ABSTRACT
New species of Megalothorax Willem, 1900 from Dobsinská Ice Cave, Slovakia, M. dobsinensis sp. n., is described and illustrated. New species inhabits a cold habitat along an inversed temperature gradient at the cave entrance. M. dobsinensis sp. n. differs from other species of the genus by the lack of chaeta X on Ant. IV and by T-shaped inner chaetae of thoracic and abdominal sensory fields. Only two other species, M. tuberculatus Deharveng Beruete, 1993 and M. sanctistephani Christian, 1998 lack chaeta X on Ant. IV. M. dobsinensis sp. n. differs from both species by chaetotaxy of antennae and abdomen. Summary tables of antennae and legs chaetotaxy and dichotomous identification key for species with smooth mucro are provided.
Subject(s)
Arthropods , Ice , Animals , Caves , Ecosystem , Slovakia , TemperatureABSTRACT
Vertical distribution of collembolan communities along a depth gradient was studied at three forested karst scree slopes in the Western Carpathians, differing in topography, microclimate, soil-chemical parameters, and forest associations. Two different fixative solutions were used in subterranean pitfall traps. The activity and species richness of Collembola in the vertical scree profiles were significantly higher in traps filled with ethylene glycol than in those filled with formaldehyde at all three sites. Using traps filled with formaldehyde, both Collembola species numbers and activity positively correlated with the soil moisture and carbon content, while for ethylene glycol traps this relation was the same only for species numbers and carbon content. Ecological groups of Collembola showed a different response, distinguished by the level of association to subterranean habitats, to environmental factors and to the fixation liquid used in the subterranean traps. Eutroglophiles, the forms relatively well-adapted to subterranean habitats, were associated with depth exclusively when using ethylene glycol traps. This implies that ethylene glycol is a more suitable preservative in terms of species richness and activity of Collembola in deeper scree layers compared to traditionally used formaldehyde. Thus, the effect of environmental factors on diversity and vertical distribution of Collembola in scree habitats may be substantially superimposed by the type of fixation used in subterranean traps.
Subject(s)
Arthropods , Ecosystem , Entomology/methods , Animals , DemographyABSTRACT
The climatic variability hypothesis was applied to the thermal tolerance of edaphic and cave Collembola occupying contrasting environments. Collembola belonged to four categories - trogloxene, subtroglophile, eutroglophile and troglobiont - with a different degree of affinity to subterranean habitats. Altogether, specimens of 17 species were exposed to a one-hour laboratory survival test. The impact of temperature, species and species-temperature interaction on cold and heat survival was statistically significant. There was a decrease trend in cold and heat tolerance from trogloxenes, over subtroglophiles and eutroglophiles to troglobionts. It was shown that obligate cave species, restricted to climatic-stable cave conditions, retain a functional thermal resistance, i.e. the genetically determined ability to tolerate relatively broader temperature ranges. Our results outlined the direct relationship between the thermal tolerances of species and the size of their geographic distributions. It was also observed that cold resistance of Collembola decreased significantly with increasing species body length, indicating that body size plays an important role in temperature tolerances of arthropods inhabiting soil and subterranean habitats.