Searching behaviour and prey preference by the predatory bug Tupiocoris cucurbitaceus, a potential biocontrol candidate of Tuta absoluta

Generalist arthropod predators usually exhibit a degree for prey acceptance and this behavior can ultimately determine their potential as biocontrol agents. Tuta absoluta is a key pest of tomato crops. The use of predatory mirid bugs has showed positive results to control this pest in several countries. In a laboratory study we assessed: 1) prey searching behavior, and 2) feeding preference of Tupiocoris cucurbitaceus, a mirid bug present in Argentinian tomato crops as a biocontrol candidate of T. absoluta. The arena consisted of a tomato leaflet placed in a Petri dish and offered simultaneously three patches of preys to one T. cucurbitaceous individual: the target patch (TP) with 30 T. absoluta eggs and two non-target patches (NTP) with 30 Ephestia kuehniella eggs and 5 Trialeurodes vaporariorum nymphs. Predation traits were tested using nymphs and adults of both sexes of T. cucurbitaceous. Predation was first observed during 30 min using the software EthoVision®, and later units were conditioned to check prey consumption at 24h. At 30 min, we found that all mirids spent more time on the tomato leaflet than feeding on TP and NTP patches; considering the food patches, they visited equally all although males revisited more frequently the TP patches. At 24 h, all mirid stages showed feeding preference for NTP patches. These results prove that T. absoluta eggs can be part of the prey diet of T. cucurbitaceous but it preferentially feeds on other prey items, compromising its performance as a biocontrol agent in field conditions.