Macrolophus pygmaeus (Mp) and Nesidiocoris tenuis (Nt) are valuable biological control agents against Tuta absoluta. However, their predation rate on T. absoluta eggs over the entire plant has not been sufficiently studied. The aim of this study was to record the density and map the T. absoluta egg distribution per plant under different female densities.
The study also explored the predation rates of single (Mp/Nt), conspecific (2Mp/2Nt), or heterospecific pairs (MpNt) of predators on tomato plants on which T. absoluta eggs had been placed at the respective densities and sites as those selected by the T. absoluta females. The number of eggs laid per female was highest when the females were used singly. Females made active egg-laying decisions preferring to oviposit on the 3rd and 4th leaves. Single M. pygmaeus showed higher predatory efficacy than N. tenuis when 14 and 30 eggs were used per plant.
Conspecifics of M. pygmaeus were more effective than N. tenuis at densities of 17 and 110 eggs. Interestingly, a pair was as effective as a single predator at 14, 17, and in many cases at the 30 and 110 egg/plant densities. The multiplicative model revealed that prey density has a strong impact on the effects of multiple predators on prey suppression. In all cases, 30% or more of the eggs were left unconsumed. These results suggest that the study of predation under field conditions and different pest pressure levels reveals useful information for the evaluation of predator efficacy in T. absoluta control.
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Dervisoglou, Sofia & Perdikis, Dionysios & Papanikolaou, Nikos & Fantinou, Argyro. (2022). Is the control efficacy of two interacting predator species affected by the distribution and density of Tuta absoluta eggs on tomato plants? Journal of Pest Science. 1-13. 10.1007/s10340-022-01556-7.