Functional response of Nesidiocoris tenuis on different densities of Ephestia kuehniella and Tuta absoluta eggs

The response of a natural enemy to its host’ densities has been defined as “functional response”. It has been considered a feasible technique to measure the efficacy of biocontrol agents. We employed the concept to evaluate the functional response of adult female and male of Nesidiocoris tenuis under laboratory conditions by feeding on different densities (1, 2, 4, 8, 16, 32, 64, and 96) of Ephestia kuehniella and Tuta absoluta eggs in 7 replicates. The predators were kept unfed for 24 hours. Then the number of eaten prey was recorded after 24 hours. The results showed type III functional response for all tests based on logistic regression. The attack constants (b) of females and males fed on E. kuehniella and T. absoluta eggs were 0.0061 ± 0.0018, 0.0048 ± 0.0009, and 0.0093 ± 0.0037, 0.0042 ± 0.001, respectively. The estimated handling times (Th) for females and males on the respective preys were 0.3598 ± 0.0193, 0.2905 ± 0.0136, and 0.9032 ± 0.0511 and 0.5859 ± 0.0303 h. In conclusion, N. tenuis females had shorter handling time, greater attack rate and maximum daily consumption (73.86 eggs) compared with those of males. Therefore, results strongly support that female predators could be more effective in controlling T. absoluta.