**3. Ground beetles and non-biting midges as flagship organisms: richness and adaptation**

Ground beetles (**Figure 1**) occur in almost all terrestrial environments and geographical areas and have different trophic requirements (e.g., predators, seed eaters and phytophagous), it is easy to collect them and their sensitivity to environmental and climate changes is known [19]. In addition, they can be considered among the most important meso- and macrofauna living on recently deglaciated terrains and on the glaciers in terms of species richness and abundance of individuals [13]. Last but not least, there is an ongoing awareness about the extinction risk for some endemic cryophilous species due to the habitat destruction (e.g., glacier

#### **Figure 1.**

*The ground beetle* Nebria germari *(approx. body length = 1 cm) walking on the Presena Glacier (2700 m a.s.l.) (Adamello-Presanella Mts., Italian Alps) (photo by F. Pupin/archive MUSE).*

disappearing) or changes in microhabitat conditions (e.g., permafrost melt). Most of the species living at high altitudes and latitudes have low dispersal abilities due to the lack of wings and are walking colonizers, ground hunters and small-sized, which are traits typical of species living in cold, wet and gravelly habitats [17]. To date, about 40,000 species are known in the world [20] and most of them are endemic to specific areas [21–23]; for instance, about 28% of the total species belonging to the Italian carabid fauna are endemic.

Non-biting midges (**Figure 2**) are the freshwater insect family that comprises the highest number of species, both in lentic and lotic habitats [24]. They are the most widespread of all aquatic insect families, with individual species occurring from Antarctica to the equator lands and the Arctic, from lowlands to thousands of meters of altitudes. There are species that thrive in almost every conceivable freshwater environment. Ice-cold glacial trickles, hot springs, thin films, minute containers of water in the leaf axils of plants and the depths of great lakes all have their characteristic species or communities. There are semiaquatic species, living in moist soil or vegetation and others that are truly terrestrial with few species occurring in marine water. Some species tolerate brackish water, others thrive in intertidal pools and, unusually among the insects, and a few are truly marine. Survival in harsh environments is due to a series of adaptations. Among these are the production of melanin, their small size, capacity for mating on the ground instead of in flight (they therefore have small or totally absent wings), the building of cocoons, diapause and resistance to cold [25]. To date, about 6500 species are known in the world; one tenth of which are in Italy and one thousandth in Alpine streams, springs and lakes.

Thanks to their species richness, adaptation to cold environments, key role in the ecological network structure and robustness and sensitivity to short-term and longterm climate changes, ground beetles and non-biting midges might be considered flagship organisms of the glacial biodiversity.
