A tale of two species: Parthenogenetic and sexual populations of the genus Haploembia Verhoeff found in California

Webspinners in the genus Haploembia (Order Embioptera) were introduced into California from their native range in the Mediterranean region. In this region, the genus has long been thought to comprise of a single widespread species Haploembia solieri with both sexual and asexual populations, and two additional sexual species with restricted ranges in the eastern Mediterranean. For most of its known history in California only asexual populations were collected; however, within the last couple of decades sexual populations have been discovered. The purpose of this project is to determine whether a single species exists in California, that may imply reacquisition of sex, or whether these populations represent two or more species. To resolve this question, molecular DNA sequence data were acquired across Californian, New Mexican, and Mediterranean specimens, including both nuclear (histone 3) and mitochondrial (cytochrome oxidase subunit I) genes. Specimens from multiple populations from the western United States were sequenced. These included both sexual and asexual specimens from California and asexual specimens from central New Mexico. Also included were specimens from Sardinia, where only asexual populations occur, and mainland Italy, where only sexual populations occur. These data were included in a phylogenetic analysis to resolve relationships between these individuals. Our analysis shows asexual California specimens grouping with the asexual specimens in Italy, whereas the sexual California specimens group separately from both asexual specimens and sexual Mediterranean specimens. Therefore, we conclude that there are two species of Haploembia solieri introduced into California.