CAN PARTHENOGENETIC CNEMIDOPHORUS-LAREDOENSIS (TEIIDAE) COEXIST WITH ITS BISEXUAL CONGENERS

Wright and Lowe (1968) Cuellar (1977) suggested that parthenogenetic Cnemidophorus can survive only in isolation from their bisexual congeners because the latter would otherwise eliminate the parthenoforms through competition and/or destabilizing hybridization. Data from studies of the parthenogenetic clone LAR-A of the Cnemidophorus laredoensis subgroup suggest this hypothesis is not correct. The bisexual species C. gularis occurs at 24 of the 39 sites at which LAR-A has been found, and neither form is consistently more abundant than the other at syntopic sites. The literature documents many cases where parthenogenetic whiptails coexist with their bisexual congeners, suggesting parthenoforms do not require isolation as previously believed. One of two things must be happening to allow parthenoforms to coexist with bisexuals: (1) competition and destabilizing hybridization do not occur; or (2) these processes do occur but some other factor counteracts their effect. At present, too little data exist to evaluate which of these alternatives is correct. However, analysis of lizard diets at three sites of syntopy and data reported in studies of other parthenoforms are used to advance testable hypotheses in the hope of stimulating future research.