Pg. Milonas et M. Savopoulou-soultani, Diapause induction and termination in the parasitoid Colpoclypeus florus (Hymenoptera : Eulophidae): Role of photoperiod and temperature, ANN ENT S A, 93(3), 2000, pp. 512-518
The processes involved in the induction and termination of facultative larv
al diapause in the parasitoid Colpoclypeus florus (Walker) was investigated
in the laboratory. Larval diapause in C. florus is under maternal control.
Photoperiod is the major factor governing the induction of larval diapause
in C. florus. The pupa of the maternal generation is the most sensitive st
age though the adult is also sensitive. Adult sensitivity increases with ag
e, in particular at low temperatures. Photoperiod has no effect on the deve
loping larva. The critical photoperiod for diapause induction for parasitoi
ds maintained throughout the life cycle at 15 and 20 degrees C was found to
be 15 and 13.5 h, respectively. No diapause was induced at 25 degrees C at
any photoperiod examined. A chilling period of >5 wk is a prerequisite for
diapause termination. After 8 wk at 5 degrees C, all diapausing larvae pup
ate within 20 d whether held under short or long daylength. Chilling temper
ature and duration of chilling significantly affected diapause termination.
Diapause development proceeds rapidly as chilling period increases and tem
perature decreases. The role of diapause in the biology of this parasitoid
is discussed.