Department of Environmental Sciences, Gurukul Kangri University, Haridwar-249407, Uttaranchal, (India).
1Division of Entomology, Indian Agricultural Research Institute, New Delhi-110012, (India).
The Mexican beetle, Zygogramma bichlorata Pal. was found active on Parthenium histerophorus L. during May to September 2000. Studies on biology revealed that eggs were laid on the dorsal surface of the leaves and flowers. The incubation period of eggs was 4 days. The insect moulted thrice and passed through 4 larval stages. Duration of each stage ranged from 2–3, 2–3, 2–3 and 3–4 days, respectively. Pupation took place 1–3 cm. inside the soil in a muddy case and pupal stage lasted for 8 to 10 days. The females emerged prior to the males. Mating took place 3–4 days after adult emergence. The female started laying eggs 2 to 5 days after mating. The pre oviposition period in laboratory lasted about 7–10 days. A female could lay a maximum of 65 eggs per day during peak of production and on an average laid around 2500 eggs in its oviposition period. The longevity was more in males, (4–8 months) than the females (3–6 months).
