BMC ecology and evolution最新文献

Pterosaurs were the first vertebrates to evolve active flight. The lack of many well-preserved pterosaur fossils limits our understanding of the functional anatomy and behavior of these flight pioneers, particularly from their early history (Triassic to Middle Jurassic). Here we describe in detail the osteology of an exceptionally preserved Middle Jurassic pterosaur, the holotype of Dearc sgiathanach from the Isle of Skye, Scotland. We identify new autapomorphies of the flight apparatus (humerus and sternum), which further support the distinctiveness of Dearc compared with other early-diverging pterosaurs and describe features, such as the vertebral morphology, shared with later-diverging pterosaurs that probably developed convergently to support a large body size or as a sign of modular evolution. We used extant phylogenetic bracketing to infer the principal cranial and antebrachial musculature, indicating that Dearc had large and anteriorly placed palatal musculature that compensated for weak temporal jaw adductors and wing musculature suggestive of flight style reliant on powerful adduction and protraction of the humerus. Comparisons with other pterosaurs revealed that non-pterodactyloids such as Dearc, despite their overall conservative bauplans, adapted various flight and feeding styles. The osteology and myology of Dearc are indicative of a large predator that flew and hunted above lagoons and nearshore environments of the Middle Jurassic.

Wings are primarily used in flight but also play a role in mating behaviour in many insects. Drosophila species exhibit a variety of pigmentation patterns on their wings. In some sexually dimorphic Drosophilids, a pigmented spot pattern is found at the top-right edge of the male wings. Our understanding of wing spot thermal plasticity in sexually dimorphic species is limited with wing spots being primarily associated with sexual selection. Here, we investigated the wing pigmentation response of two species with wing spots: D. biarmipes and D. suzukii species to thermal variation. We exposed freshly hatched larvae of both the species to three different growth temperatures and checked for wing pigmentation in adult males. Our results indicate wing pigmentation is a plastic trait in the species studied and that wing pigmentation is negatively correlated with higher temperature. In both species, wings were darker at lower temperature compared to higher temperature. Further, D. suzukii exhibits darker wing pigmentation compared to D. biarmipes. Variation in wing pigmentation in both D. suzukii and D. biarmipes could reflect habitat level differences; indicating a strong G*E interaction. Raman spectral analysis indicated a shift in chemical profiles of pigmented vs. non-pigmented areas of the wing. The wing spot was found enriched with carbon-carbon double-bond compared to the non-pigmented wing area. We report that C = C formation in spotted area is thermally controlled and conserved in two members of the suzukii subgroup i.e. D. biarmipes and D. suzukii. Our study indicated a conserved mechanism of the spot formation in two Drosophila species coming from contrasting distribution ranges.

As the extinction risk of plants increases globally, there is need to prioritize areas with high floristic richness and diversity to inform the design of evidence-based conservation interventions. As such, this study aimed to comparatively analyse floristic diversity in six central forest reserves (CFR) of north eastern Uganda. This was guided by two objectives namely; (i) to determine the floristic richness and diversity in the CFRs and (ii) to evaluate the similarity and complementarity of floristic composition. Data was collected from nested quadrats (20 × 20 m for trees, 10 × 10 m for shrubs and 5 × 5 m for herbaceous climbers, forbs and grasses) placed at intervals of 100 m along a transect of 1000 - 1500 m. Species richness, diversity and evenness were determined for each CFR. Binary similarity coefficients were computed because only presence/absence data of plant species was recorded. A sum of 417 plant species in 76 families were recorded representing 8.7% of known vascular plants reported in Uganda. The CFRs have significantly variable Shannon-Wiener diversity indices ranging from 4.2 in Kano CFR to 4.47 in Bululu hill CFR (t = 85.291, df = 4, p = 0.00). The CFRs cluster into two groups namely Onyurut and Ogera hills and Akur, Kano, Bululu hills and Mount Moroto. The lowest similarity index was between Ogera hills and Moumt Moroto CFRs (0.37 or 37%) while the highest was between Akur and Kano CFRs (0.63 or 63%). The CFRs complement one another by supporting plant species not recorded elsewhere with three CFRs (Bululu hills, Mount Moroto and Onyurut) accounting for 81.53% of the plant taxa. The CFRs in NE Uganda have richness and floristic diversity with up to 8.7% of the known plants in Uganda present. The conservation status of these species is Vulnerable (4), Near Threatened (4), Least Concern (137), Data Deficient (1) and Not Evaluated (271). The two similarity clusters depict variation in altitudinal, proximity and climatic conditions. Five CFRs are required to conserve 95% of the species recorded. Therefore, the CFRs investigated play a complementary role in conserving the floristic diversity in north eastern Uganda.

Background: Trait variation is shaped by functional roles of traits and the strength and direction of selection acting on the traits. We hypothesized that in butterflies, sexually selected colouration is more variable owing to condition-dependent nature and directional selection on sexual ornaments, whereas naturally selected colouration may be less variable because of stabilising selection. We measured reflectance spectra, and extracted colour parameters, to compare the amount of variation in sexually versus naturally selected colour patches across wing surfaces and sexes of 20 butterfly species across 4 families (Nymphalidae, Papilionidae, Pieridae, Lycaenidae).

Results: We found that: (a) males had more conspicuous, i.e., brighter and more saturated colour patches compared with females (as expected of sexually selected traits but not necessarily of naturally selected traits), and (b) dorsal surfaces in both sexes had more conspicuous sexual ornaments as well as protective (aposematic/mimetic) colour patches on darker wing backgrounds, compared with ventral surfaces. However, colour patches did not differ in the amount of variation either in selection (ecological/sexual functions), sex or wing surface-specific manner.

Conclusions: These findings show that functional roles and selection influence colour parameters but not the amount of variation in butterfly wing colour patterns.

Climate warming has become a hot issue of common concern all over the world, and wind energy has become an important clean energy source. Wind farms, usually built in wild lands like grassland, may cause damage to the initial ecosystem and biodiversity. However, the impact of wind farms on the functional diversity of plant communities remains a subject with unclear outcomes. In this study, we chose 108 sample plots and identified 10 plant functional traits through a field vegetation survey. We used general linear regression analysis to assess how wind farm influenced vegetation community diversity, focusing on ten distinct plant functional traits. The study revealed that wind farm had significant impacts on grassland plant communities, diminishing diversity and functional traits, which leads to species composition convergence. Additionally, wind farm increased certain functional traits, like height and leaf area, while decreasing phosphorus content. Furthermore, the productivity of these plant communities was reduced by wind farm presence. This study highlights the negative consequences of wind farms in Inner Mongolia on plant diversity, aiming to offer scientific recommendations for the optimal arrangement of wind farms to safeguard biodiversity.

Background: Semi-aquatic mammals represent a transitional phase in the evolutionary spectrum between terrestrial and aquatic mammals. The sense of balance is crucial for mammalian locomotion, and in semi-aquatic mammals, the structural foundation of this sense (the vestibular system) shows distinct morphological adaptations to both aquatic and terrestrial environments compared to their terrestrial counterparts. Despite this, the precise molecular mechanisms driving these adaptations remain elusive. Our study endeavors to unravel the genetic components associated with the sense of balance in semi-aquatic mammals and to examine the evolutionary trajectories of these genes, shed light on the molecular mechanisms underlying the adaptive evolution of balance perception in semi-aquatic mammals.

Results: We selected 42 mammal species across 20 orders, 38 families, and 42 genera for analysis. We analyzed a comprehensive set of 116 genes related to the vestibular system's development or function. Our findings indicate that 27 of these genes likely experienced adaptive evolution in semi-aquatic mammals. Particularly, genes such as SLC26A2, SOX10, MYCN, and OTX1 are implicated in collectively orchestrating morphological adaptations in the semicircular canals to suit semi-aquatic environments. Additionally, genes associated with otolith development, including SLC26A2, OC90, and OTOP1, likely regulate otolith sensitivity across various locomotor modes. Moreover, genes linked to vestibular disorders, such as GJB2, GJB6, and USH1C, may provide a molecular foundation for averting vertigo amidst intricate locomotor scenarios in semi-aquatic mammals.

Conclusions: Our research offers insights into the molecular mechanisms underlying the evolution of the sense of balance in semi-aquatic mammals, while also providing a new research direction for the adaptive evolution of mammals undergoing a secondary transition to an aquatic lifestyle.

Background: Protein evolution is central to molecular adaptation and largely characterized by modular rearrangements of domains, the evolutionary and structural building blocks of proteins. Genetic events underlying protein rearrangements are relatively rare compared to changes of amino-acids. Therefore, these events can be used to characterize and reconstruct major events of molecular adaptation by comparing large data sets of proteomes.

Results: Here we determine, at unprecedented completeness, the rates of fusion, fission, emergence and loss of domains in five eukaryotic clades (monocots, eudicots, fungi, insects, vertebrates). By characterizing rearrangements that were previously considered "ambiguous" or "complex" we raise the fraction of resolved rearrangement events from previously ca. 60% to around 92%. We exemplify our method by analyzing the evolutionary histories of protein rearrangements in (i) the extracellular matrix, (ii) innate immunity across Eukaryota, Metazoa, and Vertebrata, and (iii) Toll-Like-Receptors in the innate immune system of Eukaryota. In all three cases we can find hot-spots of rearrangement events in their phylogeny which (i) can be related with major events of adaptation and (ii) which follow the emergence of new domains which become integrated into existing arrangements.

Conclusion: Our results demonstrate that, akin to the change at the level of amino acids, domain rearrangements follow a clock-like dynamic which can be well quantified and supports the concept of evolutionary tinkering. While many novel domain emergence events are ancient, emerged domains are quickly incorporated into a great number of proteins. In parallel, the observed rates of emergence of new domains are becoming smaller over time.

Caves are one of the most exciting environments on earth, often considered an evolutionary laboratory due to the suite of convergent adaptive traits (troglomorphisms) of organisms inhabiting them. Sinonychia martensi Zhang & Derkarabetian, 2021, is the first and only Travunioidea species recorded in China and is endemic to Beijing, being known from multiple caves. However, nothing is known regarding its phylogeographic or evolutionary history. In this study, we assessed the species boundaries of S. martensi from nine caves using morphological and molecular methods to elucidate its phylogenetic position and genealogical relationships. We also investigated the genetic diversity, population genetic structure and demographic history of S. martensi to clarify the population-level relationships and make inferences about historical phylogeography. The results indicate that the species from different caves all belonged to S. martensi but represent different populations. These populations exhibit strong population structure and low genetic diversity. Cave populations may share a common ancestor and multiple independent invasions to different caves. The diversification within S. martensi was likely driven by climate change and subtropical evergreen broadleaf forests associated with the middle Miocene. This study highlights the need for further conservation efforts and exploration in Beijing caves.

Background: The destructive human activities, encroachment of natural habitats, and hyperarid climate threaten the wild flora of the unprotected mountainous areas facing the Gulf of Suez, Egypt. So, this study aims to revise and give an updated systematic status of the flowering plants growing there to conserve and utilize valuable biodiversity.

Results: This study showed the presence of 136 species, including 7 sub-species of vascular plants, 12 species of monocots, and 124 species dicots belonged to 98 genera and 37 families. The most species-rich families were Asteraceae (22 species) and Amaranthaceae (19 species). Therophytes and Chamaephytes were the most dominant life- forms in the study area, representing 38.2%. They were followed by Phanerophytes, Hemicryptophytes, and Cryptophytes, which represented 11%, 8.8%, and 2.9%, respectively. Five plant assemblages were identified by TWINSAPN classification namely, Zygophyllum coccineum -Haloxylon salicornicum assemblage, Zilla spinosa -Zygophyllum coccineum assemblage, Zygophyllum coccineum-Tamarix nilotica assemblage, Tamarix nilotica - Phargmites australis assemblage and Tamarix nilotica-Chenopodium murale assemblage. Several invasive species were recorded in some wadis. However, their presence is unusual to the floristic composition of the wadis in general and acts as an alarm to protect the native species from anthropogenic interference. Moisture content, organic matter, electrical conductivity, pH, cations, anions, and total carbonate were identified as the significant factors controlling distribution of plant clusters by detrended correspondence analysis. This study recorded Tribulus mollis as a new addition to Egypt's flora of Eastern desert.

Conclusion: The comparative analysis of the present and past floral studies in the study area reveals a significant change in the plant community composition. This shift is likely attributed to the adverse impacts of climate change and anthropogenic activities. Thus, this area has to be safeguarded with practical strategies that aid in preserving the significant uncommon flora.