Multiple paternity and sperm storage in the Cape Dwarf Chameleon (Bradypodion pumilum)

Although multiple paternity and sperm storage are common in squamates, neither has been conclusively demonstrated in the chameleons (Chamaeleonidae). To examine whether these traits are present in chameleons, the Cape Dwarf Chameleon (Bradypodion pumilum) was investigated. This viviparous species inhabits a temperate climate in southern Africa, has aseasonal breeding, and can produce multiple clutches annually. Given this reproductive schedule, we hypothesised that females may mate opportunistically and store sperm, and that single clutches may have multiple sires. To examine this, six females and their clutches were genotyped using microsatellite markers, and assessed for multiple paternity. In addition, 46 females were assessed for sperm storage structures and presence of sperm in the oviduct. Multiple paternity was found in all six clutches, based on the presence of multiple alleles at all loci that could not be assigned to the mother. No evidence of specialised sperm storage structures was found, but sperm was present in the lumen of the posterior oviduct in 74% of females. While sperm storage cannot be concluded with finality, it seems likely to occur, rather assuming that three out of four of the females in the sample had mated just prior to capture. Furthermore, two post-partum females retained sperm in the oviducts after the delivery of a clutch, but in the absence of additional copulation. Given that this species has aseasonal reproduction, if sperm is indeed stored long-term, this combination of traits would be advantageous given the lack of defined breeding season and presumably low rates of mate encounter.