BMC ecology and evolution最新文献

Soil nematodes are essential indicator of organisms for assessing the health of grassland ecosystems, and their community structure is sensitive to changes in grassland utilization practices. However, there is still a lack of research on how long different mowing frequencies affect the characteristics of soil nematode communities. Therefore, this study aimed to address this gap by studying the impacts of different mowing frequencies M1, M2, and M3 on the nematode community structure and metabolic footprints. The results showed that a total of 45,320 soil nematodes were captured in the experimental area. Among them, the most dominant genera were Cervidellus and Acrobeloides (23.84%), and the dominant genera were Nygolaimus, Chiloplacus and Cephalobus (20.57%). Compared with no mowing treatment, the total abundance of soil nematodes and the abundance of each trophic group showed inflection points in the M2 treatment. The life history of nematode community tended to be k-strategist, and the Wasilewska index was > 1, indicating that soil microbivores were sensitive to the environment and the soil mineralization pathway did not change. NCR value was > 0.5, indicating that the decomposition of grassland organic matter is still dominated by bacterial and fungal channels, which is not affected by mowing frequency. In addition, Soil pH and ammonium nitrogen (NH₄⁺-N) are environmental factors that affect nematode communities. In summary, M2 treatment can increase nematode diversity and metabolic activity, improve anti-interference and soil health, and promote soil food web maturation. It is the best cutting frequency for grassland soil health, and has potential benefits for grassland restoration.

Background: Vertebral morphology in cetaceans is linked to various functional abilities that promote ecological diversity and adaptive radiation. While morphometric studies have examined vertebral shape evolution, few have quantified evolutionary trends in a phylogenetic framework. Here, we used three-dimensional landmark configurations and phylogenetic comparative methods to investigate how the vertebral morphology of Delphinidae is influenced by phylogenetic constraints, ecological adaptation, and allometric effects and how these influences vary along the vertebral column.

Results: Phylogenetic ordination methods revealed that species with particular habitat requirements differ greatly from their closest relatives, exhibiting biomechanically advantageous vertebral shapes. A comparison of the orientations of these ordination methods, phylogenetic ANOVAs and phylogenetic signal tests revealed that vertebral morphology is affected by overlapping allometric, ecologic, and phylogenetic signals, with their relative importance differing across regions, phylogenetic levels, and dimensions of shape. In the anterior thorax, the posterior thorax, and the synclinal point, diversification was associated primarily with size and habitat, resulting in low phylogenetic signals. Conversely, the mid-torso and tail stock retain strong phylogenetic signals, reflecting subfamily level conservatism. Notably, in the Tm region, the ecological demands for fast swimming remain highly relevant to vertebral morphology, emphasising the functional significance of this region.

Conclusion: Vertebral morphology in Delphinidae may reflect a complex interplay of ecological, allometric and phylogenetic influences, with distinct regions evolving under different combinations of selective and historical constraints. These region-specific patterns highlight the modularity of the vertebral column and provide new insights into the adaptive radiation of oceanic dolphins. Further studies, including evolutionary modelling and considering intraspecific variation, will be essential to fully understand macroevolutionary trends in vertebral morphology and their implications for axial locomotion.

Background: Conspicuous color patterns are traditionally believed to advertise the toxicity of prey to potential predators. However, many aposematic species show drastic variation in coloration, indicating the possibility of other functions of coloration such as intraspecific communication. To study these other functions, we can investigate the influence of intrinsic (e.g., sex) and external factors (e.g., climate) on color variation. We used the aposematic European fire salamander (Salamandra salamandra) to study drivers of variation in the yellow-to-black ratio of the dorsal coloration based on citizen science data available in a new online database.

Results: Our results suggest a widespread sexual dichromatism in fire salamanders in Germany with males displaying a larger yellow-to-black ratio, i.e. are more yellow, than females. This dichromatism persisted even after correcting for a sex-difference in body shape that accounts for some of the variation in the yellow-to-black ratio. Among six investigated putative drivers of this color variation, the proportion of the aposematic yellow coloration increased with latitude but showed no association with other environmental variables such as temperature or the productivity of the habitat.

Conclusions: Integrating citizen science data in this study enabled a comparison of fire salamander populations across large parts of their distribution and highlights widespread sexual dichromatism. Future studies should further investigate potential mechanisms of mate choice in fire salamanders and other selective forces on coloration such as differential predation pressure between both sexes or the role in crypsis. Lastly, multi-national studies supported by citizen science data could fully unravel the extent of color variation in this species.

An important tree in Eurasia, Malus orientalis Uglitzk. (Caucasian apple) provides ecological and economic benefits. To evaluate the genetic diversity of this species, we sampled 167 individuals from 20 populations across the Zagros Mountains (6 populations) and Hyrcanian forests (14 populations). We assessed six quantitative morphological traits and employed 26 microsatellite (SSR) markers, which revealed a total of 455 alleles in the wild apple populations, all of which were polymorphic. The markers revealed mean values for genetic diversity indices, including allelic richness (Ar = 0.21), private alleles (Ap = 0.65), expected heterozygosity (H_E = 0.74), and observed heterozygosity (H_O = 0.71). Our analyses identified three major genetic clusters and two significant genetic barriers among the studied populations. Estimations of gene flow indicated limited connectivity among M. orientalis populations in the Caucasus region, suggesting habitat fragmentation as a key factor shaping genetic structure. Based on genetic diversity assessments, two areas within the Hyrcanian forest (Siamarzkoh region, Tokestan region, Abesk region, Asalem region) and one in the Zagros forest (Sepedkoh region) were identified as priority regions for conservation efforts to protect this valuable species.

Moray eels (Anguilliformes: Muraenidae) are commonly found in subtropical and tropical waters, where they favor sheltered habitats and occasionally exhibit aggressive behavior. Nowadays, mitochondrial genomes (mitogenomes) information of moray eels remains poorly understood, and analysis of gene re-arrangements and evolutionary history within Anguilloidei remain largely unknown. In this study, mitochondrial genomes from 12 Gymnothorax spp. and 2 Echidna spp species were sequenced, assembled and annotated, and most of which were not published before. Our results showed that the mitochondrial genomes of the 14 species were approximately 16.5 kb in length, with GC content ranging from 41.1 to 46.1%. The mitochondrial genomes of these 12 Gymnothorax spp. and 2 Echidna spp are circular molecules that encode a total of 37 genes, including 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA (small and large subunit rRNA encoding genes) and a non-coding control region (CR). In addition, three types of gene arrangement have been identified for the first time in the mitogenomes of Anguilloidei. Phylogenetic relationships of 51 moray eel mitogenomes based on the protein-coding genes indicate that mitogenome sequences reveals the higher-order relationships of different Anguilloidei. Gene order and phylogenetic data are valuable for elucidating the evolutionary connections among various Anguilloidei species. Cox3 exhibited the smallest non-synonymous mutation value among all the 13 protein-coding genes, indicating that the role of Cox3 in maintaining energy metabolism under warm water conditions is a hypothesis based on observed evolutionary conservation. The complete information of mitogenomes in these 12 Gymnothorax spp. and 2 Echidna spp species provides genetic markers for species identification and temperature adaptation studies in Anguilloidei.

Background: The origin of the flight stroke in vertebrate flight evolution remains obscure. However, using forelimbs to control aerodynamic forces while gliding provides a possible exaptation from which wingless taxa evolved incipient wing flapping and powered flight. We used flat-tailed house geckos (Hemidactylus platyurus) to model the possible dynamics of those gliding taxa ancestral to vertebrate flyers, and characterized their limb and body kinematics while gliding in a vertical wind tunnel, so as to determine biomechanical consequences of forelimb movements during controlled aerial behavior.

Results: Geckos mostly assumed a stereotypical skydiving posture but intermittently would flex the body ventrally as the forelimbs were retracted posteriorly. Shoulder retraction, spinal column flexion, and subsequent translational velocity in the vertical and cranial directions were positively correlated; such alteration of body posture with simultaneous forelimb displacement thus modulates the directions and magnitudes of aerodynamic forces, including horizontal thrust production. Independent of shoulder retraction and body bend, body pitch correlated positively with vertical acceleration and negatively with horizontal acceleration.

Conclusions: Gliding geckos actively use their forelimbs to alter body speed and to generate thrust, suggesting aerodynamic function for limb displacement and reciprocation in the absence of wings. Prior to the origin of the flapping of winglike structures, analogous forelimb motions (including symmetric reciprocation) may have thus provided biomechanical advantage in the evolution of volant vertebrates.