Abstract
In Europe, many potential and confirmed vectors of Xylella fastidiosa (Xf) are polyphagous but appear to aggregate on their preferred host plants at local scales. For example, Philaenus spumarius is found most often on Asteraceae on the Californian coast, or on Apiaceae and Rubiaceae in the meadows of central Italy. However, vectors keep the ability to exploit multiple host-plants, which can be crucial in primary Xf transmission to crops.In this study, we assessed the habitat preferences of spittlebugs on and in the vicinity of Corsican clementine and olive groves, focusing on four habitats: Cistus monspeliensis border, Dittrichia viscosa cover, crop foliage and grove ground vegetation. Spittlebug abundance was assessed three times a year during two years on five to nine clementine and olive organic groves. Nymph and adult abundances were quantified based on spittle mass counts and nymph identification in April and sweep net sampling in June and October. Habitat preferences were inferred based on generalized linear mixed models.Overall, 6647 spittle masses and 1714 adults belonging to four species were found. Philaenus spumarius had a significant preference for Cistus monspeliensis, and to a lesser extent for Dittrichia viscosa. Neophilaenus campestris mostly occurred on ground vegetation of the grove and on Dittrichia viscosa. Lepyronia coleoptrata was less abundant on crop foliage than on ground vegetation and Aphrophora alni showed an even abundance in all habitats.This study demonstrates the specialization of P. spumarius on C. monspeliensis in the diversified Corsican landscape as well as strong habitat preferences for N. campestris. All recorded species were able to colonize clementine or olive foliage, but rarely, and in similar abundancies for all species. Should they be proven equivalent effective vectors, this suggests similar roles of these four species in Xf transmission to crops.