Temperature variation in caves and its significance for subterranean ecosystems.

Climate change affects all ecosystems, but subterranean ecosystems are repeatedly neglected from political and public agendas. Cave habitats are home to unknown and endangered species, with low trait variability and intrinsic vulnerability to recover from human-induced disturbances. We studied the annual variability and cyclicity of temperatures in caves vis-à-vis surface in different climatic areas. We hypothesize that cave temperatures follow the average temperature pattern at the surface for each location with a slight delay in the signal, but we found three different thermal patterns occurring in caves: (1) high positive correlation and a similar thermal pattern to the surface, (2) low correlation and a slight thermal delay of the signal from the surface, and (3) high negative correlation with an extreme delay from the surface. We found daily thermal cycles in some caves, which may potentially control the circadian rhythms of cave organisms. Our results show that caves had lower thermal amplitude than the surface, and that thermal averages within caves approximately correspond to the to the annual average of surface temperature. Caves buffer external temperature and act as refugia for biota in extreme climatic events. Likewise, temperature increases at surface will lead to increment in caves, threatening subterranean biota and ecosystem services.

Feeding habits and multifunctional classification of soil-associated consumers from protists to vertebrates.

Soil organisms drive major ecosystem functions by mineralising carbon and releasing nutrients during decomposition processes, which supports plant growth, aboveground biodiversity and, ultimately, human nutrition. Soil ecologists often operate with functional groups to infer the effects of individual taxa on ecosystem functions and services. Simultaneous assessment of the functional roles of multiple taxa is possible using food-web reconstructions, but our knowledge of the feeding habits of many taxa is insufficient and often based on limited evidence. Over the last two decades, molecular, biochemical and isotopic tools have improved our understanding of the feeding habits of various soil organisms, yet this knowledge is still to be synthesised into a common functional framework. Here, we provide a comprehensive review of the feeding habits of consumers in soil, including protists, micro-, meso- and macrofauna (invertebrates), and soil-associated vertebrates. We have integrated existing functional group classifications with findings gained with novel methods and compiled an overarching classification across taxa focusing on key universal traits such as food resource preferences, body masses, microhabitat specialisation, protection and hunting mechanisms. Our summary highlights various strands of evidence that many functional groups commonly used in soil ecology and food-web models are feeding on multiple types of food resources. In many cases, omnivory is observed down to the species level of taxonomic resolution, challenging realism of traditional soil food-web models based on distinct resource-based energy channels. Novel methods, such as stable isotope, fatty acid and DNA gut content analyses, have revealed previously hidden facets of trophic relationships of soil consumers, such as food assimilation, multichannel feeding across trophic levels, hidden trophic niche differentiation and the importance of alternative food/prey, as well as energy transfers across ecosystem compartments. Wider adoption of such tools and the development of open interoperable platforms that assemble morphological, ecological and trophic data as traits of soil taxa will enable the refinement and expansion of the multifunctional classification of consumers in soil. The compiled multifunctional classification of soil-associated consumers will serve as a reference for ecologists working with biodiversity changes and biodiversity-ecosystem functioning relationships, making soil food-web research more accessible and reproducible.

Subterranean Campodeidae fauna from Sicily (Diplura): its biogeographical interest with the description of a new species of Plusiocampa.

A description is given of a biogeographically interesting new species of Campodeidae (Diplura), Plusiocampa (Plusiocampa) tinoamorei sp. nov., a troglobiotic species found in the Sicilian Villasmundo and Scrivilleri caves. A second subterranean species already known from three caves in northwest Sicily near Palermo, Campodea (Campodea) majorica sicula Condé, 1957, also was studied. Both species were characterized with SEM. Each species belongs to a different monophyletic group: Plusiocampa s. str., with thoracic medial posterior macrosetae, and the group related to Campodea (Campodea) grassi Silvestri, 1912. Both groups are widely distributed on almost all of the large western Mediterranean islands. Nevertheless, although these two monophyletic groups have a different origin both could be dispersed via land connections between the mainland and the islands during the Messinian Age. This new discovery shows the great value of Sicilian caves that hold species with unique features and of high biogeographic significance.

Catalogue of the type material in the entomological collection of the Natural History Museum of Denmark: basal hexapods.

A catalogue of type specimens of basal hexapods (Collembola, Protura, Diplura, Archaeognatha, Zygentoma) in the collection of the Natural History Museum of Denmark, University of Copenhagen is presented. The NHMD collection harbours type material of 175 species, and it is composed of 132 holotypes, 4 neotypes, 3 syntypes, 32 lectotypes, and 39 paratypes. For Diplura one neotype is newly designated. The order Protura is represented by 5 families, Collembola by 7 families, Diplura by 6 families, Archaeognatha by 1 family and Zygentoma by 2 families.

Energy and speleogenesis: Key determinants of terrestrial species richness in caves.

The aim of this study was to unravel the relative role played by speleogenesis (i.e., the process in which a cave is formed), landscape-scale variables, and geophysical factors in the determination of species richness in caves. Biological inventories from 21 caves located in the southeastern Iberian Peninsula along with partial least square (PLS) regression analysis were used to assess the relative importance of the different explanatory variables. The caves were grouped according to the similarity in their species composition; the effect that spatial distance could have on similarity was also studied using correlation between matrices. The energy and speleogenesis of caves accounted for 44.3% of the variation in species richness. The trophic level of each cave was the most significant factor in PLS regression analysis, and epigenic caves (i.e., those formed by the action of percolating water) had significantly more species than hypogenic ones (i.e., those formed by the action of upward flows in confined aquifers). Dissimilarity among the caves was very high (multiple-site ßsim = 0.92). Two main groups of caves were revealed through the cluster analysis, one formed by the western caves and the other by the eastern ones. The significant-but low-correlation found between faunistic dissimilarity and geographical distance (r = .16) disappeared once the caves were split into the two groups. The extreme beta-diversity suggests a very low connection among the caves and/or a very low dispersal capacity of the species. In the region under study, two main factors are intimately related to the richness of terrestrial subterranean species in caves: the amount of organic material (trophic level) and the formation process (genesis). This is the first time that the history of a cave genesis has been quantitatively considered to assess its importance in explaining richness patterns in comparison with other factors more widely recognized.

New Species of Campodeidae (Diplura) from Mexican caves.

Six new taxa of Campodeidae (Diplura) are described in the genera Litocampa, Juxtlacampa, Oncinocampa, and Tachycampa. We also redescribe the interesting species Juxtlacampa juxtlahucensis Wygodzinsky, 1944 from Juxtlahuaca cave in Guerrero, Mexico. All of these taxa are cave-dwelling species with more or less noticeable troglobiomorphic features They inhabit the subterranean ecosystem in six limestone massifs and one lava tube cave in the central states of Mexico. Four of these species are included in the "tachycampoide" group and one species in the "podocampoide" group (sensu Bareth & Conde). Nine species already known in Central and South America of the "tachycampoide" group, in such poorly-sampled regions compared with the eight species in the well-sampled Mediterranean region (Ibero-Sardinia and north Africa), suggest an American origin for this group.

The "Alluvial Mesovoid Shallow Substratum", a new subterranean habitat.

In this paper we describe a new type of subterranean habitat associated with dry watercourses in the Eastern Iberian Peninsula, the "Alluvial Mesovoid Shallow Substratum" (alluvial MSS). Historical observations and data from field sampling specially designed to study MSS fauna in the streambeds of temporary watercourses support the description of this new habitat. To conduct the sampling, 16 subterranean sampling devices were placed in a region of Eastern Spain. The traps were operated for 12 months and temperature and relative humidity data were recorded to characterise the habitat. A large number of species was captured, many of which belonged to the arthropod group, with marked hygrophilous, geophilic, lucifugous and mesothermal habits. In addition, there was also a substantial number of species showing markedly ripicolous traits. The results confirm that the network of spaces which forms in alluvial deposits of temporary watercourses merits the category of habitat, and here we propose the name of "alluvial MSS". The "alluvial MSS" may be covered or not by a layer of soil, is extremely damp, provides a buffer against above ground temperatures and is aphotic. In addition, compared to other types of MSS, it is a very unstable habitat. It is possible that the "alluvial MSS" may be found in other areas of the world with strongly seasonal climatic regimes, and could play an important role as a biogeographic corridor and as a refuge from climatic changes.

Revision of the genus Coletinia (Zygentoma: Nicoletiidae) in the Iberian Peninsula, with descriptions of nine new species.

The discovery of several members of the genus Coletinia Wygodzinsky, 1980, from subterranean habitats (endogean and troglobiont), prompted the review of this genus in the Iberian Peninsula. Most of the samples came from caves of the Mediterranean basin of Spain, from Cádiz to the Tarragona province. As a result of this revision, nine new species have been established: C. herculea n. sp., an endogean from Cádiz; C. vergitana n. sp. from the Gádor calcareous mountains in Almería; C. calaforrai n. sp. from the gypsum karst in Almería; C. intermedia n. sp. from caves in Murcia and Alicante; C. diania n. sp., found in the north of the province of Alicante; C. longitibia n. sp. and C. tessella n. sp., both troglobites from Valencia; C. redetecta n. sp. from Castellón caves and finally C. hernandoi n. sp., an endogean from Tarragona. Moreover, Coletinia maggii (Grassi, 1887) is reported for the first time in the Iberian Peninsula, and new data are presented regarding C. mendesi, C. tinautiand C. capolongoi that widen their geographic distribution and enhance the information about their anatomic characteristics and biology. These results increase the number of known species of this genus to 14 in the region and to 21 in the world. The new species are described and compared with the most closely related previously known species of the genus. Characters with the most taxonomic relevance are discussed using optical and scanning microscope studies. A key for the identification of the Iberian Coletinia species and a distribution map including all of them are also provided.