Habitat selection and morphology of Saga pedo (Pallas, 1771) in Alps (Susa Valley, Piedmont, NW Italy) (Insecta: Orthoptera, Tettigoniidae, Saginae)

Abstract

This paper is a contribution to the knowledge of Saga pedo (Pallas, 1771), summarizing the results of a field study carried out on a population of the Italian W Alps. The peculiar eco-ethological traits of this species make its observation difficult in nature and overall also its biology is little known, especially in Italy. The habitat selection is outlined from 34 unpublished presence data, collected between 2016 and 2018. Moreover, some biometric traits are compared between adult individuals observed in two different and disjointed survey areas. The results show that the environments in which this species lives in Susa Valley should not be referred exclusively to xerothermic oases in strict sense. This species appears to be also associated, in fact, with xeric environments of agricultural origin, mostly abandoned vineyards. These land uses (especially viticulture) could have guaranteed the survival of S. pedo over time. The closure of these open areas by shrub and tree vegetation, constitutes an important threat factor. Phenology and morphology of this species in Susa Valley, seem do not differ from those reported for other European populations. However, from the biometric analysis some significant differences emerge (p<0.05) among the individuals sampled in the two areas, that are difficult to interpret. The observation of imagoes, always combined with high densities of potential prey and sometimes grouped, suggests some hypotheses that it would be interesting to test, to learn more about the ethology and ecology of this enigmatic protected species.