SEX-DIFFERENCES AND PRIOR RESIDENCE EFFECTS IN SHELTER COMPETITION INJUVENILE LOBSTERS, HOMARUS-AMERICANUS MILNE-EDWARDS

Using a resident-intruder paradigm, a four-experiment study of competi tion for a single shelter between same- and mixed-sex dyads of juvenil e lobsters, Homarus americanus Milne-Edwards, revealed a significantly greater advantage for male residents than female residents against in truders of either sex. However, there was no significant direct compet itive advantage for residents of one sex over intruders of the other, as occurs for adult males over females in this species. There was a pr ior residence effect only in the male-male dyad condition. Unexpectedl y, there was a reliable intruder advantage in female-female dyads. The methods employed showed that the shelter-seeking response of the juve nile lobster is a phylogenetic adaptation and that juvenile aggressive behavior differs little in form from that of adult lobsters but appea rs to be more intense. (C) 1998 Elsevier Science B.V. All rights reser ved.