Revealing parthenogenetic reproduction in a praying mantis inhabiting South American grasslands

Mantids are charismatic insects due to their appearance and behaviors, but knowledge about them, in particular at the Neotropics, is scarce. Brunneria subaptera (Coptopterygidae) is the most abundant praying mantis species in Uruguay, inhabiting one of the world's largest natural grasslands. Data from collections and field observations indicated that Uruguayan samples of B. subaptera only included females, whereas both sexes were found in Argentina. This extreme-biased sex ratio could be explained through thelytokous parthenogenesis. Endosymbiotic bacteria, such as Wolbachia, can induce parthenogenesis, though their role in sex ratio distortions in diploid insects is understudied, with limited evidence from species like Mantis religiosa, where no phenotypic effects were observed. To test if B. subaptera females from Uruguay reproduce by parthenogenesis and evaluate Wolbachia infection as a possible cause, we bred virgin females in the laboratory. All produce viable offspring, confirming parthenogenesis in the studied Uruguayan localities. However, Wolbachia infection was not detected. Future studies will focus on studying other factors that may cause parthenogenesis in this species. These findings advance our understanding of mantids in the Neotropics, but will also constitute a very important step to unravel the reproductive biology and evolutionary processes behind reproduction in Neotropical mantids.