Temperature-dependent effects on some biological aspects of two ectoparasitoids of Phyllocnistis citrella (Lepidoptera: Gracillariidae)

Abstract

Abstract Background Temperature alters host suitability for the development of parasitoids through direct (thermal effect) and indirect (parental effect) pathways. The effects of three temperature regimes on the development and survival of two parasitoid species, Citrostichus phyllocnistoides (Narayanan) and Cirrospilus ingenuus Gahan (Eulophidae: Hymenoptera) of the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) was evaluated. The experiment was conducted at 20, 25, and 30°C temperatures with 65 ± 2% relative humidity (R.H.) and 16h: 8h (L: D) photoperiod. Results In C. phyllocnistoides, the pre-ovipositional period was longer at 20°C, while non- significant difference was observed in the pre-ovipositional period of C. ingenuus under the effect of different temperatures (P > 0.05). The ovipositional period of C. phyllocnistoides and C. ingenuus was higher at 20°C and gradually decreased by increasing the temperature. Non- significant (P > 0.05) difference was found in post-ovipositional period of both parasitoid species. Both species exhibited the maximum fecundity at 25°C, while, the minimum fecundity was recorded at 30°C. However, the adult longevity of both parasitoid species was highest at 20°C and gradually decreased by increasing the temperature. In both parasitoids, the parasitism rate was highest at 25°C. Conclusion This study highlighted the importance of thermal effects on some parasitoid species of insect pests to predict the future of trophic dynamics in global warming situations.

Keywords

• Citrus leafminer
• Citrostichus phyllocnistoides
• Cirrospilus ingenuus
• Parasitism
• Temperature