| Title | Niche differentiation in Meta bourneti and M. menardi (Araneae, Tetragnathidae) with notes on the life history |
| Abstract | Meta menardi and M. bourneti are two species of spiders inhabiting caves and other subterranean habitats. The occurrence of both species within the same cave has never been proved convincingly and several authors hypothesized a complete niche differentiation mainly based on microclimatic conditions. In order to study the apparent niche differentiation of the two species, we studied several populations of M. menardi and M. bourneti occurring in six caves in the Western Italian Alps (NW Italy). A series of squared plots were monitored monthly from March 2012 to February 2013. At each survey, we counted individuals and we collected the main environmental variables at each plot, namely distance from cave entrance, structural typology (wall, floor, or ceiling), light intensity, wind speed and counts of potential prey. Moreover, temperature and relative humidity were continuously logged in each cave. We run several statistical models (GLMMs) in order to relate the counts of individuals to the environmental parameters. The distance from the cave entrance, structural typology and prey availability resulted most important factors driving the abundance of both species within the cave. On the other hand, despite life cycles appeared very similar, the two species seems to exhibit different tolerance to the microclimatic variations within the cave, which emerged as the main factors determining the differentiation of their niche. At least in our study area, M. bourneti tolerates broad microclimatic fluctuations and is potentially able to colonize a wide variety of caves. On the other hand, when the climatic conditions in a cave are suitable for M. menardi (narrow ranges of relatively low temperature and high humidity), M. bourneti is excluded. |
| Source | International Journal of Speleology (Testo stamp.) 43 (3), pp. 343–353 |
| Keywords | cave dwelling spiderconditional differentiationecological nicheGLMMswestern Italian Alps |
| Journal | International Journal of Speleology (Testo stamp.) |
| Editor | Swets and Zeitlinger, Bologna, Italia |
| Year | 2014 |
| Type | Articolo in rivista |
| DOI | 10.5038/1827-806X.43.3.11 |
| Authors | Mammola, Stefano; Isaia, Marco |
| Text | 412055 2014 10.5038/1827 806X.43.3.11 ISI Web of Science WOS 000346603400012 cave dwelling spider conditional differentiation ecological niche GLMMs western Italian Alps Niche differentiation in Meta bourneti and M. menardi Araneae, Tetragnathidae with notes on the life history Mammola, Stefano; Isaia, Marco Univ Turin Meta menardi and M. bourneti are two species of spiders inhabiting caves and other subterranean habitats. The occurrence of both species within the same cave has never been proved convincingly and several authors hypothesized a complete niche differentiation mainly based on microclimatic conditions. In order to study the apparent niche differentiation of the two species, we studied several populations of M. menardi and M. bourneti occurring in six caves in the Western Italian Alps NW Italy . A series of squared plots were monitored monthly from March 2012 to February 2013. At each survey, we counted individuals and we collected the main environmental variables at each plot, namely distance from cave entrance, structural typology wall, floor, or ceiling , light intensity, wind speed and counts of potential prey. Moreover, temperature and relative humidity were continuously logged in each cave. We run several statistical models GLMMs in order to relate the counts of individuals to the environmental parameters. The distance from the cave entrance, structural typology and prey availability resulted most important factors driving the abundance of both species within the cave. On the other hand, despite life cycles appeared very similar, the two species seems to exhibit different tolerance to the microclimatic variations within the cave, which emerged as the main factors determining the differentiation of their niche. At least in our study area, M. bourneti tolerates broad microclimatic fluctuations and is potentially able to colonize a wide variety of caves. On the other hand, when the climatic conditions in a cave are suitable for M. menardi narrow ranges of relatively low temperature and high humidity , M. bourneti is excluded. 43 Published version Articolo in rivista Swets and Zeitlinger 0392 6672 International Journal of Speleology Testo stamp. International Journal of Speleology Testo stamp. Int. J. Speleol. Testo stamp. International Journal of Speleology. Testo stamp. International Journal of Speleology Lisse Testo stamp. stefano.mammola MAMMOLA STEFANO |
