Rearing of Mallada basalis (Neuroptera: Chrysopidae) on modified artificial diets.

Abstract

Mallada basalis (Walker) has the potential to be a valuable biological control agent because of its predatory abilities, strong reproductive capacity, and broad prey range. This study aimed to improve on a previously used artificial diet for M. basalis, to achieve a longer oviposition period and greater survival rate and fecundity. We analyzed the development, survival, longevity, and reproduction of M. basalis (F1 and F2 generations) fed two artificial diets (AD1 and AD2). Both diets contained chicken egg yolk, beer yeast powder, honey, trehalose, seawater spirulina, and potassium sorbate. AD1 also contained sucrose and vitamin C. The duration of F1 1st larvae, F1 2nd larvae, F1 pupae, F2 egg, and F2 2nd larvae reared on AD1 were significantly shorter than those reared on AD2. F1 adult longevity and F2 oviposition period for AD1 (45.40 d and 31.00 d) were significantly longer than for AD2 (30.74 d and 20.80 d). All the following were significantly greater for AD1 compared with AD2: F1 female proportion, F1 daily oviposition, F1 female oviposition, F2 daily oviposition, F2 female oviposition, F1 emergence rate, F2 pupation rate, and F3 egg hatching rate. Moreover, for M. basalis fed AD2, the duration of F2 2nd and 3rd larvae (9.00 d and 8.64 d) were significantly longer than for F1 (4.70 d and 4.92 d). The F1 oviposition period (31.57 d) was significantly longer than F2 (20.80 d). The F2 female oviposition (189.20 egg/female) was significantly less than F1 (307.14 egg/female). We found that the oviposition period and female longevity of F1 reared on AD1 was longer than that reared on the artificial diet in a previous study. The daily oviposition and female oviposition of F1 from AD1 was larger, while the F2 egg hatching rate was greater compared with that from the previous diet. However, the offspring of M. basalis fed AD2 were less thrifty. We found diet AD1 supported development and reproduction better than AD2 and the diets in our previous study. These findings may contribute to the mass rearing of this economically important predatory green lacewing.