Notes on coexistence of closely related Leiobunum rupestre and L. subalpinum (Opiliones, Eupnoi, Sclerosomatidae).

Two closely related, syntopic species, Leiobunum rupestre and L. subalpinum, spend the day at apparently randomly distributed resting sites. In this preliminary research, we studied differences in their microclimatic preferences at a locality in the Pohorje Mts., Slovenia. We measured air temperature and relative humidity at individual resting sites, and found that L. subalpinum occupied a slightly wider air temperature-relative humidity ecospace as compared to L. rupestre. Individuals of L. rupestre rested at more humid sites than L. subalpinum. Regression analyses revealed that the presence of L. rupestre was most likely at resting sites with air temperature in the range of 1217°C and with relative air humidity of 98.1%. In contrast, the presence of L. subalpinum was most likely at resting sites with air temperature 23.1°C and relative air humidity in the range of 6585%. Nevertheless, microclimatic niches of both species overlapped almost completely, indicating that niche filtering may allow the coexistence of the two species.