Calliptamus italicus at 3050 m: a first evidence of dispersal across the Alps? (Orthoptera: Acrididae)

Abstract

Calliptamus italicus (Linnaeus, 1758) is a polyphagous grasshopper widely distributed from Europe to central Asia, known to perform long-range migrations during its gregarious phase, especially in the eastern part of its range. In the Alps, this species mostly occurs in dry grassland habitats in valley floors or on well-exposed slopes, usually establishing resident populations below 2000 m, but information on its dispersal patterns in this geographical area are still lacking. This short note reports an unusual observation of C. italicus at high eleva- tion (3050 m) in the Cottian Alps, with a description of the associated local habitat features and short-term weather conditions. Although based on a single record, hypotheses on the possible underlying dispersal processes are provided, discussing whether this observation may represent or not a first evidence of a migration behaviour by Italian locusts across the Alpine ridge. The performance of either a local movement or a long-range migration is firstly hypothesized, due to the apparent suitability of the short-term weather conditions (i.e. no rain, increase in temperatures and wind intensity). However, since the specimen was missing the left hind leg, thus potentially compro- mising its dispersal capacity, a third hypothesis of an animal- or human-mediated transport is also considered. Given that the available data are not sufficient to definitely ascertain whether C. italicus is able to disperse in autonomy across the Alps or not, further records are needed in future to verify the hypotheses presented here and to enhance the detail of the environmental variables possibly involved.