Paternal Behavior in Rodents

The literature on paternal behavior in rodents includes reportsof many species; however, paternal behavior appears more prevalentamong muroid and hystricomorph rodents than in the sciurids.Many reports of paternal behavior are based on small numbersof animals observed under special conditions. Where systematicstudies have been conducted, the most salient feature of rodentpaternal behavior is its lability. The occurrence varies withobserver constraints, genotype, experience, social conditionsduring observation, and stimulus characteristics. This intraspecificvariability renders application of the comparative method inunderstanding evolution difficult but may provide a key in theremarkable adaptation of rodents to diverse habitats. Althoughspecies differences exist the evolution of rodent paternal behaviorappears to entail changes in the thresholds and conditions forthe occurrence of a relatively few basic motor patterns of paternalcare.     

Laboratory Research on Behavioral Interactions as Generators of Population Phenomena in Rodents

Many population phenomena are driven by the behavior of individualanimals. The effects of behavior on differential reproductionvary with the mating system and with ecological factors; understandingof the complex interactions requires both laboratory and fieldresearch. Ecologically-relevant laboratory research should bedesigned using generalizable behavioral patterns with animalsof appropriate species, meaningful genotypes, and known earlyexperience that are studied in carefully-designed situations.Three exemplars of research of potential relevance to populationphenomena are discussed. Studies of dominance and differentialreproduction in deer mice in seminatural enclosures suggestthat dominant males make disproportionately large contributionsto gene pools and that dominance may be heritable. Laboratorystudies of reproductive function in individuals bearing differentalleles, determined electrophoretically, appear relevant topopulation processes reported correlated with changes in genefrequencies at these loci. Patterns of mate choice in two speciesof Microtus may be important in generating their contrastingmating systems in the field. Well-designed laboratory researchcan help reveal behavioral processes critical to populationphenomena.