To our knowledge, this study is the first to report multiple paternity in the Guatemalan beaded lizard, H. charlesbogerti, and represents the first record in the family Helodermatidae. Furthermore, we show that females will produce offspring with multiple males across seasons, and that males will sire offspring from multiple females within and across seasons. Hence, the mating system of this species when housed in a group is highly promiscuous with within season polyandry. Although novel, the capacity for multiple paternity in this species is unsurprising given the high incidence of multiple paternity in reptiles; indeed, multiple paternity has been reported across many reptile taxa (Uller and Olsson 2008) and is common outside of Reptilia (reviewed in Taylor et al. ). Nonetheless, these findings have important consequences for the management of captive-breeding programs at zoological facilities and private collections, where mating among captive lizards is often promoted through the pairing of single males and females. However, by allowing multiple males to participate in reproduction, multiple paternity may elevate within-clutch genetic diversity among offspring and allow for cryptic female choice of sperm potentially with higher genetic quality, thereby contributing to the maintenance of genetic variation in this species (Uller and Olsson 2008, Taylor et al. 2014). If indicative of the natural mating system, multiple paternity may also minimize the potentially deleterious effects of inbreeding (Tregenza and Wedell, 2002). While females were observed to exhibit serial polyandry, females were also found to produce offspring with the same male across seasons, either in single- or multiple- paternity clutches. It was not possible here to determine whether these resulted from long-term sperm storage (LTSS) across seasons, however LTSS has been reported in other reptiles, with the production of viable offspring resulting from the storage of sperm for up to six years (Booth & Schuett, 2011; Levine et al. 2021). Observations at Zoo Atlanta of eggs laid by females that had been with males in previous seasons but not housed with males in following seasons have not provided evidence of LTSS as in all cases eggs failed to show signs of development. Both within and across seasons, males were found to be polygamous. Overall, under this captive environment, H. charlesbogerti was found to be highly promiscuous, with multiple paternity common within clutches.
Regardless of the evolutionary significance, multiple paternity and a promiscuous mating system within a captive environment may reflect a previously unknown aspect of the natural mating system of this, and other helodermatid, species, that should be promoted in captivity. It should be cautioned however, that when developing breeding programs for species of conservation concern, pairings should be strategically planned in order to minimize inbreeding and prevent a bias of offspring sired by single or a few males. Although multiple mating has never been observed in the wild in helodermatids (Beck 2005), anecdotal observations indicate the potential for it. As such, efforts should be directed towards understanding the significance of promiscuity and multiple paternity within wild populations of helodermatid lizards, including the Guatemalan beaded lizards, and address the potential implications for the conservation and management of natural populations and captive colonies. Furthermore, within captive colonies, the existence of long-term sperm storage should be studied, given the significant implications for captive management.