Reproductive compatibility between mite populations previously identified as Euseius concordis (Acari: Phytoseiidae)

The objective of the present research is to study the reproductive compatibility between populations of predatory mites previously identified as Euseius concordis (Chant) based on morphological characteristics. Colonies of these mite populations were established in the lab with specimens collected from different localities and host plants. Reproductive compatibility was evaluated through crosses and backcrosses within and between populations and the subsequent observation of females' oviposition, over a period of 10 days. The levels of oviposition obtained in the crosses between individuals from the same population were higher than those obtained in the crosses between individuals from different populations. Results indicate the occurrence of post-mating reproductive incompatibility between the mite population from Petrolina and the other populations studied. Crosses and backcrosses between populations involving female mites from Petrolina did not produce offspring, although endospermatophores were present inside the spermathecas of those females. Oviposition was reduced, and only sons were obtained, in crosses between populations with males from Petrolina. Crosses of females from Pontes e Lacerda and males from Jaguariúna and vice versa produced only male progeny. Our results established that the populations originating from Arroio do Meio, Pontes e Lacerda, Jaguariúna and Viçosa, are reproductively compatible. However, the latter populations and the population from Petrolina are genetically isolated. Based on these results we suggest that more cytological and genetic studies are needed to establish if this reproductive isolation represents a species barrier.