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opennotspecifiedJun 2006View details →

FIGURE 1 in Natural history and distribution of the enigmatic southern Appalachian opilionid, Fumontana deprehendor Shear (Laniatores: Triaenonychidae), with an assessment of morphological variation

FIGURE 1. Distribution of sampled Fumontana deprehendor in the southern Appalachian mountains. A total of 24 localities were sampled, including both previously published localities (Shear 1977, 1978), labeled here as GREENBR and JOYCE. Dark circles represent sampled localities, with the size of circles proportional to the number of specimens collected. Open circles represent unsuccessful collecting attempts. Dark lines represent the four regions of "predicted endemism" (defined in the text) used as grouping variables in morphological analyses. These areas are regional highlands separated by major lowland riverine barriers. Stippled areas indicate elevations above 1000 meters.

opencc-zeroJan 2022View details →

Natural variation further increases resilience of sorghum bred for chronically drought-prone environments

Moisture stress is one of the major constraints for crop production in African Sahel. Here, we explore the potential to use natural genetic variation to build on the inherent drought tolerance of an elite sorghum cultivar (Teshale) bred for Ethiopian conditions including chronic drought, evaluating a backcross nested-association mapping population using 12 diverse founder lines crossed with Teshale under three drought-prone environments in Ethiopia. All twelve populations averaged higher head exsertion and lower leaf senescence than the recurrent parent in the two highest-stress environments, reflecting new drought resilience mechanisms from the donors. 154 QTLs were detected for eight drought responsive traits – the validity of these were supported in that 113 (73.4%) overlapped with QTLs previously detected for the same traits, concentrated in regions previously associated with 'stay-green' traits. Allele effects show that some favorable alleles are already present in the Ethiopian cultivar, however the exotic donors offer rich scope for increasing drought resilience. Using model-selected SNPs associated with eight traits in this study and three in a companion study, phenotypic prediction accuracies for grain yield were equivalent to genome-wide SNPs and were significantly better than random SNPs, indicating that these studied traits are predictive of sorghum grain yield.

opencc-zeroMay 2022View details →

Natural variation at a single gene generates sexual antagonism across fitness components in Drosophila

Mutations with conflicting fitness effects in males and females accumulate in sexual populations, reducing their adaptive capacity. Although quantitative genetic studies indicate that sexually antagonistic polymorphisms are common, their molecular basis and population genetic properties remain poorly understood. Here, we show in fruit flies how natural variation at a single gene generates sexual antagonism through phenotypic effects on cuticular hydrocarbon (CHC) traits that function as both mate signals and protectors against abiotic stress across a latitudinal gradient. Tropical populations of Drosophila serrata have polymorphic CHCs producing sexual antagonism through opposing but sex-limited effects on these two fitness-related functions. We dissected this polymorphism to a single fatty-acyl CoA reductase gene, DsFAR2-B, that is expressed in oenocyte cells where CHCs are synthesised. RNAi mediated disruption of the DsFAR2-B ortholog in D. melanogaster oenocytes affected CHCs in a similar way to that seen in D. serrata. Population genomic analysis revealed that balancing selection likely operates at the DsFAR2-B locus in the wild. Our study provides insights into the genetic basis of sexual antagonism in nature and connects sexually varying antagonistic selection on phenotypes with balancing selection on genotypes that maintains molecular variation.

opencc-zeroJul 2022View details →

Spatio-temporal dynamics of genetic variation at the quantitative and molecular levels within a natural Arabidopsis thaliana population

Evolutionary change begins at the population scale. Therefore, understanding adaptive variation requires the identification of the factors maintaining and shaping standing genetic variation at the within-population level. Spatial and temporal environmental heterogeneity represent ecological drivers of within-population genetic variation, determining the evolutionary trajectory of populations along with random processes. Here, we focused on the effects of spatio-temporal heterogeneity on quantitative and molecular variation in a natural population of the annual plant Arabidopsis thaliana. We sampled 1,093 individuals from a Spanish A. thaliana population across an area of 7.4 ha for 10 years (2012-2021). Based on a sample of 279 maternal lines, we estimated spatio-temporal variation in life-history traits and fitness from a common garden experiment. We genotyped 884 individuals with nuclear microsatellites to estimate spatio-temporal variation in genetic diversity. We assessed spatial patterns by estimating spatial autocorrelation of traits and fine-scale genetic structure. We analyzed the relationships between phenotypic variation, geographic location and genetic relatedness, as well as the effects of environmental suitability and genetic rarity on phenotypic variation. The common garden experiment indicated that there was more temporal than spatial variation in life-history traits and fitness. Despite the differences among years, genetic distance in ecologically relevant traits (e.g. flowering time) tended to be positively correlated to genetic distance among maternal lines, whilst isolation by distance was less important. Genetic diversity exhibited significant spatial structure at short distances, which were consistent among years. Finally, genetic rarity, and not environmental suitability, accounted for genetic variation in life-history traits. Synthesis. Our study highlighted the importance of repeated sampling to detect the large amount of genetic diversity at the quantitative and molecular levels that a single A. thaliana population can harbor. Overall, population genetic attributes estimated from our long-term monitoring scheme (genetic relatedness and genetic rarity), rather than biological (dispersal) or ecological (vegetation types and environmental suitability) factors, emerged as the most important drivers of within-population structure of phenotypic variation in A. thaliana.

opencc-zeroAug 2022View details →

Sexually mediated phenotypic variation within and between sexes as a continuum structured by ecology: The mosaic nature of skeletal variation across body regions in Threespine stickleback (Gasterosteus aculeatus L.)

Ecological character displacement between the sexes, and sexual selection, integrate into a convergent set of factors that produce sexual variation. Ecologically-modulated, sexually mediated variation within and between sexes may be a major contributor to the amount of total variation that selection can act on in species. Threespine stickleback (Gasterosteus aculeatus) display rapid adaptive responses and sexual variation in many phenotypic traits. We examined phenotypic variation in the skull, pectoral and pelvic girdles of threespine stickleback from two freshwater and two coastal marine sites on the Sunshine Coast of British Columbia, Canada, using an approach that avoids a priori assumptions about bimodal patterns of variation. We quantified shape and size of the cranial, pectoral and pelvic regions of sticklebacks in marine and freshwater habitats using 3D geometric morphometrics and an index of sexually mediated variation. We show that the expression of phenotypic variation is structured in part by the effects of both habitat marine vs freshwater and the effects of individual sites within each habitat. Relative size exerts variable influence, and patterns of phenotypic variation associated with sex vary among body regions. This fine-grained quantification of sexually mediated variation in the context of habitat difference and different anatomical structures indicates a complex relationship between genetically inferred sex and environmental factors, demonstrating that the interplay between shared genetic background and sexually mediated, ecologically-based selective pressures structures the phenotypic expression of complex traits.

FIGURE 3. A in Vocalizations, tadpole, and natural history of Crossodactylus werneri Pimenta, Cruz & Caramaschi, 2014 (Anura: Hylodidae), with comments on distribution and intraspecific variation

FIGURE 3. A density plot of the first discriminant axis (DAPC) on morphological traits from adult males of Crossodactylus werneri. Note the low discrimination among topotypes (blue) and specimens from Serra das Cabras (red). Six principal component axes were retained and explained 95% of total variance.

FIGURE 5 in Vocalizations, tadpole, and natural history of Crossodactylus werneri Pimenta, Cruz & Caramaschi, 2014 (Anura: Hylodidae), with comments on distribution and intraspecific variation

FIGURE 5. Geographic distribution of Crossodactylus werneri in southeastern Brazil. Red circle: type locality (Itatiaia, between the limits of the Brazilian states of Rio de Janeiro, São Paulo, and Minas Gerais); white circles: localities reported by Pimenta et al. (2014); white triangles: new records (present study) from Mococa (above), and Serra das Cabras (Campinas) and Valinhos (below).

FIGURE 4 in Vocalizations, tadpole, and natural history of Crossodactylus werneri Pimenta, Cruz & Caramaschi, 2014 (Anura: Hylodidae), with comments on distribution and intraspecific variation

FIGURE 4. The tadpole (stage 31) of Crossodactylus werneri. From top to bottom: lateral view; dorsal and ventral views of body; oral disc (bottom right). Specimen from Serra das Cabras, Campinas, São Paulo (lot AAG-UFU 5236).

FIGURE 2 in Vocalizations, tadpole, and natural history of Crossodactylus werneri Pimenta, Cruz & Caramaschi, 2014 (Anura: Hylodidae), with comments on distribution and intraspecific variation

FIGURE 2. (A) Adult male specimens of Crossodactylus werneri in life from Serra das Cabras, Campinas, São Paulo: above— AAG-UFU 0981, SVL 21.7 mm; below—AAG-UFU 0982, SVL 21.6 mm. (B) Adult males of Crossodactylus werneri in dorsal view. Left—Serra das Cabras, Campinas, São Paulo (AAG-UFU 1880; SVL 23.0 mm); right—Parque Nacional do Itatiaia, Rio de Janeiro (topotype ZUEC-AMP 7981; SVL 22.1 mm). (C) Adult males of Crossodactylus werneri from Serra das Cabras (Campinas, São Paulo), depicting variation in size and in the degree of reticulation on the belly (right—AAG-UFU 1875, SVL 21.6 mm; left—AAG-UFU 1878, SVL 25.1 mm).

FIGURE 1 in Vocalizations, tadpole, and natural history of Crossodactylus werneri Pimenta, Cruz & Caramaschi, 2014 (Anura: Hylodidae), with comments on distribution and intraspecific variation

FIGURE 1. (A) From top to bottom: oscillogram of a 29-note advertisement call of Crossodactylus werneri preceded by five isolated notes (second note identified by a red arrow); spectrogram of three median notes and respective oscillogram. Sound file: Crossod_werneriSousasSP1aAAGm671. (B) Spectrogram and respective oscillogram of the territorial call of Crossodactylus werneri. Sound file: Crossod_werneriSousasSP1eAAGm671. Further information on these recordings is provided in Appendix III.

opencc-by-4.0Nov 2019View details →

DataSet - Muscle structure governs joint function: linking natural variation in medial gastrocnemius structure with isokinetic plantar flexor function

Experimental data used in analysis and computational model files for research study 'Muscle structure governs joint function: linking natural variation in medial gastrocnemius structure with isokinetic plantar flexor function'

opencc-zeroDec 2016View details →

Data from: Singing from North to South: latitudinal variation in timing of dawn singing under natural and artificial light conditions

1. Animals breeding at northern latitudes experience drastic changes in daily light conditions during the breeding season with decreasing periods of darkness, whereas those living at lower latitudes are exposed to naturally dark nights throughout the year. Nowadays, many animals are also exposed to artificial night lighting (often referred to as light pollution). 2. Animals strongly rely on variation in light levels to time their daily and seasonal behaviour. Previous work on passerine birds showed that artificial night lighting leads to earlier onset of dawn song. However, these studies were carried out at intermediate latitudes with more limited seasonal changes in daylength, and we still lack an understanding of the impact of artificial night lighting in relation to variation in natural light conditions. 3. We investigated the influence of natural and artificial light conditions on the timing of dawn singing in five common songbird species in each of three regions in Europe that differed in natural variation in daylength (northern Finland, 65°N; southern Germany, 48°N; southern Spain, 37°N). In each region, we selected five peri-urban forest sites with and five without street lighting, and recorded dawn singing at the beginning of the local breeding season. 4. Our results show that the earliest natural singers, i.e., European robins (Erithacus rubecula) and common blackbirds (Turdus merula), started dawn singing earlier along with the natural increase in night brightness in Finland, with no additional effects of artificial night lighting. In contrast, the later singers, i.e., great tits (Parus major), blue tits (Cyanistes caeruleus), and chaffinches (Fringilla coelebs), showed similar onsets of dawn song relative to sunrise across the season and similar effects of artificial night lighting at all latitudes. 5. Artificial night lighting affected great tits, blue tits and chaffinches even in northern Finland where nights became very bright. Proximate factors such as differential light sensitivities may explain why early singers showed more plastic behavioural responses to naturally and artificially bright nights. The maintenance of rhythmicity in the late singers during bright northern nights and under artificial night lighting may also be an adaptive response to predation risk or costs of sleep loss.

opencc-zeroDec 2014View details →

Data from: Seasonal and ontogenetic variation of skin microbial communities and relationships to natural disease dynamics in declining amphibians

Recently, microbiologists have focused on characterizing the probiotic role of skin bacteria for amphibians threatened by the fungal disease chytridiomycosis. However, the specific characteristics of microbial diversity required to maintain health or trigger disease are still not well understood in natural populations. We hypothesized that seasonal and developmental transitions affecting susceptibility to chytridiomycosis could also alter the stability of microbial assemblages. To test our hypothesis, we examined patterns of skin bacterial diversity in two species of declining amphibians (Lithobates yavapaiensis and Eleutherodactylus coqui) affected by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). We focused on two important transitions that affect Bd susceptibility: ontogenetic (from juvenile to adult) shifts in E. coqui and seasonal (from summer to winter) shifts in L. yavapaiensis. We used a combination of community-fingerprinting analyses and 16S rRNA amplicon sequencing to quantify changes in bacterial diversity and assemblage composition between seasons and developmental stages, and to investigate the relationship between bacterial diversity and pathogen load. We found that winter-sampled frogs and juveniles, two states associated with increased Bd susceptibility, exhibited higher diversity compared with summer-sampled frogs and adult individuals. Our findings also revealed that hosts harbouring higher bacterial diversity carried lower Bd infections, providing support for the protective role of bacterial communities. Ongoing work to understand skin microbiome resilience after pathogen disturbance has the potential to identify key taxa involved in disease resistance.

opennotspecifiedSep 2017View details →

Figure 1 in Aspects of the natural history of Leptodactylus knudseni Heyer, 1972 (Anura: Leptodactylidae) in a pristine forest in Central Amazonia, Brazil, with comments on ontogenetic variation of its tadpoles

Figure 1. (a) Male of Leptodactylus knudseni (note hypertrophied forearms) near a temporary pond. (b) Ventral view of a male (note the black spine on each thumb and multicuspid spines on the chest). (c) Foam nest and (d) an excavated basin without foam nest in clay soil at the margin of a temporary pond. (e) Eggs removed from a foam nest. (f) Adult of the fly Beckeriella willistoni visiting a newly built foam nest during daylight. All photos were taken at Reserva Florestal Adolpho Ducke, Manaus, Amazonas, Brazil. (Photos a–e by R.M.C. Pinto, Photo f by M. Menin).

opencc-zeroJan 2023View details →

Patterns of morphological variation highlight the effect of natural selection on eyespots modularity in the butterfly Morpho telemachus - Dataset

Morphological correlations can stem from developmental constraints but also from selective pressures. Butterfly eyespots are repeated wing color pattern elements, widespread across species. As developmental serial homologues, they are controlled by similar developmental pathways imposing correlations among eyespots: selection on a single eyespot may induce correlated responses in all eyespots. We study the variations in the ventral eyespots of Morpho telemachus, where two different selective regimes are likely to act: while most eyespots are always-visible, two eyespots are conditionally-displayed: hidden at rest, they can be exposed when the butterflies are threatened, or during sexual interactions. We investigate how such contrasted selection across eyespots can alter the covariations imposed by their shared developmental origin. We quantified eyespots' co-variations within a large population of M. telemachus and compared the observed patterns to those found in M. helenor, where all eyespots are always-visible and thus probably affected by a similar selection regime. We found that M. telemachus conditionally-displayed eyespots are less variable than always-visible eyespots and that these two eyespots form a separate variational module in this species, in contrast to M. helenor. Our results suggest that eyespots' covariations were shaped by selection, highlighting how natural selection may promote the evolution of modularity.

opennotspecifiedSep 2015View details →

Figure 4 in Reproductive isolation and the causes of speciation rate variation in nature

Figure 4. Some possible relationships between the rate at which lineages evolve reproductive isolation and their rate of speciation. A, direct correspondence, where the evolution of reproductive evolution shows a one-to-one relationship with the macroevolutionary rate of speciation. In this scenario, the evolution of reproductive isolation is the exclusive determinant of macroevolutionary speciation dynamics. B, offset/dampened relationship, where the rate of evolution of reproductive isolation is the dominant control on speciation rates, although speciation rates are lower than predicted by the rate of evolution of reproductive isolation alone. This relationship implies that many populations evolving reproductive isolation fail to persist through deep time. C, decoupled, such that reproductive isolation shows no predictive relationship with macroevolutionary speciation rates. This scenario suggests that reproductive isolation is not the rate-limiting control on the rate of speciation. Adapted from Rabosky (2013).

opennotspecifiedSep 2015View details →

Figure 3 in Reproductive isolation and the causes of speciation rate variation in nature

Figure 3. Pairwise postzygotic isolation from interspecific crosses of birds as a function of the pairwise genetic distance between them. Results are shown for two major clades (pheasants, Phasianidae; parrots, Psittacidae). For a given level of genetic divergence, pheasants show greater levels of postzygotic isolation than the parrots, indicating that this sort of reproductive isolation accumulates more quickly in pheasants than in parrots. If intrinsic postzygotic isolation (hybrid inviability and sterility) is the dominant control on speciation rates, pheasants should have faster rates of speciation than parrots. Note that relationships are bounded at 0 (all hybrid offspring fully viable and fertile) and 1 (no offspring produced, or all offspring sterile). Lines show fitted linear relationships between reproductive isolation and genetic distance for each clade. Data are from Price & Bouvier (2002) and Gray (1958); analyses are from Rabosky and Matute (2013). For this pair of clades, speciation rates are faster in the clade with faster rates of evolution of reproductive isolation (pheasants: speciation = 0.26 lineages Myr–1; parrots: speciation = 0.22 lineages Myr–1). However, across all birds, these quantities appear to be unrelated.

opennotspecifiedSep 2015View details →

Figure 1. A in Reproductive isolation and the causes of speciation rate variation in nature

Figure 1. A, per-lineage rates of speciation across a time-calibrated phylogenetic tree of 6670 species of extant birds (67% of the total diversity) as inferred using a statistical model that simultaneously estimates the magnitude of rate variation through time and across lineages. Colours correspond to the instantaneous rate of speciation at each point in the tree. The fastest 5% of rates exceed 0.4 species Myr –1 (dark red). Analysis of evolutionary rates explicitly accounts for extinction, although only speciation rates are shown. B, estimated present-day speciation rates for all 6670 species; these are simply the best estimate of the instantaneous rate of speciation for each tip in the phylogeny. Inset images depict representative birds with fast (western gull, Larus occidentalis) and slow (go-away-bird, Corythaixoides leucogaster) rates of speciation. The phylogenetic dataset is from Jetz et al. (2012) and speciation rate analysis is described in Rabosky & Matute (2013).

opennotspecifiedOct 2020View details →

Fig. 9 in Natural variation in specialised metabolites production in the leafy vegetable spider plant (Gynandropsis gynandra L. (Briq.)) in Africa and Asia

Fig. 9. Relative levels of glucosinolates and isothiocyanates in 43 accessions of Gynandropsis gynandra from Asia (red), East/Southern Africa (black) and West Africa (blue). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)