How plants maintain body-guards: plant exudate as a food source for phytoseiid mites

Abstract

Typhlodromalus limonicus (Garman and McGregor) is the most abundant species of the Phytoseiidae in South American cassava (Manihot esculenta Crantz). It persists in the crop in the absence of arthropod prey. This study established that this persistence is due, at least in part, to a resource provided by the plant. Cassava exudes, mainly from the petioles, a cyanide-free sugary solution. When confined on leaf discs with this exudate, the mites survive longer than those provided with water (control) and, in addition, they can develop from egg to adult. Moreover, we have been able to demonstrate that the exudate elicits an olfactory response in predators after a food-deprivation period of 24 hours. Two-choice disc experiments showed that it also had a strong arresting effect on larvae but less so on adult females. However, a diet of exudate alone does not result in oviposition.