Mating Strategy and Reproductive Success in the Teiid Lizard, Ameiva Plei

Abstract

Current selection on sexual size dimorphism was studied in a widely foraging non-territorial lizard, Ameiva plei. Males were significantly larger than females. Large males won intrasexual agonistic encounters and guarded females during their entire receptive period (1-4 days). Guarding males spent significantly less time foraging than males who were alone. Only males that guarded females were observed to mate. Mating success was highly skewed with only six of 21 mature males in the study site observed mating. All six males who mated were 141 mm SVL (males mature at 62 mm SVL). The four largest males obtained 84% of all observed matings and were estimated to have fertilized 88% of the eggs. Sexual selection appears to favor large size in males due to competition among males to guard females. Large females on Anguilla also had higher reproductive success bccause SVL was positively correlated with clutch size and number of clutches in a season. It appears that natural selection has favored different trade-offs between growth and reproduction in males and females.

Mating behavior and female accompaniment in the whiptail lizard Cnemidophorus ocellifer (Squamata, Teiidae) in the Caatinga region of northeastern Brazil

“…To date, female accompaniment in teiids is known to occur in a few species of the genera Aspidoscelis (Anderson & Vitt 1990, Zaldívar-Rae & Drummond 2007, Ancona et al 2010 and Ameiva (Censky 1995). Based on these reports, Zaldívar-Rae et al (2008) remarked that this behavioral trait seems to be widespread in mating systems of teiids.…”

“…Because males usually arrange their territories to enclose the female's territory and exclude other males from their own territories, females have little opportunity to see more than one male at a time; thus, females tend to be monogamous (Stamps 1983). In non-territorial lizards, however, polygyny often is sequential, with males usually searching for females, and staying with them for various lengths of time after successful mating (Anderson & Vitt 1990, Olsson 1993, Censky 1995, Cooper & Vitt 1997, Olsson & Shine 1998. Because females of these species have the opportunity to mate with several males, the primary mechanism available to males to ensure paternity is to accompany the female and guard her from access by other males (Bull 2000).…”

“…Teiids are heliothermic, active foragers, and commonly abundant in open habitats. Sexual dimorphism in size and shape is widespread in the family, with males attaining larger body sizes than females and having relatively larger heads, a trend that is attributed to sexual selection (Anderson & Vitt 1990, Censky 1995. Among teiids, the cnemidophorines (whiptail lizards) occupy various habitats in the Americas, with the genus Cnemidophorus occurring throughout South America (Reeder et al 2002).…”

“…The social interactions of teiids have proven to be difficult to study in the wild because of the lizard's active mode of foraging, which tends to lead to enlarged home ranges (Censky 1995), and strong wariness, which is linked to foraging mode and predator escape tactic (Vitt & Price 1982). Thus, studies reporting social interactions in teiids often are based on casual observations (e.g.…”

“…Thus, studies reporting social interactions in teiids often are based on casual observations (e.g. Vitt 1983, Costa et al 2010, and the few studies that investigated social interactions quantitatively were performed mainly with insular populations (Censky 1995, 1997, Baird et al 2003, Zaldívar-Rae & Drummond 2007, Ancona et al 2010, in which the lizards often occur in elevated densities, facilitating observations by investigators. Little is known about courtship and mating behavior of mainland teiid species, especially Cnemidophorus.…”