ACCLIMATIZATION OF BIOCONTROL AGENT, ZYGOGRAMMA BICOLORATA PALLISTER (COLEOPTERA : CHRYSOMELIDAE) TO ECOCLIMATIC CONDITION IN NORTH WESTERN UTTAR PRADESH

Zygogramma bicolorata Pallister is a potential biocontrol agent of abnoxious weed Parthenium hysterophorus L. (Asteraceae) which causes several diseases in human and livestock. This Mexican beetle is a voracious feeder, eats each and every part of the weed except root and hard stem. On the onset of winter, in last week of November, most of the adults begins to hibernate and pupae proceed for diapause but some adults and larvae were observed even during December and January. These left over beetles were found developing adaptation to cold environment. These beetles changed their colour from light brown to dark blackish to absorb more sun heat during winter. The adults and larvae generally observed attracted to sun light. During night, morning and evening time the beetle hide in buds or axillae region in winter and such beetle remain on exposed dorsal surface or leaf to get heat from Sun light in noon. Moreover, the size of these beetles also decreased upto 2 mm. in length to survive on low calories and low metabolic activities. Though, the beetle population was very less in winter than rainy and summer months but these were active during winter against low temperature. Furthermore, it was also observed population of beetle and infestation percentage were increased gradually year after year in Winter in this area where fluctuation occurs in wheather and other abiotic factors throughout the year. The beetle population might have developed quick adaptations to low temperature of Winter either by variations or gene mutations. This has to be further explored.