Mass rearing of Cheilomenessexmaculata (Coleoptera: Coccinellidae) on different diets under laboratory conditions

The ladybird beetle, Cheilomenes sexmaculata is a potential biocontrol agent for use in augmentative release programmes. The survival (%) of coccinellid larvae varied significantly among the seven different selected diets (egg yolk, chicken liver, chicken liver with aphids, chicken liver with legume juice, aphids, house fly maggots, fish meal powder) (F=1478 df =98; 6 p<0.05). The highest survival was recorded when the larvae were fed on aphids (95.0 ± 3.0%). Larvae did not survive when fed on egg yolk and fish meal powder. The survival of L2 larvae was 72% when fed on chicken liver. The total larval duration significantly varied with different diets (F=767 df =63; 6 p<0.05). The shortest total larval duration was recorded when all larval instars were fed exclusively on aphids (7.60 ± 0.1days). When L2 larvae were fed on chicken liver, 10.86 ± 0.13 days were taken to develop into an adult. The highest growth rate was recorded when all larval instars were fed exclusively on aphids. The longest duration was recorded for L1 larvae fed on aphids and other three instars fed on chicken liver. To test the effect of substrates on the number of egg laid eggs laid during the lifespan, five substrates (plastic boxes, paper pieces, fresh bean leaves, bean cotyledons, sand layer) were also tested. It varied significantly among the five different substrates (F=2502.07 df =70: 4 p< 0.05). The highest number of eggs was laid on the sides of plastic boxes (n=823.7 ± 2.2) while the lowest number of eggs was laid on the sand layer (n= 80.1 ± 10.4). The findings indicate that the replacement of aphid feed by chicken liver for larval instars L2, L3 and L4 is possible with a compromised survival (%) of larvae.