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Hipposideros spp. are insectivorous bats and karst cave dwellers. This study aimed to study the roosting ecology, reproduction, and population fluctuations of three species H. diadema, H. larvatus, and H. ater in Gunung Sewu Karst region, Indonesia. Age and reproductive status of individuals were identified and analyzed using a combination of forearm length (FA) and body mass grades (W). Multiple regression analysis was used to determine the correlation between population size, rainfall and population structure based on FA, reproductive status, and W. Crude birth rate (CBR) and general fertility rate (GFR) were used to determine the population’s birth rate and female fertility. The results showed that the population of the three Hipposideros species were quite stable over the year with a peak in January which classified them as monoestrous, with mating, pregnancy, and lactation occurring once a year with no delay between mating and pregnancy. Pregnancy lasted 8–12 weeks and lactation 4–5 weeks. The population structure of the three species tended to be stable over the year. The CBR and GFR values can be used for rapid assessment guidelines in an area. [ABSTRACT FROM AUTHOR]

Specialized subterranean species are iconic examples of convergent evolution driven by environmental constraints, representing an ideal model system for eco-evolutionary studies. However, scientific research on the behavioural adaptations of subterranean organisms has lagged and is biased mostly towards a few model species. Through a systematic literature review, we aimed to assess quantitatively whether a congruent evolution of behavioural traits among subterranean species exists. We considered four types of behaviours (exploratory, feeding, social and anti-predator) and tested predictions about their occurrence among species with different degrees of adaptation to subterranean environments. We argue that these behaviours constitute the earliest adaptations to three main ecological factors characterizing subterranean habitats, namely the constant darkness, the limited food resources and the reduced predator pressure. Darkness selects for individuals that rely on non-visual cues to explore their surroundings, track food resources and locate potential sexual partners. The reduced availability of food promotes high foraging plasticity and deters species from adopting aggressive behaviours towards conspecifics. The reduced predator pressure allows species to abandon specific anti-predator behaviours and permits safer execution of their biological activities. Our analyses show that these four behaviours are likely to represent the result of an early convergent adaptation to the subterranean realm. [ABSTRACT FROM AUTHOR]

The Balkan region is rich in limestone deposits, which have created one of the largest hotspots of subterranean biodiversity. This paper gives an overview of the diversity of subterranean terrestrial arthropods in Resava Cave in eastern Serbia. This cave is protected and has the status of a natural monument. At the same time, it is one of the most visited caves in Serbia and its surroundings. Our study comprises the results of three years of biospeleological investigations of the famous Serbian cave in combination with data from the few available literature sources on the arthropod fauna of the cave. The arthropod samples were collected both manually and with pitfall traps. A total of 107 arthropod species from the four major subphyla were registered in the cave: 66 species of Hexapoda, 27 species of Chelicerata, 11 species of Myriapoda and three species of Crustacea. For four troglobitic, 16 troglophilic and 87 trogloxenic species recorded in the cave, descriptions of their microhabitats and information on their distribution in the cave are given. Considering the medium size of Resava Cave and the lack of permanent water flow in the two main levels on the one hand, and the large number of arthropod species recorded on the other, the cave is relatively rich in hypogean terrestrial arthropod fauna compared to other caves in Serbia that have been biospeleologically studied so far. [ABSTRACT FROM AUTHOR]

In the Lessini Mountains, the southernmost prealpine area in the Veneto region, thousands of caves are found, many of which have been extensively studied from the biological point of view. Numerous studies have been carried out on taxonomic and biogeographic aspects over the last hundred years. Two caves, in particular, have been found to be extremely rich in species adapted to life in subterranean environments. These are the Arena Cave in the Monti Lessini Veronesi and the Buso della Rana cave system in the Monti Lessini Vicentini. The two caves have extremely different development: Arena Cave is about 100 meters in length, and the Buso della Rana-Pisatela cave system is more than 37 km in length. Despite this huge difference in size, they both have the highest number of subterranean dwelling species in northern Italy (16 troglobionts and 8 stygobionts in Arena Cave, and 7 troglobionts and 11 stygobionts in the Buso della Rana-Pisatela cave system). [ABSTRACT FROM AUTHOR]

Green Cave could be referred to as the extension part of the Kotumsar Cave of Kanger Valley National Park, but one can not traverse from one to another. In this study, we mapped the cave carefully and the environmental conditions have been checked carefully at each defined zone of this cave. Based on observed habitat and other behavioural characteristics the species identified from this cave are given their proper cavernicolous status. [ABSTRACT FROM AUTHOR]

A new genus and new species of Trechina (Coleoptera: Carabidae: Trechinae: Trechini), Ryukyuaphaenops pulcherrimus gen. & sp. nov. is described from the Ryukyu Archipelago, Japan. This is the first troglomorphic Carabidae in the Ryukyus and probably the most cave-adapted beetle in Japan. Interestingly, our observations suggest that this new trechine beetle is not similar to any genera of Trechina distributed in Kyushu and Taiwan, which are geographically close to the Ryukyu Archipelago, but is more similar to several aphaenopsian genera distributed in the inland of China. The genetic diversity of the new species is discussed based on mitochondrial DNA (COI-5', COI-3', 16S). [ABSTRACT FROM AUTHOR]

Interest in cave fungal diversity is flourishing because it may represent a reservoir of new species and metabolites. However, the mycobiota remains poorly studied in the underground environment, especially in neotropical regions. During surveys that aimed to investigate the fungal diversity in quartzite and limestone caves in the Southern Espinhaço Mountain in Brazil, six Chaetomiaceae isolates were obtained from different cave substrates. Five taxonomical novelties of Chaetomiaceae in Brazilian caves were discovered based on phylogenetic analyses using DNA sequences from the ITS, LSU, TUB, and RPB2 genes. Chaetomium meridionalense, Pseudohumicola alba, and Pseudohumicola lutea are new species found in Gruta da Extração and Gruta Velha Nova caves. Parahumicola is introduced as a new genus representing a novel phylogenetic lineage with unique morphological characteristics in the family Chaetomiaceae. This new monotypic genus is typified by P. guana, which was found in a bat guano sample in the Gruta Monte Cristo cave. Furthermore, this is the first report of Collariella bostrychodes in a neotropical cave. Overall, these findings emphasise that Brazilian caves constitute an untapped source of fungal resources. [ABSTRACT FROM AUTHOR]

The Dinaric Karst is a global hotspot for subterranean diversity, with two distinct peaks of species richness in the northwest and southeast, and an area of a lower species richness in the central part. In this article, we present a species list and describe the ecological conditions of the Lukina jama–Trojama cave system, located in the central part of the Dinaric Karst. This cave system is the deepest and one of the most logistically challenging cave systems sampled so far in the Dinaric Karst. Repeated sampling resulted in a list of 45 species, including 25 troglobionts, 3 troglophiles, 16 stygobionts, and 1 stygophile. Most of the recorded species are endemic to the Velebit Mountain, while three species are endemic to the Lukina jama–Trojama cave system. Within the system, species richness peaks in the deepest third of the cave, most likely reflecting the harsh ecological conditions in the upper parts, including ice, cold winds, and occasional waterfalls. Milder and more stable deeper parts of the cave contain a rich subterranean species community, part of which is associated with two very distinct aquatic habitats, the cave hygropetric and the phreatic zone. The newly recognized hotspot of subterranean biodiversity in the central Dinaric Karst, which has emerged between the two known centers of biodiversity, further highlights the species richness in large cave systems, but also challenges the diversity patterns in the Dinaric Karst overall. [ABSTRACT FROM AUTHOR]

A new genus and species of the Microtrombidiidae, Troglotrombidium dolichopodum n. gen. et n. sp. is described based on ectoparasitic larvae collected from two Dolichopoda lycia (Galvagni 2006) (Orthoptera: Rhaphidophoridae) specimens from a cave in Western Taurus Mountains, Turkey. The new genus can be distinguished from other genera by the absence of eyes, highly modified claws of tarsi III, sensillary setae structure of the anterior dorsal scutum, and the number of adoral setae. The new species is a typical troglobite, and this interspecific interaction is a well-documented case for the little-known host-parasite relationships from subterranean ecosystems. [ABSTRACT FROM AUTHOR]

Carl Leavitt Hubbs (1894-1979) was a prominent and internationally renowned American ichthyologist whose publications include taxonomic descriptions of several North American blindfishes including the Mexican Cave Characin. His archived personal papers reveal a wide-ranging interest in the biology and evolutionary origins of cave and blindfishes, and his discussions and disputes with colleagues about their taxonomy. He also took opportunities to collect other fauna from American caves during the inter-war decades. Drawing upon his unpublished archive and other relevant sources his biospeleological work is chronicled in detail and discussed in the context of his other work. [ABSTRACT FROM AUTHOR]

IntroductionUsing an integrative taxonomic approach, we investigated the morphological and molecular characters to identify the species of the genus Pseudosinella occurring in caves of the Western Carpathians and to clarify their phylogenetic relationships. Based on morphological characters, we hypothesized that Pseudosinella aggtelekiensis (Stach, 1929) and Pseudosinella paclti (Rusek, 1961) originated from different phyletic lineages.MethodsWe used the barcoding fragment of the mtDNA COI gene from 87 individuals from 16 caves to reconstruct the phylogenetic history of the genus Pseudosinella.ResultsThe molecular phylogenetic tree revealed two distinct species groups with allopatric distributions. The first group consisted of P. aggtelekiensis populations from the Slovak Karst and three undescribed species from fragmented and isolated karst areas in southeastern Slovakia. The second group, P. paclti populations in the Central Western Carpathians, was merged. This group included Pseudosinellamuranensis, a new species taxonomically described in this work. It is characterized by highly developed troglomorphic features and is restricted to a small karst area, the Muranska planina Plateau. The phylogeny of the genus Pseudosinella from the caves of the Western Carpathians revealed a Miocene diversification. According to molecular calibration, the two distinct Pseudosinella lineages were separated in the Middle Miocene, about 14.51 Mya, followed by further diversification in the P. paclti lineage 10.89 Mya and in the P. aggtelekiensis lineage 11.14 Mya.DiscussionThis phylogeny is consistent with the uplift of Triassic limestones during the early formation of the Western Carpathians in the Paratethys region and the initial development of caves during this period. The study provides further important evidence that the Western Carpathians played a significant role as an independent speciation center of the obligate cave fauna in Europe.

In the Lessini Mountains, the southernmost prealpine area in the Veneto region, thousands of caves are found, many of which have been extensively studied from the biological point of view. Numerous studies have been carried out on taxonomic and biogeographic aspects over the last hundred years. Two caves, in particular, have been found to be extremely rich in species adapted to life in subterranean environments. These are the Arena Cave in the Monti Lessini Veronesi and the Buso della Rana cave system in the Monti Lessini Vicentini. The two caves have extremely different development: Arena Cave is about 100 meters in length, and the Buso della Rana-Pisatela cave system is more than 37 km in length. Despite this huge difference in size, they both have the highest number of subterranean dwelling species in northern Italy (16 troglobionts and 8 stygobionts in Arena Cave, and 7 troglobionts and 11 stygobionts in the Buso della Rana-Pisatela cave system).

The Snezhnaya (=Snow) Cave System (depth −1760 m; total length 40.8 km), located in the West Caucasus, is inhabited by distinctly troglomorphic collembolan species from several families. Two new species of the family Arrhopalitidae occur in the deep parts of the system. Both are highly morphologically specialized; however, they evolved into different troglobiont life forms. Arrhopalites profundus sp. nov. with extremely long claws, lamellate mucro, and an enlarged sensory organ of third antennal segment lives exclusively in hygropetric and epineustonic habitats, whereas Pygmarrhopalites rystsovi sp. nov., with greatly elongated and multi-subsegmentated antennae and long legs, prefers open terrestrial spaces. The troglomorphy, as well as ecological life forms of the obligate cave-dwelling Arrhopalitidae, in general, are discussed and classified as neustonic-hygropetric, atmobiont, intrasubstrate, and intermediate troglomorphs. [ABSTRACT FROM AUTHOR]

Subterranean ecosystems are among the most widespread environments on Earth, yet we still have poor knowledge of their biodiversity. To raise awareness of subterranean ecosystems, the essential services they provide, and their unique conservation challenges, 2021 and 2022 were designated International Years of Caves and Karst. As these ecosystems have traditionally been overlooked in global conservation agendas and multilateral agreements, a quantitative assessment of solution‐based approaches to safeguard subterranean biota and associated habitats is timely. This assessment allows researchers and practitioners to understand the progress made and research needs in subterranean ecology and management. We conducted a systematic review of peer‐reviewed and grey literature focused on subterranean ecosystems globally (terrestrial, freshwater, and saltwater systems), to quantify the available evidence‐base for the effectiveness of conservation interventions. We selected 708 publications from the years 1964 to 2021 that discussed, recommended, or implemented 1,954 conservation interventions in subterranean ecosystems. We noted a steep increase in the number of studies from the 2000s while, surprisingly, the proportion of studies quantifying the impact of conservation interventions has steadily and significantly decreased in recent years. The effectiveness of 31% of conservation interventions has been tested statistically. We further highlight that 64% of the reported research occurred in the Palearctic and Nearctic biogeographic regions. Assessments of the effectiveness of conservation interventions were heavily biased towards indirect measures (monitoring and risk assessment), a limited sample of organisms (mostly arthropods and bats), and more accessible systems (terrestrial caves). Our results indicate that most conservation science in the field of subterranean biology does not apply a rigorous quantitative approach, resulting in sparse evidence for the effectiveness of interventions. This raises the important question of how to make conservation efforts more feasible to implement, cost‐effective, and long‐lasting. Although there is no single remedy, we propose a suite of potential solutions to focus our efforts better towards increasing statistical testing and stress the importance of standardising study reporting to facilitate meta‐analytical exercises. We also provide a database summarising the available literature, which will help to build quantitative knowledge about interventions likely to yield the greatest impacts depending upon the subterranean species and habitats of interest. We view this as a starting point to shift away from the widespread tendency of recommending conservation interventions based on anecdotal and expert‐based information rather than scientific evidence, without quantitatively testing their effectiveness. [ABSTRACT FROM AUTHOR]

The Dinaric Karst is a global hotspot for subterranean diversity, with two distinct peaks of species richness in the northwest and southeast, and an area of a lower species richness in the central part. In this article, we present a species list and describe the ecological conditions of the Lukina jama–Trojama cave system, located in the central part of the Dinaric Karst. This cave system is the deepest and one of the most logistically challenging cave systems sampled so far in the Dinaric Karst. Repeated sampling resulted in a list of 45 species, including 25 troglobionts, 3 troglophiles, 16 stygobionts, and 1 stygophile. Most of the recorded species are endemic to the Velebit Mountain, while three species are endemic to the Lukina jama–Trojama cave system. Within the system, species richness peaks in the deepest third of the cave, most likely reflecting the harsh ecological conditions in the upper parts, including ice, cold winds, and occasional waterfalls. Milder and more stable deeper parts of the cave contain a rich subterranean species community, part of which is associated with two very distinct aquatic habitats, the cave hygropetric and the phreatic zone. The newly recognized hotspot of subterranean biodiversity in the central Dinaric Karst, which has emerged between the two known centers of biodiversity, further highlights the species richness in large cave systems, but also challenges the diversity patterns in the Dinaric Karst overall.

An extraordinary longevity has been observed in some cave species, and this raised the hypothesis that a longer lifespan may be considered one of the characteristic traits of these animals. However, only a few cave species have been studied thus far, and a firm conclusion remains to be drawn. Here we review the available knowledge on the longevity of subterranean species, point out the limitations of previous studies, and provide suggestions for future studies to answer important questions regarding the longevity in cave animals, its adaptive value and the related promoting factors. We also argue that studying the longevity in cave animals will contribute to the field of aging, especially to understanding the evolution of this phenomenon.

Although there are no published studies and limited data documenting damage by rodents in Hawaiian caves, our incidental observations during more than 40 years of surveying caves indicate that introduced rodents, especially the roof rat, Rattus rattus, pose significant threats to vulnerable cave resources. Caves, with their nearly constant and predictable physical environment often house important natural and cultural features including biological, paleontological, geological, climatic, mineralogical, cultural, and archaeological resources. All four invasive rodents in Hawai‘i commonly nest in cave entrances and rock shelters, but only the roof rat (Rattus rattus) habitually enters caves and utilizes areas in total darkness. Skeletons and feces have been found in the deepest passages, sometimes over a kilometer from the nearest known entrance although the animals may have used nearby small, inconspicuous entrances. Their impacts include damage to rare native plants in cave entrances; predation on vulnerable cave-inhabiting species, such as Thaumatogryllus tree crickets, and native moths roosting in caves; destruction of the irreplaceable remains of the extinct terrestrial fauna; damage to organic material associated with cultural and archaeological resources, thereby obscuring the historical record of humans in the islands; introduction of unnatural nutrients into subterranean ecosystems via their bodies and feces allowing the colonization of caves by other harmful alien species; and disturbance of research sites. Furthermore, the extirpation of colonies of cave-roosting moths has impacted native birds nesting in the entrance and twilight zones.

This article is an editorial that discusses the adaptations of species to subterranean environments. It highlights the unique conditions that subterranean species face and the traits that have evolved as a result. The article emphasizes that there is still much to learn about the adaptive traits of subterranean species and that recent studies have uncovered previously unrecognized traits. The editorial also mentions the importance of behavioral adjustments, metabolic changes, and modifications to the nervous system in adapting to subterranean life. The article concludes by summarizing the content of the research topic, which includes reviews and original research articles on various aspects of subterranean adaptations. The authors declare no conflicts of interest, and the claims expressed in the article are solely those of the authors. [Extracted from the article]

The Snezhnaya (=Snow) Cave System (depth −1760 m; total length 40.8 km), located in the West Caucasus, is inhabited by distinctly troglomorphic collembolan species from several families. Two new species of the family Arrhopalitidae occur in the deep parts of the system. Both are highly morphologically specialized; however, they evolved into different troglobiont life forms. Arrhopalites profundus sp. nov. with extremely long claws, lamellate mucro, and an enlarged sensory organ of third antennal segment lives exclusively in hygropetric and epineustonic habitats, whereas Pygmarrhopalites rystsovi sp. nov., with greatly elongated and multi-subsegmentated antennae and long legs, prefers open terrestrial spaces. The troglomorphy, as well as ecological life forms of the obligate cave-dwelling Arrhopalitidae, in general, are discussed and classified as neustonic-hygropetric, atmobiont, intrasubstrate, and intermediate troglomorphs.

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Our series of interviews with leading karstologists now turns to cave biologist. David Culver, an emeritus professor of environmental science at the American University (Washington DC, USA), talks about his relationship to karst and what subterranean biology has given to the geoscientific disciplines and what it has taken from them. His science approach is well reflected in the statement: “In the last few decades, I have done valuable little completely independent research, and collaboration with people with different skill groups has been critical”.

The importance of biofilms in caves, the diversity of microorganisms in them, their mutual relationship and relationship with the substratum are among the advancing research topics in microbial biospeleology. This research is making contribution to the knowledge about biofilms at cave entrances and phototrophic communities in them. In that manner, biofilms from the entrance zone of the Petnica Cave were examined. Light microscopy showed that cyanobacteria were exclusively dominant phototrophs (34 taxa out of 39 total taxa recorded) with coccoid forms prevailing (28 taxa); simple trichal forms were present to a lesser extent, while heterocytous ones were completely absent. Genera Gloeocapsa, Chroococcus, Gloeothece and Leptolyngbya were the most diverse. Four green algal genera characteristic for aerophytic habitats (Apatococcus, Desmococcus, Haematococcus and Trentepohlia) were also recorded, while Bacillariophytawere observed sporadically. Three groups of sampling sites were distinguished based on recorded taxa, their richness and similarity, using non-metric multidimensional scaling (NMDS). Quantitative biofilm characteristics were also assessed - the content of chlorophyll a (Chl a) was determined, as well as the contents of water, organic and inorganic matter. Chl a had a significant positive correlation with the content of organic matter (r=0.904, P=0.013). [ABSTRACT FROM AUTHOR]

A new species of Cryptops Leach, 1814, C. speleorex sp. nov., is described from Movile Cave, Dobrogea, Romania. The cave is remarkable for its unique ecosystem entirely dependent on methane- and sulfuroxidising bacteria. Until now, the cave was thought to be inhabited by the epigean species C. anomalans, which is widespread in Europe. Despite its resemblance to C. anomalans, the new species is well-defined morphologically and molecularly based on two mitochondrial (cytochrome c oxidase subunit I COI and 16S rDNA) and one nuclear (28S rDNA) markers. Cryptops speleorex sp. nov. shows a number of troglomorphic traits such as a generally large body and elongated appendages and spiracles, higher number of coxal pores and saw teeth on the tibia of the ultimate leg. With this record, the number of endemic species known from the Movile Cave reaches 35, which ranks it as one of the most species-rich caves in the world. [ABSTRACT FROM AUTHOR]

Five decades ago, a landmark paper in Science titled The Cave Environment heralded caves as ideal natural experimental laboratories in which to develop and address general questions in geology, ecology, biogeography, and evolutionary biology. Although the 'caves as laboratory' paradigm has since been advocated by subterranean biologists, there are few examples of studies that successfully translated their results into general principles. The contemporary era of big data, modelling tools, and revolutionary advances in genetics and (meta)genomics provides an opportunity to revisit unresolved questions and challenges, as well as examine promising new avenues of research in subterranean biology. Accordingly, we have developed a roadmap to guide future research endeavours in subterranean biology by adapting a well‐established methodology of 'horizon scanning' to identify the highest priority research questions across six subject areas. Based on the expert opinion of 30 scientists from around the globe with complementary expertise and of different academic ages, we assembled an initial list of 258 fundamental questions concentrating on macroecology and microbial ecology, adaptation, evolution, and conservation. Subsequently, through online surveys, 130 subterranean biologists with various backgrounds assisted us in reducing our list to 50 top‐priority questions. These research questions are broad in scope and ready to be addressed in the next decade. We believe this exercise will stimulate research towards a deeper understanding of subterranean biology and foster hypothesis‐driven studies likely to resonate broadly from the traditional boundaries of this field. [ABSTRACT FROM AUTHOR]

Subterranean habitats house a wide range of species which show a number of adaptations to prevailing ecological conditions. Spiders are among the most abundant predators in caves; however, most studies on cave spiders focus on species adapted to these habitats. This is the first study related to the occurrence of the Black lace-weaver spider, Amaurobius ferox, in caves. The species lacks adaptations to the subterranean habitats and has been observed within meters from the cave entrance all year round, except in late winter until early spring. Furthermore, its occupancy is positively related to the presence of other three cave-dwelling spiders: Metellina merianae, Meta menardi and Tegenaria sp.

A new species of Cryptops, C. (Cryptops) legagus sp. nov., occurs in caves in the Koanaka and Gcwihaba Hills in northwestern Botswana. Bayesian molecular phylogenetics using 18S rRNA, 28S rRNA, 16S rRNA and cytochrome c oxidase subunit I corroborates a morphological assignment to the subgenus Cryptops and closest affinities to southern temperate species in South Africa, Australia and New Zealand. The new species is not conspicuously modified as a troglomorph. [ABSTRACT FROM AUTHOR]

Background: Karst caves are considered as extreme environments with nutrition deficiency, darkness, and oxygen deprivation, and they are also the sources of biodiversity and metabolic pathways. Microorganisms are usually involved in the formation and maintenance of the cave system through various metabolic activities, and are indicators of changes environment influenced by human. Zhijin cave is a typical Karst cave and attracts tourists in China. However, the bacterial diversity and composition of the Karst cave are still unclear. The present study aims to reveal the bacterial diversity and composition in the cave and the potential impact of tourism activities, and better understand the roles and co-occurrence pattern of the bacterial community in the extreme cave habitats. Results: The bacterial community consisted of the major Proteobacteria, Actinobacteria, and Firmicutes, with Proteobacteria being the predominant phylum in the rock, soil, and stalactite samples. Compositions and specialized bacterial phyla of the bacterial communities were different among different sample types. The highest diversity index was found in the rock samples with a Shannon index of 4.71. Overall, Zhijin cave has relatively lower diversity than that in natural caves. The prediction of function showed that various enzymes, including ribulose-bisphosphate carboxylase, 4-hydroxybutyryl-CoA dehydratase, nitrogenase NifH, and Nitrite reductase, involved in carbon and nitrogen cycles were detected in Zhijin cave. Additionally, the modularity indices of all co-occurrence network were greater than 0.40 and the species interactions were complex across different sample types. Co-occurring positive interactions in the bacteria groups in different phyla were also observed. Conclusion: These results uncovered that the oligotrophic Zhijin cave maintains the bacterial communities with the diverse metabolic pathways, interdependent and cooperative co-existence patterns. Moreover, as a hotspot for tourism, the composition and diversity of bacterial community are influenced by tourism activities. These afford new insights for further exploring the adaptation of bacteria to extreme environments and the conservation of cave ecosystem. [ABSTRACT FROM AUTHOR]

Cave adaptation has evolved repeatedly across the Tree of Life, famously leading to pigmentation and eye degeneration and loss, yet its macroevolutionary implications remain poorly understood. We use the North American amblyopsid fishes, a family spanning a wide degree of cave adaptation, to examine the impact of cave specialization on the modes and tempo of evolution. We reconstruct evolutionary relationships using ultraconserved element loci, estimate the ancestral histories of eye‐state, and examine the impact of cave adaptation on body shape evolution. Our phylogenomic analyses provide a well‐supported hypothesis for amblyopsid evolutionary relationships. The obligate blind cavefishes form a clade and the cave‐facultative eyed spring cavefishes are nested within the obligate cavefishes. Using ancestral state reconstruction, we find support for at least two independent subterranean colonization events within the Amblyopsidae. Eyed and blind fishes have different body shapes, but not different rates of body shape evolution. North American amblyopsids highlight the complex nature of cave‐adaptive evolution and the necessity to include multiple lines of evidence to uncover the underlying processes involved in the loss of complex traits. [ABSTRACT FROM AUTHOR]

Subterranean habitats house a wide range of species which show a number of adaptations to prevailing ecological conditions. Spiders are among the most abundant predators in caves; however, most studies on cave spiders focus on species adapted to these habitats. This is the first study related to the occurrence of the Black lace-weaver spider, Amaurobius ferox, in caves. The species lacks adaptations to the subterranean habitats and has been observed within meters from the cave entrance all year round, except in late winter until early spring. Furthermore, its occupancy is positively related to the presence of other three cave-dwelling spiders: Metellina merianae, Meta menardi and Tegenaria sp. [ABSTRACT FROM AUTHOR]

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In this paper, we try to present a chronological sequence of the most important stages in the history of discovery and knowing the Ialomița cave from Bucegi Mountains (Southern Carpathians, Romania). The most important documents, articles, books and studies related to this karst phenomenon are also mentioned. [ABSTRACT FROM AUTHOR]

Abstract Background The underlying mechanisms and processes that prompt the colonisation of extreme environments, such as caves, constitute major research themes of evolutionary biology and biospeleology. The special adaptations required to survive in subterranean environments (low food availability, hypoxic waters, permanent darkness), and the geographical isolation of caves, nominate cave biodiversity as ideal subjects to answer long-standing questions concerning the interplay amongst adaptation, biogeography, and evolution. The present project aims to examine the phylogeographic patterns exhibited by two sympatric species of surface and cave-dwelling peracarid crustaceans (Asellus aquaticus and Niphargus hrabei), and in doing so elucidate the possible roles of isolation and exaptation in the colonisation and successful adaptation to the cave environment. Results Specimens of both species were sampled from freshwater hypogean (cave) and epigean (surface) habitats in Hungary, and additional data from neighbouring countries were sourced from Genbank. Sequencing of mitochondrial and nuclear loci revealed, through haplotype network reconstruction (TCS) and phylogenetic inference, the genetic structure, phylogeographic patterns, and divergence-time estimates of A. aquaticus and N. hrabei surface and cave populations. Contrasting phylogeographic patterns were found between species, with A. aquaticus showing strong genetic differentiation between cave and surface populations and N. hrabei lacking any evidence of genetic structure mediated by the cave environment. Furthermore, N. hrabei populations show very low levels of genetic differentiation throughout their range, which suggests the possibility of recent expansion events over the last few thousand years. Conclusions Isolation by cave environment, rather than distance, is likely to drive the genetic structuring observed between immediately adjacent cave and surface populations of A. aquaticus, a predominantly surface species with only moderate exaptations to subterranean life. For N. hrabei, in which populations exhibit a fully ‘cave-adapted’ (troglomorphic) phenotype, the lack of genetic structure suggests that subterranean environments do not pose a dispersal barrier for this surface-cave species.

Speleomantes are the only plethodontid salamanders present in Europe. Multiple studies have been performed to investigate the trophic niche of the eight Speleomantes species, but none of these studies included hybrid populations. For the first time, we studied the trophic niche of five Speleomantes hybrid populations. Each population was surveyed twice in 2020, and stomach flushing was performed on each captured salamander; stomach flushing is a harmless technique that allows stomach contents to be inspected. We also assessed the potential divergence in size and body condition between natural and introduced hybrids, and their parental species. Previously collected data on Speleomantes were included to increase the robustness of these analyses. In only 33 out of 134 sampled hybrid Speleomantes we recognized 81 items belonging to 11 prey categories. The frequency of empty stomachs was higher in females and individuals from natural hybrid populations, whereas the largest number of prey was consumed by males. We compared the total length and body condition of 685 adult salamanders belonging to three types of hybrids and three parental (sub)species. Three group of salamanders (one hybrid and two parental species) showed significantly larger size, whereas no difference in body condition was observed. This study provided novel ecological information on Speleomantes hybrid populations. We also provided insights into the potential divergence between hybrids and parental species in terms of size and body condition. We discuss our findings, and formulate several hypotheses that should be tested in the future.

Abstract Background Bacteria present in cave often survive by modifying their metabolic pathway or other mechanism. Understanding these adopted bacteria and their survival strategy inside the cave is an important aspect of microbial ecology. Present study focuses on the bacterial community and geochemistry in five caves of Mizoram, Northeast India. The objective of this study was to explore the taxonomic composition and presumed functional diversity of cave sediment metagenomes using paired end Illumina sequencing using V3 region of 16S rRNA gene and bioinformatics pipeline. Results Actinobacteria, Proteobacteria, Verrucomicrobia and Acidobacteria were the major phyla in all the five cave sediment samples. Among the five caves the highest diversity is found in Lamsialpuk with a Shannon index 12.5 and the lowest in Bukpuk (Shannon index 8.22). In addition, imputed metagenomic approach was used to predict the functional role of microbial community in biogeochemical cycling in the cave environments. Functional module showed high representation of genes involved in Amino Acid Metabolism in (20.9%) and Carbohydrate Metabolism (20.4%) in the KEGG pathways. Genes responsible for carbon degradation, carbon fixation, methane metabolism, nitrification, nitrate reduction and ammonia assimilation were also predicted in the present study. Conclusion The cave sediments of the biodiversity hotspot region possessing a oligotrophic environment harbours high phylogenetic diversity dominated by Actinobacteria and Proteobacteria. Among the geochemical factors, ferric oxide was correlated with increased microbial diversity. In-silico analysis detected genes involved in carbon, nitrogen, methane metabolism and complex metabolic pathways responsible for the survival of the bacterial community in nutrient limited cave environments. Present study with Paired end Illumina sequencing along with bioinformatics analysis revealed the essential ecological role of the cave bacterial communities. These results will be useful in documenting the biospeleology of this region and systematic understanding of bacterial communities in natural sediment environments as well.

The presence of mycobacteria was studied in Bull Rock Cave ("Byci skala") and the water catchment area of Jedovnice Brook ("Jedovnicky potok") using direct microscopy after Ziehl-Neelsen (ZN) staining, culture examination and molecular techniques. Mycobacteria were detected in 47.1% of a total of 68 samples. The mycobacterial genes hsp65 and dnaA were detected and sequenced in 37 (74.0%) out of the 50 cave environmental samples and in 10 (55.6%) out of the 18 samples of water catchment sediments. Nine species of slowly growing mycobacteria (M. terrae, M. arupense, M. gordonae, M. lentiflavum, M. parascrofulaceum, M. parmense, M. saskatchewanense, M. simiae and M. xenopi) and two subsp. (M. avium subsp. avium and M. avium subsp. hominissuis) were detected. Fourteen species of rapidly growing mycobacteria (M. chelonae, M. chubuense, M. poriferae, M. flavescens, M. fortuitum, M. porcinum, M. rhodesiae, M. gilvum, M. goodii, M. peregrinum, M. mageritense, M. vanbaalenii, M. gadium and M. insubricum) were detected. The highest mycobacterial presence was documented by ZN staining and/or culture examinations in earthworm castings and bat guano (73.3% positivity out of the 15 samples) in the cave environment and in the water sediments collected under the outflow from the wastewater treatment plants (77.8% positivity out of nine samples). The highest total organic carbon (TOC) was detected in wooden material and earthworm castings with pH values between 5.0 and 7.7 in the cave environment and in water sediments collected under the outflow from the wastewater treatment plants with pH between 5.8 and 7.0. It could be concluded that the karst cave environment with its running surface water contaminated with different microorganisms or chemical substances creates favourable conditions not only for animals (especially earthworms) but also for mycobacteria. This fact is also demonstrated by the presence of these mycobacteria in the cave environment mainly in earthworm castings and bat guano.

The karstic cave Križna jama in the South Western part of Slovenia is one of the largest, well known and most beautiful Slovene water caves. The cave consists of more than 8 km of corridors with impressive halls, colossal dripstone formations, a subterranean river and numerous lakes. Considering the subterranean fauna, Križna jama has been identified amongst the richest caves in the world. So far, 60 troglobionts, the obligate subterranean species among them 32 aquatic and 28 terrestrial taxa have been recorded and documented. Križna jama has scientific importance, as well as ten subterranean taxa, which have been described based on specimens from this cave. Despite Križna jama is relatively well-studied, new recent unexpected findings are promising. Thus, further discoveries of specialized subterranean species in the cave are expected.

The genus Troglophilus Krauss includes species with a rather limited dispersal ability and a wide distribution range, making it a good model for biogeographic, phylogeographic and phylogenetic investigations, with growing interest in recent years. However, a crucial prerequisite for addressing biogeographic issues is the knowledge about species complete distribution range. In particular, Troglophilus cavicola (Kollar) and Troglophilus neglectus Krauss are the species of the genus Troglophilus with the widest distribution in Europe, where their main areal extends westward to Northern Italy, but their precise distribution and range limits are still uncertain. In this study, the presence of these two species, which overwinter in hypogean habitats, was investigated in caves of the westernmost area of Northern Italy (Lombardy, Provinces of Lecco and Como) where populations belonging to the genus Troglophilus were reported. The individuals of these populations were described by previous literature as T. cavicola or as Troglophilus sp. without species determination. In this work, an in situ morphological identification of all individuals detected in the surveyed caves, and a molecular identification on 12 specimens through the COI barcoding, were performed. An effective, fast, simple, economical and easily reproducible protocol for DNA extraction was optimized for this taxon. The presence of T. cavicola in the investigated area was confirmed and the presence of T. neglectus was reported for the first time. These new data allowed us to hypothesize different scenarios about their dispersal route in Lombardy. Moreover, these new findings must be considered to define sampling plans to elucidate the biogeography of this genus. [ABSTRACT FROM AUTHOR]

Lithobius matulici Verhoeff, 1899 is redescribed based on type material and newly collected specimens. Strandiolus jugoslavicus Hoffer, 1937, described from another cave in the same region in Bosnia and Hercegovina, is presented as a junior subjective synonym of L. matulici (syn. nov.). L. matulici is shown to be most closely related to Lithobius remyi Jawłowski, 1933, type species of the subgenus Thracolithobius Matic, 1962. The completeness of the chitin-lines on the forcipular coxosternite is discussed as a promising character for interspecific differentiation within Lithobiomorpha. Documentation of hitherto unknown semiaquatic behaviour in L. matulici and other cave-dwelling centipede species from Herzegovinian-, Montenegrin- and Pyrenean caves is presented. [ABSTRACT FROM AUTHOR]