Macrolophus pygmaeus and Nesidiocoris tenuis (Hemiptera: Miridae) searching ability under four Tuta absoluta (Lepidoptera: Gelechiidae) egg densities and different prey distribution patterns

Abstract: Tuta absoluta is one of the most devastating pests of tomato crops. Efficacy of
biological agents such as the predators Macrolophus pygmaeus (Mp) and Nesidiocoris tenuis
(Nt) is associated with their prey searching efficiency, which is affected by the prey density and distribution. Our study aimed to compare the searching behaviour of both predators on T. absoluta eggs when prey was offered in different densities (3, 5, 8 or 10 eggs) and distribution patterns: i) the natural oviposition pattern followed by T. absoluta females, ii) the linear pattern, by placing the eggs on the central vein, iii) the clumped, placing the eggs in a group one close to the other iv) the peripheral, placing the eggs close to the edge to the edge of the leaflet. Τhe number of consumed eggs was recorded after 15′, 30′, 60′, 120′ and 180′. Results showed that Mp consumed more eggs than Nt at 15′ when 3 eggs/leaflet were positioned linearly or clumped. In case of 5 eggs/leaflet Mp consumed more eggs in 15′ and 30′ when were clumped positioned or peripheral of leaflet. When 8 eggs were offered Mp consumed more eggs than Nt in 15′. Also, when 10 eggs were offered Mp consumed more eggs in 30′ and 60′ in all cases except of the natural pattern. Consequently, Mp showed higher prey searching efficiency than Nt whereas similar prey searching efficiency by both predators was recorded when the eggs were positioned according to the natural egg distribution pattern of T. absoluta.