Parena nigrolineata (Chaudoir)

Parena nigrolineata has been recognized predating on Opisina arenosella. It is widely distributed in South India.

The adult consumes on an average 6 to 11 Opisina caterpillars and the grub consumes on an average 9 -12 caterpillars. The adults are also capable of feeding on the pupae of Opisina.

Five adults of Parena nigrolineata are released in each of the specimen glass jars (15 x 5 cm) and covered with mull cloth. Fresh coconut leaf bits, 10 cm long, containing adequate number of fourth instar caterpillars of Opisina arenosella are provided in each jar. The leaf bits are examined daily for oval shaped egg. The eggs are removed daily with small bits of the leaf lamina and kept in glass tubes (8 x 2.5 cm) for hatching.

Additional moisture is provided in glass tubes by keeping small rolls of cotton wool soaked in water. The tubes are either plugged firmly with cotton rolls or covered with mull cloth.

The hatched grubs are collected daily and transferred individually to separate glass vials (8 x 2.5 cm). In view of the cannibalistic behaviour of grubs in the early stages they are reared individually in separate glass vials. Initially each grub is provided with one second instar caterpillar of Opisina arenosella as food. Thereafter fourth instar caterpillars, are provided as and when required.

When the grubs attain maturity and stop feeding they are maintained in glass bottles 15 x 5 cm) with moistened moss. The 1ife cycle is completed in about 24 days (17-36 days).

The roundish egg, three larval instars, pre-pupal and pupal stages last 5.2 (5-6), 11(6-16), 34(2-5) and 5.4(5-6) days, respectively. The male and female adult beetles live for 214 (7-497) and 196 (21- 486) days respectively. The grub consumes only 4.4 fourth instar caterpillars in 3.5 days. The adult male consumes 6.7 caterpillars in 214 days and female 67.59 caterpillars in 196.2 days.