Wild Populations Research Articles

Rediscovery of the Neotropical orchid Porroglossum parsonsii and recommendations for its conservation

Abstract Understanding the distribution and habitat requirements of species is crucial for designing conservation actions, yet this information is not available for many plant species. We report the first confirmed wild populations of Porroglossum parsonsii, which, because of its horticultural value, is commercialized in national and international markets, from where it was first described to science. Our large-scale survey of 341 10 × 30 m plots spanning Andean forests, paramo habitats and pasturelands in Colombia suggests that P. parsonsii has a restricted geographical distribution in Andean forests with high forest cover (71.4–86.2%), where it occurs in low numbers (5–17 individuals per plot). Because of its market value (USD 18–20 per plant) there is a risk the species could be collected illegally, and therefore the habitat of the species in the Santuario de Fauna y Flora de Iguaque requires appropriate conservation.

Wolbachia and Asaia Distribution among Different Mosquito Vectors Is Affected by Tissue Localization and Host Species.

Microbial communities play an important role in the fitness of mosquito hosts. However, the factors shaping microbial communities in wild populations, with regard to interactions among microbial species, are still largely unknown. Previous research has demonstrated that two of the most studied mosquito symbionts, the bacteria Wolbachia and Asaia, seem to compete or not compete, depending on the genetic background of the reference mosquito host. The large diversity of Wolbachia-Asaia strain combinations that infect natural populations of mosquitoes may offer a relevant opportunity to select suitable phenotypes for the suppression of pathogen transmission and for the manipulation of host reproduction. We surveyed Wolbachia and Asaia in 44 mosquito populations belonging to 11 different species of the genera Anopheles, Aedes, and Culex using qualitative PCR. Through quantitative PCR, the amounts of both bacteria were assessed in different mosquito organs, and through metagenomics, we determined the microbiota compositions in some selected mosquito populations. We show that variation in microbial community structure is likely associated with the species/strain of mosquito, its geographical position, and tissue localization. Together, our results shed light on the interactions among different bacterial species in the microbial communities of mosquito vectors, and this can aid the development and/or improvement of methods for symbiotic control of insect vectors.

Ultrasonography of the neotropical primate female reproductive system.

The Neotropical (e. g., Aotus sp., Callithrix jacchus, Saguinus sp., Saimiri sp., and Sapajus sp.) primates are important models for biomedical research and studies on reproductive physiology and biotechnology. Consequently, studies about gynecological and obstetric ultrasonography are crucial. B-mode ultrasonography is a non-invasive imaging technique that provides real-time bidimensional or three-dimensional/four-dimensional B-mode images. In association with Doppler ultrasonography, B-mode ultrasonography can also be used to monitor the mammalian blood flow to the reproductive tract during important events such as ovulation and gestation. Thus, gynecological and obstetric ultrasonography is essential for establishing the female reproductive anatomical and physiological ovarian and uterine health status, gestational diagnosis, and fetal growth monitoring. For instance, the paper presents and discusses the state-of-the-art gynecological and obstetric ultrasonography in the Neotropical primates, species that are models for biomedical research, and some recent studies on species targets for conservation strategies for wild animal populations.

Spatial covariation between genetic and epigenetic diversity in wild plant and animal populations: a meta-analysis.

Epigenetic variation may be crucial in understanding the structure of wild populations, thereby aiding in their management and conservation. However, the relationship between epigenetic and genetic variation remains poorly understood, especially in wild populations. To address this, we conducted a meta-analysis of studies that examined the genetic and epigenetic structures of wild plant and animal populations. We aimed to determine whether epigenetic variation is spatially independent of genetic variation in the wild and to highlight the conditions under which epigenetic variation might be informative. We show a significant positive correlation between genetic and epigenetic pairwise differentiation, indicating that in wild populations, epigenetic diversity is closely linked to genetic differentiation. The correlation was weaker for population pairs that were weakly differentiated genetically, suggesting that in such cases, epigenetic marks might be independent of genetic marks. Additionally, we found that global levels of genetic and epigenetic differentiation were similar across plant and animal populations, except when populations were weakly differentiated genetically. In such cases, epigenetic differentiation was either higher or lower than genetic differentiation. Our results suggest that epigenetic information is particularly relevant in populations that have recently diverged genetically or are connected by gene flow. Future studies should consider the genetic structure of populations when inferring the role of epigenetic diversity in local adaptation in wild populations. Furthermore, there is a need to identify the factors that sustain the links between genetic and epigenetic diversity to improve our understanding of the interplay between these two forms of variation in wild populations.

Optimizing release strategies for red king crab stock enhancement: Effects of release timing

Red king crab, Paralithodes camtschaticus, was commercially important around Kodiak, Alaska, USA, in the 1960s and 1970s; however, the stock crashed in the late 1970 s and has remained closed since 1983. The lack of recovery inspired consideration of stock enhancement through the release of hatchery-reared juveniles as a means to bolster the wild population. We examined the effects of release timing on in situ survival of hatchery-reared red king crab by releasing juveniles in June, August, and September 2015 in Trident Basin, Kodiak. We monitored densities inside and outside of release plots for six months using quadrat counts to determine loss and emigration rates. Relative predation risk was determined using tethering experiments performed after each release, and predator densities were quantified using quadrat counts and predator transect counts. Initial mortality over the first 24 h was approximately 53%, and subsequent mortality rates decreased with month-of-release, likely due to a combination of larger size-at-release and seasonal changes in predation. Although predator density was consistent over time, relative predation risk of tethered crabs decreased with season, suggesting later releases may be beneficial. However, the extended hatchery rearing period needed for later releases presents other challenges, including cannibalism, and the potential for developing maladaptive traits. Stock enhancement programs must balance these trade-offs to maximize overall success. Early releases of small juveniles immediately after settlement may be optimal if large-scale hatchery communal rearing results in significant juvenile production loss and/or hatchery conditioning is impractical.

Population genomic analysis of the greater amberjack (Seriola dumerili) in the Mediterranean and the Northeast Atlantic, based on SNPs, microsatellites, and mitochondrial DNA sequences

The greater amberjack (Seriola dumerili) has attracted considerable economic interest since the 1990s because it possesses traits that distinguish it as a promising candidate in aquaculture. However, the challenges of its successful rearing, combined with the need to develop proper management practices, underline the importance of research into the genetic diversity of both wild and farmed stocks. We aimed to decipher the genetic structure of S. dumerili in the Eastern Mediterranean and the Northeast Atlantic using three types of genetic markers (mitochondrial control region sequences, microsatellites, and single nucleotide polymorphisms, or SNPs) to evaluate the population genetic structure of the species. The results were compared to those of previous studies of the species focusing on the Central Mediterranean and confirmed the presence of two divergent mtDNA haplogroups distributed without any detectable geographical structuring within the Mediterranean and the Atlantic. However, population analyses of the genetic structure of the species using either 10 microsatellites or a set of 1,051 SNP markers suggest that the species forms three genetically distinct groups, one in the Mediterranean and two in the Atlantic. The latter has so far not been reported in the Northeast Atlantic, and that this differentiation refers to samples from the Canary Islands is surprising. Fifteen candidate outlier SNP loci were identified in the data set, one located within the tead1a/TEF-1A gene, which has been associated with temperature acclimation of the medaka. This work enriches our knowledge of the genetic diversity of wild populations of the greater amberjack in the Mediterranean and the Northeast Atlantic and attempts to investigate signs of local adaptation toward a better understanding of the species distribution patterns. Future studies should be conducted to investigate the genomic regions associated with temperature acclimation in marine organisms that have to adapt to the ongoing climate change pressures, such as sea temperature rise, in order to survive.

In vitro germination and micropropagation of the Balkan endemic Lilium chalcedonicum L., a potential ornamental lily

Lilium chalcedonicum L., a bulbous perennial endemic to the Balkans, is recognized for its considerable ornamental potential. In this study, seeds were gathered from a wild population and subjected to surface disinfection. Subsequently, they were placed in Petri dishes containing a half-strength Murashige and Skoog (MS) nutrient substrate (MS/2), with temperature conditions at 15 °C and 20 °C, followed by cycles of 5 °C and return to 15 °C and 20 °C, respectively. The in vitro-cultivated seedlings were then transplanted for further growth in MS medium enriched with either 30 g L-1 or 60 g L-1 sucrose and 0.1 mg L-1 6-N-benzyladenine (BA). In the following stage, the resulting bulblets were separated and cultivated in MS/2, either without hormones (Hf) or with BA at concentrations of 0.2 mg L-1, 0.5 mg L-1, or 1 mg L-1. Moreover, the combined influence of 1-naphthaleneacetic acid (NAA) at a concentration of 1.0 mg L-1 and 0.2 mg L-1 BA was examined. This stage was succeeded by a further division of the bulblets, and the explants were cultured in Hf, MS/2 or with the inclusion of 0.5 mg L-1 BA or a combination of BA and NAA at ratios of 0.2/1 and 0.5/0.05 mg L-1; zeatin at 0.5 mg L-1 was also used, combined with 0.05 mg L-1 NAA. Notably, all seeds exhibited a 100% germination rate following alternating temperature regimes including periods of low temperature. During the initial cultivation phase, each seedling gave rise to two bulblets measuring 0.6 cm in diameter. Subsequent subcultures on Hf substrates and those containing BA without NAA, resulted in the highest number of bulblets (1.6-2.2 bulbs/plant) of the largest diameter (0.8-0.9 cm). Particularly noteworthy was the substantial increase in the average number of produced bulblets during the subsequent subcultures (multiplication stage), where 16.9 bulbs were formed in MS/2 medium containing 0.5 mg L-1 BA, with a median diameter of 1.7 cm.

Declining potential nectar production of the herb layer in temperate forests under global change

Abstract Wild pollinators are crucial for ecosystem functioning and human food production and often rely on floral resources provided by different (semi‐) natural ecosystems for survival. Yet, the role of European forests, and especially the European forest herb layer, as a potential provider of floral resources for pollinators has scarcely been quantified. In this study, we measured the potential nectar production (PNP) of the forest herb layer using resurvey data across 3326 plots in temperate forests in Europe, with an average time interval of 41 years between both surveys in order to assess (i) the importance of the forest herb layer in providing nectar for wild pollinators, (ii) the intra‐annual variation of PNP, (iii) the overall change in PNP between survey periods and (iv) the change in intra‐annual variation of PNP between survey periods. The PNP estimates nectar availability based on the relative cover of different plant species in the forest herb layer. Although PNP overestimates actual nectar production, relative differences amongst plots provide a valid and informative way to analyse differences across time and space. Our results show that the forest herb layer has a large potential for providing nectar for wild pollinator communities, which is greatest in spring, with an average PNP of almost 16 g sugar/m2/year. However, this potential has drastically declined (mean plot‐level decline >24%). Change in light availability, associated with shifts in canopy structure and canopy composition, is the key driver of temporal PNP changes. Synthesis. Our study shows that if management activities are carefully planned to sustain nectar‐producing plant species for wild pollinators, European forest herb layers and European forests as a whole can play key roles in sustaining wild pollinator populations.

Endogenous virophages are active and mitigate giant virus infection in the marine protist Cafeteria burkhardae

Endogenous viral elements (EVEs) are common genetic passengers in various protists. Some EVEs represent viral fossils, whereas others are still active. The marine heterotrophic flagellate Cafeteria burkhardae contains several EVE types related to the virophage mavirus, a small DNA virus that parasitizes the lytic giant virus CroV. We hypothesized that endogenous virophages may act as an antiviral defense system in protists, but no protective effect of virophages in wild host populations has been shown so far. Here, we tested the activity of virophage EVEs and studied their impact on giant virus replication. We found that endogenous mavirus-like elements (EMALEs) from globally distributed Cafeteria populations produced infectious virus particles specifically in response to CroV infection. However, reactivation was stochastic, often inefficient, and poorly reproducible. Interestingly, only one of eight EMALE types responded to CroV infection, implying that other EMALEs may be linked to different giant viruses. We isolated and cloned several reactivated virophages and characterized their particles, genomes, and infection dynamics. All tested virophages inhibited the production of CroV during coinfection, thereby preventing lysis of the host cultures in a dose-dependent manner. Comparative genomics of different C. burkhardae strains revealed that inducible EMALEs are common and are not linked to specific geographic locations. We demonstrate that naturally occurring virophage EVEs reactivate upon giant virus infection, thus providing a striking example that eukaryotic EVEs can become active under specific conditions. Moreover, our results support the hypothesis that virophages can act as an adaptive antiviral defense system in protists.

Feasibility study of UAV based ecological monitoring and habitat assessment of cervids in the floating meadows of Keibul Lamjao National Park in Manipur, India

Technological interventions such as remote sensing can play a crucial role in conserving inaccessible wetlands and their associated species. The floating meadows of Keibul Lamjao National Park (KLNP) in Manipur, India, are the only home to the last remaining wild population of the endangered and endemic Eld’s Deer, locally known as Sangai (Rucervus eldii eldii). Besides the rampant change in land use and altering water regimes induced by anthropogenic pressure, monitoring the population and habitat quality remains challenging. Moreover, conventional in-situ surveys that involve infiltrating animal habitats could adversely affect the habits and behavior of such shy species as a response to human presence. This study assesses the scope of Uncrewed Aerial Vehicles (UAVs) to non-invasively access such a challenging habitat and detect the ungulate individuals of interest. A quadcopter, mounted with an optical (RGB) and a thermal camera, was tested in this landscape conditions for its durability, failsafe range, flexibility, camera capabilities for visualization and detection, and resolution. The results of the drone survey based on three different time frames suggest that it is feasible to soar through the floating meadows to detect deer, best during dawn and dusk. Detection yielded the best results without creating a disturbance in animal behavior, with thermal infrared (TIR) imaging at night and both TIR and optical during the early morning. A flying height of nearly 90 m with RGB for vegetation and 20–25 m with TIR for animal presence yielded the best results. We have also established the least distracting sampling technique by analyzing the behavioral response of the deer to the presence of a drone. This study has paved a safe and practical way for acquiring accurate ground information that can assist in population estimation, habitat assessment, and burnt area estimation due to wildfire, to aid the conservation of an invaluable natural asset.

Unveiling the evolutionary significance: Atavisms transition from ancestral traits to a fundamental biological phenomenon

This essay delves into the nuanced concept of atavism, tracing its evolution from the abrupt manifestation of ancestral traits in wild populations to a pivotal element in contemporary biology. Explored through recent studies such as the Atavism Theory of Cancer, Single-Cell Atavism of Cnidocytes, and Atavism in the Developmental Polarity of Chicken Limb, this research reveals atavisms journey from speculative fiction to empirical reality. By scrutinizing cancer as a series of atavistic changes, experimental atavism at the single-cell level, and the atavism observed in avian limb development, the essay proposes that atavism offers fresh perspectives on evolution, adaptation, and the dynamic reuse of gene reservoirs. This study underscores atavisms transition into a tangible and crucial component of ecological and developmental biology, providing insights that traverse disciplinary boundaries and deepen our comprehension of the natural world.

Wild populations of Pacific oysters (Magallana gigas) emerge during the blob heatwave in south Puget Sound, Washington USA

Marine heatwaves have altered ecosystems globally, including changing community composition and facilitating the spread of invasive species. In south Puget Sound, Washington (USA), non-native Pacific oysters (Magallana gigas) have been farmed extensively for almost a century and grown in enhancement sites, however, they have only recently recruited in the wild. This study explores how the appearance of Pacific oysters was related spatially (eight sites) and temporally (decade) to warmer summer water temperatures in south Puget Sound and compares oyster persistence across five sites where recruitment occurred. The largest recruitment event from 2012-2020 was in the summer of 2015, in the middle of the east Pacific Blob marine heatwave which led to warm water temperatures off the west coast of North America. Throughout the study period, the number of oyster recruits each year was positively correlated with warmer water temperatures. Oyster population densities differed across the five sites where recruitment occurred and generally declined after 2015, but showed no site by year interactions, which is consistent with spatially-variable recruitment and similar post-recruitment survival. Mean oyster shell heights also differed among sites, which could reflect different growth trajectories or recreational harvest patterns. This study supports the claim that warming sea surface temperatures may interact with species introductions to change modern biogeography.

Resequencing of reindeer genomes provides clues to their docile habits

Abstract Reindeer have long been served as vital subsistence resources for inhabitants of Arctic and subarctic regions owing to their domestication. However, the evolutionary relationships and divergence times among different reindeer populations, genetic traits that distinguish domesticated reindeer, and factors that contribute to their relative docility compared with that of other Cervidae specie, remain unclear. In this study, we sequenced the genomes of 32 individuals from wild and domestic reindeer populations that inhabit Arctic and subarctic regions. We found that reindeer experienced 2 or more independent domestication events characterized by weak artificial selection pressure and limited significant differences in genomic parameters between wild and domestic populations. Alterations in conserved noncoding elements in the reindeer genomes, particularly those associated with nervous system development, may have contributed to their domestication by rendering the nervous system less responsive. Together, our results suggest that inherent species-specific traits, rather than intense artificial selection, may have played a significant role in the relatively docile behavior of reindeer and offer valuable insights into the domestication process of these animals.

Unveiling the co-phylogeny signal between plunderfish Harpagifer spp. and their gut microbiomes across the Southern Ocean.

Although challenging to detect in wild populations, phylogenetic congruence between marine fish and its microbiome is critical, as it highlights intimate associations between hosts and ecologically relevant microbial symbionts. Our study leverages a natural system of closely related fish species in the Southern Ocean to unveil new insights into the contribution of host evolutionary trajectory on gut microbiome assembly, an underappreciated driver of the global marine fish holobiont. Notably, we unveiled striking evidence of co-diversification between Harpagifer and its microbiome, demonstrating both phylosymbiosis of gut bacterial communities and co-phylogeny of some specific bacterial symbionts, mirroring the host diversification patterns. Given Harpagifer's significance as a trophic resource in coastal areas and its vulnerability to climatic and anthropic pressures, understanding the potential evolutionary interdependence between the hosts and its microbiome provides valuable microbial candidates for future monitoring, as they may play a pivotal role in host species acclimatization to a rapidly changing environment.

Using UAVRS and deep learning to conduct resource surveys of threatened Tibetan medicinal plants in the Qinghai-Tibet Plateau

Gentiana szechenyii Kanitz. and Gentiana veitchiorum Hemsl. are two wild medicinal plants widely used in Tibetan medicine. In recent decades, their wild populations have declined rapidly due to persistent over-harvesting of their flowers. Because their flowers are small and dense, it is difficult to rely on manual counting under wild conditions. The combination of deep learning and unmanned aerial vehicle remote sensing (UAVRS) is a new method for plant surveys. We trained 12 of the most advanced or widely used YOLO models on a custom dataset to achieve quantitative detection of both plant flowers in UAVRS images. The accuracy, precision and recall of G. szechenyii Flower (GSF) detection can reach 97.00%, 90.40% and 95.40%, respectively (based on YOLOv7). Similarly, those of G. veitchiorum Flower (GVF) detection can reach 93.40%, 91.30% and 90.60%, respectively (based on YOLOv5n), and the highest mAP can reach 94.90% (based on YOLOv5m). Based on the detection results, it is calculated that the total yield of dried GSF and GVF that can be harvested as medicinal materials in study area ranges from 1.88 to 2.10 g·m−2 and 4.42–4.62 g·m−2, respectively. The results show that deep learning and UAVRS can be used for quantitative detection of GSF and GVF, which is helpful for further research and protection of these two plants.

Evidencia de variación morfológica en una población de refugio aislada del cachorrito de Sonoyta (Cyprinodon eremus) (Teleostei: Cyprinodontidae)

The Sonoyta pupfish (Cyprinodon eremus) is an endangered species endemic to the Sonoyta River basin in northwestern Mexico and southwestern United States. To assist the conservation efforts for this species in Mexico, a refuge population was established in an artificial pond in 1988 at Centro Ecológico de Sonora in Hermosillo, Sonora by translocating individuals from the Sonoyta River population. We used multivariate morphometric methods to delineate body shape variations in the refuge population after 29 years of isolation in comparison with wild individuals collected from the same sample. Significant variations were observed in the body shape between the refuge and wild populations. These variations are potentially attributable to different environmental conditions that influenced the refuge and wild populations.

Mating harassment may boost the effectiveness of the sterile insect technique for Aedes mosquitoes

The sterile insect technique is based on the overflooding of a target population with released sterile males inducing sterility in the wild female population. It has proven to be effective against several insect pest species of agricultural and veterinary importance and is under development for Aedes mosquitoes. Here, we show that the release of sterile males at high sterile male to wild female ratios may also impact the target female population through mating harassment. Under laboratory conditions, male to female ratios above 50 to 1 reduce the longevity of female Aedes mosquitoes by reducing their feeding success. Under controlled conditions, blood uptake of females from an artificial host or from a mouse and biting rates on humans are also reduced. Finally, in a field trial conducted in a 1.17 ha area in China, the female biting rate is reduced by 80%, concurrent to a reduction of female mosquito density of 40% due to the swarming of males around humans attempting to mate with the female mosquitoes. This suggests that the sterile insect technique does not only suppress mosquito vector populations through the induction of sterility, but may also reduce disease transmission due to increased female mortality and lower host contact.

Weapon allometry and shape variation in the Helm’s stag beetle (Geodorcus helmsi)

Abstract Many animals develop and use exaggerated weapons in contests over access to mating opportunities. Stag beetles (family Lucanidae) show striking sexual dimorphism, where the males have heavily exaggerated mandibles that the females do not possess. In some genera, size and shape can also vary drastically between small and large males resulting in discrete alternative male morphs, described as male dimorphism. The genus Geodorcus is a poorly studied and threatened group of stag beetles that are endemic to New Zealand. Geodorcus helmsi is the most widespread species in this genus and presents an opportunity to test for the presence of both sexual and male dimorphism and investigate the scaling relationships (allometry) of mandibles in this group. We used linear and geometric morphometric analyses on wild populations and museum specimens from Stewart Island, New Zealand, to assess whether G. helmsi exhibits male dimorphism. We found that within a single population, there is no evidence for alternative male morphs, but a gradual shift between smaller and larger individuals. We also found that male mandibles exhibit steep positive allometry in contrast to the negative allometry found in the mandibles of females, as is often found for sexually selected weaponry. Moreover, we found evidence that left and right mandibles of G. helmsi are subtly asymmetric. Our results provide context for the competitive behaviour observed in this species, and give insights into potential trade-offs between smaller and larger individuals of the Helm’s stag beetle.

The prohibition of recreational hunting of wild ungulates in Spanish National Parks: Challenges and opportunities

A new regulation has led to the prohibition of recreational hunting on estates located within Spanish National Parks (NPs). Before the ban, eleven NPs in Spain had already reported negative ecological consequences associated with high densities of wild ungulates. The new situation that has occurred after the ban signifies that policies with which to control populations of wild ungulates in NPs, most of which do not have a sufficient natural capacity to regulate populations, depend exclusively on the parks' authorities. The banning of recreational hunting implies a series of social, ecological, economic and logistic challenges. The control of wild ungulate populations in NPs requires: i) the legal basis for culling; ii) social acceptance as regards removing animals and the extractive procedures employed in NPs; iii) the long-term monitoring of wild ungulates and the damages that they cause, and iv) sufficient financial and human resources. A more integrated management and policy plan is, therefore, required, which should be supported by two pillars: i) the sustainability of natural resources and the conservation of functional environments, and ii) providing society with explanations regarding the need to manage wild ungulates. In order to bridge the potential gap between these key pillars, it is important to involve stakeholders in the decision-making processes concerning wild ungulate management. The forthcoming changes in Spanish NPs provide a promising opportunity to make a substantial improvement to wild ungulate management in these protected areas. This management approach could, moreover, serve as an example and be transferred to other protected spaces.

A first exploratory comparison of the behaviour of wolves (Canis lupus) and wolf-dog hybrids in captivity

Extensive introgression of genes from domesticated taxa may be a serious threat for the genomic integrity and adaptability of wild populations. Grey wolves (Canis lupus) are especially vulnerable to this phenomenon, but there are no studies yet assessing the potential behavioural effects of dog-introgression in wolves. In this study, we conducted a first systematic comparison of admixed (N = 11) and non-admixed (N = 14) wolves in captivity, focusing on their reaction to unfamiliar humans and novel objects, and the cohesiveness of their social groups. When exposed to unfamiliar humans in the experimental task, wolves were more vigilant, fearful and aggressive than admixed wolves, and less likely to approach humans, but also more likely to spend time in human proximity. When exposed to novel objects, wolves were more aggressive than admixed wolves, less likely to spend time in object proximity, and more likely to interact with objects, but also less vigilant and as fearful as admixed wolves. Finally, social networks were more cohesive in wolves than in admixed wolves. Although caution is needed when comparing groups of captive individuals with different life experiences, our study suggests that dog admixture may lead to important behavioural changes in wolves, with possible implications for conservation strategies.