Hyla Japonica Research Articles

Ontogenetic Expression of Aquaporins in the Kidney and Urinary Bladder of the Japanese Tree Frog, Dryophytes japonicus.

For adult anuran amphibians, the kidney and urinary bladder play important osmoregulatory roles through water reabsorption. In the present study, we have examined ontogenetic expression of aquaporins, i.e., AQP2, AQPamU (AQP6ub, AQPa2U), and AQP3, in these organs using the Japanese tree frog, Dryophytes japonicus. Immunohistochemistry using the metamorphosing larvae at stages 40-43 localized AQP2 protein to the collecting ducts in the dorsal zone of the mesonephric kidney. At prometamorphic stages 40 and 41, labelling of AQP2 protein was observed in the apical/ subapical regions of the collecting duct cells. At climax stages 42 and 43, labels for AQP2 and AQP3 became observed in the apical/subapical regions and basolateral membrane of the collecting duct cells, respectively, as seen in the adults. As for the urinary bladder, immuno-positive labels for AQPamU were localized to the apical/subapical regions of granular cells in the mucosal epithelium at stages 40-43. On the other hand, AQP3 immunoreactivity was hardly observed in the urinary bladder at stage 40, and weakly appeared in many granular cells at stage 41. Thereafter, labels for AQP3 became evident along the basolateral membrane of granular cells at stages 42 and 43, together with AQPamU in the apical/subapical regions. These results suggest that the kidney and urinary bladder might be capable of water reabsorption, via AQP2, AQPamU, and AQP3, at stage 42, contributing to the acclimation of the tree frogs to terrestrial environments.

Development of molecular identification methods for Dryophytes suweonensis and D. japonicus, and their hybrids.

As hybridization can reduce biodiversity or cause extinction, it is important to identify both purebred parental species and their hybrids prior to conserving them. The Suwon tree frog, Dryophytes suweonensis, is an endangered wildlife species in Korea that shares its habitat and often hybridizes with the Japanese tree frog, D. japonicus. In particular, D. suweonensis, D. japonicus, and their hybrids often have abnormal ovaries and gonads, which are known causes that could threaten their existence. We collected 57 individuals from six localities where D. suweonensis is known to be present. High-resolution melting curve (HRM) analysis of the mitochondrial 12S ribosomal RNA gene was performed to determine the maternal species. Thereafter, the DNA sequences of five nuclear genes (SIAH, TYR, POMC, RAG1, and C-MYC) were analyzed to determine their parental species and hybrid status. The HRM analysis showed that the melting temperature of D. suweonensis was in the range of 79.0-79.3°C, and that of D. japonicus was 77.7-78.0°C, which clearly distinguished the two tree frog species. DNA sequencing of the five nuclear genes revealed 37 single-nucleotide polymorphism (SNP) sites, and STRUCTURE analysis showed a two-group structure as the most likely grouping solution. No heterozygous position in the purebred parental sequences with Q values ≥ 0.995 were found, which clearly distinguished the two treefrog species from their hybrids; 11 individuals were found to be D. suweonensis, eight were found to be D. japonicus, and the remaining 38 individuals were found to be hybrids. Thus, it was possible to unambiguously identify the parental species and their hybrids using HRM analysis and DNA sequencing methods. This study provided fundamental information for D. suweonensis conservation and restoration research.

Swarmalators on a ring with uncorrelated pinning.

We present a case study of swarmalators (mobile oscillators) that move on a 1D ring and are subject to pinning. Previous work considered the special case where the pinning in space and the pinning in the phase dimension were correlated. Here, we study the general case where the space and phase pinning are uncorrelated, both being chosen uniformly at random. This induces several new effects, such as pinned async, mixed states, and a first-order phase transition. These phenomena may be found in real world swarmalators, such as systems of vinegar eels, Janus matchsticks, electrorotated Quincke rollers, or Japanese tree frogs.

Coronary artery established through amniote evolution.

Coronary arteries are a critical part of the vascular system and provide nourishment to the heart. In humans, even minor defects in coronary arteries can be lethal, emphasizing their importance for survival. However, some teleosts survive without coronary arteries, suggesting that there may have been some evolutionary changes in the morphology and function of coronary arteries in the tetrapod lineage. Here, we propose that the true ventricular coronary arteries were newly established during amniote evolution through remodeling of the ancestral coronary vasculature. In mouse (Mus musculus) and Japanese quail (Coturnix japonica) embryos, the coronary arteries unique to amniotes are established by the reconstitution of transient vascular plexuses: aortic subepicardial vessels (ASVs) in the outflow tract and the primitive coronary plexus on the ventricle. In contrast, amphibians (Hyla japonica, Lithobates catesbeianus, Xenopus laevis, and Cynops pyrrhogaster) retain the ASV-like vasculature as truncal coronary arteries throughout their lives and have no primitive coronary plexus. The anatomy and development of zebrafish (Danio rerio) and chondrichthyans suggest that their hypobranchial arteries are ASV-like structures serving as the root of the coronary vasculature throughout their lives. Thus, the ventricular coronary artery of adult amniotes is a novel structure that has acquired a new remodeling process, while the ASVs, which occur transiently during embryonic development, are remnants of the ancestral coronary vessels. This evolutionary change may be related to the modification of branchial arteries, indicating considerable morphological changes underlying the physiological transition during amniote evolution.

Seasonal Pattern of Advertisement Calling and Physiology in Prolonged Breeding Anurans, Japanese Tree Frog (Dryophytes japonicus).

The calling behavior of anurans should be studied in detail as it greatly influences their physiology and immunity, particularly in prolonged breeding species. The effect can be further complicated by the emergence timing in the breeding season. We conducted a study comparing the physiology and calling behavior of the Japanese tree frog (Dryophytes japonicus), a prolonged breeder species, according to the breeding timing. During the middle of the breeding season, a high chorus size appeared, indicating a breeding peak. However, chorus size did not dominate physiology and calling behavior. In the early breeding season, frogs had a high energy storage state and immunity. In the middle of the breeding season, individuals from the early breeding season were considered to have exhausted their energy stores and had low immunity. Towards the end of the breeding season, frogs appeared to have newly introduced, at which time energy stores and immunity were as high as in the beginning. However, unlike the physiology, the pattern of calling constantly varied as the breeding season progressed. Frogs from the early season conserved energy used for calling, and frogs from the late season showed a breeding spurt for mating. Our results can help in understanding the energy metabolism of calling behavior, physiology, and disease epidemiology in prolonged breeder species. They also suggest that individuals coordinate their participation in the breeding season and that the timing of their appearance at breeding sites may not be random.

High ranavirus infection rates at low and extreme temperatures in the tadpoles of Japanese treefrogs (Dryophytes japonicus) that breed in rice paddies in the summer

High ranavirus infection rates at low and extreme temperatures in the tadpoles of Japanese treefrogs (<i>Dryophytes japonicus</i>) that breed in rice paddies in the summer

Assessing the inhibition of glycation of ζ-crystallin by thymoquinone: A mechanistic approach using experimental and computational methods

The taxon-specific protein, ζ-crystallin is abundantly present in the eye lens of several ecologically divergent species like the camelids, Japanese tree frog and few hystricomorphic rodents, and also in comparatively in lesser amount in humans. The glycation of eye lens proteins is a prime cause of cataract. Here, for the first time, the inhibition of glycation of ζ-crystallin by thymoquinone (TQ) has been revealed using biochemical, biophysical and computational methods, to unravel the plausible anti-glycating mechanism of TQ. Significant inhibition in the formation of early and advanced glycation end products (AGEs), and notable recoveries in the biochemical and free amino group modifications were observed in presence of TQ. Computational studies were employed to decipher the specificity of methylglyoxal (MGO) binding with the free amino group residues. Furthermore, molecular docking was performed to explore the protective binding of TQ with ζ-crystallin which was found to be spontaneous and energetically favorable. Molecular dynamics (MD) simulation showed stable binding nature of ζ-crystallin-TQ complex. The binding energies for the ζ-crystallin-TQ complex were evaluated using molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) calculations which were significantly contributed by van der Waals forces and moderately with electrostatic and solvent accessible surface area (SASA) energy. All these findings clearly demonstrate TQ as an anti-glycating agent, facilitating its emergence as a therapeutic agent against glycation of ζ-crystallin.

Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions

Amphibians are famous for their ability to change colours. And a considerable number of studies have investigated the internal and external factors that affect the expression of this phenotypic plasticity. Evidence to date suggests that thermoregulation and camouflage are the main pressures that influence frogs’ adaptive colour change responses. However, certain gaps in our knowledge of this phenomenon remain, namely: (i) how do frogs adjust their colour in response to continuously changing external conditions?; (ii) what is the direction of change when two different functions of colour (camouflage and thermoregulation) are in conflict?; (iii) does reflectance in the near-infrared region show thermally adaptive change?; and (iv) is the colour change ability of each frog an individual trait (i.e., consistent within an individual over time)? Using Dryophytes japonicus (Hylidae, Hyla), we performed a series of experiments to answer the above questions. We first showed that frogs’ responses to continuously-changing external conditions (i.e., background colour and temperature) were not linear and limited to the range they experience under natural conditions. Second, when a functional conflict existed, camouflage constrained the adaptive response for thermoregulation and vice versa. Third, though both temperature and background colour induced a change in near-infrared reflectance, this change was largely explained by the high correlation between colour (reflectance in the visible spectrum) and near-infrared reflectance. Fourth, within-individual variation in colour change capacity (i.e., the degree of colour change an individual can display) was lower than inter-individual variation, suggesting individuality of colour change capacity; however, we also found that colour change capacity could change gradually with time within individuals. Our results collectively reveal several new aspects of how evolution shapes the colour change process and highlight how variation in external conditions restricts the extent of colour change in treefrogs.

Pinning in a system of swarmalators.

We study a population of swarmalators (swarming/mobile oscillators) which run on a ring and are subject to random pinning. The pinning represents the tendency of particles to stick to defects in the underlying medium which competes with the tendency to sync and swarm. The result is rich collective behavior. A highlight is low dimensional chaos which in systems of ordinary, Kuramoto-type oscillators is uncommon. Some of the states (the phase wave and split phase wave) resemble those seen in systems of Janus matchsticks or Japanese tree frogs. The others (such as the sync and unsteady states) may be observable in systems of vinegar eels, electrorotated Quincke rollers, or other swarmalators moving in disordered environments.

Change in the Guild Structure of a Snake Community in Japan over 30 Years

Long-term field studies have provided evidence of worldwide declines in vertebrate populations, including amphibians and reptiles. However, studies investigating the decline in snake populations are scarce. As obligate predators, snakes play important roles in local ecosystems and are in turn affected by their food resources. In the present study we investigated the seasonal abundance of snakes and their food habits in a rice paddy field and compared the results of the present study with those of a previous study that was conducted at the same site approximately 30 years ago. Our results showed that Elaphe quadrivirgata, a dietary generalist snake that had been one of the dominant species at the site, has drastically declined and that Rhabdophis tigrinus and Gloydius blomhoffii have remained as dominant species. Furthermore, in the present study, most of the stomach contents of R. tigrinus consisted of the Japanese tree frog, Dryophytes japonicus, whereas three frog species, D. japonicus, Rana japonica, and Pelophylax porosus porosus, had been the main prey of R. tigrinus 30 years ago. In addition, fewer individuals of R. tigrinus and G. blomhoffii contained food in their stomachs than 30 years ago. Our findings imply that a change in prey availability may have affected the guild structure of snakes at this study site, although further investigation is necessary to verify the reasons for the decline of the dietary generalist, E. quadrivirgata.

Osteological and histological comparison of the development of the interphalangeal intercalary skeletal element between hyloid and ranoid anurans.

Some frog species have a unique skeletal element, referred to as the intercalary element (IE), in the joints between the terminal and subterminal phalanges of all digits. IEs are composed of cartilage or connective tissue and have a markedly differ shape than the phalanges. IEs are highly related to the arboreal lifestyle and toe pads. The IE is found only in neobatrachian frogs among anurans, suggesting that it is a novelty of Neobatrachia. IEs are widely distributed among multiple neobatrachian lineages and are found in the suborders Hyloides and Ranoides (the two major clades in Neobatrachia). However, it is unclear whether the IEs found in multiple linages resulted from convergent evolution. Therefore, in this study, we aimed to examine how similar or different the developmental trajectories of the IEs are between Hyloides and Ranoides. To that end, we compared the osteological and histological developmental processes of the IEs of the hyloid frog Dryophytes japonicus and the ranoid frog Zhangixalus schlegelii. Both species shared the same IE-initiation site and level of tissue differentiation around the IE when it began to form in tadpoles, although the IE developments initiated at different stages which were determined by external criteria. These results suggest that similar mechanisms drive IE formation in the digits of both species, supporting the hypothesis that the IEs did not evolve convergently. This article is protected by copyright. All rights reserved.

The Bi-Functional Paxilline Enriched in Skin Secretion of Tree Frogs (Hyla japonica) Targets the KCNK18 and BKCa Channels.

The skin secretion of tree frogs contains a vast array of bioactive chemicals for repelling predators, but their structural and functional diversity is not fully understood. Paxilline (PAX), a compound synthesized by Penicillium paxilli, has been known as a specific antagonist of large conductance Ca2+-activated K+ Channels (BKCa). Here, we report the presence of PAX in the secretions of tree frogs (Hyla japonica) and that this compound has a novel function of inhibiting the potassium channel subfamily K member 18 (KCNK18) channels of their predators. The PAX-induced KCNK18 inhibition is sufficient to evoke Ca2+ influx in charybdotoxin-insensitive DRG neurons of rats. By forming π-π stacking interactions, four phenylalanines located in the central pore of KCNK18 stabilize PAX to block the ion permeation. For PAX-mediated toxicity, our results from animal assays suggest that the inhibition of KCNK18 likely acts synergistically with that of BKCa to elicit tingling and buzzing sensations in predators or competitors. These results not only show the molecular mechanism of PAX-KCNK18 interaction, but also provide insights into the defensive effects of the enriched PAX.

Diversity of cortical bone morphology in anuran amphibians.

The cortical bones of mammals, birds, and reptiles are composed of a complex of woven bone and lamellar bone (fibrolamellar bone) organized into a variety of different patterns; however, it remains unclear whether amphibians possess similar structures. Importantly, to understand the evolutionary process of limb bones in tetrapods, it is necessary to compare the bone structure of amphibians (aquatic to terrestrial) with that of amniotes (mostly terrestrial). Therefore, this study compared the cortical bones in the long bones of several frog species before and after metamorphosis. Using micro-computed tomography (CT), we found that the cortical bones in the fibrolamellar bone of Xenopus tropicalis (Pipoidea superfamily) and Lithobates catesbeianus (Ranoidea superfamily) froglets are dense, whereas those of Ceratophrys cranwelli (Hyloidea superfamily) are porous. To clarify whether these features are common to their superfamily or sister group, four other frog species were examined. Histochemical analyses revealed porous cortical bones in C. ornata and Lepidobatrachus laevis (belonging to the same family, Ceratophryidae, as C. cranwelli). However, the cortical bones of Dryophytes japonicus (Hylidae, a sister group of Ceratophryidae in the Hyloidea superfamily), Microhyla okinavensis (Microhylidae, independent of the Hyloidea superfamily), and Pleurodeles waltl, a newt as an outgroup of anurans, are dense with no observed cavities. Our findings demonstrate that at least three members of the Ceratophryidae family have porous cortical bones similar to those of reptiles, birds, and mammals, suggesting that the process of fibrolamellar bone formation arose evolutionarily in amphibians and is conserved in the common ancestor of amniotes.

Issue Information

Upper left: Some of the red blood cells (RBCs) in the liver of metamorphic Xenopus laevis express both larval globin (magenta) and the proliferation marker PCNA (green), indicating that larval type cells as well as adult ones (not shown) proliferate during metamorphosis in this species (see Yamaguchi et al. issue 8, pp. 420‐432).Upper middle: in vitro reconstruction of nuclei using Xenopus laevis sperm chromatin and X. laevis (left) or X. tropicalis (right) egg extract. Note that cytoplasmic factors influence the size of reconstructed nuclei consisting of chromatin DNA (magenta) and membrane (green) (see Heijo et al. pp. 501‐507).Upper right: Sox2‐ (green) and radial glia‐like cell marker GFAP‐ (magenta) immunoreactive cells around the lateral ventricle in the adult telencephalon of the newt Cynops pyrrhogaster. This study showed the proliferative and neurogenic zones as well as the fate of proliferated cells in the adult brain, providing a clue to clarify the significance of neurogenesis in adulthood (see Iwasa et al. pp. 474‐485).Middle left: Glucose is considered to act as one of the cryoprotectants in the Japanese tree frog (Hyla japonica) as indicated by a marked elevation of the type 2 glucose transporter (red) expression in the liver of the frozen frog (see Okada et al. pp. 486‐493).Lower left: Dynamic post‐translational modifications of histone H3 during early Xenopus development (see Zhou et al. pp. 508‐516).Lower right: Neurospheres generated from spinal cord cells of the newt Pleurodeles waltl (upper left) expressed the radial glia‐like cell marker GFAP (red) and the neural stem cell marker Nestin (green; weakly) (upper right); or the neural stem cell marker Vimentin (green) and the proliferation marker phospho‐histone H3 (red) (lower left). Cells in the neurosphere differentiated into beta‐III tubulin‐positive neurons (green) and GFAP‐positive astrocytes (magenta) (lower right) (see Seki‐Omura et al. pp. 494‐500). image

Male wasp genitalia as an anti-predator defense

Predators can cause selection that drives the evolution of various anti-predator defenses in prey1,2,3. Some prey species have evolved specific defensive devices, while others simply use body parts that evolved for reasons other than defense to repel predators1. For example, many animal species have strong canine teeth or mandibles to kill prey and to counterattack their enemies1,2,3. Bees and wasps (Insecta: Hymenoptera) use their ovipositors as stings to repel attackers, including humans4. Stinging by injecting venom can cause intense pain and allergic reactions in humans4. Therefore, stinging hymenopterans that are recognized as dangerous have evolved warning signals, such as conspicuous body coloration4. Hymenopteran males, which lack ovipositors, are believed to be harmless, and the males avoid predators by mimicking the females' coloration and behavior4. Here, we report that males of the mason wasp Anterhynchium gibbifrons (Hymenoptera: Vespidae: Eumeninae) use sharp genital spines to counterattack predators. A potential predator, the tree frog Dryophytes japonica (= Hyla japonica) (Anura: Hylidae) or the pond frog Pelophylax nigromaculatus (Anura: Ranidae), was housed with male A. gibbifrons under laboratory conditions. All tree and pond frogs attacked the male wasps. Although all of the pond frogs ate the male wasps, 35.3% of the tree frogs ultimately rejected them. Male wasps were frequently observed to pierce the mouth or other parts of frogs with their genitalia while being attacked. The tree frogs were also housed with male wasps from which the genitalia were removed. All these frogs ate the genitalia-less males. Therefore, male wasps used their genitalia to prevent tree frogs from swallowing them. This study highlights the importance of male genitalia as an anti-predator defense and provides a new perspective for understanding the ecological roles of male genitalia in animals.

Involvement of glucose in freeze tolerance in the Japanese tree frog Hyla japonica.

Glycerol and aquaporin 9 (aquaglyceroporin) are known to be involved in freeze tolerance in the Japanese tree frog Hyla japonica. However, the regulatory mechanisms of freeze tolerance in this species have not been fully elucidated. In the present study, we focused on the inter- and intracellular dynamics of glucose to analyze the role of glucose and glucose-related proteins such as transporter and metabolic enzymes in freeze tolerance. Serum glucose concentrations were compared among the frogs that were nonhibernating, hibernating, and thawed after freezing at -4°C for 6hr. Serum concentrations of glucose in thawed frogs were significantly higher than those in hibernating and nonhibernating, active frogs. Periodic acid-Schiff staining showed that the accumulation of glycogen in the hepatocytes increased before hibernation and decreased after freezing and thawing. Quantitative RT-PCR analysis using the liver showed that, compared with active frogs, the type 2 glucose transporter gene (glut2) was upregulated in frozen frogs, the liver glycogen phosphorylase gene (pygl) was upregulated in frozen or thawed frogs, and the type 2 glycogen synthase gene (gys2) was upregulated in hibernating frogs. Immunohistochemistry of liver sections showed that, compared with nonhibernating frogs, Glut2 proteins were clearly increased most likely on the plasma membrane of hepatocytes in hibernating frogs and further increased by freezing, then decreased after thawing. These results suggest the possibility that glucose acts as a cryoprotectant in H. japonica.

Prevalence of Ranavirus Infection in Three Anuran Species across South Korea.

To cope with amphibian die-offs caused by ranavirus, it is important to know the underlying ranavirus prevalence in a region. We studied the ranavirus prevalence in tadpoles of two native and one introduced anuran species inhabiting agricultural and surrounding areas at 49 locations across eight provinces of South Korea by applying qPCR. The local ranavirus prevalence and the individual infection rates at infected locations were 32.6% and 16.1%, respectively, for Dryophytes japonicus (Japanese tree frog); 25.6% and 26.1% for Pelophylax nigromaculatus (Black-spotted pond frog); and 30.5% and 50.0% for Lithobates catesbeianus (American bullfrog). The individual infection rate of L. catesbeianus was significantly greater than that of D. japonicus. The individual infection rate of P. nigromaculatus was related to the site-specific precipitation and air temperature. The individual infection rate gradually increased from Gosner development stage 39, and intermittent infection was confirmed in the early and middle developmental stages. Our results show that ranavirus is widespread among wild amphibians living in agricultural areas of South Korea, and mass die-offs by ranavirus could occur at any time.

Wind Turbine Noise Behaviorally and Physiologically Changes Male Frogs

Simple SummaryWe analyzed the behavioral–physiological–immunological interconnected process of Japanese tree frogs (Dryophytes japonicus) during their breeding season when exposed to wind turbine noise. Frogs collected from paddy fields with wind power generators exhibited a faster call rate, higher salivary concentrations of corticosterone, and lower innate immunity. However, frogs exposed to the turbine noise for a short period of time only showed faster call rates. An increase in corticosterone was correlated with an increase in call rate and a decrease in immunity. It seems that the need for energy mobilization due to an increase in the call rate leads to a decrease in innate immunity through an increase in corticosterone. The decrease in immunity due to energy tradeoff or physiological response can change disease epidemiology in the population and create new adaptive patterns within these habitats.As the advantages of wind energy as an eco-friendly strategy for power generation continue to be revealed, the number of offshore wind farms also increases worldwide. However, wind turbines can induce behavioral and physiological responses in animals by emitting various types of noises. In this study, we investigated the behavioral, physiological, and immunological responses of male Japanese tree frogs (Dryophytes japonicus) when exposed to wind turbine noise. To determine the effects during the breeding season, frogs were collected from areas with and without wind turbines. Additionally, we exposed the frogs to recorded wind turbine noise at a site without a wind generator for 1 h to 24 h to analyze the short-term effects. Three types of calling patterns (dominant frequency, note duration, and call rate) were analyzed to investigate behavioral responses. Physiological responses were assessed using two steroid hormones assays, namely testosterone and corticosterone detection in the saliva. The immunity of each individual was assessed using a bacterial killing assay. The wind turbine group in the field had a higher call rate and corticosterone levels and lower immunity than the group in the field without turbines present, and all three of these variables were correlated with each other. Conversely, in the noise exposure experiment, a higher call rate was only observed post-exposure compared to pre-exposure. Thus, turbine noise seems to induce decreased immunity in Japanese tree frogs as an increase in energy investment that triggers a behavioral response rather than acting as a sole physiological response that leads to a direct increase in corticosterone. This decreased immunity due to energy tradeoff or physiological response can change the disease epidemiology of the population and create new adaptive patterns in these habitats.

East palearctic treefrog past and present habitat suitability using ecological niche models.

Ecological niche modeling is a tool used to determine current potential species’ distribution or habitat suitability models which can then be used to project suitable areas in time. Projections of suitability into past climates can identify locations of climate refugia, or areas with high climatic stability likely to contain the highest levels of genetic diversity and stable populations when climatic conditions are less suitable in other parts of the range. Modeling habitat suitability for closely related species in recent past can also reveal potential periods and regions of contact and possible admixture. In the east palearctic, there are five Dryophytes (Hylid treefrog) clades belonging to two groups: Dryophytes japonicus group: Clades A and B; and Dryophytes immaculatus group: Dryophytes immaculatus, Dryophytes flaviventris, and Dryophytes suweonensis. We used maximum entropy modeling to determine the suitable ranges of these five clades during the present and projected to the Last Glacial Maximum (LGM) and Last Interglacial (LIG) periods. We also calculated climatic stability for each clade to identify possible areas of climate refugia. Our models indicated suitable range expansion during the LGM for four clades with the exclusion of D. immaculatus. High climatic stability in our models corresponded to areas with the highest numbers of recorded occurrences in the present. The models produced here can additionally serve as baselines for models of suitability under climate change scenarios and indicate species ecological requirements.

Guest Editorial: Hybrid Approaches to Nature-Inspired Population-Based Intelligent Optimization for Industrial Applications

These days, hybrid nature-inspired population-based intelligent optimization methods are a wide range of the algorithms, which are used very often to solve real-world (industrial) optimizationproblems. As it was shown in [item 1) in the Appendix] by Slowik and Cpalka, nature-inspired methods can be divided into several groups of algorithms. In these groups of nature-inspired algorithms, we can find physics-based algorithms (gravitational search algorithm, harmony search algorithm, big bang-big crunch algorithm, etc.) and bio-inspired methods. In bio-inspired methods, we can find evolutionary algorithms (genetic algorithms, evolution strategies, genetic programming, etc.), swarm intelligence algorithms (particle swarm optimization algorithm, ant colony optimization algorithm, bat algorithm, etc.), immune algorithms (clonal selection algorithm, negative selection algorithm, etc.), and others (flower pollination algorithm, great Salomon run, Japanese tree frogs calling, etc.). These four selected groups of nature-inspired population-based optimization algorithm are commonly used in creating hybrid methods.