Ecology and Evolution最新文献

Gyrodactylus nigeri Zhou & Chen, 2024 was merely distributed in Yunnan Province, Southwest China; meanwhile, its mitochondrial genome remains unclear. This study aims to sequence the mitogenome of G. nigeri and clarify its phylogenetic relationship within the Gyrodactylidea. The mitogenome of G. nigeri was sequenced using the next-generation sequencing (NGS) method, annotated, and analyzed using bioinformatic tools. The mitochondrial genome of G. nigeri is 14,903 bp in length, containing 12 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and two major non-coding regions (NCR: NC1 and NC2). The overall A + T content of the mitogenome is 76.6%, a higher content compared with all reported mitochondrial genomes of monogeneans. The mitogenome of G. nigeri presents a clear bias in nucleotide composition with a negative AT-skew and a positive GC-skew. All tRNAs have the typical cloverleaf secondary structure except for tRNA ^Cys , tRNA ^Ser1 , and tRNA ^Ser2 , which lack the dihydrouridine (DHU) arm. Furthermore, two different repetitive non-coding regions of 88 bp repeats occurred in the NCR regions (NC1 and NC2) with a poly-T stretch, two stem-loop structures with obvious differences in the first loop, and a G(A)n motif. The gene order is identical to the mitochondrial genomes reported from other Gyrodactylus species except Gyrodactylus sp. FZ-2021. Co-phylogenetic analyses showed phylogenetic divergence patterns of Gyrodactylus correspond to those of their fish hosts, and the overall coevolutionary fit between the parasites and hosts was consistently significant. Meanwhile, the results supported the sister relationship between G. nigeri and Gyrodactylus sp. FY-2015 from the hosts within the Nemacheilidae cluster together with high nodal support based on 12 PCGs sequences and amino acid sequences. Gyrodactylidae forms an independent and monophyletic clade within Gyrodactylidea.

Climate change is considered a key driver for shaping ecological and evolutionary processes of Arctic animals. Historical glaciation has profoundly influenced the distribution and genetic differentiation of Arctic vertebrates, and recently Arctic species are facing new and intensifying threats from rapid global warming. Understanding how past, recent and future climate change has, and will influence the evolution of Arctic animals is, therefore, crucial for effective conservation planning. Here we combine whole-genome sequencing, demographic inference, and species distribution modeling (SDM) to assess the eco-evolutionary responses of the gyrfalcon (Falco rusticolus), a resident Arctic apex predator, to climate change. Assembling a genome reference and using samples from three breeding regions across the Eurasian Arctic (Kola, Yamal, and Chukotka peninsulas), we found genetic differentiation of gyrfalcon populations from west to east, that arose during the late Pleistocene (12.9-14.7 thousand years ago (ka)) and subsequently persisted in isolation, until gene flow into the Yamal population resumed during the late Holocene. The extant gyrfalcon populations exhibit low genetic diversity, elevated inbreeding coefficients, and high genetic loads compared to the closely related saker falcon (Falco cherrug), and some other threatened species with small populations, likely due to a population bottleneck about 1 ka, which might compromise the long-term viability of this Arctic raptor. Additionally, the effective population size (Ne) of the Kola gyrfalcon population was inferred to be in decline over the past 165-60 years. SDM based on ensemble models further predicts a substantial reduction of climatically suitable areas for Kola gyrfalcons under future global warming scenarios. Our study highlights how past climatic fluctuations and ongoing warming jointly shape the genomic landscape of endemic Arctic birds and provides insights into making conservation strategies for Arctic animals in a rapidly warming environment.

Oceanic islands have high biodiversity, which is severely threatened by invasive species. Functional traits serve as a framework to investigate invasive-native dynamics, but most studies investigating native-invasive plant functional trait differences on islands focus on live foliage traits, while litter traits remain understudied. It is hypothesized that invasive species produce higher quality litter (e.g., high nutrient content, low tannins and leaf mass per area) than native species, and furthermore, that this high-quality litter decomposes more rapidly, in turn providing a positive feedback that facilitates their expansion. To investigate native vs. invasive plant litter quality in a highly endemic island flora, we conducted a systematic review to synthesize litter trait data from Hawai'i. To account for the extensive heterogeneity that occurs across the Hawaiian Islands, litter trait variability was synthesized with respect to elevation and climate gradients. Litter quality varies extensively across the Hawaiian Islands in native and invasive species. Although invasive plants have higher quality litter than native species overall, species origin accounts for relatively little trait variance, and native and invasive species overlap considerably in litter multivariate trait space. Moreover, intraspecific variation exceeds interspecific variation, highlighting the important role of environmental heterogeneity for widespread species. Climate influences native and invasive litter quality in distinct ways, leading to a reversal in strategy across climate gradients. When controlling for the full direct effects of climate, native and invasive plant litter traits are not significantly different. Climate heterogeneity, more than plant species origin, plays a key role in shaping plant litter trait variation and resource-use strategies at the landscape or archipelago scale. Litter quality could be more commonly sampled as part of the functional syndrome of plants and for a better understanding of how traits differ between native and invasive plants.

Environmental pressures, particularly those driven by anthropogenic activity, can induce rapid behavioural and physiological adaptation. Insects, due to their ecological importance, are especially affected by the widespread use of insecticides. While physiological resistance to insecticides is well documented, less is known about how such resistance influences behaviour, particularly oviposition site choice, a decision with direct consequences for offspring survival. Using Drosophila melanogaster, we investigated whether genetic resistance conferred by the detoxification gene Cyp6g1 affects oviposition preferences and survival across life stages when exposed to insecticides. We presented resistant and susceptible female flies with a choice between food laced with acetone, insecticides to which they are resistant, or insecticides to which Cyp6g1 does not confer resistance, and examined larval and adult survival under matching exposure conditions. We found that resistant females differ from susceptible flies by avoiding laying eggs on food containing DDT, an insecticide they are resistant to, suggesting that resistance is associated with a parallel shift in behaviour. Larval survival was closely tied to maternal oviposition choice, with Cyp6g1-mediated resistance conferring survival benefits only against insecticides it can detoxify. In contrast, adult survival was less affected by genotype, highlighting the importance of oviposition site selection in shaping transgenerational fitness. Our results suggest that resistance alleles can impact not only physiological resistance but also incur behavioural adaptations such as toxin avoidance that act synergistically to mitigate insecticide exposure. Furthermore, our results show that these resistance alleles influence behaviour in ways that affect their frequency in natural populations.

Community biomass allocation is jointly determined by habitat conditions and plant functional traits. Studies of biomass allocation patterns in topographic-soil climax communities of karst ecosystems remain scarce. According to the trait-driven paradigm, topographic gradients and soil properties indirectly influence karst forest biomass, via their control over community-level functional structure. In the 25-ha Maolan Dynamic Plot of the Karst Forest Ecosystem in South China, we compiled 1255 high-quality trait records for six key plant functional traits related to biomass from 48 dominant species, individual biomass data for 12,354 stems, and fine-scale environmental variables. Partial least-squares structural equation modeling (PLS-SEM) was used to quantify the direct and indirect factors affecting biomass allocation in this climax karst forest community. We observed that the trade-offs in biomass among different forest layers were more effective in predicting the biomass status of natural communities (R ² = 0.69). Topographic heterogeneity acted as an environmental filter, driving the assembly of distinct karst climax communities. Community-level trait distributions and abiotic variables significantly influenced both community biomass and its trade-offs, although trait patterns explained biomass trade-offs more effectively than environmental factors. PLS-SEM identified slope position as the primary driver of biomass trade-offs in the karst climax communities, with community-level variation in specific leaf area (SLA) mediating biomass allocation. Slope position decline reduced the community-weighted mean of functional traits (SLA, Wood density, Leaf nitrogen content) and concurrently increased biomass of the stable layer. In parallel, lower community-weighted variance of traits (SLA) attenuated biomass loss in the regeneration layer. These results underscore the pivotal role of trait composition in mediating biomass partitioning at the community scale.

Summer programs are a powerful educational tool for increasing student interest in science, technology, engineering, and mathematics (STEM) careers. However, barriers such as lack of awareness, transportation challenges, and financial constraints can hinder participation. This study examines Water Dawgs, a paid summer initiative designed to provide high school students with hands-on freshwater science education while ensuring accessibility for all interested students. Using Water Dawgs as a case study, we explore how proactive planning and budgeting can help mitigate these participation barriers. Water Dawgs successfully engaged 16 participants, and survey results indicate increased self-efficacy in STEM as well as greater awareness of how environmental science impacts daily life and career opportunities. We identify five key barriers-information gaps, resource deficiencies, transportation disparities, food insecurity, and economic limitations-and offer practical recommendations for addressing them through proactive planning and budgeting of direct costs. Strategies include planning and engagement well in advance of the event, allocating direct expenditures to compensate teacher partners and participants for their work, providing all necessary supplies for both classroom and field activities, offering transportation options for all participants, and ensuring access to meals. Our case study highlights the importance of thoughtful program planning and budget development that fully accounts for direct costs associated with removing barriers, making STEM summer programs an option for all interested students.

Over the Quaternary, the geographic distributions of many species have experienced shifts in response to climatic changes. We examined the range-shift patterns of six oak (Quercus) species occupying different climatic zones of the western Palearctic under both past and future climate conditions. Using ecological niche models, we reconstructed distributions during the Last Glacial Maximum (LGM, ~22,000 years before present), compared them to the Present, and projected future changes under two scenarios for 2081-2100 (SSP1-2.6 and SSP5-8.5). Quantitative metrics of latitudinal centroid movement, range limits, and area change revealed consistent contrasts among climatic groups. During the LGM, temperate (Q. robur and Q. petraea) and transition-zone (Q. cerris and Q. pubescens) species contracted strongly, persisting in southern refugia across Anatolia, the Balkans, and the western Mediterranean, whereas Mediterranean oaks (Q. coccifera and Q. suber) retained more stable ranges. Future projections suggest that temperate and transition-zone species will undergo substantial range loss and poleward shifts, particularly under the pessimistic scenario, whereas Mediterranean oaks will experience limited latitudinal shifts but pronounced expansion in to northern latitudes and temperate regions. These findings indicate Mediterranean oaks are ecologically distinct from temperate and transition-zone species, which show similar climate sensitivities. Our results emphasize the need for climate-zone-specific conservation strategies, including enhancing connectivity and genetic diversity for temperate and transition-zone species, and prioritizing drought-resilient populations and adaptive management for Mediterranean species, to support the long-term resilience of European oak forests under ongoing and future climate change.

Understanding the early life-stage responses of tree species to climate change is critical for predicting forest regeneration success and guiding conservation and management efforts. We investigated the effects of temperature, cold stratification, and light on germination and early seedling performance of Abies nordmanniana subsp. equi-trojani (Trojan fir), an endangered endemic tree from north-western Anatolia (Türkiye). Germination was tested under fixed (10°C, 15°C, 20°C, 25°C, 30°C) and alternating (15°C/25°C, 20°C/30°C) incubation temperatures with and without cold stratification. Early seedlings were monitored for 10 days under controlled, nutrient-free agar conditions. Our results show that while higher fixed and alternating temperatures enhance germination, early seedling survival declined at the warmest temperature (30°C), and root growth peaked at 20°C and decreased at higher temperatures. Cold stratification significantly improved germination across all temperature regimes, reducing the need for warmer incubation temperatures to achieve high germination. Light had a limited effect on overall germination. These findings indicate stage-specific responses to warming, as warmer conditions favor germination, whereas cooler conditions favor early seedling survival and root allocation. Consequently, successful regeneration assessments and conservation planning should consider both germination and early seedling stages, alongside local thermal contexts, when evaluating the impacts of climate change on Trojan fir.

Hyalomma rufipes is a widely distributed tick species and a competent vector of Crimean-Congo Hemorrhagic Fever Virus (CCHFV), a serious zoonotic pathogen endemic to over 30 countries. Despite the epidemiological importance of CCHFV and H. rufipes in East Africa, little is known about the genetic structure and movement of H. rufipes populations, limiting the understanding of CCHFV transmission dynamics in this region. This study developed and characterized 14 polymorphic microsatellite markers to support population genetic studies of H. rufipes. H. rufipes ticks were collected from livestock in Garissa and Isiolo counties in northern Kenya. Morphological identification was confirmed using 16S rRNA Sanger sequencing and phylogenetic analysis. Low-pass whole genome sequencing was performed on representative samples, and the Quality and Diversity of DNA (QDD) pipeline was used to identify and design microsatellite primers. Of 59,201 candidate loci, 30 were selected for initial screening; 14 loci consistently amplified and were polymorphic. These included mostly tetranucleotide repeats and showed high allelic richness and gene diversity. Several loci showed signs of null alleles, but no evidence of stuttering or allelic dropout was found. These newly developed microsatellite markers provide a valuable tool for investigating H. rufipes population dynamics and dispersal, with the ultimate goal of understanding CCHFV transmission dynamics in East Africa.

Miridae is the most species-rich family of true bugs and plays an important role in both natural and agricultural ecosystems. However, contemporary controversies surrounding their phylogenetic relationships and subfamily classification still lack consensus. This study employs molecular systematics to resolve Miridae phylogeny, utilizing mitochondrial genomes from 42 species spanning 39 genera across six of the seven currently recognized subfamilies. Four outgroup species from Tingidae (2 species) and Thaumastocoridae (2 species) were also included in the analyses. Our results demonstrate that: (1) Bryocorinae is paraphyletic as the stem groups of Miridae; and (2) the clade ((Deraeocorinae + Mirinae) + (Orthotylinae + Phylinae)) is consistently and strongly supported as a monophyletic group across all datasets and analytical methods. We report newly sequenced mitochondrial genomes based on high-throughput sequencing platforms for four Miridae genera and species: Chlamydatus sp. (Phylinae), Deraeocoris punctulatus (Deraeocorinae), Scirtetellus sp. (Orthotylinae), and Prodromus clypeatus (Bryocorinae). These findings provide a progressive phylogenetic framework with new significance for the future phylogenetic improvement and taxonomic revision of Miridae.