The influence of barriers and orientation on the dispersal ability of wood cricket (Nemobius sylvestris) (Orthoptera: Gryllidae)

Abstract

Dispersal is an important process determining species spread and survival in fragmented landscapes. However, information on the dispersal ability of woodland-associated invertebrate species is severely lacking. A study was conducted examining the ability of wood cricket (Nemobius sylvestris) (Orthoptera: Gryllidae) to cross small watercourses and to orientate themselves towards habitat edges. A series of experiments were conducted where juvenile (i.e. nymph) and adult wood crickets were released and observed over time. The results of this investigation indicated that (i) nymphs and adults were equally able to swim across a small (≤35 cm) watercourse; and (ii) adult wood cricket were able to positively orientate themselves towards a mature woodland edge at a visual angle of ≥19°, when less than 50 m away. Together, this investigation suggests that these traits likely facilitate the ability of this species to disperse within fragmented wooded landscapes, however, further study is needed to strengthen the significance of these findings for this and similar species.