The ground beetle Pseudophonus rufipes revealed as predator of Ceratitis capitata in citrus orchards

Abstract

The Mediterranean fruit fly Ceratitis capitata (Wiedemann) is a major citrus pest in Spain. Although medfly is being controlled chemically, alternative biorational strategies should be developed, like those based on conservation biological control of polyphagous predators. The ground beetle Pseudophonus rufipes (De Geer) is the most abundant carabid inhabiting the ground of citrus orchards in eastern Spain. However, little is known about its activity-density and predatory role against C. capitata in the citrus agroecosystem. Here, we report on its predatory potential on the medfly's developmental stages that take place in the citrus ground. This carabid species preyed efficiently on C. capitata third instar larvae and especially on pupae but not on teneral adults. Moreover, predation under field conditions was evaluated by detecting C. capitata DNA remains using PCR-based gut-content analysis. Half-life DNA detectability of C. capitata was of 32.33 h. Pseudophonus rufipes specimens were field-collected after C. capitata sterilized pupae were deployed in a commercial citrus orchard. Thereafter, the carabids captured by pitfall traps were analyzed, being DNA-remains of C. capitata detected in 22.2% of them. Data reported here clearly suggest that P. rufipes could play an important role in regulating medfly populations in citrus orchards. This information is particularly useful when biological control conservation strategies are being considered to control this pest.