Contribution to the Fennoscandian distribution of Chionea Dalman, 1816 (Diptera, Limoniidae), with notes on the ecology

Updated information is given on the distribution of Chionea araneoides Dalman, 1816 and C. crassipes Boheman, 1846 in Norway. While C. araneoides is very common in southern Norway, there are only two records in northern Norway. C. crassipes has been taken numerously and in several localities in Finnmark, but in southern Norway, only a few individuals have been found in three alpine sites. These may represent relict populations. C. lutescens Lundström, 1907 is reported new to Sweden. Three samples of C. crassipes from Oulanka national park in Finland confirm the few earlier records from this country. Information is given on phenology, temperature and weather conditions, as well as some ecological aspects for C. araneoides in southern Norway, based on long term data

Ecosystem birth near melting glaciers: A review on the pioneer role of ground-dwelling arthropods

As glaciers retreat, their forelands represent “natural laboratories” for the study of primary succession. This review describes how certain arthropods conquer pristine ground and develop food webs before the establishment of vascular plants. Based on soil samples, pitfall traps, fallout and sticky traps, gut content studies, and some unpublished data, we compare early arthropod succession on glacial forelands of northern Europe (Iceland, Norway including Svalbard, and Sweden) and of the Alps (Austria, Italy). While macroarthropod predators like ground beetles (Coleoptera: Carabidae), harvestmen (Arachnida: Opiliones), and spiders (Arachnida: Araneae) have usually been considered as pioneers, assumed to feed on airborne prey, this review explains a different pattern. Here, we highlight that springtails (Collembola), probably feeding on biofilm made up of algae or cyanobacteria, are super-pioneers, even at high altitudes and under arctic conditions. We also point out that macroarthropod predators can use locally available prey, such as springtails or non-biting midges (Diptera: Chironomidae). Pioneer arthropod communities vary under different biogeographical and climatic conditions. Two pioneer food webs, from northern Europe and the Alps, respectively, differed in structure and function. However, certain genera and orders were common to both. Generalists and specialists live together in a pioneer community. Cold-adapted specialists are threatened by glacier melting

Rafting in Antarctic Collembola

Darwin was an early exponent of the importance of ‘occasional means of dispersal’ in accounting for the present-day distribution of plants and animals. This study examined the implications of capture on the water surface of meltwater and seawater for the local and long-range dispersal of Antarctic springtails. Individuals of the maritime Antarctic collembolan Cryptopygus antarcticus, were floated on tap water and seawater at 0, 5 and 10°C. LT50s on seawater were 34 (10°C), 65 (5°C) and 75 (0°C) days. On tap water, LT50s were 69 (10°C), 126 (5°C) and 239 (0°C) days. Less than 20% escaped from the water surface. A significantly greater proportion of springtails moulted on tap water and viable offspring were produced on both tap water and seawater. Comparison across treatments of survival of moulting and non-moulting individuals found significantly greater survival in moulting animals for three of the treatment combinations. It is suggested that moult exuviae facilitate survival on the water film through the simultaneous provision of a flotation aid and a source of nourishment – that is, an ‘edible raft’. A separate experiment measuring changes in haemolymph osmolality over time on tap water and seawater at 2 and 5°C found significant differences in all treatments. Causes of mortality are discussed in relation to osmoregulatory failure and starvation