Eine verbesserte Technik zur Gewinnung eines höheren Weibchenanteils beim Parasitoiden Bracon brevicornis Wesm. (Hym., Braconidae)

The effect on sex ratio ofBracon brevicornis progeny when male, female, and host larva (Sesamia cretica) were placed together in different time sequences, was investigated. Placing a parasitoid female first, a male after 3 hours, and a host larva after 24 hours, yielded significantly the highest proportion of females (48%). In this case female/male sex ratio was 1∶1 approximately, while other manipulations, they ranged from 1∶4 to 1∶20 (with preponderance to males).