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opencc-zeroJul 2019View details →

Data from: Hybridization and geographic distribution shapes the spatial genetic structure of two co-occurring orchid species

Multiple ecological and life-history traits shape the fine-scale spatial genetic structure (FSGS) of a given population. The occurrence in core versus peripheral populations, levels of outcrossing, pollen and seed dispersal, and hybridization are important biological properties that influence the kinship of individuals within populations. We examined spatial genetic structure within 15 populations of Epidendrum fulgens and E. puniceoluteum distributed along a linear gradient of Brazilian coastal vegetation, including both allopatric and sympatric populations where the two orchid species hybridize. We analyzed 581 mapped specimens using nine simple sequence repeat loci, aiming to investigate how geographic distribution and hybridization shape within-population FSGS. A significant increase in FSGS was found towards peripheral populations, compared to core populations. Analysis of short- and long-distance components of FSGS identified biparental inbreeding and higher levels of FSGS at peripheral populations, when compared to core populations. In contrast, the relatively high density of reproductive adults in core populations potentially leads to highly overlapping seed and pollen movement, decreasing FSGS. Hybridization was an important factor shaping within-population spatial genetic structure at sympatric sites, decreasing the FSGS observed in parental species. Our results indicate that different ecological forces act in concert to create a gradient of FSGS along species distribution ranges, shaped by extensive levels of intra- and interspecific gene exchange.

opencc-zeroDec 2011View details →

Data from: Ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring species

BACKGROUND: In the mid 20th Century, Ernst Mayr and Theodosius Dobzhansky championed the significance of circular overlaps or ring species as the perfect demonstration of speciation, yet in over 50 years since only a handful of such taxa are known. We developed a topographic model to evaluate whether the geographic barriers that favor processes leading to ring species are common or rare, and to predict where other candidate ring barriers might be found. RESULTS: Of the 952,147 geographic barriers identified on the planet, only about 1% are topographically similar to barriers associated with known ring taxa, with most of the likely candidates occurring in under-studied parts of the world (e.g., marine environments, tropical latitudes). Predicted barriers separate into two distinct categories: (i) single cohesive barriers (<50,000 km2), associated with taxa that differentiate at smaller spatial scales (salamander: Ensatina eschscholtzii; tree: Acacia karroo); and (ii) composite barriers – formed by groups of barriers (each 184,000 to 1.7 million km2) in close geographic proximity (totaling 1.9 to 2.3 million km2) – associated with taxa that differentiate at larger spatial scales (birds: Phylloscopus trochiloides and Larus [sp. argentatus and fuscus]). When evaluated globally, we find a large number of cohesive barriers that are topographically similar to those associated with known ring taxa. Yet, compared to cohesive barriers, an order of magnitude fewer composite barriers are similar to those that favor ring divergence in species with higher dispersal. CONCLUSIONS: While these findings confirm that the topographic conditions that favor evolutionary processes leading to ring speciation are in fact rare, they also suggest that many understudied natural systems could provide valuable demonstrations of continuous divergence towards the formation of new species. Distinct advantages of the model are that it (i) requires no a priori information on the relative importance of features that define barriers, (ii) can be replicated using any kind of continuously distributed environmental variable, and (iii) generates spatially explicit hypotheses of geographic species formation. The methods developed here – combined with study of the geographical ecology and genetics of taxa in their environments – should enable recognition of ring species phenomena throughout the world.

opencc-zeroDec 2018View details →

Data from: Ecological niche modeling as a tool for prediction of the potential geographic distribution of Bacillus anthracis spores in Tanzania

Introduction: Anthrax is caused by the spore-forming, Gram-positive bacterium Bacillus anthracis. The aim of this study was to predict the potential distribution of B. anthracis in Tanzania and produce epidemiological evidence for the management of anthrax outbreaks in the country. Methods: The Maxent algorithm was used to predict areas at risk of anthrax outbreaks based on the occurrence and environmental data in Arusha and Kilimanjaro regions; the model was later transferred to predict the entire country. Seventy percent of the occurrence data were used to train the model, while 30% were used for model evaluation. Results: Four regions of northern Tanzania are predicted to have a high risk for anthrax outbreaks, while the southern and western regions had low-risk areas. Soil type (56.5%), soil pH (23.7%), and isothermally (10.4%) were the most important variables for the model prediction, and the most significant soil types were solonetz, fluvisols, and lithosols. Conclusions: A strong risk level across districts of the Tanzania mainland was identified in this study. A total of 18 districts in Tanzania Mainland are predicted to be at very high risk of an anthrax outbreak occurrence. These findings are important for policymakers to effectively mount targeted control measures for anthrax outbreaks in Tanzania.

opencc-zeroDec 2014View details →

Data from: Contrasting patterns of clonality and fine-scale genetic structure in two rare sedges with differing geographic distributions

For plants with mixed reproductive capabilities, asexual reproduction is more frequent in rare species and is considered a strategy for persistence when sexual recruitment is limited. We investigate whether asexual reproduction contributes to the persistence of two co-occurring, rare sedges that both experience irregular seed set and if their differing geographic distributions have a role in the relative contribution of clonality. Genotypic richness was high (R=0.889±0.02) across the clustered populations of Lepidosperma sp. Mt Caudan and, where detected, clonal patches were small, both in ramet numbers (less than or equal to3 ramets/genet) and physical size (1.3±0.1 m). In contrast, genotypic richness was lower in the isolated L. sp. Parker Range populations, albeit more variable (R=0.437±0.13), with genets as large as 17 ramets and up to 5.8 m in size. Aggregated clonal growth generated significant fine-scale genetic structure in both species but to a greater spatial extent and with additional genet-level structure in L. sp. Parker Range that is likely due to restricted seed dispersal. Despite both species being rare, asexual reproduction clearly has a more important role in the persistence of L. sp. Parker Range than L. sp. Mt Caudan. This is consistent with our prediction that limitations to sexual reproduction, via geographic isolation to effective gene exchange, can lead to greater contributions of asexual reproduction. These results demonstrate the role of population isolation in affecting the balance of alternate reproductive modes and the contextual nature of asexual reproduction in rare species.

opencc-zeroDec 2010View details →

Data from: The geographical and institutional distribution of ecological research in the tropics

We reviewed 1333 papers published in Biotropica and the Journal of Tropical Ecology from 1995 to 2004. Only 62 percent of tropical countries were represented in our survey, with 62 percent of the publications based on research conducted in only ten countries. Sixty-two percent of papers had lead authors that were based at institutions outside the country where the research was conducted. Cross-national collaboration was limited, accounting for only 28 percent of papers with multiple authors. To evaluate if our choice of focal journals could have biased our results, we also reviewed 652 papers published in Ecology, Oecologia, Conservation Biology, and Biological Conservation for five randomly selected years from the same time period. While some differences in authorship and the geographic distribution of research existed, the results from these journals generally mirrored patterns observed in the two focal ones—almost 54 percent of publications were based on research conducted in only ten countries, and most studies had lead authors from a developed country. The results of our review suggest that the geographical distribution of research in the tropics is unequal, and that some important regions remain understudied. The results also suggest a need for a greater focus on establishing collaborative relationships with scientists from tropical countries.

opencc-zeroNov 2019View details →

Data from: Museums and cradles of diversity are geographically coincident for narrowly distributed Neotropical snakes

<p>Factors driving the spatial configuration of centres of endemism have long been a topic of broad interest and debate. Due to different eco-evolutionary processes, these highly biodiverse areas may harbour different amounts of ancient and recently diverged organisms (paleo- and neo-endemism, respectively). Patterns of endemism still need to be measured at distinct phylogenetic levels for most clades and, consequently, little is known about the distribution, the age and the causes of such patterns. Here we tested for the presence of centres with high Phylogenetic Endemism (PE) in the highly diverse Neotropical snakes, testing the age of these patterns (paleo- or neo-endemism), and the presence of PE centres with distinct phylogenetic composition. We then tested whether PE is predicted by topography, by climate (seasonality, stability, buffering and relictualness), or biome size. We found that most areas of high PE for Neotropical snakes present a combination of both ancient and recently diverged diversity, which is distributed mostly in the Caribbean region, Central America, the Andes, the Atlantic Forest and on scattered highlands in central Brazil. Turnover of lineages is higher across Central America, resulting in more phylogenetically distinct PE centres compared to South America, which presents a more phylogenetically uniform snake fauna. Finally, we found that elevational range (topographic roughness) is the main predictor of PE, especially for paleo-endemism, whereas low paleo-endemism levels coincide with areas of high climatic seasonality. Our study highlights the importance of mountain systems to both ancient and recent narrowly distributed diversity. Mountains are both museums and cradles of snake diversity in the Neotropics, which has important implications for conservation in this region.</p>

FIGURES 35 in Redescription, shell variability and geographic distribution of Plagiodontes dentatus (Wood, 1828) (Gastropoda: Orthalicidae: Odontostominae) from Uruguay and Argentina

FIGURES 35. Representative shells of the three species of Plagiodontes under comparison. 3, Plagiodontes dentatus (Wood, 1828); 4, P. multiplicatus (Doering, 1874); 5, P. patagonicus (d'Orbigny, 1835).

FIGURES 813 in Redescription, shell variability and geographic distribution of Plagiodontes dentatus (Wood, 1828) (Gastropoda: Orthalicidae: Odontostominae) from Uruguay and Argentina

FIGURES 813. SEM photographs of the protoconch sculpture in Plagiodontes spp. 8, P. dentatus; 9, newly hatched P. patagonicus; 10, P. multiplicatus; 11, closeup of Fig. 9, showing the maximum development of the spiral lines crossing the axial striae; 12, eroded apex of P. multiplicatus; 13, closeup of figure 12, showing the remains of spiral sculpture in the protoconch. Bar "a" scales Figures 8, 9, 10, and 12; bar "b" scales Figures 11 and 13.

opennotspecifiedDec 2004View details →

FIGURES 9–12. Tympallopatrum geographical distributions. —9. T. longitudum. —10. T. aureolum. —11. T. curvicostum. —12. T in A revision of the Western Australian endemic humicolous beetle genus Tympallopatrum Perkins (Coleoptera: Hydraenidae)

FIGURES 9–12. Tympallopatrum geographical distributions. —9. T. longitudum. —10. T. aureolum. —11. T. curvicostum. —12. T. callosum.

opennotspecifiedDec 2004View details →

FIGURES 18–21. Gymnanthelius geographical distributions. —18. G. clypeatus. —19. G. cupreus. —20. G. lamingtonensis. —21. G in A revision of the Australian endemic water beetle genus Gymnanthelius Perkins (Coleoptera: Hydraenidae)

FIGURES 18–21. Gymnanthelius geographical distributions. —18. G. clypeatus. —19. G. cupreus. —20. G. lamingtonensis. —21. G. porchi.

opennotspecifiedDec 2004View details →

FIGURES 22–25. Gymnanthelius geographical distributions. —22. G. opacicollis. —23. G. hieroglyphicus. —24. G. t u n i c u s. —25. G in A revision of the Australian endemic water beetle genus Gymnanthelius Perkins (Coleoptera: Hydraenidae)

FIGURES 22–25. Gymnanthelius geographical distributions. —22. G. opacicollis. —23. G. hieroglyphicus. —24. G. t u n i c u s. —25. G. maxipunctus.

FIGURES 56–63. Leptopilina boulardi. 56 in Eucoilinae species (Hymenoptera: Cynipoidea: Figitidae) parasitoids of fruitinfesting dipterous larvae in Brazil: identity, geographical distribution and host associations

FIGURES 56–63. Leptopilina boulardi. 56. Head, anterior view (407x, 20 m); 57. Female antenna (309x, 20 m); 58. Flagellomerous 1 and 2 of male (267x, 20 m); 59. Pronotal plate (790x, 20 m); 60. Head, mesosoma and anterior part of metasoma, lateral view (100x, 100 m); 61. Mesosoma, dorsal view (335x, 20 m); 62. Forewing (10x, 0.14mm); 63. Metacoxa (230x, 100 m).

FIGURES 48–55. Aganaspis nordlanderi. 48 in Eucoilinae species (Hymenoptera: Cynipoidea: Figitidae) parasitoids of fruitinfesting dipterous larvae in Brazil: identity, geographical distribution and host associations

FIGURES 48–55. Aganaspis nordlanderi. 48. Head, anterior view (174x, 100 m); 49. Female antenna (66x, 250 m); 50. Flagellomerous 1 and 2 of male (84x, 100 m); 51. Pronotal plate (105x, 100 m); 52, Head, mesosoma and anterior part of metasoma, lateral view (35x, 500 m); 53. Mesosoma, dorsal view (74x, 250 m); 54. Forewing (10x, 0,5mm); 55. Metacoxa (120x, 100 m).

FIGURES 40–47. Trybliographa infuscata. 40 in Eucoilinae species (Hymenoptera: Cynipoidea: Figitidae) parasitoids of fruitinfesting dipterous larvae in Brazil: identity, geographical distribution and host associations

FIGURES 40–47. Trybliographa infuscata. 40. Head, anterior view (218x, 100 m); 41. Female antenna (109x, 100 m); 42. Flagellomerous 1 and 2 of male (182x, 100 m); 43. Pronotal plate (568x, 20 m); 44. Mesosoma and anterior part of metasoma, lateral view (161x, 100 m); 45. Mesosoma, dorsal view (193x, 100 m); 46. Forewing (10x, 0,5mm); 47. Metacoxa (161x, 100 m).

FIGURES 3239. Aganaspis pelleranoi. 32 in Eucoilinae species (Hymenoptera: Cynipoidea: Figitidae) parasitoids of fruitinfesting dipterous larvae in Brazil: identity, geographical distribution and host associations

FIGURES 3239. Aganaspis pelleranoi. 32. Head, anterior view (170x, 100 m); 33. Female antenna (97x, 100 m); 34. Flagellomerous 1 and 2 of male (130x, 100 m); 35. Pronotal plate (288x, 100 m); 36. Head, mesosoma and anterior part of metasoma, lateral view (48x, 250 m); 37. Mesosoma, dorsal view (64x, 250 m); 38. Forewing (10x, 0,5mm); 39. Metacoxa (163x, 100 m).

FIGURES 24–31. Odontosema anastrephae. 24 in Eucoilinae species (Hymenoptera: Cynipoidea: Figitidae) parasitoids of fruitinfesting dipterous larvae in Brazil: identity, geographical distribution and host associations

FIGURES 24–31. Odontosema anastrephae. 24. Head, anterior view (201x, 100 m); 25. Female antenna (135x, 100 m); 26. Flagellomerous 1 and 2 of male (145x, 100 m); 27. Pronotal plate (130x, 100 m); 28. Head, mesosoma and anterior part of metasoma, lateral view (37x, 250 m); 29. Mesosoma, dorsal view (68x, 250 m); 30. Forewing (10x, 0,5mm); 31. Metacoxa (84x, 100 m).

FIGURES 16–23. Dicerataspis grenadensis. 16 in Eucoilinae species (Hymenoptera: Cynipoidea: Figitidae) parasitoids of fruitinfesting dipterous larvae in Brazil: identity, geographical distribution and host associations

FIGURES 16–23. Dicerataspis grenadensis. 16. Head, anterior view (140x, 100 m); 17. Female antenna (204x, 100 m); 18. Flagellomerous 1 and 2 of male (280x, 100 m); 19. Pronotal plate (366x, 20 m); 20. Head, mesosoma and anterior part of metasoma, lateral view (120x, 100 m); 21. Mesosoma, dorsal view (130x, 100 m); 22. Forewing (10x, 0,5mm); 23. Metacoxa (130x, 100 m).

FIGURES 1–8. Lopheucoila anastrephae. 1 in Eucoilinae species (Hymenoptera: Cynipoidea: Figitidae) parasitoids of fruitinfesting dipterous larvae in Brazil: identity, geographical distribution and host associations

FIGURES 1–8. Lopheucoila anastrephae. 1. Head, anterior view (183x, 100 m); 2. Female antenna (58x, 250 m); 3. Flagellomerous 1 and 2 of male (170x, 100 m); 4. Pronotal plate (160x, 100 m); 5. Head, mesosoma and anterior part of metasoma, lateral view (74x, 250 m); 6. Mesosoma, dorsal view (172x, 100 m); 7. Forewing (10x, 0,5mm); 8. Metacoxa (163x, 100 m).

FIGURES 9–15. Tropideucoila weldi. 9 in Eucoilinae species (Hymenoptera: Cynipoidea: Figitidae) parasitoids of fruitinfesting dipterous larvae in Brazil: identity, geographical distribution and host associations

FIGURES 9–15. Tropideucoila weldi. 9. Head, anterior view (228x, 100 m); 10. Female antenna (179x, 100 m); 11. Pronotal plate (391x, 20 m); 12. Mesosoma and anterior part of metasoma, lateral view (168x, 100 m); 13. Head and mesosoma, dorsal view (215x, 100 m); 14. Forewing (10x, 0,25mm); 15. Metacoxa (261x, 100 m).

FIGURES 67 in Redescription, shell variability and geographic distribution of Plagiodontes dentatus (Wood, 1828) (Gastropoda: Orthalicidae: Odontostominae) from Uruguay and Argentina

FIGURES 67. SEM photographs of the teleoconch sculpture near the aperture lip. 6, Plagiodontes dentatus; 7, P. multiplicatus.