Behavior Genetics, Vol. 25, No. 3, 1995 A Comparison Between House Mouse Lines Selected for Attack Latency or Nest-Building: Evidence for a Genetic Basis of Alternative Behavioral Strategies Frans Sluyter, 1,4 Abel Bult, 2 Carol B. Lynch, 3 Geert A. van Oortmerssen, 1 and Jaap M. Koolhaas 1 Received 2 May 1994--Final 1 Dec. 1994 House mouse lines bidirectionally selected for either nest-building behavior or attack latency were tested for both attack latency and nest-building behavior under identical conditions. Male mice selected for high nest-building behavior had shorter attack laten- cies, i.e., were more aggressive, than those selected for low nest-building behavior and their randomly bred control lines. Conversely, male wild house mice selected for short attack latency showed more nest-building behavior than those selected for long attack latency when tested at 110 days of age. These findings imply a common genetic basis for control of aggression and nesting and support earlier proposals as to how animals may exhibit fundamentally different responses to environmental challenges, either react- ing actively to aversive situations (aggressive and high-nesting animals: active copers) or adopting a passive strategy (nonaggressive and low-nesting animals: passive copers). KEY WORDS: Aggression; nest-building behavior; wild house mice; behavioral strategies; bi- directional selection; genetic correlation. INTRODUCTION The idea that rodents may display genetically based individual differences in behavioral strategies in re- sponse to environmental challenges is well estab- lished. Henry and Stephens (1977) presented the first evidence that differential patterns of neuroen- docrine activation are related to the contrasting be- havioral response patterns of individual mice to social interactions. Three distinct artificial selection experiments support this evidence. First, lines of University of Groningen, Department of Animal Physiology, P.O. Box 14, 9750 AA Haren, The Netherlands. 2 Yale University, Child Study Center, P.O. Box 207900, New Haven, Connecticut 06520-7900. 3 University of Colorado, Department of Environmental, Pop- ulation, and Organismic Biology, Boulder, Colorado 80309-0334. 4 To whom correspondence should be addressed at Grn&ique, Neurogrn&ique et Comportement, URA 1294 CNRS, Univ- ersit6 Paris V, UFR Biomrdicale, 45 Rue des Saint-Pbres, 75270 Paris Cedex 06, France. Fax: 31-50-63-52-05. rats selected for superior and inferior active shock avoidance acquisition, Roman high-avoidance (RHA/Verh) and low-avoidance (RLA/Verh), differ not only in their response to their selection crite- rion, i.e., a footshock in a two-way shuttle box (Bignami, 1965), but also in other behavioral, neu- rochemical, and hormonal traits (Driscoll et al., 1990; Driscoll and B~ittig, 1982). Second, rats have also been bidirectionally se- lected for susceptibility to apomorphine (a dopa- mine agonist) by measuring the amount of gnawing behavior elicited. The difference between the sus- ceptible (APO-SUS) and the not susceptible (APO- UNSUS) lines is not limited to gnawing elicited by apomorphine but extends to other behavioral and neurochemical correlates (Cools et al., 1990). The differential use of external and internal information in organizing behavior seems to underlie all inter- line differences. This interpretation is also appli- cable to RHA/Verh and RLA/Verh rats. 247 0001-8244/95/0500-0247507.50/0 91995 PlenumPublishing Corporation