Ecological Similarity Research Articles

Facing the facts: adaptive trade-offs along body size ranges determine mammalian craniofacial scaling.

The mammalian cranium (skull without lower jaw) is representative of mammalian diversity and is thus of particular interest to mammalian biologists across disciplines. One widely retrieved pattern accompanying mammalian cranial diversification is referred to as 'craniofacial evolutionary allometry' (CREA). This posits that adults of larger species, in a group of closely related mammals, tend to have relatively longer faces and smaller braincases. However, no process has been officially suggested to explain this pattern, there are many apparent exceptions, and its predictions potentially conflict with well-established biomechanical principles. Understanding the mechanisms behind CREA and causes for deviations from the pattern therefore has tremendous potential to explain allometry and diversification of the mammalian cranium. Here, we propose an amended framework to characterise the CREA pattern more clearly, in that 'longer faces' can arise through several kinds of evolutionary change, including elongation of the rostrum, retraction of the jaw muscles, or a more narrow or shallow skull, which all result in a generalised gracilisation of the facial skeleton with increased size. We define a standardised workflow to test for the presence of the pattern, using allometric shape predictions derived from geometric morphometrics analysis, and apply this to 22 mammalian families including marsupials, rabbits, rodents, bats, carnivores, antelopes, and whales. Our results show that increasing facial gracility with size is common, but not necessarily as ubiquitous as previously suggested. To address the mechanistic basis for this variation, we then review cranial adaptations for harder biting. These dictate that a more gracile cranium in larger species must represent a structural sacrifice in the ability to produce or withstand harder bites, relative to size. This leads us to propose that facial gracilisation in larger species is often a product of bite force allometry and phylogenetic niche conservatism, where more closely related species tend to exhibit more similar feeding ecology and biting behaviours and, therefore, absolute (size-independent) bite force requirements. Since larger species can produce the same absolute bite forces as smaller species with less effort, we propose that relaxed bite force demands can permit facial gracility in response to bone optimisation and alternative selection pressures. Thus, mammalian facial scaling represents an adaptive by-product of the shifting importance of selective pressures occurring with increased size. A reverse pattern of facial 'shortening' can accordingly also be found, and is retrieved in several cases here, where larger species incorporate novel feeding behaviours involving greater bite forces. We discuss multiple exceptions to a bite force-mediated influence on facial proportions across mammals which lead us to argue that ecomorphological specialisation of the cranium is likely to be the primary driver of facial scaling patterns, with some developmental constraints as possible secondary factors. A potential for larger species to have a wider range of cranial functions when less constrained by bite force demands might also explain why selection for larger sizes seems to be prevalent in some mammalian clades. The interplay between adaptation and constraint across size ranges thus presents an interesting consideration for a mechanistically grounded investigation of mammalian cranial allometry.

Behavioral dominance interactions between two species of burying beetles (Nicrophorus orbicollis and Nicrophorus pustulatus).

Closely related species with ecological similarity often aggressively compete for a common, limited resource. This competition is usually asymmetric and results in one species being behaviorally dominant over the other. Trade-offs between traits for behavioral dominance and alternative strategies can result in different methods of resource acquisition between the dominant and subordinate species, with important consequences for resource partitioning and community structure. Body size is a key trait thought to commonly determine behavioral dominance. Priority effects (i.e., which species arrives at the resource first), however, can also determine the outcome of interactions, as can species-specific traits besides size that give an advantage in aggressive contests (e.g., weapons). Here, we test among these three alternative hypotheses of body size, priority effects, and species identity for what determines the outcome of competitive interactions among two species of burying beetles, Nicrophorus orbicollis and N. pustulatus. Both overlap in habitat and seasonality and exhibit aggressive competition over a shared breeding resource of small vertebrate carrion. In trials, we simulated what would happen upon the beetles' discovery of a carcass in nature by placing a carcass and one beetle of each species in a container and observing interactions over 13 h trials (n = 17 trials). We recorded and categorized interactions between beetles and the duration each individual spent in contact with the carcass (the key resource) to determine which hypothesis predicted trial outcomes. Body size was our only significant predictor; the largest species won most aggressive interactions and spent more time in contact with the carcass. Our results offer insight into the ecology and patterns of resource partitioning of N. orbicollis and N. pustulatus, the latter of which is unique among local Nicrophorus for being a canopy specialist. N. pustulatus is also unique among all Nicrophorus in using snake eggs, in addition to other carrion, as a breeding resource. Our results highlight the importance of body size and related trade-offs in ecology and suggest parallels with other coexisting species and communities.

Carrion converging: Skull shape predicts feeding ecology in vultures

AbstractThe link between skull shape and dietary ecology in birds at macroevolutionary scales has recently been called into question by analyses of 3D shape that reveal that cranial anatomy is mainly influenced by other factors such as allometry. It is still unknown whether this form‐function disconnect also exists at smaller evolutionary scales, for example within specialized ecological guilds. Vultures are a diverse guild of 23 extant species in two families (Accipitridae and Cathartidae) that exhibit evolutionary convergence as a result of highly specialized feeding ecology. Vultures are the only known obligate scavengers among vertebrates and are usually grouped together under this single dietary category, but within this specialized diet there are three distinct, species‐specific feeding strategies termed ripper, gulper, and scrapper. We use three‐dimensional geometric morphometrics to quantify the relative contributions of feeding ecology, allometry, and phylogeny on vulture skull shape, along with several non‐vulture raptors of similar size, range and ecology. Families show clear separation in shape, but phylogenetic signal is comparatively weak (Kmult = 0.33). Taking into account the influence of phylogeny, skull shape is not significantly correlated with either skull size or feeding type, but there are examples of strong, significant convergence and parallel shape evolution across feeding groups. Furthermore, skull shape performs strongly in predicting feeding ecology in a phylogenetic discriminant function analysis. These findings highlight the importance of detailed assessment of feeding behavior in studies of ecomorphology, rather than broader dietary categories alone, and reveal that ecology can be readily inferred from form given appropriate information.

Haemosporidian parasite infections of Malagasy Philepittidae and Nectariniidae are driven by phylogeny rather than ecology.

The nectarivorous common sunbird asity (Neodrepanis coruscans) is phylogenetically closely related to the frugivorous velvet asity (Philepitta castanea), yet it shares similar habitat and foraging behaviour as the Malagasy sunbirds (Cinnyris spp.). As ecological factors have been shown to influence blood parasite prevalence, it should be tested whether parasite abundance, prevalence and diversity of N. coruscans are more similar to the sunbirds than to its relative. Therefore, blood samples (n = 156) and smears (n = 60) were tested for different blood parasites (Haemosporida, trypanosomes, filarioid nematodes) using molecular and microscopic methods. High prevalence of haemosporidian parasites was observed in all bird taxa, with rates ranging from 23% in N. coruscans to 84.6% in C. notatus. The Malagasy Cinnyris spp. exhibited a high occurrence of mixed haemosporidian infections (>76%) with various specialized lineages. Within the Philepittidae family, no Haemoproteus infection was detected and just a few cases of mixed infections. Nectariniidae species predominantly had specialized haemosporidian lineages, while Philepittidae had infections mainly caused by generalist lineages. These findings emphasize the diverse range of blood parasites in Nectariniidae, while additionally highlighting the high diversity of trypanosomes and filarioid nematodes in Philepittidae. Additionally, several newly discovered haemosporidian lineages, Trypanosoma isolates and filarioid nematode isolates were identified. Notably, Philepittidae exhibited a lower prevalence of avian haemosporidian parasites compared to Nectariniidae, possibly due to potential resistance mechanisms. Despite N. coruscans sharing similar habitat and behavioural ecology with both Cinnyris spp., it closely resembles its relative, P. castanea, in all aspects of haemosporidian parasitism.

AETIOLOGICAL CHARACTERISTICS OF DENTAL IMPLANT FAILURE

Dental implant placement is a predictable and widely used procedure in modern dentistry. Nevertheless, several factors can negatively affect the functioning and duration of implant restoration. Considering the significant data supporting the role of the microbial factor in the development of tissue inflammation around the prosthesis, the purpose of this review was to investigate the etiological structure of implant loss from a microbiological point of view. Materials and methods. We conducted a comprehensive content analysis of scientific publications available in the PubMed/MEDLINE and Google Scholar databases. Results and discussion. Six groups of microorganisms are known as potential contributor to the dental biofilm. These groups are designated by a specific color – yellow, green, purple, orange and red. The orange and red groups include pathogens of periodontal inflammation, and also play a significant role in the development of peri-implant (PI) inflammation. Implants and teeth share histopathological and ecological similarities, thus, we can suggest that the microbial communities around these structures are similar. In the studies, the composition of the PI-associated complex of microorganisms including Porphyromonas gingivalis, Porphyromonas endodontalis, Tannerella forsythia, Filifactor alocis, Fretibacterium fastidiosum, Desulfobulbus spp. and Treponema lecithinolyticum was decsribed. It has been reported that the PI microbiome is specific to the site where an implant is placed, and the microbial composition of the biofilm of the contralateral healthy sites is more similar to the spectrum of healthy prostheses, including other subjects, than those from the same oral cavity. We can suggest that the changes in the implant microbiocenosis are dynamic. Several studies have shown the long-term consequences of dental implant restoration that can include the modification of the microbiome consisting in the progressive increase of P. gingivalis, T. forsythia, A. actinomycetemcomitans and Prevotella intermedia within 3-6 months following the procedure of implant placement. There is also an opinion about the peculiarities of the biofilm microbiota of the peri-implant tissues in case of early and late loss of the dental prosthesis. Bacteria are an important component of the microbiocenosis in any ecological niche, but the role of archaea is often overlooked. Methanogenic archaea, and Methanobrevibacter oralis are components of the normal oral microbiome, but their considerable prevalence may also be associated with peri-implant tissue inflammation. Conclusions. We have elucidated the complex nature of microbial communities within peri-implant sites and established an association between peri-implant diseases and the dysbiosis of subgingival microbial communities. Our study underscores the pivotal role of microbiota in peri-implant diseases.

The functional traits of host fish can act as good predictors for parasite composition in a neotropical floodplain.

Parasite diversity can be influenced by the interaction of environmental factors and host traits, but understanding which traits can be decisive for the establishment of the parasite may provide subsidies fora better understanding of the host-parasite relationship. In this study, we investigated whether functional traits, diet, and host phylogeny can predict the similarity of the endoparasite composition of a fish assemblage in a Brazilian floodplain. Of the three evaluated components, the host's diet was the factor that showed the greatest influence on the composition and similarity of endoparasites, demonstrating the highest value of the explanation. The functional traits and phylogeny, despite presenting significant values (unique effect and global effect), showed low explainability in the composition of the endoparasites. When analyzing the joint effects, all components showed significant influence. Hosts that live in the same environment that are phylogenetically related and have a similar ecology have a certain degree of homogeneity in their parasite assemblages and, because they are endoparasites (which are acquired trophically along the chain), diet is the main driver of parasite richness and similarity. Overall, host traits can be one of the main determinants of parasite composition, so studies that address the functional traits of the host provide a representation of local diversity and define the possible patterns of these parasite communities.

Red fruits exhibit lower colour diversity than red flowers as perceived by birds

Abstract Pollination and seed dispersal are crucial processes for plant reproduction, sharing ecological relevance and similarities, yet they have rarely been considered together. Flowers appear to express greater phenotypic diversity than fruits due to multiple confounding factors, which pose challenges for comparative analyses. The colours of flowers and fruits are important visual signal traits in pollination and seed dispersal, evolving under different selective pressures from their respective pollinators and seed dispersers. Birds constitute a unique plant‐interacting group that participates in both pollination and seed dispersal events. In this study, we focus on red flowers and red fruits associated with avian mutualists to gain insight into the intrinsic differences between flowers/pollination and fruits/seed dispersal. We conducted comparisons of colouration between 94 red flowers pollinated by birds and 99 red fruits dispersed by birds. The colour diversity was compared in both the spectral space and the avian colour vision spaces. Colour conspicuousness was analysed using avian colour vision models, as well as bee models. Pigeon colour preference was tested by controlled experiments utilizing red stimuli with and without secondary peaks at short wavelengths. Red fruits had lower colour diversity than red flowers, with redder hues and fewer secondary reflectance peaks. Avian colour vision models illustrated that fruits were more conspicuous than flowers achromatically, but not chromatically. Pigeons did not show preference for red with or without a secondary peak. Although both are red, there are significant differences between flowers and fruits in terms of colour diversity, spectral properties and colour perceptions. As we exclusively considered avian mutualists, these differences cannot be attributed to the differences in interacting animal groups or to their colour vision properties. This implies that the differences in evolutionary history between flowers and fruits may deserve further attention to understand the colour evolution. Read the free Plain Language Summary for this article on the Journal blog.

Mesocarnivores activity patterns in the Northern Colombian Andes

Temporal segregation plays an important role as a coexistence mechanism between potentially competing and closely related species, especially in species with similar morphology and ecological requirements, such as mesocarnivores. This study investigates the temporal niche ecology of mesocarnivores coexisting in the southeastern Aburrá Valley, northern Colombian Andes. Specifically, this study i) evaluated the daily activity patterns of six mesocarnivore species, ii) analyzed the influence of the lunar cycle on the activity patterns of nocturnal species, iii) estimated the temporal overlap between pairs of mesocarnivores, and iv) estimated the functional similarities of these species. We hypothesized that mesocarnivores with similar functional traits exhibit greater temporal niche segregation, thus showing low overlap in their activity patterns to reduce competition. We used data from tracking cameras (10,744 camera-days) and estimated daily activity patterns using Kernel density analysis, non-negative trigonometric summation, and overlap analysis with the Overlap package in R. Also, lunar influence was evaluated using circular statistics in the software Oriana 4.02. Functional similarity was analyzed by similarity clustering using Jaccard's index in PAST. Nine species were recorded; six were included in the analyses of daily activity patterns. Activity patterns were not uniform throughout the circadian cycle. Cerdocyon thous, Leopardus tigrinus, and Nasuella olivacea showed mainly nocturnal activity, while Eira barbara, Nasua nasua, and Neogale frenata displayed a diurnal activity pattern. Only Leopardus tigrinus showed significant activity related to the lunar cycle. The activity overlap between pairs of species was variable, with a tendency to a low overlap, showing a high ecological similarity between species. This study represents the first estimate of the activity patterns of mesocarnivore species in the southeastern Aburrá Valley. The observed activity patterns are similar to those reported in other works. Species with high overlap showed ecological differences, especially in size and diet. The low number of records for some species may be associated with poor detectability but also with low abundance as a result of urban development and anthropogenic disturbance (e. g., roadkills). Our results suggest that temporal segregation contributes to mediating intra-gremial interactions and coexistence between sympatric and potentially competing species. These results will hopefully contribute to the knowledge of the ecology of mesocarnivores, mainly in ecosystems surrounding large cities in the northern Andes.

Different demographic responses of three species of container Aedes (Diptera: Culicidae) larvae to timing of extrinsic mortality.

Mortality imposed on a population can interact with negatively density-dependent mortality to produce overcompensation, wherein added mortality results in more survivors. Experimental mortality can cause overcompensation in mosquito larvae, which would be counterproductive if it resulted from mosquito control in nature. We tested for different demographic responses to mortality among 3 container Aedes species when impacted by density dependence. We imposed 48.2% mortality on cohorts of larvae 2, 6, or 8 days after hatching and compared adult production, development times, and female size to those variables for controls without mortality. Mortality significantly increased adult production compared to controls, but the 3 species varied in the details of that response. Aedes albopictus (Skuse) produced more adults with mortality on day 2 primarily because of greater production of males. Aedes triseriatus (Say) yielded more adults with mortality on day 2 primarily because of greater production of females. Aedes aegypti (L.) adult production was not significantly affected by mortality, but development times for both sexes were significantly shorter with mortality on day 8. There were no effects of mortality on female wing length. None of our mortality treatments yielded significant reductions of adults for any species. These species responses to mortality are not the same, despite their similar ecologies and life histories. Thus, we cannot assume that killing almost half the larvae present in a dense population will reduce adult production, nor can we assume that different Aedes species will respond to mortality in the same way.

Geographical isolation as reproductive barrier in phylogenetically related Aquilegia species (Ranunculaceae)

Knowing the determinants of biodiversity is crucial to understanding the differentiation of living organisms. Several gene-flow limiting processes can drive divergence, including adaptive ecological differentiation or geographical isolation both constituting environmental-dependent reproductive barriers. Furthermore, the strength of these processes may be associated to the degree to which ecological niches are conserved and shared by phylogenetically related species. Here, we aim to disentangle these two alternatives reproductive barriers by evaluating the degree of ecological niche similarity among phylogenetically related species. We performed ecological niche modelling (ENM) on four species belonging to a recently diversified genus (Aquilegia, Ranunculaceae) occurring in montane environments of the Alpine and Apennine chains (southern Europe). Results show that niche differentiation among species is related to phylogenetic distinctiveness. Nevertheless, niche similarity tests indicated that the conditions selected by the species are more similar than expected from the null models, even though they are sparsely available in the respective ecological spaces, suggesting that the observed pattern may result from phylogenetic niche conservatism. These results, highlight that paleogeographic events in south-European mountains may have driven divergence by isolation in Aquilegia while partially retaining the possibly ancestral characters of the niches.

A new approach to an old problem: how to categorize the habit of ferns and lycophytes.

Substrate preferences are often treated as species traits and are used to distinguish different habits, i.e. an epiphytic, lithophytic or terrestrial habit. Such a categorization, however, ignores substantial intraspecific variation. An approach that takes biological variability within a species into account is needed. We focused on four large genera of ferns and lycophytes and found relevant information in >500 sources, such as online databases, checklists, floras and species descriptions. Translating textual information into a quantitative index, we quantified the propensity to grow on either substrate as a continuous trait for 1475 species. Only a minority of species exhibited strict substrate fidelity, but a majority of them showed clear habitat preferences. The relative frequencies of intermediates between strict lithophytes, epiphytes and terrestrials does not support the frequent notion of ecological similarity of the lithophytic and epiphytic habitat. The compiled data are useful immediately for ecological and evolutionary studies with the focal taxa. More importantly, we propose the replacement of the concept of distinct habits with one of gradual differences. This should have a profound impact on any such study with plants in general.

Coevolutionary maintenance of forked tails and song in hirundines (Aves: Hirundininae)

Both conspicuous plumage ornamentation and song are well‐known examples of sexually selected traits, but their interrelationship is not well known, perhaps in part because of confounding factors, including interspecific variation in ecology, habitat, morphology, and type of ornamentation. Here, using a phylogenetic comparative approach and the 69 species with available information (i.e. 96% of all 72 species), I examined the evolutionary relationship between forked tails and the presence/absence of song in hirundines (Aves: Hirundininae). Hirundines have similar ecology (e.g. aerial insectivores, social monogamy, and biparental provisioning), morphology (e.g. syrinx with nearly complete bronchial rings), and plumage ornamentation (i.e. a sexually selected forked tail), which provides a unique opportunity to examine the evolutionary associations between plumage ornamentation and song. In particular, hirundines have repeatedly lost their ornamentation, forked tails, setting up a condition to test their association with the evolutionary gain/loss of their simple song. After controlling for phylogeny and covariates, I demonstrated that song was less likely to be found in species with forkless tails than in species with forked tails. Two correlates of tail shape, sexual dimorphism in the overall plumage characteristics as a well‐known proxy of sexual selection and incubation type as a measure of extrapair mating opportunity, were not positively related to the presence or absence of song, indicating the importance of forked tails, rather than their correlates. The analysis of the correlated evolution of discrete characters further supported the correlated evolution of the two traits, in which forked tails and song are maintained together and less likely to be lost under the presence of each other. The current study provided macroevolutionary support for the integrated use of visual and acoustic courtship traits.

Field Screening of Elite Cassava (Manihot esculenta) Mutant Lines for their Response to Mosaic and Brown Streak Viruses

Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease (CMD) have been major limiting biotic factors to the productivity of cassava farming in Kenya. Development of resistant cassava varieties is most effective way. The study was to determine response of elite cassava lines to CBSD and CMD under field conditions on different agro-ecological zones in Kenya. Screening was done under hot-spot field conditions where five lines together with their parents were evaluated in Randomized Complete Block Design with three replications at University of Eldoret (UoE), Solai and Marakwet sites in Kenya. Severity assessment done on 1-5 rating scale where 1 very resistant and 5 most susceptible. Elite cassava lines had significant differences in their response (p < 0.05) to CBSD and CMD. Additionally, genotypes, site and time interval were also significant (p < 0.05). The three elite lines (CAS1, CAS2 and CAS3) had better tolerance to both diseases compared to their parents (KME3 and KME4) with KME4 showing visible brown rings on the root typical of CBSD The elite lines CAS1, CAS2 and CAS3 identified to have better adaptability to both CBSD and CMD could be further exploited in breeding for new cassava varieties for Kenya and other countries in the region with similar ecology.

Rhizosphere effects on the microbial community: Specificity and conservatism across geographically disjunct Panax species

A deeper understanding of plant control over the rhizosphere, especially from the evolutionary perspective, is needed for environmentally friendly breeding to take advantage of soil microbes. In the present study, paired bulk and rhizosphere soil samples from 810 plants of three Panax species (P. ginseng, PG; P. quinquefolium, PQ; P. notoginseng, PN) were used to assess rhizosphere effects on microbial diversity, phylogenetic structure, and community composition. The rhizosphere effects were generally stronger in tetraploid PG/PQ than in diploid PN, and the edaphic factors capable of explaining within-species effect variations differed among the three species. However, these species were consistent in terms of the greater biodiversity and stronger phylogenetic clustering in the rhizosphere than in bulk soil, as well as the upward trend of effect strength with plant age. The rhizosphere-enriched taxa of the three species showed strong phylogenetic clustering, as indicated by phylogenetic sampling theory (z score = −11.33) and UniFrac distances, and the coenrichment was mainly reflected in specific orders of Alpha- and Gammaproteobacteria. The potential ecological similarity of rhizosphere-enriched taxa might represent the evolutionarily conserved part of genetic traits involved in rhizosphere recruitment and microbial function requirements in the three species. In summary, this study reveals the specificity and conservatism of rhizosphere effect evolution in these related but Holarctic disjunct Panax species, which advances our understanding of plant–microbe coevolution in the rhizosphere.

Different mechanisms underpin the decline in growth of anchovies and sardines of the Bay of Biscay.

Declines in individuals' growth in exploited fish species are generally attributed to evolutionary consequences of size-selective fishing or to plastic responses due to constraints set by changing environmental conditions dampening individuals' growth. However, other processes such as growth compensation and non-directional selection can occur and their importance on the overall phenotypic response of exploited populations has largely been ignored. Using otolith growth data collected in European anchovy and sardine of the Bay of Biscay (18 cohorts from 2000 to 2018), we parameterized the breeder's equation to determine whether declines in size-at-age in these species were due to an adaptive response (i.e. related to directional or non-directional selection differentials within parental cohorts) or a plastic response (i.e. related to changes in environmental). We found that growth at age-0 in anchovy declined between parents and their offspring when biomass increased and the selective disappearance of large individuals was high in parents. Therefore, an adaptive response probably occurred in years with high fishing effort and the large increase in biomass after the collapse of this stock maintained this adaptive response subsequently. In sardine offspring, higher growth at age-0 was associated with increasing biomass between parents and offspring, suggesting a plastic response to a bottom-up process (i.e. a change in food quantity or quality). Parental cohorts in which selection favoured individuals with high growth compensation produced offspring high catch up growth rates, which may explain the smaller decline in growth in sardine relative to anchovy. Finally, on non-directional selection differentials were not significantly related to the changes in growth at age-0 and growth compensation at age-1 in both species. Although anchovy and sardine have similar ecologies, the mechanisms underlying the declines in their growth are clearly different. The consequences of the exploitation of natural populations could be long lasting if density-dependent processes follow adaptive changes.

High trophic similarity between non-native common carp and gibel carp in Turkish freshwaters: Implications for management

Although the detrimental ecological and economic effects of introducing freshwater fish species have been extensively documented, non-native freshwater fishes continue to be introduced in large numbers globally to enhance fisheries and aquaculture. In Turkey, stocking of common carp Cyprinus carpio is practised to provide food security for people and job security for artisanal fishers, resulting in a country-wide distribution. These stockings, however, increase the risk of accidental introductions and have led to introductions and subsequent invasions of gibel carp Carassius gibelio, a globally invasive and highly detrimental fish species. Here, we assessed the growth types, body conditions and trophic interactions via bulk carbon and nitrogen stable isotope analysis of common and gibel carp in both natural and artificial water bodies in Turkey. The results indicated that common and gibel carp express similar growth types and body conditions in all waters and have similar trophic ecologies. This leads to substantial trophic niche overlaps in waters where they co-occur, with the potential for strong interspecific competition. Considering the ongoing stocking of common carp for fishery enhancement, we recommend to specifically target these stockings in waters where gibel carp has already become invasive. Our findings, indeed, suggest that common carp releases have the potential to hamper invasive gibel carp populations by increasing the competitive interactions between the two species.

Introgression between highly divergent fungal sister species.

To understand how species evolve and adapt to changing environments, it is important to study gene flow and introgression due to their influence on speciation and radiation events. Here, we apply a novel experimental system for investigating these mechanisms using natural populations. The system is based on two fungal sister species with morphological and ecological similarities occurring in overlapping habitats. We examined introgression between these species by conducting whole genome sequencing of individuals from populations in North America and Europe. We assessed genome-wide nucleotide divergence and performed crossing experiments to study reproductive barriers. We further used ABBA-BABA statistics together with a network analysis to investigate introgression, and conducted demographic modelling to gain insight into divergence times and introgression events. The results revealed that the species are highly divergent and incompatible in vitro. Despite this, small regions of introgression were scattered throughout the genomes and one introgression event likely involves a ghost population (extant or extinct). This study demonstrates that introgression can be found among divergent species and that population histories can be studied without collections of all the populations involved. Moreover, the experimental system is shown to be a useful tool for research on reproductive isolation in natural populations.

Evaluation of Black Cumin (Nigella sativa L.) Genotypes for Yield and Yield Related Parameters in Potential Growing Areas of Ethiopia

Multi-environment trials were carried out at 3 locations in different black cumin growing zones of Ethiopia during June-December, 2017–2018 and 2018–2019 to select high yielding and adaptable genotypes for commercial production in Ethiopia. Ten advanced black cumin genotypes were evaluated with one standard check variety. The genotypes were arranged in Randomized Complete Block Design with three replications. The ANOVA revealed that the differences in seed yield among genotypes (G), environments (E) and genotype by environment interaction (GEI) were highly significant (p<0.01). Besides, significant (p<0.01) differences were obtained for days to 50% flowering, days to maturity, plant height, number of pod plant-1, number of seeds pod-1, seed yield plant-1, and thousand seed weight. However, days to emergence, number of primary and secondary branches plant-1 were not significant (p>0.05). The highest seed yield was recorded from genotype 242840 (1102 kg ha-1) followed by 242841(1038 kg ha-1) and these genotypes had 35% and 26.39% yield advantage over the check variety-Aden respectively. Moreover, the two genotypes were better in oleoresin content among others. The partitioning of GE through GGE biplot analysis showed that PC1 and PC2 accounted for 47.09% and 18.18%, explaining 65.27% of the total variance. The GGE biplot ranked the genotypes for yield performance; the genotypes viz. 24840 and 24841 were among the five marker (winning) genotypes and showed their wider adaptability across the testing environments. Therefore, the genotypes were selected as potential candidate genotypes for on farm verification and possible release for commercial production in the testing environments and similar agro ecologies.

Signal size allometry in Anolis lizard dewlaps.

Positive allometry of signalling traits has often been taken as evidence for sexual selection. However, few studies have explored interspecific differences in allometric scaling relationships among closely related species that vary in their degree of ecological similarity. Anolis lizards possess an elaborate retractable throat fan called a dewlap that is used for visual communication and differs greatly in size and colour among species. We observed that Anolis dewlaps demonstrate positive allometry: relative dewlap size increases with body size. We also observed that coexisting species are divergent in signal size allometries, while convergent species-similar in other aspects of ecology, morphology and behaviour-typically share similar dewlap allometric scaling relationships. These patterns suggest that dewlap scaling relationships may follow the same pattern as other traits in the anole radiation, where ecologically different sympatric species have evolved a suite of divergent traits.

Determination of Macro Element Contents of Herbages of Elâzığ/Karakoçan/Savucak Village Pasture with Different Nitrogen and Phosphorus Fertilization

The study was carried out in the natural pasture of the Savucak village of Karakoçan district in Elazığ province in 2021 and 2022. The aim of the study is to determine the macro element contents of the herbages of the pasture where five different nitrogen doses (0, 5, 10, 15, 20 kg da-1) and phosphorus (0, 4, 8, 12, 16 kg da-1) were applied. Calcium (Ca), magnesium (Mg), potassium (K) and phosphorus (P) levels were determined in the herbages cut from the pasture. The determination of Ca, Mg, K and P in dried and ground herbs was made by ICP-MS and the research was carried out in randomized blocks with three replications in accordance with a two-factor factorial experiment design. In the study, it was determined that the effect of increasing nitrogen and phosphorus doses on the macro element contents of pasture herbage was statistically significant. It was observed that Ca, Mg, K and P contents of pasture herbage decreased with the increase of phosphorus doses applied to the pasture, and macro element contents increased with the increase of nitrogen doses. It was determined that the Ca, Mg, K and P contents increased with the increase of the nitrogen dose, but the increase in the phosphorus ratio did not have any effect on the Ca, Mg, K and P contents of the pasture herbage. According to the results obtained from the research, it was concluded that 10 kg da-1 nitrogen and 4 kg da-1 phosphorus fertilization is appropriate in Elazig and pastures with similar ecologies.