Abstract

PEREYRA, Patricia C. Evidence of intraspecific competition in early instars of the tomato moth, Tuta absoluta (Lepidoptera: Gelechiidae). Ecol. austral [online]. 2002, vol.12, n.2, pp.143-148. ISSN 1667-782X.

The tomato moth (Tuta absoluta) is the major pest of this crop in many South American countries. Although larvae initiate new mines when they molt to the third instar, their density during the sedentary early instars may be critical for larval survival, developmental time and pupal weight. The objective of this study was to explore whether both the density of eggs and the leaf area influence intraspecific competition among early larval instars of this species in terms of larval survival, developmental time and weight of pupae. Increasing densities of eggs were negatively correlated with larval survival. The weight of pupae was positively related with fecundity and decreased with egg density. Increasing within-leaf egg density had a positive but weak effect on developmental time. About 39% of the variation in egg number was explained by leaf area, thus other factors might be influencing the selection sites for oviposition. Larval survival was negatively but weakly related with leaf area. This variable did not explain neither pupal weight nor developmental time.

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