Abstract:

To investigate the effects of reduced aphid feeding on larval survival and adult oviposition of Coelophora biplagiata, controlled laboratory experiments were conducted using a rearing system where early-instar larvae were fed Aphis craccivora and late-instar larvae received artificial diet under five density conditions (5, 10, 15, 20, and 30 larvae/container), combined with graded aphid reduction (0%, 25%, 50%, 75%, and 100%) during adult stage. Results demonstrated: (1) In Group A (artificial diet introduced from 3^rd instar larvae), the 3^rd instar larvae survival rate under the feeding density of 30 larvae/container was 65.56%, significantly lower than other densities (P<0.05). 4^th instar larvae survival rate reached 100% under the feeding density of 5 larvae/container. Pupal survival rates ranged 82%-94% without significant differences (P>0.05). Adult emergence rate decreased with increasing density, peaking at 80.00% under the feeding density of 5 larvae/container. (2) In Group B (artificial diet introduced from 4^th instar larvae), 4^th instar larvae survival rates remained 74%-87% without significant differences (P>0.05). The lowest pupal survival rate occurred under the feeding density of 30 larvae/container (79.53%). Adult emergence rates under the feeding densities of 5-15 larvae/container ranged 75%-87% with no significant differences (P>0.05). (3) Group C showed highest adult emergence rate. (4) Oviposition performance declined with increasing aphid reduction, achieving 80% of full-aphid diet productivity at 25% aphid reduction. Artificial diet-fed adults showed minimal egg production. No significant differences were observed in egg hatch rates or adult survival across feeding regimes (P>0.05). In conclusion, partial replacement of aphids with an artificial diet is feasible for both larval rearing and adult oviposition of C. biplagiata.

Key words: Coelophora biplagiata, aphid, artificial diet, survival rate, fecundity