ABSTRACT
The development of sensory structures in the dark is relatively well documented for some subterranean species. In contrast, the development of other organs not directly linked to sight has been very poorly studied, for example exocrine glands, producing pheromones. Cave beetles from the sub-family Leptodirinae that possess several types of glands with varying degrees of development or involution (depending on the phyletic line) have been described. The sternal gland is a multicellular gland present in the males of several Leptodirinae species. The Speonomus spp. are characterized by enhanced development of this gland but in marked contrast, Batysciola spp. are characterized by reduction of the sternal gland (Juberthie-Jupeau & Cazals, 1984; Moldovan & Juberthie, 1998) (see Figure 2). In the latter case, there is also a change from a secretion with less volatile particles to a very volatile secretion. However, this gland is absent in beetles highly adapted to life in subterranean habitats.
