A New Species of Vietnamophryne with an Extended Description of Vietnamophryne orlovi

We describe Vietnamophryne cuongi sp. nov., a new species of microhylid frog from northern Vietnam, based on morphological and molecular differences. Although superficially similar to remaining Vietnamophryne members, the new species differs by a number of diagnostic morphological characters, such as body size, habitus, head dimensions, finger and toe morphology, skin texture, as well as colour pattern. Phylogenetic analyses based on a fragment of the mitochondrial 16S gene place the new species to be sister to V. orlovi, from which it differed by 2.4% genetic divergence. We also describe the first female known of V. orlovi, collected in the forest of Phia Oac-Phia Den National Park, Cao Bang Province. The latter species, for which we provide an extended description herein, was recently described based on the single male type specimen only from the same site in northern Vietnam. Vietnamophryne cuongi sp. nov. is only known from three specimens, two adult females and a juvenile, from the evergreen tropical forest of Ba Vi National Park, Hanoi. As such, it is likely to be at high risk of habitat loss. Considering its high ecological specialization and the small known distribution range of the new species, we propose Endangered as IUCN Red List status.

Ecological specialization, rather than the island effect, explains morphological diversification in an ancient radiation of geckos

Island colonists are often assumed to experience higher levels of phenotypic diversification than continental taxa. However, empirical evidence has uncovered exceptions to this ‘island effect’. Here, we tested this pattern using the geckos of the genus Pristurus from continental Arabia and Africa and the Socotra Archipelago. Using a recently published phylogeny and an extensive morphological dataset, we explore the differences in phenotypic evolution between Socotran and continental taxa. Moreover, we reconstructed ancestral habitat occupancy to examine if ecological specialization is correlated with morphological change, comparing phenotypic disparity and trait evolution between habitats. We found a heterogeneous outcome of island colonization. Namely, only one of the three colonization events resulted in a body size increase. However, in general, Socotran species do not present higher levels or rates of morphological diversification than continental groups. Instead, habitat specialization explains better the body size and shape evolution in Pristurus . Particularly, the colonization of ground habitats appears as the main driver of morphological change, producing the highest disparity and evolutionary rates. Additionally, arboreal species show very similar body size and head proportions. These results reveal a determinant role of ecological mechanisms in morphological evolution and corroborate the complexity of ecomorphological dynamics in continent–island systems.

Ecological dependencies make remote reef fish communities most vulnerable to coral loss

Ecosystems face both local hazards, such as over-exploitation, and global hazards, such as climate change. Since the impact of local hazards attenuates with distance from humans, local extinction risk should decrease with remoteness, making faraway areas safe havens for biodiversity. However, isolation and reduced anthropogenic disturbance may increase ecological specialization in remote communities, and hence their vulnerability to secondary effects of diversity loss propagating through networks of interacting species. We show this to be true for reef fish communities across the globe. An increase in fish-coral dependency with the distance of coral reefs from human settlements, paired with the far-reaching impacts of global hazards, increases the risk of fish species loss, counteracting the benefits of remoteness. Hotspots of fish risk from fish-coral dependency are distinct from those caused by direct human impacts, increasing the number of risk hotspots by ~30% globally. These findings might apply to other ecosystems on Earth and depict a world where no place, no matter how remote, is safe for biodiversity, calling for a reconsideration of global conservation priorities.

Molecular Rationale of Insect-Microbes Symbiosis—From Insect Behaviour to Mechanism

Insects nurture a panoply of microbial populations that are often obligatory and exist mutually with their hosts. Symbionts not only impact their host fitness but also shape the trajectory of their phenotype. This co-constructed niche successfully evolved long in the past to mark advanced ecological specialization. The resident microbes regulate insect nutrition by controlling their host plant specialization and immunity. It enhances the host fitness and performance by detoxifying toxins secreted by the predators and abstains them. The profound effect of a microbial population on insect physiology and behaviour is exploited to understand the host–microbial system in diverse taxa. Emergent research of insect-associated microbes has revealed their potential to modulate insect brain functions and, ultimately, control their behaviours, including social interactions. The revelation of the gut microbiota–brain axis has now unravelled insects as a cost-effective potential model to study neurodegenerative disorders and behavioural dysfunctions in humans. This article reviewed our knowledge about the insect–microbial system, an exquisite network of interactions operating between insects and microbes, its mechanistic insight that holds intricate multi-organismal systems in harmony, and its future perspectives. The demystification of molecular networks governing insect–microbial symbiosis will reveal the perplexing behaviours of insects that could be utilized in managing insect pests.

Riverscape genomics of cichlid fishes in the lower Congo: Uncovering mechanisms of diversification in an extreme hydrological regime

Rivers provide excellent models to understand how species diversity is generated and maintained across heterogeneous habitats. The lower Congo River (LCR) consists of a dynamic hydroscape exhibiting extraordinary aquatic biodiversity, endemicity, and ecological specialization. Previous studies have suggested that the numerous high-energy rapids throughout the LCR form physical barriers to gene flow, thus facilitating diversification and speciation, and generating ichthyofaunal diversity. However, this hypothesis has not been fully explored using genome-wide SNPs for fish species distributed across the LCR. In this study, we examined four species of lamprologine cichlids endemic to the LCR, of which three are sequentially distributed along the LCR without range overlap. Using genome-wide SNP data, we tested the hypotheses that high-energy rapids serve as physical barriers to gene flow that generate genetic divergence at inter- and intraspecific levels, and that gene flow occurs primarily in a downstream direction. Our results are consistent with the prediction that the rapids sometimes serve to reduce gene flow, but also suggest that at certain temporal and spatial scales, they may also act as promoters of gene flow. Furthermore, we detected both upstream and downstream gene flow between some populations of Lamprologus tigripictilis as well as hybridization between congeneric species. These results suggest that powerful high-energy rapids may therefore provide occasional multidirectional dispersal opportunities for riverine cichlid fishes, highlighting the complexity of factors driving evolutionary processes in the LCR.

Thyroid-Mediated Metabolic Differences Underlie Ecological Specialization of Extremophile Salmonids in the Arctic Lake El’gygytgyn

El’gygytgyn, the only “ancient lake” in the Arctic (3.6 MY), is a deep (176 m) and extremely cold (always ≤ 4°C) waterbody inhabited by unique salmonids, which colonized the ecosystem stepwise during the global fluctuations of the Quaternary climate. The descendant of the first-wave-invaders (long-finned charr) dwells in the deep waters and feeds on amphipods. The second-wave-invaders (smallmouth charr) consume copepods in the mid-waters. Recent third-wave-invaders (Boganida charr) are spread throughout the ecosystem and feed on insects when they are young shifting to piscivory at an older age. Here, we present the data on the charrs’ thyroid status and metabolic characteristics, confirming their ecological specialization. The long-finned charr exhibits an extremely low thyroid content, the substitution of carbohydrates for lipids in the cellular respiration, an increased hemoglobin level and a high antioxidant blood capacity. These traits are likely to be the legacy of anaerobic survival under perennial ice cover during several Quaternary glaciations. Moderate thyroid status and reduced metabolic rate of the smallmouth charr, along with an inactive lifestyle, could be regarded as a specialization to saving energy under the low food supply in the water column. The piscivorous Boganida charr could be sub-divided into shallow-water and deep-water groups. The former demonstrates a significantly elevated thyroid status and increased metabolism. The latter is characterized by a reduced thyroid level, metabolic rate, and lipid accumulation. Thus, the endemic El’gygytgyn charrs represent a wide spectrum of contrast physiological adaptation patterns essential to survive in sympatry under extremely cold conditions.

Genetic diversity of wild stone fruit species: specific aspects of ex situ conservation

Background. One of the most important tasks faced by the scientists of Krymsk Experiment Breeding Station of VIR is the long-term preservation of the stone fruit gene pools (over 1,000 genotypes of 44 species) collected during plant explorations. It is much more difficult to preserve representatives of the wild flora than cultivars, due to their ecological specialization to specific environments and the need to create conditions for their successful development. This aspect concerns, first of all, such species as Louiseania pedunculata (Pall.) Pachom., L. ulmifolia (Franch.) Pachom., Prunus cocomilia Ten., P. brigantiaca Vill., Armeniaca sibirica (L.) Lam., Padus ssiori (F. Schmidt) C.K. Schneid., and some others.Methods. The studies were carried out in the collection plantations of the field genebank at Krymsk Experiment Breeding Station of VIR according to VIR’s guidelines. Accessions of wild stone fruit species were the objects of the studies.Results. Many years of field research into ex situ conservation of introduced wild species proved the efficiency of stone fruit cultivation in tub culture and a modified technique of dense planting with crown formation according to the “border-hedge” pattern. It takes into account biological characteristics of genotypes shaped in natural areas, the use of own-root or grafted plants on clonal rootstocks of various growth rates depending on their life form (tree or shrub), resistance to biotic and abiotic stressors, soil and terrain requirements, and the tasks posed before researchers. The recommended planting schemes (2.5–4.0 × 0.5–1.0 m) significantly reduce the area occupied by the same number of plants in conventional cultivation patterns and cut down power and labor inputs into technological practices.

Land use in remote areas: socio-economic prospects

Okinsky district (the Republic of Buryatia, Russia) is characterized by entanglement of heterogeneous economies formed by the global demand for gold, Chinese values of jade, remnants of Soviet planning systems at the local and municipal level, traditional Soyot and Buryat land use practices, and nascent extreme and recreational tourist flows. In a situation when most of the economic and social relations remain informal and rarely captured in the official documents, landscapes become the most visible marker of changes and intersecting and sometimes conflicting networks of diverse multiscale relations. Using the interviews and in-situ observations we collected and analysed data on the pertinent social, cultural, and professional ties and examined local expectations on education, living conditions and economic prospects. Networking as a key conception has been used to untangle the complexity of the studied systems, interconnections and interdependencies of the system components. A new draft network model stimulates experts to assess if the changes planned for the regional development really benefit people in local communities, nation in whole and in global scale. In addition, the new discourse of ecosystem services motivates experts to discuss the prospects for the ecological specialization of the territories from different angles while preserving biodiversity.

Intraspecific Competition and the Promotion of Ecological Specialization

The evolution of ecological specialization can be summed up in a single question: why would a species evolve a more-restricted niche space? Various hypotheses have been developed to explain the promotion or suppression of ecological specialization. One hypothesis, competitive diversification, states that increased intraspecific competition will cause a population to broaden its niche breadth. With individuals alike in resource use preference, more individuals reduce the availability of preferred resources and should grant higher fitness to those that use secondary resources. However, recent studies cast doubt on this hypothesis with increased intraspecific competition reducing niche breadth in some systems. We present a game-theoretic evolutionary model showing greater ecological specialization with intraspecific competition under specific conditions. This is in contrast to the competitive diversification hypothesis. Our analysis reveals that specialization can offer a competitive advantage. Largely, when facing weak competition, more specialized individuals are able to acquire more of the preferred resources without greatly sacrificing secondary resources and therefore gain higher fitness. Only when competition is too great for an individual to significantly affect resource use will intraspecific competition lead to an increased niche breadth. Other conditions, such as a low diversity of resources and a low penalty to specialization, help promote ecological specialization in the face of intraspecific competition. Through this work, we have been able to discover a previously unseen role that intraspecific competition plays in the evolution of ecological specialization.