Body size and leg length variation in several species of darkling beetles (Coleoptera: Tenebrionidae) along a rainfall and altitudinal gradient in the Negev Desert (Israel)

We studied body size (elytra length) and leg length variation in seven tenebrionid species along a rainfall and environmental gradient from the Ramon erosion cirque (Israel). Body size was not correlated with altitude in three species, while four species demonstrated changes in body size with altitude. Three species decreased their body size along the altitudinal gradient, whereas Sepidium dathan demonstrated the opposite trend. The pattern of variation of body size along the altitudinal gradient in Adesmia metallica, Erodius edomitus and Zophosis complanata may be explained by ambient temperature rather than productivity variation. Neither elevation nor species abundance affected variance in body size of any species. Femur length changed significantly along the altitudinal gradient in A. metallica only. Both males and females had relatively longer legs in low elevations and relatively shorter legs in high elevations. Individuals with the longest legs were recorded on soils with low clay and high rock and gravel content. The texture of the soil had no noticeable effect on the leg length of all other beetle species.