Light and Dark Phase Maternal and Paternal Behaviors in the Polygamous House Mouse (Mus musculus domesticus) April Sparkman, Department of Biological Science, York College The house mouse (Mus musculus domesticus) uses a polygamous mating system with social group territoriality (Bonhomme 1992). When raised as mated pairs, males and females use a more monogamous mating system with strong paternal investment (Kleiman 1977). Polygamous males, however, invest more time in mating effort to increase reproductive success, leading to lower levels of paternal care (Wright 2000). The light and dark cycles of a mouse’s circadian rhythm influence both activity and social behavior and will each represent confounding factors for experimental results (Roedel et al. 2006, Stephan & Zucker 1972)). Parental behavior has been distinguished into direct and indirect parental behavior. Direct parental behavior involves thermal protection, huddling with the young, feeding, licking, and retrieving (Kleiman 1977). Time spent in covering the pups and pup retrievals are criteria for parental care investment and indicate responsiveness toward the young (Patris and Baudoin 2000). Introduction Project Summary My research began in the Spring of As a student enrolled in Animal Behavior I chose to study the behaviors of mice. In addition to developing an intensive behavioral ethogram, we were asked to design an experiment that looked at the behaviors of our species. I designed an experiment that looked at maternal and paternal behaviors during both light and dark phases of the day. Maternal and paternal behaviors can be measured in many different ways however in this instance I chose to look at pup retrievals and time in the nest during days post partum as indicators of responsiveness to the young for both males and females. After conducting the behavioral experiment I noticed that paternal and maternal care are much the same when mice are housed as mated pairs in a monogamous environment and there are significant differences in the willingness to retrieve pups when comparing light and dark phases. The results of my pilot study led me to question what would happen if the mice were housed not as mated pairs but in an environment similar to the polygamous one seen in the wild. In this project proposal I am comparing housed mated pairs and groups of males and females to represent polygamy. I will be looking at number of pup retrievals and time spent in the nest post partum during light and dark phases. Review of Literature Questions ?? Expected Results Research Design Figure 1 shows the number of pup retrievals for males and females in both monogamous and polygamous environments. Figure 2 shows the number of pup retrievals for all males including the determined father in a polygamous environment. Literature Cited Acknowledgements Monogamous 10 housed mating pairs 3 days after birth mother and father will be removed and pups will be placed at random in tank Figure 3 shows the number of pup retrievals for males and females in both light and dark phase. # of retrievals, type of retrieval and time of retrieval will be recorded 1.Do maternal and paternal behaviors differ when mice are housed in monogamous and polygamous environments? H 1 : There will be greater paternal behavior in a monogamous environment and more maternal behavior in a polygamous environment 2. Does paternity play a role in the level of paternal care by mice in a polygamous environment? H 2 :The biological father will show increased levels of paternal care in comparison to other males. 3.Are there differences in maternal and paternal care during light and dark phases? H 3 :Males will show greater levels of parental care during dark phases while females will show greater parental care during the light phase. Parameters for both environments: 15 minute time limit Trials should be spread out 3-5 days post partum to reduce stress Trials will take place in both light and dark phases 30 minute observation sessions will take place days 1-7 post partum to record time spent in the nest for both males and females Basic Specifications: Mice will be obtained from the wild and reared for 15 generations At 21 days : unisex sibling groups At 4-6 months, the mice will be placed as mated pairs (mono) and or in groups (poly) 14:10 light to dark cycle Food and water will be provided ad libitum Litter size will not limit our experiments, 5 pups from each litter will be used to standardize our results Conclusions Females in the polygamous setting will show greater levels of parental care than males. When males have access to more than one female paternal care is not as important. In a monogamous setting, males will exhibit the same if not more parental care in comparison to females. Males who are the father in a polygamous setting will retrieve more pups than non-fathers. Females will retrieve less pups during the dark phase than the light phase suggesting slightly changing roles during phases. There will be an increased number of pup retrievals during the light phase for both males and females which could be explained by levels of stress and motivation during phases of circadian cycles. 10 with male and female 10 males alone 10 females alone Polygamous 5 housed groups: 2 females / 3 males After birth of a litter paternity will be determined using a PureGene Kit 3 days after birth all males and females will be removed and pups will be placed at random in tank 10 non-fathers10 fathers10 mothers of retrievals, type of retrieval and time of retrieval will be recorded A comparative study tested the hypothesis that the mound building mouse (M. spicilegus ) has a higher level of paternal care than the polygamous house mice (Patris and Baudoin 2000). This article was important to my proposal as I used their animal and breeding conditions, as well as some of their methods for pup retrievals. In a second comparative study between the perhaps monogamous Algerian mouse and the house mouse, their results suggested higher levels of paternal care in the Algerian mouse (Cassaing et al. 2010) In my pilot study, results show that paternal care is much the same if not better than maternal care in a monogamous environment. There are differences in the number of pup retrievals for females when comparing light and dark phases. There lies a gap in research dedicated to comparing light and dark phases and perhaps changing roles during these phases. Bonhomme, F Genetic diversity and evolution in the genus Mus. Techniques in the Behavorial Neural Sciences. 8: Cassaing,J., Cervera, S., Isaac, F Laboratory and field evidence of paternal care in the Algerian mouse (Mus spretusi). Journal of Ethology. 28:7-13. Kleiman, D.G. ( 1977) Monogamy in mammals. Quarterly Review of Biology. 52: Patris, B., Baudoin, C A comparative study of parental care between two rodent species: implications for the mating system of the mound-building mouse Mus spicilegus. Behavioral Processes. 51: Roedel, A., Storch, C., Holsboer, F., Ohl, F Effects of light and dark phase testing on behavioral and cognitive perfomance in DBA mice. Laboratory Animals. 40: Stephan, F.K., Zucker, I Circadian rhythms in drinking behvior and locomotor activity of rats are eliminated by hypothalamic lesions. Proceeding of the National Academy of Science USA. 69: Wright, S.L., Brown, R.E. (2000) Maternal behavior, paternal behavior, and pup survival in CD-1 albino mice in three different housing conditions. Journal of Comparative Psychology,40, Special thanks to Bradley Rehnberg.