Mh. Figler et al., INTRUDING MALE RED SWAMP CRAYFISH, PROCAMBARUS-CLARKII, IMMEDIATELY DOMINATE MEMBERS OF ESTABLISHED COMMUNITIES OF SMALLER, MIXED-SEX CONSPECIFICS, Aggressive behavior, 21(3), 1995, pp. 225-236
The effects of competing asymmetries (intruder size advantage vs. prio
r residence) on dominance relationships were investigated in a laborat
ory setting. Sexually mature (Form I) male red swamp crayfish, 25%-27%
larger than the average member of several mixed-sex communities of 20
-25 sexually mature conspecifics, individually intruded upon these com
munities on successive days. Each community was invaded once a day, wi
th each of these large intruders invading every community once during
the experiment. Five days after the last large intruder invasion, nove
l intruder group males, approximately the same size as the average com
munity member, individually invaded the same communities, all communit
ies being invaded once during a single day of testing. These novel int
ruders were used to differentiate the effects of intruder size from th
ose effects of being put into a novel environment. During each intrusi
on, the frequencies of dominance, submission, aggressive standoffs, an
d nonaggressive interactions between the intruder and members of the c
ommunity were recorded. The large intruders on each day immediately an
d virtually completely dominated all encountered community members, an
d the large intruders were significantly more dominant than the novel,
smaller-sized intruders. The size advantage of the large intruders ov
erwhelmed prior residence in influencing dominance outcomes, even in t
hese well established communities. (C) 1995 Wiley-Liss, Inc.