Colonization of invasive weevils with different reproductive modes

RODRIGUERO M. S.; CONFALONIERI V.A.; A.A. LANTERI; GUZMAN N. V.

Orlando

Simposio; XXV International Congress of Entomology; 2016

Asexuality provides demographic advantages for invading new areas. A single, unmated female can initiate a new colony, thus avoiding the impact of inbreeding depression and the cost of both male production and mate searching. However, pre-existing adaptations of parthenogens are identified as key factors contributing to a successful outcome. Parthenogenesis is common in weevils, accounting for about 22% of all known species of asexual insects. Naupactus leucoloma and N. cervinus (Coleoptera: Curculionidae: Naupactini) are parthenogenetic weevils native to and partially co-distributed in South America, that have been able to successfully invade very distant locations around the world. Naupactus xanthographus is a bisexual weevil whose geographic distribution partially overlaps in South America to the former species, but that has been never found outside the continent. All these insects are considered pests for economically important crops.We applied phylogeographic and Ecological Niche Modeling (ENM) approaches to investigate whether parthenogenesis in these weevils was associated with higher colonization ability in marginal environments . Phylogeography allowed formulating hypothesis on central and marginal areas of distribution, detecting demographic and range expansions, and establishing routes of colonization. ENM allowed defining the geographic areas with most suitable environments for the species under study. Our results support the idea that parthenogenetic species are more successful than bisexual ones in colonizing new environments. However, only certain asexual lineages would have been able to adapt to unsuitable conditions. We postulate that parthenogenesis not only provides demographic advantages, but would also prevent the break-up of successful gene combinations for adaptation to marginal environments.