ODORS IN TRAPS - DOES MOST RECENT OCCUPANT INFLUENCE CAPTURE RATES FOR HOUSE MICE

Responses of house mice (Mus domesticus) to odors in live traps were s tudied in a series of eight 0.1-ha outdoor field enclosures. It was as sumed that the most recent mouse capture would provide the predominant odor in a trap for at least one week. Three different populations wer e tested, one in 1989 and two in 1992, involving over 800 different mi ce. Similar response patterns were recorded from all three groups. Two types of questions were tested: (1) Were there any biases contingent upon what had been previously caught? (2) Were there consistent respon ses of mice of particular age, sex, or reproductive classes to trap od ors? Traps soiled by juvenile females caught adult females significant ly less often than expected, but there were no consistent relationship s in terms of the effects of specific residual odors on the subsequent capture at a particular trap. For various age, sex, and reproductive classes, (1) adult males preferred odors from juvenile and estrous fem ales and avoided odors of other males significantly more than expected , (2) juvenile females selected traps with odors of other juvenile fem ales and avoided all other types of female odors significantly more th an expected, (3) nonestrous females exhibited a significant preference for adult male odor, and (4) estrous females selected traps containin g odors from adult males but avoided those that had previously contain ed either nonestrous or pregnant/lactating females significantly more than expected. These findings have potential implications with regard to both the methods used for trapping small rodents and the social bio logy of house mice.