دانلود رایگان مقاله تاثیر تجربه اولیه و ارتباط با رفتارهای دیگر در موش صحرایی

Abstract

Socially monogamous prairie voles (Microtus ochrogaster) display remarkable individual variation in social behaviors, which has been associated with differences in early life experience and neuropeptide receptor densities. These differences are also seen in the wild, where approximately 70% of young voles remain in their natal group as non-breeding alloparents, while the other 30% disperse. We investigated whether natural variation in early parental care could contribute to offspring’s willingness to “disperse” (willingness to explore) in a laboratory context. Behavioral differences between dispersers and residents could also provide a way to interpret individual variation in other behaviors commonly observed under laboratory conditions. Breeder pairs ranked as high, medium or low-contact, according to the amount of early parental care they provided to offspring, were used to produce and rear experimental subjects. Effects of early parental care on the offspring’s willingness to disperse were seen at post-natal day 21, with high-contact offspring spending more time in the start cage and low-contact offspring spending more time exploring. Variations in parental care were also associated with differences in juvenile and adult behaviors that could potentially encourage philopatry or dispersal behavior in the wild. High-contact offspring displayed less anxiety-like behavior compared to low-contact animals. Low-contact offspring displayed the lowest amount of alloparental care. High-contact offspring spent more time in side-by-side contact with a potential partner compared to medium and low-contact offspring. These results suggest that variations in early parental care can impact weanlings’ exploratory behavior, but that philopatry is not driven by high anxiety.

4. Discussion

Our findings showed that variations in parental care had an effect on offspring’s social and exploratory behavior as juveniles and adults. Natural variations in early parental care influenced the willingness of young offspring (PND 21)to explore a novel environment rather than spending time inside their start cage. Despite our prediction that individuals raised by high-contact parents would show lower anxiety and therefore disperse earlier, offspring reared by high-contact parents dispersed less and stayed longer in the start cage than did the medium and low-contact offspring. On average, high-contact offspring spent around 80% ofthe totaltime ofthe first dispersal test in the start cage. Social behavior might be an important determinant of the likelihood of dispersal in prairie voles, in that young individuals thattend to socialize with other members of their group wouldbe less likely todisperse (Bekoff, 1977). Therefore we propose that high-contact offspring spent more time atthe start cage as a preference for social interaction with their family members and not as an anxiety-like response to the dispersal tube. This hypothesis is supported by the evidence that high-contact offspring displayed less anxiety-like behavior, and similar levels of exploration, when tested in the elevated plus maze, and higher social behaviors across their life span, including high alloparental behavior during the juvenile period and affiliative behaviors when tested in an adult preference test, compared to low-contact offspring.