Intra- and inter-seasonal variation in the socio-spatial behavior of adultmale collared lizards, Crotaphytus collaris (Reptilia, Crotaphytidae)

Ta. Baird et al., Intra- and inter-seasonal variation in the socio-spatial behavior of adultmale collared lizards, Crotaphytus collaris (Reptilia, Crotaphytidae), ETHOLOGY, 107(1), 2001, pp. 15-32
Citations number
Categorie Soggetti
Animal Sciences","Neurosciences & Behavoir
Journal title
ISSN journal
0179-1613 → ACNP
Year of publication
15 - 32
SICI code
When individuals maintain strong inter-seasonal philopatry to the same terr itories, males may be able to re-establish territory occupancy without inte nse intrasexual aggression, and instead spend more time courting females ea rly in the reproductive season. Furthermore, when some males have prior exp erience defending the same territories, it may be necessary for young males to exhibit higher levels of aggression because they are establishing a ter ritory for the first time. We tested these hypotheses by examining within-s eason (1992 and 1997) temporal variation in the social behavior of adult ma le collared lizards of known age and prior territorial experience in a popu lation where inter-season philopatry to territories is high. Contrary to ex pectations, the frequency of aggression exhibited by males with and without prior territorial experience did not differ. The frequency of intra-sexual aggression was higher in 1992 than in 1997, perhaps because male competito rs were more abundant in 1992. Although there was an interactive effect of year, male display and patrol were low at the beginning of the reproductive season in Apr. and May, reached peaks during midseason in June, and then d ecreased as reproduction ended in July. The size of territories showed a si milar pattern, with males defending larger areas in June. Our data support the philopatry hypothesis in that the establishment of territories occurred without high levels of aggression early in the season, perhaps because ter ritory boundaries have been well defined by high rates of patrol and advert isement during the middle of the previous season. Inter-sexual interactions were most frequent in June rather than at the beginning of the reproductiv e season. Adult females are producing their second clutches and yearling fe males are producing their first clutches in June. The high rate of inter-se xual encounters in June supports the hypothesis that males allocate more ti me to courtship when females are receptive because there are more reproduct ively active females at this time. The temporal pattern of activities in ad ult Crotaphytus collaris appears to function as a compromise between compet ing intra- and inter-sexual social demands on males, allowing males to maxi mize mating opportunities as well as maintain future access to productive t erritories.