MATE GUARDING IN MALE SAND LIZARDS (LACERTA-AGILIS)

We investigated factors that may determine mate guarding tactics in ma le sand lizards. In a sample of lizards from a museum collection, larg er males had larger testis, but in laboratory experiments and in a nat ural population larger males did not sire more offspring. Males with l ong inter-copulatory intervals were more successful in sperm competiti on than males with short inter-copulatory intervals. In the wild, the operational sex ratio (OSR, No of receptive females/No of sexually act ive males) declined throughout the mating season. Mean duration of mat e guardings was unaffected by OSR, time to ovulation, female age and m ass, and clutch size. Larger males guarded females longer and were mor e likely to mate guard a female of similar age. Larger males had more partners but there was no correlation between male size or guarding ti me and the proportion of young that males sired in clutches from femal es mated with several partners. Males with more partners were more suc cessful at siring offspring in clutches from females that mated with m ore than one partner. We suggest that fitter males are better at both mate acquisition and have more competitive sperm.