Intrapopulation Variability of the Qualitative and Quantitative Photoperiodic Responses in Habrobracon hebetor (Say) (Hymenoptera, Braconidae)
S. Ya. Reznik, Konstantin Samartsev, M. Yu. Dolgovskaya
Abstract
Females of the hymenopteran parasitoid Habrobracon hebetor show two types of photoperiodic response: development under short day conditions results in an increase of the adult size (quantitative response) and in the induction of reproductive diapause (qualitative response). In a study conducted with individuals from a laboratory population, the progeny of each female was divided into two groups, which developed under the short (10 h) and long (18 h) day conditions. Females significantly differed both in the mean body size of the progeny and in the proportion of diapausing individuals. The qualitative and quantitative responses interact: short day caused an increase in size only in diapausing individuals. In addition, family analysis revealed significant positive correlations between the proportion of diapausing individuals (a manifestation of the qualitative response) and the mean size of the progeny (a manifestation of the quantitative response). The results of the study support the hypothesis on the unity of the mechanism of the qualitative and quantitative photoperiodic responses.