Induction of males in thelytokous populations of Encarsia meritoria and Encarsia protransvena: A systematic tool

Males from thelytokous females of Italian uniparentalpopulations of Encarsia meritoria and Encarsiaprotransvena were obtained by feeding wasps with tetracycline orrearing parasitoids at high temperatures respectively. Two thermictreatments were tested on E. protransvena: 31°C constanttemperature versus an alternation of 12 hours at 33°C and 23°Con a daily basis. Females of E. meritoria fed with tetracyclineproduced 80.87% of male progeny. Tetracycline did not induce maleoffspring in E. protransvena. For this species hightemperatures were required even though only a few males were obtained(0.31–5.43%). These results confirm the infection ofparthenogenesis-inducing micro-organisms in E. meritoria, whilethis is doubtful in E. protransvena. Males derived fromthelytokous populations of the two species were described. Males of theuniparental population of E. meritoria were similar to those ofbiparental ones, suggesting that the two populations are conspecific.Males of E. protransvena are slightly different from thosedescribed previously, supporting the hypothesis that E.protransvena is a complex of cryptic species. Our results suggestthe possibility of using ``induced males' by either antibiotics or hightemperatures as a taxonomic tool in the genus Encarsia toseparate similar (if not undistinguishable) uniparentalspecies.