Extending beyond individual caves: a graph theory approach broadening conservation priorities in Amazon iron ore caves.

The Amazon is renowned worldwide for its biological significance, but it also harbors substantial mineral reserves. Among these, the ferruginous geosystems of the region are critical for iron ore extraction, accounting for 10% of Brazil's export revenue. Additionally, this region holds a significant speleological heritage with more than 1,000 caves. However, cave conservation efforts are often in conflict with land use, necessitating mediation through environmental regulations. While conservation decisions typically consider only the caves' characteristics, such an approach fails to account for the interactions among cave communities and their surrounding landscape. This poses a challenge to reserve design for cave conservation purposes. To address this issue, we assessed the predictors that influence the similarity among cave communities, suggesting the use of this parameter as a proxy for subterranean connectivity. Applying graph theory, we proposed a tool to aid in the selection of priority caves for conservation purposes. Our study involved the sampling of invertebrates in 69 iron ore caves and analyzing 28 environmental variables related to these subterranean habitats and adjacent landscape. Our analysis revealed that landscape and habitat characteristics are more important than geographical distance in determining patterns of similarity among caves. Our graph approach highlighted densely interconnected clusters based on similarity. However, specific caves stood out for harboring exclusive fauna and/or exhibiting habitat specificity, making them unique in the study area. Thus, we recommend prioritizing cave clusters for conservation, assembling both singular caves and others that influence them. It is crucial to note that protocols for the protection of subterranean biodiversity must consider measures that encompass both the caves and the surrounding landscape. Our methodology provides insights into the connectivity among caves, identifies existing groups, highlights singular (or unique) cavities that require preservation, and recognizes those influencing these unique habitats. This methodological advancement is crucial for the development of better conservation policies for the speleological heritage in areas under constant economic pressure.

Are males just passive? Coupling mechanism of the Brazilian cave insects with inverted genitalia.

Species of the Brazilian cave barklouse genus Neotrogla (Psocodea: "Psocoptera": Trogiomorpha: Prionoglarididae: Sensitibillini) are known to have a "female penis (gynosome)" that functions as an intromittent organ inserted into the membranous pouches in the simple male genital chamber during copulation to receive semen. However, the functions of other male and female genital structures and the copulatory processes of Neotrogla were completely unknown to date. Based on µCT observation of the male and female postabdomen and connected muscles both before and in copula, we clarified the functions of the male and female genital structures. In addition, based on the analyses of the established 3D models, we concluded that precise and rigid contact of multiple genital structures, and step-by-step releases of each holding mechanism achieved by the cooperation of both sexes are involved in the copulatory processes. The coevolution between the male and female genital structures in Neotrogla may provide a new example for the evolution of tolerance traits.

Three new troglobitic species of Pseudochthonius Balzan, 1892 (Pseudoscorpiones, Chthoniidae) from northeastern Brazil.

Three new pseudoscorpion species, Pseudochthonius pali sp. nov., Pseudochthonius diamachi sp. nov., and Pseudochthonius koinopoliteia sp. nov., are herein described from caves of Bahia state, Brazil. They can be distinguished from congeners mainly by the absence of eyes or eyespots, chelal and cheliceral dentition, coxal chaetotaxy and body size. Some ecological remarks on each species, possible threats, recommendations for future research and a key to the Pseudochthonius species from Brazil are provided.

Acquisition of novel muscles enabled protruding and retracting mechanisms of female penis in sex-role reversed cave insects.

Brazilian sex-role reversed cave insects (genus Neotrogla) have a striking structure called the gynosome (or female penis), which deeply penetrates male vagina-like genitalia during copulation to receive nutritious semen. However, the protruding and retracting mechanisms of the female penis, including their evolutionary origin, are poorly understood. By using micro-computed tomography (µCT), we compared the genital morphology and musculature between species with a gynosome and others lacking this structure. As a result, we discovered two groups of muscles related to the protrusion and retraction of gynosomes. These muscles were also observed in species with non-protrusible prepenis. This suggests that evolution of these muscles preceded the acquisition of the protruding function of the gynosome, originally having a putative stimulatory function to receive nutritious semen. This intermediate stage probably allowed for the reversal of genital functions.

Towards evidence-based conservation of subterranean ecosystems.

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.

Worldwide distribution of cave-dwelling Chelodesmidae (Diplopoda, Polydesmida)

Chelodesmidae is one of the most species rich families within the Myriapoda. However, little is known regarding their association with caves. We provide a list of all Chelodesmidae taxa reported from caves, map their worldwide distribution, and discuss the troglomorphic features of the group. A total of 25 species and subspecies from 20 genera and 2 subfamilies have been recorded from 59 caves and cave systems in 11 countries. These numbers represent a surprisingly modest proportion (~3%) of the approximately 800 described species in the family. Records of cave-dwelling chelodesmids appear to be geographically biased with most taxa reported from the Neotropics, likely due to the greater diversity of the group in the region. The lack of published records from the Afrotropics can undoubtedly be attributed to low sampling efforts. In addition, many studies focusing on cave invertebrates, especially in the tropics, often fail to identify chelodesmid taxa to the species level, thus precluding their inclusion on checklists. The majority of the Chelodesmidae reported from caves do not display obvious adaptations to a subterranean lifestyle and are not troglomorphic. The five troglobitic taxa indicated in this study may represent relictual lineages suggesting that few, if any, radiations of chelodesmids within caves have occurred in the past. Increased efforts are needed to bridge the gap between our current understanding and the true diversity of the group in these fragile and threatened habitats, which is necessary to allow policy makers to prioritize appropriate and effective conservation efforts, including the protection of environments severely impacted by human activities.

Scarabs in the dark: occurrence of Scarabaeoidea beetles (Insecta: Coleoptera) in Brazilian caves

ABSTRACT Scarabeoidea (Insecta: Coleoptera) present more than 2000 species recorded from all over Brazil. They have been scarcely recorded from caves, and truly troglobitic species are yet to be found in the country. In this study, we carried out a review of all existing scarab beetles deposited until 2017 in the Coleção de Invertebrados Subterrâneos de Lavras (ISLA), at the Universidade Federal de Lavras (UFLA) (Minas Gerais, Brazil), one of the most important collections of subterranean invertebrates in South America. Ninety-two individuals belonging to 52 species were recorded, distributed in six families (Cetoniidae, Hybosoridae, Melolonthidae, Passalidae, Scarabaeidae and Trogidae). Scarabaeidae was the most diverse of them, representing more than 50% of the total of species recorded. We found Scarabeoidea beetles in 51 of the ~ 1600 caves examined, distributed in nine Brazilian states: Alagoas, Bahia, Distrito Federal, Espírito Santo, Goiás, Minas Gerais, Pará, Piauí, and Tocantins. Our results provide evidence that Scarabaeoidea beetles are not frequent in Brazilian caves, and their records in this kind of environment are mostly accidental. Exceptions include Trogidae and Aphodiinae species, which may be associated with bat guano. Our study presents the first list of Scarabaeoidea species sampled in Brazilian caves.

A new species of the genus Gaucha Mello-Leito, 1924 from Minas Gerais, Brazil (Solifugae, Mummuciidae).

A new sun-spider species of the ibirapemussu species-group of the genus Gaucha is described based on males and a female collected in Southeastern Brazil. The newly described species can be readily distinguished from its congeners by the reduction of the cheliceral fixed finger, distal tooth (FD), closely positioned and smaller than the medial tooth (FM); the presence of cheliceral fixed finger profondal subproximal (PFSP) and retrofondal submedial (RFSM) teeth; and by the cheliceral movable finger, medial tooth (MM) well developed, larger than submedial tooth (MSM) and smaller than proximal tooth (MP). This is the thirteenth described species in the genus Gaucha, all known from South America.

Evolution of nuptial gifts and its coevolutionary dynamics with male-like persistence traits of females for multiple mating.

BACKGROUND: Many male animals donate nutritive materials during courtship or mating to their female mates. Donation of large-sized gifts, though costly to prepare, can result in increased sperm transfer during mating and delayed remating of the females, resulting in higher paternity. Nuptial gifting sometimes causes severe female-female competition for obtaining gifts (i.e., sex-role reversal in mate competition) and selection on females to increase their mating rate, changing the intensity of sperm competition and the resultant paternity gains. We built a theoretical model to simulate such coevolutionary feedbacks between nuptial gift size (male trait) and propensity for multiple mating (female trait). Donation of nuptial gifts sometimes causes development of female persistence trait for gift acquisition. We also analyzed the causes and consequences of this type of traits, taking double receptacles for nutritious seminal gifts, which are known to occur in an insect group with a "female penis" (Neotrogla spp.), as an illustrative example. RESULTS: Our individual-based simulations demonstrated that female-female competition for male-derived nutrients always occur when the environment is oligotrophic and mating costs are low for females. However, a positive correlation between donated gift size and the resultant paternity gain was a requisite for the co-occurrence of large gifts and females' competitive multiple mating for the gifts. When gift donation satisfied female demands and thus resulted in monandry, exaggeration of nuptial gift size also occurred under the assumption that the last male monopolizes paternity. The evolution of double slots for gift acquisition and digestion (female persistence trait) always occurred when males could not satisfy the demands of females for gifts. However, through coevolutionary reduction in male gift size, fixation of this trait in a population drastically reduced the average female fitness. CONCLUSION: Sperm usage patterns, which have rarely been examined for animals with nuptial gifts, can be a critical factor for determining the extent of exaggeration in nuptial gifting. Sex-role reversals in mate competition, as a result of donation of nuptial gifts from males to females, can involve the evolution of male-like, persistent traits in females that reduce population productivity, as is the case with persistence traits in males.

Fine structure of the epicuticular secretion coat and associated glands of Pedipalpi and Palpigradi (Arachnida).

Pedipalpi Latreille, 1810 is a poorly studied clade of arachnids comprising the whip spiders (Amblypygi Thorell, 1883), short-tailed whip scorpions (Schizomida Petrunkevitch, 1945) and whip scorpions (Thelyphonida Cambridge, 1872). It has recently been shown that whip spiders coat their exoskeleton with a solid cement layer (cerotegument) that forms elaborate microstructures and turns the cuticle into a super-hydrophobic state. The amblypygid cerotegument provides taxonomic information due to its fine structural diversity, but its presence and variation in the sister groups was previously unknown. The present contribution reports the surface structure of the cuticle in species of Palpigradi, Thelyphonida, and Schizomida to determine if these taxa possess a solid epicuticular secretion coat. Scanning electron microscopy revealed that in addition to Amblypygi only species of Thelyphonida possess solid epicuticular secretion layers. Unlike in Amblypygi, in the Thelyphonida this layer does not usually form microstructures and is less rigidly attached to the underlying cuticle. A species of Typopeltis Pocock, 1894, which exhibited globular structures analogous to the amblypygid cerotegument, was an exception. Glandular structures associated with cement secretions in Amblypygi and Thelyphonida were considered homologous due to similar structure. Solid epicuticular secretion coats were absent from Schizomida, which is interpreted as a secondary loss despite the presence of slit-like glandular openings that appear to produce such epicuticular secretions. The micro-whip scorpion order Palpigradi Thorell, 1900 exhibited markedly different cuticular surface structures and lacked solid epicuticular secretions, consistent with the hypothesis that this order is not closely related to Pedipalpi. These results enhance the knowledge of the small, enigmatic orders of Arachnida.

A new troglobitic palpigrade from Central Brazil, with notes on a new opisthosomal character (Arachnida: Palpigradi).

A new species of palpigrade from the cave Gruta Cabeceira d'água in Goiás state in Central Brazil is described and illustrated based on 11 specimens: five adult males, two adult females, two immatures C and two immatures B. Eukoenenia audax sp. nov. was collected mainly in the sand banks near the main water stream, where flooding and important water fluctuations occur in the cave. The new Brazilian species shows three uncommon morphological traits: the presence of 7 + 7 setae on the propeltidium, one deuto-tritosternal seta, and 9-11 blades in the lateral organs; these characters relate Eukoenenia audax sp. nov. with only a handful of species in the world. The presence of a pair of cavities was identified in the intersegmental furrow between opisthosomal sternites III-IV, IV-V, V-VI and VI-VII. A comprehensive study of this new character was performed in other species available to the authors, and a discussion of its possible origin and function is presented.

Spelaeobochica mahnerti, a new cave-dwelling pseudoscorpion from Brazil (Arachnida: Pseudoscorpiones: Bochicidae), with comments on the troglomorphism of the Brazilian bochicid species.

Spelaeobochica mahnerti sp. n., found in a limestone cave located in the municipality of Monjolos (Minas Gerais state, Southeastern Brazil), is described. It differs from congeneric species mainly by the rallum with 3 apically dentate blades, the position of the trichobothrium ib in the far distal half of the hand dorsum (near the base of fixed finger), the smooth subterminal setae, and by the arolia that are a little longer than the claws. A key to the species of Spelaeobochica is provided, as well as information on the habitat and threats for this new species. We further discuss troglomorphic traits in Brazilian species of Bochicidae.

A new troglobitic species of Typhloroncus (Arachnida: Pseudoscorpiones: Ideoroncidae) from Guatemala.

Typhloroncus guatemalensis sp. n., found in Gruta de Lanquín, a limestone cave located in the municipality of Lanquín (Alta Verapaz, Guatemala), is described. It can be distinguished from the congeneric species mainly by the presence of lanceolate ventrodistal telotarsal setae on all legs; by the chelal teeth, which exhibit a varied morphology; by the number of trichobothria (30‒32); and by its measurements. Typhloroncus guatemalensis sp. n. represents the first record for the genus in Guatemala and is considered to be troglobitic.

Why Did a Female Penis Evolve in a Small Group of Cave Insects?

The evolution of a female penis is an extremely rare event and is only known to have occurred in a tribe of small cave insects, Sensitibillini (Psocodea: Trogiomorpha: Prionoglarididae). The female penis, which is protrudable and inserted into the male vagina-like cavity during copulation to receive semen, is thought to have evolved independently twice in this tribe, in the Brazilian Neotrogla and the African Afrotrogla. These findings strongly suggest that there are some factors unique to Sensitibillini that have facilitated female penis evolution. Here, several hypothetical factors are presented that may have enabled the evolution of the female penis in Sensitibillini. The female-female competition for nutritious semen, the oligotrophic environment, and the twin insemination slots with switching valve are considered to be the driving factors for female penis evolution. Additionally, the following factors are considered responsible for relaxing the constraint against female penis evolution: preexistence of the female-above mating position, the elongated duct connecting the female pre-penis with the sperm storage organ, and the small male genital cavity accepting the female genital tubercle bearing the opening of this duct. Understanding the factors enabling female penis evolution may also shed light on the evolution of the male penis.

Independent origins of female penis and its coevolution with male vagina in cave insects (Psocodea: Prionoglarididae).

The cave-dwelling psocid tribe Sensitibillini (Afrotrogla, Neotrogla and Sensitibilla) is of special morphological and evolutionary interest because of its possession of reversed copulatory organs: i.e. females of Afrotrogla and Neotrogla have a penis-like organ. The female penis structure is highly variable among taxa, as is the case of the male penis in animals with normal copulatory organs. Here, we present the first molecular phylogeny of Sensitibillini and analyse the evolutionary pattern of their genitalia. Afrotrogla and Neotrogla did not form a monophyletic clade, and their female penis structures are significantly different, suggesting two independent origins of the female penis within Sensitibillini. In Neotrogla, the species that has a simple female penis is embedded among species that have an elaborate penis, and detailed structures of the female penis elaborations are in exact agreement among species, suggesting a secondary simplification of the female penis. A correlated evolutionary pattern between male and female genitalia was also detected. This coevolution of genitalia may suggest that sexual conflict or cryptic 'male' choice drove the diversity of the female penis, as is the case of male penile diversity in animals with conventional genitalia.

A biological switching valve evolved in the female of a sex-role reversed cave insect to receive multiple seminal packages.

We report a functional switching valve within the female genitalia of the Brazilian cave insect Neotrogla. The valve complex is composed of two plate-like sclerites, a closure element, and in-and-outflow canals. Females have a penis-like intromittent organ to coercively anchor males and obtain voluminous semen. The semen is packed in a capsule, whose formation is initiated by seminal injection. It is not only used for fertilization but also consumed by the female as nutrition. The valve complex has two slots for insemination so that Neotrogla can continue mating while the first slot is occupied. In conjunction with the female penis, this switching valve is a morphological novelty enabling females to compete for seminal gifts in their nutrient-poor cave habitats through long copulation times and multiple seminal injections. The evolution of this switching valve may have been a prerequisite for the reversal of the intromittent organ in Neotrogla.

A new highly troglomorphic Loxosceles (Araneae: Sicariidae) from Brazil.

The spiders of the genus Loxosceles have been reported from caves in several regions of the world. Despite their commonness in subterranean habitats, the occurrence of troglomorphic species is quite rare. A new cave-dwelling species found in the Brazilian Caatinga can be included in the restricted list of troglomorphic Loxosceles by presenting the following troglomorphic traits: eyes with reduced diameter, absence of pigment around the eyes, appendage elongation and pale coloration. Thus, the aim of this study is to describe a new highly troglomorphic species of Loxosceles from Brazil, corresponding to the first troglomorphic species from South America. Loxosceles troglobia sp. nov. belongs to the gaucho group and can be distinguished from the other species of this group mainly by the presence of the troglomorphic characteristics mentioned above and by the shape of the female spermathecae and the male palp. The morphological traits, together with the fact that the new species was found only in inner and very humid portions of two nearby caves, indicate that it is troglobitic.

Description of a second South American species in the Malagasy earwig genus Mesodiplatys from a cave habitat, with notes on the definition of Haplodiplatyidae (Insecta, Dermaptera).

The genus Mesodiplatys (Dermaptera: Diplatyidae) comprises eight species from Madagascar and one species from Peru. Based on a sample collected from a cave in Brazil, a new species of this genus, Mesodiplatysfalcifer Kamimura, sp. n., is described as the second species from South America. Based on a reexamination of the holotype of Mesodiplatysinsularis, a revised key to Mesodiplatys species is provided. The definitions of the genera Mesodiplatys and Haplodiplatys and the family Haplodiplatyidae are also reconsidered.

Anophtalmic and epigean? Description of an intriguing new species of Hyalella (Amphipoda, Hyalellidae) from Brazil.

The absence of eyes in Hyalella (Hyalellidae, Amphipoda) is typical of obligate groundwater-dwelling species. However, a new intriguing blind amphipod of this genus was found in epigean streams from the Iron Quadrangle (state of Minas Gerais, Brazil). Hyalella troglofugia sp nov. presents antenna 1 shorter than antenna 2, gnathopod 1 propodus inner face with four setae, gnathopod 2 propodus posterior margin longer than palm, dactylus slightly longer than palm, pereopod 5 shorter than others and uropod 3 shorter than telson. The absence of eyes and presence of reduced U3 and pereopods of H. troglofugia sp nov. may suggest that such species also inhabits interstitial subterranean spaces. Moreover, the presence of the new species on streams associated to distinct hydrological zones indicates that this species may be present in different types of subterranean habitats of the region. We hypothesize that at least part of the population of this species may have left the subterranean environment looking for food and when out of this habitat it preferentially inhabits high water flow stretches of the stream in function of predation avoidance.