not approach the pup an approach latency of 900 seconds will be assigned for analysis

11. Limitations • Sample size will be limited due to number of surgeries needed • Infusion of oxytocin might fail or miss target • Removal of vemeronasal organ might not be complete after a surgery

12. Significance • The results of this study could show that olfactory recognition is what overrides the oxytocin circuit in the brain • Also could give more understanding to the large individual variation in alloparental behavior