Available online at scholarcommons.usf.edu/ijs International Journal of Speleology Official Journal of Union Internationale de Spéléologie *marco.isaia@unito.it INTRODUCTION The climatic conditions occurring underground have a profound influence on hypogean fauna (Culver & Pipan, 2010). As far as hypogean beetles are concerned, it is well known that they generally dwell in environments which are relatively stable from an environmental point of view, characterized by constant temperature and an atmosphere saturated with water vapor (Moldovan, 2005). Indeed several hypogean beetles are adapted to narrow ranges of temperature and relative humidity, and thus classified as stenothermic and stenohygric (Howarth, 1980). Hence, it has been observed that they are able to react quickly when significant changes in the microclimatic conditions occurs (Juberthie, 1969), migrating inside the inner parts of the cave (and through the network Citation: Keywords: Abstract: Hypogean beetles generally live in stable environments, characterized by constant temperature and high relative humidity. Changes in the underground microclimatic conditions generally induce local migrations of the beetles through the hypogean environment in search of suitable microhabitats. We studied the seasonal dynamics and the micro-climatic preference of two Alpine endemic hypogean beetles - Sphodropsis ghilianii (Coleoptera, Carabidae) and Dellabeffaella roccae (Coleoptera, Cholevidae) - in the hypogean complex of Pugnetto (Graian Alps, Italy). We surveyed the two species for one year, using baited pitfall traps and measuring temperature and humidity along the two main caves. We used logistic regression mixed models (GLMMs) to relate the presence of the two species to several variables, namely microclimate (seasonality, temperature, and humidity), subjacency and cave length. In addition, we tested the attractive power of the bait on the two species. The thermic optimum for S. ghilianii was found to be around 7°C, with an increasing probability of finding the species in the vicinity of the cave entrance during summer, autumn and spring. The species migrates inside the cave in winter, in response to the drop in the mean daily temperature and in the relative humidity occurring in the outer parts of the cave. On the contrary, D. roccae showed a significant preference for the deeper sections of the cave, characterized by an almost constant temperature of 9°C in air saturated with water vapour. Males and females individuals of both species were found to be equally affected by the environmental variables included in the analysis. We also provided information on the life history of the two species and methodological insights about the use of the bait in the traps. Carabidae; Cholevidae; microclimatic preference; Western Italian Alps, cave ecology, Sphodropsis ghilianii; Dellabeffaella roccae Received 10 February 2015; Revised 29 May 2015; Accepted 4 June 2015 Mammola S., Piano E., Giachino P.M. and Isaia M., 2015. Seasonal dynamics and micro-climatic preference of two Alpine endemic hypogean beetles. International Journal of Speleology, 44 (3), 239-249. Tampa, FL (USA) ISSN 0392-6672 http://dx.doi.org/10.5038/1827-806X.44.3.3 Seasonal dynamics and micro-climatic preference of two Alpine endemic hypogean beetles Stefano Mammola 1 , Elena Piano 1 , Pier Mauro Giachino 2 , and Marco Isaia 1* 1 Laboratory of Terrestrial Ecosystems, Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina, 13-10123 Torino, Italy 2 Settore Fitosanitario Regionale, Environment Park, Palazzina A2, Via Livorno, 60-10144 Torino, Italy International Journal of Speleology 44 (3) 239-249 Tampa, FL (USA) September 2015 of cracks) in search of other suitable micro-habitats (Novak et al., 2004; Moldovan, 2005; Giachino & Vailati, 2010). Moreover, movements during the season proved to be influenced by air temperature, resulting in spatial migrations (e.g. Casale, 1988), seasonal rhythmicity (e.g. Crouau-Roy et al., 1992) and fluctuations in the abundances of the beetles captured in the traps (e.g. Rendoš et al., 2012). In order to achieve a better understanding of the relationship between the hypogean fauna and the abiotic parameters occurring underground, these phenomena were investigated in two species of hypogean beetles inhabiting the Pugnetto hypogean complex (Graian Alps, NW-Italy). Sphodropsis ghilianii (Schaum, 1858) s.l. (Coleoptera, Carabidae, Sphodrina) is an endemic ground beetle of the Western Alps, distributed from the Ligurian-Maritime to the Lepontine Alps (Casale, CORRECTED PROOF