Epigean Populations Research Articles

First data on the consumed prey by Speleomantes italicus from the Republic of San Marino

We here present the first study on the consumed prey by an epigean population of the Italian cave salamander (Speleomantes italicus) from the Republic of San Marino. Using the harmless technique of stomach flushing, we aimed to provide the first data on the diet and on the degree of individual specialization that characterizes the studied population. We performed two-night surveys (one in autumn 2022 and one in spring 2023) in which we opportunistically searched for salamanders in forested areas and dry walls. Captured salamanders were sexed, weighed, photographed, measured and stomach flushed. Overall, we inspected the stomach contents of 67 individuals, recognizing 1,018 prey items belonging to 28 different prey categories. The examined population was mainly composed by generalist individuals, and no differences in number and diversity of prey consumed were observed among salamanders. Contrarily to what has been observed in other Speleomantes species, flying prey provided a minor contribution to the diet of the investigated population. Our study produced the first information on the diet of Speleomantes italicus from the Republic of San Marino, representing the starting point for future assessments on the dietary habits of this specific population.

Surface newt Calotriton asper acclimation to cave conditions improved their foraging ability in darkness

Caves in temperate regions are characterized by food scarcity compared to surface habitats. Therefore, hypotheses on adaptation to cave life suggest that many characteristics, such as resistance to starvation, reduced energy demand, and increased food-finding ability, have evolved among cave dwellers to cope with food frugality. To test the hypothesis involving increased food-finding ability, the prey detection performances of three surface and three subterranean populations of the Pyrenean newt, Calotriton asper, were compared. First, the rapidity of surface individuals in capturing prey at short distances inside a restricted aquarium under dark and light conditions and their score for capturing prey in a larger aquarium under similar conditions were measured. Simultaneously the scores obtained from individuals in cave populations in darkness were compared. Individuals from one of the surface population were maintained in darkness for approximately five years and retested. The surface C. asper individuals captured prey faster at short distances under light conditions than in total darkness; however, the differences were not significant. The scores of the surface C. asper individuals in the large aquarium were significantly better in darkness than in light conditions. In addition, the scores of cave populations at short distances in darkness were better than those of epigean populations in light conditions; however, the differences were not significant. Finally, the scores of surface individuals maintained in darkness for five years improved. To explain these results, it should be noted that surface C. asper populations forage at night using non-visual cues (e.g., chemical and mechanical cues), further suggesting that vision may somewhat inhibit other senses. This ability to forage at night may be favorable for cave colonization. Moreover, some hypogean populations, when the use of prey-detecting non-visual senses has developed, may start to exhibit adaptivity.

How much we know about Brazilian subterranean aquatic fauna

The first study concerning Brazilian subterranean fauna was the description of the phreatobitic fish Phreatobius cistenarum Goeldi, 1905, followed by the stygobitic fish Pimelodella kronei (Miranda Ribeiro, 1907). After that, biospeleological studies mainly focused on terrestrial taxa description, and in 1972 the first stygobitic invertebrate, Aegla cavernicola Türkay, 1972 (Decapoda, Aeglidae), was described. Here, we provided an overview of the Brazilian subterranean aquatic fauna knowledge. To date, ca. 270 troglobitic species are described, of which 64 are aquatic (22 fishes; 42 invertebrates) and 13 have amphibian habits (all isopods). Considering aquatic species, 15 species were described between 1905 and 1999, 13 in the 2000s, 27 in the 2010s, and 9 in the 2020s. Furthermore, new stygobitic species were confirmed by experts but not published due to the deficit of trained specialists. Brazil has the second higher world diversity in stygobitic fishes, and data about habitat, biology, and ecology are available. Most of them are generalist carnivorous occurring in alluvial sediments, shallow base-level streams, flooded caves, lakes in the water table, upper vadose tributaries, or epikarst aquifers. Usually, they have small populations, but some species have large population sizes for the subterranean patterns. Some species have regression of the agonistic, cryptobiotic, and photophobic behaviors and regression of the circadian rhythms compared to their epigean relatives. Moreover, some species have morphological and behavioral intraspecific differences. Around 50 fish species have stygophilic populations, and some studies compared biological and morphological aspects of epigean and hypogean populations. There are available data about the habitat and natural history of the described stygobitic invertebrates, of which most are amphipods and planarians. Few phylogenetic relicts and epikarstic species were described. Usually, stygobites have restricted distribution in a micro-basin or are endemic within a unique cave and have small populations. Morphological and populational studies are available for few taxa (e.g., decapods and gastropods), as well as behavior studies. Community studies discuss species richness and distribution related to abiotic variables, lithology, and responses to disturbances; only a study is about epikarstic communities. For stygophilic species, there are mainly studies on distribution patterns and new records. Concerning amphibian species, five species were described in the 2010s and eight in the 2020s, with notes on their natural history and habitat. The main threats to the subterranean aquatic fauna are pollution by pesticides, decreasing aquifer levels due to deforestation and water exploitation for irrigation, headwaters of rivers outside protected areas, suppression of habitats by mining and hydroelectrical activities, allied to the current dismantling and attacks to the Brazilian environmental policies. To date, 46 stygobites (16 fishes and 30 invertebrates) and five troglobitic amphibians are on the Brazilian Red List.

Capture-mark-recapture data on the strictly protected Speleomantes italicus.

This data set collects capture-mark-recapture data, biometric data, and stomach contents of seven populations of the Italian cave salamander (Speleomantes italicus), one of the strictly protected European plethodontid species endemic to mainland Italy. We monitored six subterranean populations inside caves, and one fully epigean population living in a forest, surveying a total area of >5200 m2 . Data collection was performed 24 times throughout a year for each of the subterranean populations, and seven times in late winter-early spring for the epigean population. Salamanders were individually identified using two different marking methods: subcutaneous injection of visual implant elastomers (VIE) and photographic recognition of the dorsal pattern. Overall, the data set contains information on 1283 captured salamanders, corresponding to 783 different individuals and 500 recapture events. This type of data can be used to assess the species detection probability and to estimate the size of the populations, which are fundamental parameters for the assessment of its conservation status. Captured salamanders were weighed using a digital scale and photographed next to a reference ruler to perform post hoc measurements. This allows to assess the potential variation of the body condition of individuals through the time, and the potential divergences between conspecific populations. Furthermore, repeated measurements of recaptured individuals can allow to evaluate the seasonal growth rates of Speleomantes. Before their release, the salamanders underwent stomach flushing, a non-invasive technique that allows us to investigate the food residues in the salamanders' stomach. In 951 salamanders, we were able to recognize a total of 7077 consumed prey items belonging to 37 different prey categories (i.e., order level or lower), completing the information on the consumed prey for the entire Speleomantes genus. Data on consumed prey can be used to assess potential divergences between populations or between individuals of different ages/sexes, but also to assess the potential trophic specialization of individuals. The distinctiveness of this data set is that, by combining the capture-mark-recapture data with those on the diet of individuals, it allows to perform detailed studies on the consistency of individuals' food preference over time, an analysis that has never been performed on these salamanders. We release the data set into the public domain under Creative Commons Attribution 4.0 International license (CC-BY). When you use this data in your publication, we request that you cite this data paper; if you are using the whole data set related to the entire project, please cite all the related papers. If this data set will be an important part of the data analyzed in your study, you should consider discussing a collaboration with the data set contact person. If you plan to use data from the European plethodontid salamanders trophic niche project, please contact the contact person to find out if similar analyses are already underway or if unpublished updates are available.

The Pennsylvania grotto sculpin: population genetics

The Pennsylvania grotto sculpin is known from just two caves of the Nippenose Valley in central Pennsylvania, USA. They exhibit emergent troglobitic morphological traits and are the second northern-most cave adapted fish in the world. Two mitochondrial (16S rRNA and D-loop gene) and one nuclear (S7 ribosomal protein gene intron) gene in both cave and epigean populations were sequenced. For the three markers, a large proportion of cave specimens possess unique haplotypes not found in their local surface counterparts, suggesting a vicariance in their evolutionary history. The cave population also has haplotypes from two separate lineages of surface sculpins of the Cottus cognatus/bairdii species complex. Since morphology, nuclear, and mitochondrial markers are not correlated among cave individuals, hybridization with introgression is suggested.

Diversity of Brazilian Troglobitic Fishes: Models of Colonization and Differentiation in Subterranean Habitats

The Brazilian subterranean ichthyofauna is distinguished worldwide by high taxonomic and phylogenetic diversity, involving at least 30 exclusively subterranean (troglobitic) lineages. This may be explained by high native epigean diversty, allied to opportunities for colonization and genetic isolation in the subterranean biotope, thence originating troglobites. An updated list of Brazilian troglobitic lineages and a review of previous hypotheses on modes of colonization and differentiation in subterranean habitats are presented with fresh data and models. Colonization of and isolation in the subterranean biotope are independent processes, usually separate over time. Access to subterranean habitats varies from the (sub)horizontal through sinkholes and resurgences of base-level streams and vadose tributaries to the vertical by shallow and deep phreatic waters through the hyporheic zone. Phenotypic differentiation of subterranean populations originating troglobites may be achieved by various, non-mutually exclusive modes of genetic isolation, e.g., directly in base-level streams and upper tributaries through the extinction of epigean populations, due to drainage discontinuation in dry paleoclimatic phases (or by other causes), by topographic isolation due to a lowering of the regional base level and karst catchments or by parapatric differentiation. Differentiation may also be a consequence of transition from lotic to lentic waters in flooded caves, and from shallow to deep phreatic habitats.

Regional‐scale aquifer hydrogeology as a driver of phylogeographic structure in the Neotropical catfish Rhamdia guatemalensis (Siluriformes: Heptapteridae) from cenotes of the Yucatán Peninsula, Mexico

Abstract The Yucatán Peninsula (YP) contains one of the most spectacular and developed karstic aquifers in the world, which connects to the surface through water‐filled sinkholes locally known as cenotes. Cenotes and their associated submerged caves are home to a remarkable diversity of aquatic fauna, yet very little is known about spatial patterns of intraspecific genetic and morphological variation across the aquifer. The strong affinity to cenotes (vs. submerged caves) exhibited by most fishes inhabiting the YP aquifer raises a fundamental question about the ecology and evolutionary history of its ichthyofauna: how genetically structured and morphologically divergent are fish populations from different cenotes across the YP? To shed light on this question, we investigated phylogeographic structure in the Neotropical catfish Rhamdia guatemalensis, arguably the most ubiquitous representative of the YP aquifer ichthyofauna. Geographic patterns of genetic variation were determined through phylogeographic and population genetics analyses of mitochondrial (mt)DNA sequence data. Body shape variation was investigated using both traditional and geometric morphometrics. Dense sampling across the previously overlooked YP region, coupled with the inclusion of samples from basins unrepresented in past studies, allowed for revision of previous estimates of phylogeographic structuring across the species’ range. Our results reveal a striking spatial correspondence between major mtDNA lineages and physiographic regions defined on the basis of broad‐scale patterns of groundwater flow. Morphological variation in populations from the YP, although considerable, neither reflects the observed spatial signal of genetic differentiation nor displays any other discernible geographic pattern. The resulting range‐wide phylogeographic pattern is largely consistent with a latitudinal, isolation‐by‐distance gradient, and the expectations from catchment hydrology, while revealing an unexpectedly close relationship between YP aquifer and epigean populations (both inside and outside the YP). Although the inferred range‐wide phylogeographic history is consistent with a single aquifer colonisation event followed by multiple instances of dispersal out of the aquifer and into neighbouring epigean basins, hypotheses regarding the colonisation and exodus of the YP by R. guatemalensis require further investigation. Within the YP aquifer, regional‐scale hydrogeological differences might impose limits to underground dispersal, potentially driving genetic divergence in populations of R. guatemalensis, and possibly in other cenote‐dwelling fishes as well. Future research focused on other YP aquifer species, however, is needed to test the generality of our findings. Phylogeographic research on the stygofauna of the YP aquifer is a relatively nascent field of inquiry. Besides shedding novel light into the patterns and drivers of genetic differentiation in fish populations from across the aquifer, this study sets the stage for future research aimed at unravelling the evolutionary history of the stygofauna that inhabits the cenotes and submerged caves of the YP. The remarkable and hitherto undocumented phylogeographic pattern revealed herein (i.e. correspondence of major mtDNA lineages with physiographic regions defined by regional‐scale fracture zones) adds to a growing body of evidence in support of the notion that the architecture of freshwater aquifers may include physical barriers that can act as regional‐scale drivers of groundwater faunal distributions and genetic structuring.

Spooky Interaction at a Distance in Cave and Surface Dwelling Electric Fishes.

Glass knifefish (Eigenmannia) are a group of weakly electric fishes found throughout the Amazon basin. Their electric organ discharges (EODs) are energetically costly adaptations used in social communication and for localizing conspecifics and other objects including prey at night and in turbid water. Interestingly, a troglobitic population of blind cavefish Eigenmannia vicentespelea survives in complete darkness in a cave system in central Brazil. We examined the effects of troglobitic conditions, which includes a complete loss of visual cues and potentially reduced food sources, by comparing the behavior and movement of freely behaving cavefish to a nearby epigean (surface) population (Eigenmannia trilineata). We found that the strengths of electric discharges in cavefish were greater than in surface fish, which may result from increased reliance on electrosensory perception, larger size, and sufficient food resources. Surface fish were recorded while feeding at night and did not show evidence of territoriality, whereas cavefish appeared to maintain territories. Surprisingly, we routinely found both surface and cavefish with sustained differences in EOD frequencies that were below 10 Hz despite being within close proximity of about 50 cm. A half century of analysis of electrosocial interactions in laboratory tanks suggest that these small differences in EOD frequencies should have triggered the “jamming avoidance response,” a behavior in which fish change their EOD frequencies to increase the difference between individuals. Pairs of fish also showed significant interactions between EOD frequencies and relative movements at large distances, over 1.5 m, and at high differences in frequencies, often >50 Hz. These interactions are likely “envelope” responses in which fish alter their EOD frequency in relation to higher order features, specifically changes in the depth of modulation, of electrosocial signals.

On the evolutionary origin of Neotropical cavefish Ancistrus cryptophthalmus (Siluriformes, Loricariidae) based on the mitogenome and genetic structure of cave and surface populations

The evolutionary process of adaptation to the cave environment leads to extreme genetic, morphological, and physiological modifications commonly known as stygomorphism. The cave-dwelling armored catfish Ancistrus cryptophthalmus is a good model to understand the evolutionary processes of stygomorphism in the Neotropics as its ecology and morphology have been studied in detail. Interestingly, it has been found a non-stygomorphic epigean population named Ancistrus sp. This population is morphologically distinct to the hypogean population of A. cryptophthalmus as they present better-developed ocular structures and intense pigmentation. Here we used Illumina sequencing technology to produce partial genome sequences for specimens of Ancistrus sp. and A. cryptophthalmus; we also genotyped molecular markers from individuals of both species. Based on the high level of mitogenome similarity and metapopulation connectivity between the surface and cave populations, we suggest that the evolution of stygomorphisms observed in A. cryptophthalmus may be the result of morphologic modification, by natural selection, of Ancistrus sp. surface population to colonize the harsh cave environment.

Morphological and molecular analyses reveal a new species of stygobitic amphipod in the genus Crangonyx (Crustacea: Crangonyctidae) from Jackson County, Florida, with a redescription of Crangonyx floridanus and notes on its taxonomy and biogeography

ABSTRACTCrangonyx manubrium, a new stygobitic species, is described from hypogean localities in Jackson County, Florida. This analysis is based on detailed morphometric and genetic comparisons of Jackson County Cave populations with epigean populations of Crangonyx floridanus, including paratypes from Highlands Hammock State Park, the type locality of C. floridanus. The original description of C. floridanus was partially based on a population from Gerard’s Cave, in Jackson County, which is now assigned to C. manubrium n. sp. Crangonyx floridanus is morphologically redescribed based on paratype material from Highlands Hammock State Park, Highlands County, Florida and a population from Hogtown Creek in Gainesville, Alachua County, Florida. Molecular and morphological analyses show surprising variation across the range of C. floridanus, indicating it may represent a species complex.http://www.zoobank.org/urn:lsid:zoobank.org:pub:3E17B35E-22C7-46F9-ADD0-2B33557DAED2

Light from dark: A relictual troglobite reveals a broader ancestral distribution for kimulid harvestmen (Opiliones: Laniatores: Kimulidae) in South America.

A new troglobitic harvestman, Relictopiolus galadriel gen. nov et sp. nov., is described from Olhos d’Água cave, Itacarambi, Minas Gerais State, Brazil. Morphological characters, including male genitalia and exomorphology, suggest that this species belongs to the family Kimulidae, and it appears to share the greatest similarities with Tegipiolus pachypus. Bayesian inference analyses of a molecular dataset strongly support the inclusion of this species in Kimulidae and confirm the hypothesized sister-group relationship between R. galadriel and T. pachypus. A time calibrated phylogeny indicates that these sister-taxa diverged from a common ancestor approximately 40 Mya, during the Paleogene. The current range of Kimulidae illustrates a remarkable disjunct distribution, and leads us to hypothesize that the ancestral distribution of Kimulidae was once much more widespread across eastern Brazil. This may be attributed to the Eocene radiation associated with the warming (and humidifying) events in the Cenozoic when the best conditions for evergreen tropical vegetation in South America were established and followed by the extinction of kimulid epigean populations together with the retraction of rain forests during the Oligocene to Miocene cooling. The discovery of this relictual troglobite indicates that the Olhos d’Água cave was a stable refugium for this ancient lineage of kimulids and acted as a "museum" of biodiversity. Our findings, considered collectively with the diverse troglofauna of the Olhos d’Água cave, highlight it as one of the most important hotspots of troglobite diversity and endemism in the Neotropics. Given the ecological stresses on this habitat, the cavernicolous fauna are at risk of extinction and we emphasize the urgent need for appropriate conservation actions. Finally, we propose the transfer of Acanthominua, Euminua, Euminuoides and Pseudominua from Kimulidae to Zalmoxidae, resulting in two new synonymies and 13 new combinations.

Cave exploitation by an usual epigean species: a review on the current knowledge on fire salamander breeding in cave

Author(s): Manenti, Raoul; Lunghi, Enrico; Ficetola, Gentile Francesco | Abstract: The fire salamander (Salamandra salamandra) is a relatively common epigean amphibian, widely distributed throughout Europe, which usually gives birth to aquatic larvae. Even if epigean streams represent the most common places in which the species breeds, in some countries caves with underground waters are also used. To improve our understanding of the habitat features allowing successful breeding of salamanders in underground sites, we combined an exhaustive review of the available literature, especially the grey one, with direct observations performed from 2008 to 2017 in several natural and artificial caves of Lombardy, Liguria and Tuscany (Italy), Ariege and Provence (France). We provide a synthesis of published and unpublished caves in which the fire salamander breeding has been observed, along with a synthesis of the investigated ecological, behavioural and morphological traits. The use of underground sites is reported in several published papers and appears to be a common phenomenon not limited to single karst areas. The absence of predators, the relative stability of the aquatic habitats and the possibility to exploit new ecological resources are environmental factors that favour the breeding of the fire salamander. Our synthesis suggests that breeding of fire salamanders in caves is not a random event, but a widespread phenomenon that may be linked to specific biogeographical factors. Further insights may be obtained by performing genetic analyses on both cave and epigean populations, and considering larger landscape scales for ecological studies as well. Gene flow between salamanders that breed in caves and in streams probably occurs, but on the other hand, assortative mating might limit it, thus allowing the conservation of local adaptations driving successful cave colonisation.

Cave-epigean behavioral variation of the whip spiderPhrynus longipes(Arachnida: Amblypygi) evidenced by activity, vigilance, and aggression

Abstract Caves are peculiar ecosystems; they are most often small, isolated habitats that lack the energy that sunlight provides. Cave-adapted species, isolated from epigean (i.e., surface) selection pressures, have been discovered with aphotic adaptations like blindness, depigmentation, and enhanced extra-optic sensory systems. This evolutionary process, however, only occurs in a fraction of cave ecosystems. Many cave species, especially those in tropical latitudes, occur with epigean conspecifics with ongoing gene flow and epigean migration. This includes populations of the amblypygid Phrynus longipes (Pocock 1894), which occur in both epigean and cave environments. I hypothesized that cave and epigean populations exhibit behavioral variation to meet the selection pressures of their respective environments. I conducted open-arena and interaction behavioral assays to test for behavioral variation between populations. Assays revealed that cave and epigean amblypygids exhibited environment-specific behavio...

Ituglanis boticario, a new troglomorphic catfish (Teleostei: Siluriformes: Trichomycteridae) from Mambaí karst area, central Brazil

A new subterranean and troglomorphic species of Ituglanis Costa and Bockmann, 1993 is described from the carbonatic karst area of northeastern Goiás state, upper Tocantins River Basin, central Brazil, representing the sixth subterranean species of the genus described from the same region. Ituglanis boticario sp. nov. is diagnosed by a combination of unusual characters for the genus: body pigmentation forming longitudinal stripes, 7-8 pairs of ribs, presence of the anterior segment of the infraorbital laterosensory canal, and usually 8 pectoral-fin rays. Due to the absence of epigean populations and the presence of some degree of morphological specialization to the subterranean environment, it can be classified as a troglobite (i.e., exclusively subterranean). The description of this species increases the importance of the northeastern Goiás region as a biodiversity spot for subterranean ichthyofauna, mainly Ituglanis. The region demands urgent political efforts to ensure the preservation of its speleobiological patrimony, including the Tarimba cave system, one of the largest caves in Brazil and type-locality of I. boticario sp. nov.

The cave environment influencing the lipid profile and hepatic lipogenesis of the fish Ancistrus cryptophthalmus Reis, 1987 (Siluriformes: Loricariidae)

The metabolism of hypogean organisms is frequently molded by the cave environment traits, especially food scarcity. The aim of the present work was to evaluate the influence of such environment on lipid composition and hepatic lipogenesis in the fish Ancistrus cryptophthalmus. For this, the species was compared to an epigean population of the same species. A greater accumulation of total lipids was observed in the cave-dwelling fish (18.36 g/100 g tissue) compared to the surface fish (14.09 g/100 g tissue). The muscle fatty acid profile also varied between the populations. Arachidonic acid was only detected in the epigean fish, while docosahexaenoic acid was present in the cave fish. In the lipid profile of Ancistrus cryptophthalmus there was a higher proportion of saturated fatty acids, followed by monounsaturated and polyunsaturated fatty acids; Ancistrus sp. showed a predominance of monounsaturated fatty acids. Significant differences were also observed in the activities of the hepatic enzymes glucose-6-phosphate dehydrogenase and malic enzyme. The activities of these two enzymes were greater in the epigean animals. The differences could be related to different food availability observed in the two environments. An ecotone zone was observed, located next to the entrance of the Lapa do Angélica cave (Goiás State, Brazil), where the fishes showed characteristics that were intermediate between those of hypogean fishes from deeper within the cave, and the epigean population. It could be concluded that the characteristics of the cave environment significantly influenced the composition of muscle fatty acids and lipogenesis in the hypogean fish Ancistrus cryptophthalmus.

Osmoregulation in Hypogean Populations of the Freshwater Amphipod, Gammarus pulex (L.)

Abstract The freshwater amphipod Gammarus pulex is widely distributed in freshwater streams and rivers of Europe. This amphipod also has isolated hypogean populations, which are transparent in appearance, suggestive of adaptation to their cave environment. Since cave habitats are often food limited, physiological adaptations have been observed that reduce the energy expenditure of cave organisms. Osmoregulation is an energetically expensive mechanism that allows gammarids to survive in fresh water. This study tested the hypothesis that differences in osmoregulation existed between hypogean and epigean populations of G. pulex. The osmoregulatory parameters measured were haemolymph cation concentrations, water and sodium fluxes and gill Na+/K+-ATPase activity. The hypogean G. pulex had significantly lower haemolymph sodium and potassium concentrations, but had a significantly higher haemolymph ammonium concentration than the epigean G. pulex. The low food availability in the hypogean environment was conside...

Tempo and mode of species diversification in Dolichopoda cave crickets (Orthoptera, Rhaphidophoridae)

This study focuses on the phylogenetic relationships among ninety percent of known Dolichopoda species (44 out of 49); primarily a Mediterranean genus, distributed from eastern Pyrenees to Caucasus. A total of 2490 base pairs were sequenced corresponding to partial sequences of one nuclear (28SrRNA) and three mitochondrial genes (12S, 16S and COI). A relaxed molecular clock, inferred from Bayesian analysis was applied to estimate the divergence times between the lineages using well dated palaeoevents of the study areas. Molecular substitution rates per lineage per million years were also obtained for each analyzed gene. Based on the nearly complete species phylogeny, temporal patterns of diversification were analyzed using Lineage-Through-Time plots and diversification statistics. Alternative hypotheses about the colonization of present range by Dolichopoda species were tested by means of Approximate Bayesian Computation analysis. Results from this analysis carried out on the 90% of known Dolichopoda species confirmed the previous ones based on subgroups of species, suggesting the ABC analysis as a remarkable tool in biogeographic studies. Based on these results, the distribution of Dolichopoda species appears to have been shaped by the palaeogeographic and climatic events that occurred from Late Miocene up to the Plio-Pleistocene. Both vicariance and dispersal events appear to have influenced Dolichopoda species distributions, with many processes occurring in ancestral epigean populations before the invasion of the subterranean environment.

Cave colonization without fasting capacities: An example with the fish Astyanax fasciatus mexicanus

Subterranean animals have commonly evolved hypoactivity, hypometabolism and/or the sequential use of energetic reserves to tolerate long fasting periods imposed by the low food levels found in subterranean environments. However, some tropical caves are characterized by a potential high level of nutriments. By using the tropical fish Astyanax fasciatus that presents both populations subterranean (Astyanax fasciatus mexicanus) and epigean (Astyanax fasciatus fasciatus) populations, we described behavioral, metabolic and biochemical responses during a long-term fasting period followed by a refeeding period. The results demonstrated that fed hypogean fishes exhibited different energy stores together with a hypometabolism. But, despite drastic decreases in locomotory activity and oxygen consumption during fasting, hypogean fishes consumed significantly more glycogen, triglycerides and proteins during the starvation period than epigean fishes. This lower fasting capacity showed by hypogean fishes is confirmed by the higher activation of the compensatory metabolic pathways (ketogenesis and gluconeogenesis). After the refeeding period, cave fishes did not recover from the “food deprivation” stress, and resume fed levels in glycogen, triglyceride reserves and proteins, in contrast to epigean ones. This study thus demonstrates that starvation adaptations are not necessary for cave life, but are rather correlated to the “energetic state” of each ecosystem, and that troglomorphism is not linked to starvation capacities and thus not to the impoverished food availability.

Diverging Cave‐ and River‐Dwelling Newts Exert the Same Mate Preference in their Native Light Conditions

AbstractWhen colonizing a new habitat, populations must adapt their sexual behaviour to new ecological constraints. Because caves display drastically different conditions from surface habitats and cave animals are deprived from visual information, hypogean populations are expected to have modified their mate preference and signalling behaviour after cave colonization. Here, we experimentally examined the female preference and the sexual behaviour of brook newts Calotriton asper from different cave and river populations, either in light or in darkness. Our results suggest that females prefer large individuals in both hypogean and epigean populations, but that this preference is only expressed in the light conditions of their native habitat. Hence, some mate choice criteria would be maintained across genetically divergent populations and throughout dissimilar habitats. However, this sexual behaviour is likely to be expressed via a different sensory pathway in the different habitats, suggesting that a sensory shift has occurred in cave populations, enabling animals to communicate through a non‐visual channel.

A cave population of Isbrueckerichthys alipionis (Gosline, 1947) in the Upper Ribeira karst area, southeastern Brazil (Siluriformes: Loricariidae)

A cave population of the armored catfish Isbrueckerichthys alipionis is reported from the Santana Cave, in the rio Betari watershed, Upper Ribeira karst area, Iporanga, São Paulo State, southeastern Brazil. The cave population was compared to an epigean population of I. alipionis and no significant differences where found in morphology or degree of pigmentation. As the cave population is known for at least 30 years and is apparently isolated from epigean streams, it is classified as troglophilic. The discovery of this troglophilic species in the Santana Cave is an additional strong argument for the conservation of that cave.