Dispersal power,home range and habitat preference of cantharid larvae (Coleoptera: Cantharidae) in arable land

The dispersal ability, home range size and habitat preference of sixth instar larvae of the widespread cantharid species Cantharis fusca (L.) and C. livida (L.) were studied in a mark–recapture experiment in a meadow–field (winter grain) area between autumn and spring in 1999/2000. The main results and conclusions were: (i) The mean dispersal velocity of C. fusca/C. livida larvae was 1.4/1.6 m d^–1 with a maximum of 3.2/2.3 m d^–1. The larvae were able to disperse more than 100 m during their larval development, demonstrating that larvae and not only adults contribute to spreading. (ii) The average home range area of seven C. fusca individuals was 12.9 m² (minimum 8 m²/maximum 19 m²). The low number of multiple recaptures and the large distances larvae can cover indicate that the real home range size was underestimated. (iii) C. fusca larvae significantly preferred the meadow area compared to the bare ground of the field. This can be explained by the meadow's higher plant cover and humidity C. livida specimens that were released one month later and recaptured only in low numbers showed no such preference. (iv) Due to the high dispersal ability of soldier beetle larvae, immigration from meadows and grass bulks of boundary strips into the crop margins and inner field areas is possible; it can be augmented by creating constant plant cover, e.g. through winter grain or cover crops.