Familiarity and mating in Akodon azarae (Cricetidae: Sigmodontinae) with regard to mating system

CODA, JOSÉ A.; BONATTO, MA. FLORENCIA.; STEINMANN, ANDREA R.; PRIOTTO, JOSÉ W.

Mendoza

Congreso; International Mammalogical Congress, IMC10; 2009

Akodon azarae, one of the most abundant species living in the agroecosystems of southern Córdoba Province (Argentine), presents seasonal breeding, sexual differences in home range size, and has been proposed as a promiscuous-polygynous or polygynous species. In this study we test the hypothesis: In species with promiscuous-polygynous mating system, reproductive success (RS) of females is independent of mate familiarity; in polygynous species mate familiarity increase females RS. Adult individuals were captured between May and September 2008, in 21 lines of 30 traps (203m) separated by 500m in crop-fields borders. To minimize the effect of acclimation to laboratory conditions, the mating was carry out into the first 48hs since its arrival. Males were classified as ?familiar? (captured in the same line in the same trapping session than his partner), and ?unfamiliar? (captured in different line in the same trapping session than his partner). Thus, we obtain two experimental groups of reproductive mates: females with familiar males (FFM); females with unfamiliar males (FUM). RS was determined from pregnancy evidence or birth. Besides, we registered litter size, post-partum estrus, and infanticide. Mates that registered non-pregnancy evidence or parturition into 45 days after mate, were assumed ?non- RS?. 12 of the 87 mates conformed registered injuries: 3 FFM and 9 FUM. So, we measured RS in 26 mates FFM and 49 FUM. 92,3% mates FFM and 91,8% FUM registered RS. No significant differences in RS were observed between FFM and FUM (differences proportion test p=0,500). Moreover, no significant differences in litter size average, infanticide and post-partum estrus were registered (p>0,05). A. azarae females show no sexual preference based on familiarity. So, our results support a promiscuous-polygynous mating system.