Evolution of cave living in Hawaiian Schrankia (Lepidoptera: Noctuidae) with description of a remarkable new cave species

Although temperate cave‐adapted fauna may evolve as a result of climatic change, tropical cave dwellers probably colonize caves through adaptive shifts to exploit new resources. The founding populations may have traits that make colonization of underground spaces even more likely. To investigate the process of cave adaptation and the number of times that flightlessness has evolved in a group of reportedly flightless Hawaiian cave moths, we tested the flight ability of 54 Schrankia individuals from seven caves on two islands. Several caves on one island were sampled because separate caves could have been colonized by underground connections after flightlessness had already evolved. A phylogeny based on approximately 1500 bp of mtDNA and nDNA showed that Schrankia howarthi sp. nov. invaded caves on two islands, Maui and Hawaii. Cave‐adapted adults are not consistently flightless but instead are polymorphic for flight ability. Although the new species appears well suited to underground living, some individuals were found living above ground as well. These individuals, which are capable of flight, suggest that this normally cave‐limited species is able to colonize other, geographically separated caves via above‐ground dispersal. This is the first example of an apparently cave‐adapted species that occurs in caves on two separate Hawaiian islands. A revision of the other Hawaiian Schrankia is presented, revealing that Schrankia simplex, Schrankia oxygramma, Schrankia sarothrura, and Schrankia arrhecta are all junior synonyms of Schrankia altivolans. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156 , 114–139.     

Rediscovery of the “extinct” blind ground beetle (Coleoptera: Carabidae: Trechinae)

The blind ground beetle Ishikawatrechus intermedius (Coleoptera: Carabidae: Trechinae), called Kadota‐mekurachibigomimushi in Japanese, was first found in 1952 in the cave Ôchi‐dô, Kôchi Prefecture, Japan. However, this cave and a large part of the surrounding hill were destroyed by limestone mining in the 1970s. Because most species of blind ground beetles are restricted to specific caves or cave systems, I. intermedius has been considered endemic to very narrow areas of the cave Ôchi‐dô and the upper hypogean zone around the cave. Therefore, I. intermedius was considered to have become extinct. In this study, during 2011–2015, we collected ten individuals of a blind ground beetle, which appeared to be I. intermedius, from the upper hypogean zone, approximately 0.3–1.0 m below ground, in the southern part of the type locality. A comparison with type specimens indicated that the individuals were indeed I. intermedius. Therefore, we conclude that I. intermedius survives in the upper hypogean zone near the type locality. The results of this study will be useful for quickly establishing conservation measures for threatened or vulnerable species of Trechinae beetles.     

Origins and Relationship of Cave Populations of the Blind Mexican Tetra, Astyanax Fasciatus, in the Sierra De El Abra

The blind morph of Astyanax fasciatus (Pisces: Characidae) has been more thoroughly studied than any other cave inhabiting organism. Most studies of A. fasciatus have used individuals from different caves of the Sierra de El Abra, Mexico, and have assumed that each population independently evolved to live in the cave environment. We analyzed the relationships among several cave populations that delineate the Sierra de El Abra using RAPD markers. The results indicate that all cave populations are more closely related to one another than they are to the surface populations. This suggests that present day cave populations derived from a common ancestral stock, most likely due to a single colonization event, or alternatively, that strong gene flow among cave populations has occurred, raising precaution against considering each cave population as independent.     

Isolation and characterization of five microsatellite loci in Dolichopoda cave crickets (Orthoptera Rhaphidophoridae)

Five microsatellite loci are described for the cave cricket genus Dolichopoda. Preliminary data on allelic variation of these loci are presented for one population of D. schiavazzii and one population of D. laetitiae to test their usefulness in fine‐scale studies of the genetic aspect of cave colonization. Cross‐species amplifications were carried out in four other Dolichopoda species and in two species belonging to another cave cricket genus (Troglophilus) to test the potential use of these microsatellite markers in studies of both congeneric species and species belonging to the same family.     

Molecular Phylogenies in Dolichopoda Cave Crickets and mtDNA Rate Calibration

Five species of Dolichopoda cave crickets have been studied by means of mtDNA RFLPs. The phylogenetic relationships among them were previously inferred from two different molecular measures: allozyme polymorphisms and DNA-DNA hybridization. mtDNA data generate a phylogeny exactly matching those obtained from the other two genetic markers. This is not always the case for other organisms studied so far. This result is discussed in respect of the performance of the three molecular approaches and the population biology of these cave dwelling insects. A tentative calibration of mtDNA rate for Dolichopoda produces an estimate of about 2%/lineage/Myr. The comparison between mtDNA and scnDNA divergence estimates suggests that in these crickets changes accumulate approximately 2-3 times faster in mitochondrial than single copy nuclear sequences.     

中华菊头蝠的栖息生态特征及种群保护

中华菊头蝠(Rhinolophus sinicus)主要分布于我国境内,属于典型的洞栖食虫性蝙蝠,具有重要的研究意义与保护价值。近年,在湘西州境内的16个溶洞中对其栖息生态特征进行了观察,共记录到其个体12942只次,数据分析结果显示：该蝠是该区域溶洞中的居留型优势蝠种,具有集群冬眠的习性。每年的9月中下旬开始逐步聚群冬眠,翌年的3月底开始苏醒,其夏季的繁育场所非常隐蔽,通常位于人无法进入的洞段或人迹罕至的洞穴。总体上,其栖点主要集中于距洞口150—200 m(91.60%)的洞段,离地高度6—10 m(91.75%),多以“双足悬挂”的栖姿将身体悬空倒挂于洞道的顶壁。其体温与栖点温度之间不存在显著性差异(P>0.05),但具有明显的线性正相关关系(R~2=0.8886)。其栖点安全性春夏季高,秋冬季中等偏低。中华菊头蝠作为该区域洞栖性蝙蝠的优势种,在维持洞穴生态系统的稳定中发挥着至关重要的作用,加强对洞穴生态系统中蝙蝠伞护性的研究有助于洞穴生态保护教育及对蝙蝠种群的保护实践。     

Cyto‐nuclear discordance suggests complex evolutionary history in the cave‐dwelling salamander,Eurycea lucifuga

Our understanding of the evolutionary history and ecology of cave‐associated species has been driven historically by studies of morphologically adapted cave‐restricted species. Our understanding of the evolutionary history and ecology of nonrestricted cave species, troglophiles, is limited to a few studies, which present differing accounts of troglophiles’ relationship with the cave habitat, and its impact on population dynamics. Here, we used phylogenetics, demographic statistics, and population genetic methods to study lineage divergence, dates of divergence, and population structure in the Cave Salamander, Eurycea lucifuga, across its range. In order to perform these analyses, we sampled 233 individuals from 49 populations, using sequence data from three gene loci as well as genotyping data from 19 newly designed microsatellite markers. We find, as in many other species studied in a phylogeographic context, discordance between patterns inferred from mitochondrial relationships and those inferred by nuclear markers indicating a complicated evolutionary history in this species. Our results suggest Pleistocene‐based divergence among three main lineages within E. lucifuga corresponding to the western, central, and eastern regions of the range, similar to patterns seen in species separated in multiple refugia during climatic shifts. The conflict between mitochondrial and nuclear patterns is consistent with what we would expect from secondary contact between regional populations following expansion from multiple refugia.     

Descriptions of the first semi-aphenopsian troglobiotic Patrobini and of a new anophthalmic cave-dwelling Trechini from central Sichuan,China (Coleoptera: Caraboidea)

Summary

The first known troglobiotic species belonging to the ground beetle tribe Patrobini is reported from a limestone cave called Lianhua Dong in Pengzhou, a suburb county-level city in northern Chengdu, Sichuan Province, China. Troglopatrobus zhouchaoi n. gen., n. sp., is an eyeless and large-sized patrobine beetle with extremely elongated body (esp. head and elytra) and appendages. Duvalioblemus (Shublemus) liyuani n. subgen., n. sp., a minute anophthalmic trechine species, is also discovered from the same cave. It is the first cave-dwelling species belonging to this genus already known as endogean from Sichuan and Yunnan provinces.     

Small‐scale genetic structuring in a tropical cave snail and admixture with its above‐ground sister species†

We analyse the phylogeographical structure in the cave snail Georissa filiasaulae Haase & Schilthuizen, 2007 (Gastropoda: Hydrocenidae) and its above‐ground sister species G. saulae (van Benthem‐Jutting, 1966) at limestone outcrops in Sabah, Malaysian Borneo. Morphometric and 16S mitochondrial DNA data for some 220 individuals reveal strong morphological differentiation, despite ongoing unidirectional gene flow from the epigean into the hypogean environment, strong, small‐scale genetic structuring within the cave and underground dispersal between caves that were previously thought to be isolated. We discuss these results – which constitute the first phylogeographical analysis of a terrestrial cave snail – in the light of speciation in cave organisms and across ecotones in general. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 727–740.     

Random Amplified Polymorphic DNA Diversity among Surface and Subterranean Populations of Asellus aquaticus (Crustacea: Isopoda)

The ecological and evolutionary processes leading to isolation and adaptation of cave animals compared to their surface ancestors are not yet unequivocally understood. In this study the genetic relations of four cave and three surface population of the freshwater crustacean Asellus aquaticus in the Karst region of SW Slovenia and NE Italy were assessed using RAPDs as genetic markers. The results suggest that specialized populations from two caves invaded their subterranean habitat independently, and that their morphological similarity is a result of convergent evolution. Another, less specialized cave population seems to originate from a later colonization of a cave system already inhabited by a more specialized population, but the two populations do not interbreed. This series of temporally and spatially independent invasions has generated a diversity hotspot of non-interbreeding populations of a ubiquitous freshwatercrustacean, which is uniform over most of its range. Genetic variability estimated by the percentage of polymorphic RAPD fragments was similar (86–91%) in most cave and surface populations. Substantially lower values (as low as 49%) were found in two cave populations affected by heavy pollution. Two a priori groupings of populations, traditional subspecies and hydrologically connected groups, were rejected as not significant by means of nested analysis of molecular variance (AMOVA). On the other hand, groupings revealed by UPGMA clustering displayed a significant component of among-group variance. An analysis of gene flow between populations using estimated migration rates confirmed these findings.     

Isolation and characterization of microsatellite loci in the Bang's leaf‐nosed bat Hipposideros turpis

The Bang's leaf‐nose bat, Hipposideros turpis, is an endangered cave‐dwelling species inhabiting the southwesternmost islands of Japan. We isolated six dinucleotide microsatellite markers from the partial genomic library of the bat, and examined their allelic variation using a sample (N = 33) from the largest colony in Japan. All the loci showed a moderate allelic variation ranging from two to eight alleles, with the observed heterozygosities from 0.33 to 0.73, and conformed to Hardy–Weinberg expectations. The present microsatellite markers will be useful in assessing population genetic structure and gene flow among populations of this species.     

The Occurrence of Fungi in the Recently Discovered Jarkowicka Cave in the Karkonosze Mts. (Poland)

Our study is one of the very few cases of speleomycological research in recently discovered caves. The aim of this research was to assess the population size of fungal colonies and their species composition in the Jarkowicka cave, discovered in 2012. The air samples were taken from one location outside the cave and from two locations inside of it. Mycological evaluation of the rocks inside the cave was performed usingswab sampling procedure. In the Jarkowicka cave we found 22 species of fungi, including 13 isolated from air at the entrance and from the walls, and 8 species from air inside the cave. Cladosporium spp. were the fungi most frequently isolated from internal atmosphere of the Jarkowicka cave, and from the external air. On the other hand, the fungi most frequently isolated from the rocks were Mucor spp. We found several species not yet described as cave inhabitants: Hypocrea pachybasioides, Cladosporium uredinicola, and Embellisia abundans. Our study may provide a basis for comparison to other similar studies conducted in frequently visited caves by tourists.     

Carnoya kermarreci n.sp. (Rhigonematidae: Nematoda) from Anadenobolus politus (Porat) (Rhinocricidae: Diplopoda) from Guadeloupe

Summary Carnoya kermarreci n.sp. (Rhigonematidae; Nematoda) is described from Anadenobolus politus (Porat) (Rhinocricidae; Diplopoda) from Guadeloupe. The new species most closely resembles C. martiniquensis Adamson, 1984 from A. politus in Martinique and C. venezuelensis Adamson, 1984 from Rhinocricus flavocinctus from Venezuela in that the lips in the male are broad and the arrangement of caudal papillae is almost identical in the three species. Males of C. kermarreci are easily distinguished by the absence of spines, by the form of the cuticular projections at the base of the buccal cavity and by the fact that the most anterior pair of caudal papillae are located very close together. Females are distinguished by the presence of three pairs of somatic papillae near the level of the vulva. The nematode fauna of A. politus includes species from two distinct orders and presumably reflects the fact that diplopods are among the most ancient hosts of nematodes.     

A new and morphologically distinct population of cavernicolous Poecilia mexicana (Poeciliidae: Teleostei)

The cave molly, Poecilia mexicana, from the Cueva del Azufre, a sulfur cave in Tabasco, Mexico, ranks among the best-studied cave fishes worldwide, despite being known from a single population only. Here we describe a newly discovered second population of cave-dwelling P. mexicana from a nearby, but mostly non-sulfidic cave (Luna Azufre). Despite apparent similarities between the two populations (such as reduced eye diameter and reduced pigmentation), a geometric morphometric analysis revealed pronounced morphological differentiation between the two cave forms.     

Isolation and characterization of microsatellite markers in hoary marmots (Marmota caligata)

Microsatellite loci were developed from hoary marmots (Marmota caligata) to aid in the investigation of the social structure and mating system of this species. Seven of the microsatellite loci developed were found to be moderately polymorphic with between two and seven alleles per locus. In addition to the microsatellites developed in hoary marmots we also tested markers developed for other scuirids, namely European alpine marmots (M. marmota), Columbian ground squirrels (Spermophilus columbianus) and European ground squirrels (S. citellus). Of these markers, 13 were polymorphic when amplified in hoary marmots with between two and nine alleles per locus.     

Standing genetic variation as a potential mechanism of novel cave phenotype evolution in the freshwater isopod,Asellus aquaticus

Novel phenotypes can come about through a variety of mechanisms including standing genetic variation from a founding population. Cave animals are an excellent system in which to study the evolution of novel phenotypes such as loss of pigmentation and eyes. Asellus aquaticus is a freshwater isopod crustacean found in Europe and has both a surface and a cave ecomorph which vary in multiple phenotypic traits. An orange eye phenotype was previously revealed by F₂ crosses and backcrosses to the cave parent within two examined Slovenian cave populations. Complete loss of pigmentation, both in eye and body, is epistatic to the orange eye phenotype and therefore the orange eye phenotype is hidden within the cave populations. Our goal was to investigate the origin of the orange eye alleles within the Slovenian cave populations by examining A. aquaticus individuals from Slovenian and Romanian surface populations and Asellus aquaticus infernus individuals from a Romanian cave population. We found orange eye individuals present in lab raised surface populations of A. aquaticus from both Slovenia and Romania. Using a mapping approach with crosses between individuals of two surface populations, we found that the region known to be responsible for the orange eye phenotype within the two previously examined Slovenian cave populations was also responsible within both the Slovenian and the Romanian surface populations. Complementation crosses between orange eye Slovenian and orange eye Romanian surface individuals suggest that the same gene is responsible for the orange eye phenotype in both surface populations. Additionally, we observed a low frequency phenotype of eye loss in crosses generated between the two surface populations and also in the Romanian surface population. Finally, in a cave population from Romania, A. aquaticus infernus, we found that the same region is also responsible for the orange eye phenotype as the Slovenian cave populations and the Slovenian and Romanian surface populations. Therefore, we present evidence that variation present in the cave populations could originate from standing variation present in the surface populations and/or transgressive hybridization of different surface phylogenetic lineages rather than de novo mutations.     

Molecular phylogeny of the extinct cave lion Panthera leo spelaea

To reconstruct the phylogenetic position of the extinct cave lion (Panthera leo spelaea), we sequenced 1 kb of the mitochondrial cytochrome b gene from two Pleistocene cave lion DNA samples (47 and 32 ky B.P.). Phylogenetic analysis shows that the ancient sequences form a clade that is most closely related to the extant lions from Africa and Asia; at the same time, cave lions appear to be highly distinct from their living relatives. Our data show that these cave lion sequences represent lineages that were isolated from lions in Africa and Asia since their dispersal over Europe about 600 ky B.P., as they are not found among our sample of extant populations. The cave lion lineages presented here went extinct without mitochondrial descendants on other continents. The high sequence divergence in the cytochrome b gene between cave and modern lions is notable.     

Convergent Adaptations to Cave Life in the Rhamdia Laticauda Catfish Group (Pimelodidae, Teleostei)

The nocturnal Mexican catfish Rhamdia laticauda (Pimelodidae, Teleostei) is the surface sister species of a number of cave species. Comparison between two of them, R. zongolicensis and R. reddelli, reveals an intermediate state of reduction of the biologically functionless eyes, melanin pigmentation and the negative phototactic behavior. The surface species is perfectly adapted to life in darkness. Therefore only few constructive adaptations are developed in the cave species. For survival under conditions of low food supply in the caves the barbels are elongated to improve the senses of taste and touch and more fat can be deposited in the cave fish tissue. Due to convergent evolution the two cave species are morphologically much alike and show only minor diagnostic meristic differences. From geological data it can be concluded that the two cave species started troglobitic evolution at the end of Pleistocene.     

Identification of roots in lava tube caves using molecular techniques: implications for conservation of cave arthropod faunas

Lava tube cave ecosystems on the volcanic islands of Hawai‘i support communities of rare and highly specialized cave arthropods. In these cave ecosystems, plant roots, both living and dead, provide the main energy source for cave animals. Loss of deep-rooted plants over caves will affect populations of cave-adapted animals living below. Furthermore, the loss of native plant species will likely eliminate host specific cave animals. Thus, identification of plant roots currently found in caves is necessary for the development of effective management actions that encourage the growth of appropriate deep-rooted plant species, thereby protecting the underlying cave ecosystem. We used molecular techniques to identify plant roots found within cave ecosystems on the islands of Maui and Hawai‘i. Sequences of the internal transcribed spacer (ITS) regions and the 5.8S gene of nuclear ribosomal DNA from cave roots were compared to sequences of known plant species either collected on the surface over the footprint of each cave or to sequences accessioned in GenBank. Roots in the cave ecosystem studied on Maui belonged to two alien tree species: Eucalyptus tereticornis and Grevillea robusta. Within the Hawai‘i cave ecosystem, roots of two plant species were identified: the alien tree G. robusta and the native vine Cocculus orbiculatus. The Maui cave ecosystem supports populations of at least 28 species of arthropods, including eight that are blind obligate cave inhabitants. The Hawai‘i cave ecosystem supports 18 arthropod species, of which three are cave-adapted. Creating protected reserves around biologically significant caves, controlling, and preventing the introduction of harmful invasive plant species within the cave footprint, and encouraging the establishment of deep-rooted native plant species is essential for the continued survival of the unique ecosystems found within Hawaiian lava tube cave systems.     

Parallel evolution leads to reduced shoaling behavior in two cave dwelling populations of Atlantic mollies (<Emphasis Type="Italic">Poecilia mexicana</Emphasis>, Poeciliidae,Teleostei)

Shoaling behavior protects fishes from avian and piscine predation, but at the same time costs of group living arise due to several mechanisms including increased food competition. Most cave fishes live in an environment in which avian and piscine predators are lacking, and cave environments are often characterized by low food availability, leading to increased food competition. Altogether, this should favor the reduction of shoaling in cave fishes. We compared shoaling behavior (i.e. the tendency to associate with a stimulus shoal) among surface dwelling populations of the Atlantic molly, Poecilia mexicana, and two cave forms of that species. The first cave population of P. mexicana originated from the Cueva del Azufre and was previously recognized as the only cave form of a poeciliid fish. The second cave population examined came from a cave that was discovered only recently (Cueva Luna Azufre). In both cave forms shoaling behavior was reduced compared with surface dwelling mollies.