Diet-Dependent Survival, Development and Fecundity of the Spider Atypena formosana (Oi) (Araneae: Linyphiidae)Implications for Biological Control in Rice

The development time of Atypena formosana was assessed on four different diets: (1) brown planthopper (BPH), Nilaparvata lugens ; (2) green leafhopper (GLH), Nephotettix virescens ; (3) Collembola (Entomobryidae); and (4) a mixed diet of Collembola, hoppers and Drosophila melanogaster . A starvation treatment served as a control. We tested the hypothesis that because of differences in food quality, the diets would affect survival and development differently. Survival differed significantly among the diets. No spiders survived until adult on the diet of GLH, only a single individual survived on the diet of BPH, whereas 70% survived until adult on the Collembola diet and all survived on the mixed diet. Development times were significantly different among the diets tested. Spiders developed fastest on the mixed diet and the Collembola diet. The biomass of prey consumed within 48 h and the total biomass of prey consumed to complete an instar were highest on the mixed diet. Finally the mixed diet resulted in higher fecundity than the Collembola diet. It is concluded that alternative prey are an absolute necessity, as BPH and GLH diets alone would not be able to increase the number of predators, regardless of the number of hoppers present.

Keywords:

• Atypena Formosana
• Nilaparvata Lugens
• Nephotettix Virescens
• Collembola
• Survival
• Development
• Biological Control
• Spider
• Prey