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1.
Genome Biol Evol ; 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32433751

RESUMO

The water skinks Eulamprus tympanum and E. heatwolei show thermally-induced sex determination where elevated temperatures give rise to male offspring. Paradoxically, Eulamprus species reproduce in temperatures of 12-15 °C making them outliers when compared to reptiles that use temperature as a cue for sex determination. Moreover, these two species are among the very few viviparous reptiles reported to have thermally-induced sex determination. Thus, we tested whether these skinks possess undetected sex chromosomes with thermal override. We produced transcriptome and genome data for E. heatwolei. We found that E. heatwolei present XY chromosomes that include 14 gametologs with regulatory functions. The Y chromosomal region is 79-116 million-years-old and shared between water and spotted skinks. Our work provides clear evidence that climate could be useful to predict the type of sex determination systems in reptiles and it also indicates that viviparity is strictly associated with sex chromosomes.

2.
J Anim Ecol ; 2020 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-32198927

RESUMO

Traditionally, most studies have described the organization of host-parasite interaction networks by considering only few host groups at limited geographical extents. However, host-parasite relationships are merged within different taxonomic groups and factors shaping these interactions likely differ between host and parasite groups, making group-level differences important to better understand the ecological and evolutionary dynamics of these interactive communities. Here we used a dataset of 629 ectoparasite species and 251 species of terrestrial mammals, comprising 10 orders distributed across the Nearctic and Neotropical regions of Mexico to assess the species-level drivers of mammalian ectoparasite faunas. Specifically, we evaluated whether body weight, geographical range size and within-range mammal species richness (i.e. diversity field) predict mammal ectoparasite species richness (i.e. degree centrality) and their closeness centrality within the mammal-ectoparasite network. In addition, we also tested if the observed patterns differ among mammal orders and if taxonomic closely related host mammals could more likely share the same set of ectoparasites. We found that ectoparasite species richness of small mammals (mainly rodents) with large proportional range sizes was high compared to large-bodied mammals, whereas the diversity field of mammals had no predictive value (except for bats). We also observed that taxonomic proximity was a main determinant of the probability to share ectoparasite species. Specifically, the probability to share ectoparasites in congeneric species reached up to 90% and decreased exponentially as the taxonomic distance increased. Further, we also detected that some ectoparasites are generalists and capable to infect mammalian species across different orders and that rodents have a remarkable role in the network structure, being closely connected to many other taxa. Hence, because many rodent species have synanthropic habits they could act as undesired reservoirs of disease agents for humans and urban animals. Considering the reported worldwide phenomenon of the proliferation of rodents accompanying the demographic decrease or even local extinction of large-bodied mammal species, these organisms may already be an increasing health threat in many regions of the world.

3.
Biol Rev Camb Philos Soc ; 95(3): 802-821, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32035015

RESUMO

Surviving changing climate conditions is particularly difficult for organisms such as insects that depend on environmental temperature to regulate their physiological functions. Insects are extremely threatened by global warming, since many do not have enough physiological tolerance even to survive continuous exposure to the current maximum temperatures experienced in their habitats. Here, we review literature on the physiological mechanisms that regulate responses to heat and provide heat tolerance in insects: (i) neuronal mechanisms to detect and respond to heat; (ii) metabolic responses to heat; (iii) thermoregulation; (iv) stress responses to tolerate heat; and (v) hormones that coordinate developmental and behavioural responses at warm temperatures. Our review shows that, apart from the stress response mediated by heat shock proteins, the physiological mechanisms of heat tolerance in insects remain poorly studied. Based on life-history theory, we discuss the costs of heat tolerance and the potential evolutionary mechanisms driving insect adaptations to high temperatures. Some insects may deal with ongoing global warming by the joint action of phenotypic plasticity and genetic adaptation. Plastic responses are limited and may not be by themselves enough to withstand ongoing warming trends. Although the evidence is still scarce and deserves further research in different insect taxa, genetic adaptation to high temperatures may result from rapid evolution. Finally, we emphasize the importance of incorporating physiological information for modelling species distributions and ecological interactions under global warming scenarios. This review identifies several open questions to improve our understanding of how insects respond physiologically to heat and the evolutionary and ecological consequences of those responses. Further lines of research are suggested at the species, order and class levels, with experimental and analytical approaches such as artificial selection, quantitative genetics and comparative analyses.

4.
Genome Biol Evol ; 11(9): 2666-2677, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31557287

RESUMO

Almost all lizard families in the pleurodont clade share the same XY system. This system was meticulously studied in Anolis carolinensis, where it shows a highly degenerated Y chromosome and a male-specific X chromosome dosage compensation mechanism. Corytophanids (casque-headed lizards) have been proposed as the only family in the pleurodont clade to lack the XY system. In this study, we worked with extensive genomic and transcriptomic data from Basiliscus vittatus, a member of the Corytophanidae family that inhabits the tropical rainforests of Mexico. We confirmed that B. vittatus underwent a sex chromosome system turnover, which consisted in the loss of the pleurodont XY system and the gain of a new pair of XY chromosomes that are orthologous to chicken chromosome 17. We estimated the origin of the sex chromosome system to have occurred ∼63 Ma in the ancestor of corytophanids. Moreover, we identified 12 XY gametologues with particular attributes, such as functions related to the membrane and intracellular trafficking, very low expression levels, blood specificity, and incomplete dosage compensation in males.

5.
Sci Rep ; 8(1): 10179, 2018 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-29976993

RESUMO

We analyze the invasive potential of two Asian ambrosia beetles, Xyleborus glabratus and Euwallacea sp., into Mexico and the southern United States. The fungal symbionts of these beetles have been responsible for damage to trees of the family Lauraceae, including Persea americana and other non-cultivated tree species on both coasts of the United States. We estimate their potential threat using ecological niche modeling and spatial multi-criteria evaluation protocols to incorporate plant and beetle suitabilities as well as forest stress factors across Mexico. Mexico contains higher climatic and habitat suitability for X. glabratus than for Euwallacea sp. Within this country, the neotropical region is most vulnerable to invasion by both of these species. We also identify a corridor of potential invasion for X. glabratus along the Gulf of Mexico coast where most Lauraceae and native Xyleborus species are present; dispersal of either X. glabratus or Euwallacea sp. into this region would likely lead to major disease spread. However, the overall potential damage that these beetles can cause may be a function of how many reproductive hosts and how many other ambrosia beetles are present, as well as of their capacity to disperse. This work can also alert relevant managers and authorities regarding this threat.


Assuntos
Florestas , Espécies Introduzidas/estatística & dados numéricos , Lauraceae/parasitologia , Árvores/parasitologia , Gorgulhos , Distribuição Animal , Animais , Clima , Monitorização de Parâmetros Ecológicos/estatística & dados numéricos , México , Modelos Biológicos , Medição de Risco , Estados Unidos
6.
Am J Bot ; 102(1): 149-64, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25587157

RESUMO

UNLABELLED: • PREMISE OF THE STUDY: A recurrent explanation for phylogeographic discontinuities in the Baja California Peninsula and the Sonoran Desert Region has been the association of vicariant events with Pliocene and Pleistocene seaway breaks. Nevertheless, despite its relevance for plant dispersal, other explanations such as ecological and paleoclimatic factors have received little attention. Here, we analyzed the role of several of these factors to describe the phylogeographic patterns of the desert mistletoe, Phoradendron californicum.• METHODS: Using noncoding chloroplast regions, we assess the marginal probability of 19 a priori hypotheses related to geological and ecological factors to predict the cpDNA variation in P. californicum using a Bayesian coalescent framework. Complementarily, we used the macrofossil record and niche model projections on Last Glacial Maximum climatic conditions for hosts, mistletoe, and a bird specialist to interpret phylogeographic patterns.• KEY RESULTS: Genealogical reconstructions revealed five clades, which suggest a combination of cryptic divergence, long-distance seed dispersal, and isolating postdivergence events. Bayesian hypothesis test favored a series of Pliocene and Pleistocene geological events related to the formation of the Baja California Peninsula and seaways across the peninsula as the most supported explanation for this genealogical pattern. However, age estimates, niche projections, and fossil records show dynamic host-mistletoe interactions and evidence of host races, indicating that ecological and geological factors have been interacting during the formation and structuring of phylogeographic divergence.• CONCLUSIONS: Variation in cpDNA across the species range results from the interplay of vicariant events, past climatic oscillations, and more dynamic factors related to ecological processes at finer temporal and spatial scales.


Assuntos
DNA de Cloroplastos/genética , Phoradendron/genética , Teorema de Bayes , Clima , Ecossistema , Evolução Molecular , México , Dados de Sequência Molecular , Filogenia , Filogeografia , Análise de Sequência de DNA , Sudoeste dos Estados Unidos
7.
Ambio ; 44(5): 391-400, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25480482

RESUMO

At a global level, the relationship between biodiversity importance and capacity to manage it is often assumed to be negative, without much differentiation among the more than 200 countries and territories of the world. We examine this relationship using a database including terrestrial biodiversity, wealth and governance indicators for most countries. From these, principal components analysis was used to construct aggregated indicators at global and regional scales. Wealth, governance, and scientific capacity represent different skills and abilities in relation to biodiversity importance. Our results show that the relationship between biodiversity and the different factors is not simple: in most regions wealth and capacity varies positively with biodiversity, while governance vary negatively with biodiversity. However, these trends, to a certain extent, are concentrated in certain groups of nations and outlier countries. We discuss our results in the context of collaboration and joint efforts among biodiversity-rich countries and foreign agencies.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais/métodos , Governo , Ciência , Fatores Socioeconômicos
8.
Geospat Health ; 9(1): 221-9, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25545939

RESUMO

Emerging infectious diseases can present serious threats to wildlife, even to the point of causing extinction. Whitenose fungus (Pseudogymnoascus destructans) is causing an epizootic in bats that is expanding rapidly, both geographically and taxonomically. Little is known of the ecology and distributional potential of this intercontinental pathogen. We address this gap via ecological niche models that characterise coarse resolution niche differences between fungus populations on different continents, identifying areas potentially vulnerable to infection in South America. Here we explore a novel approach to identifying areas of potential distribution across novel geographic regions that avoids perilious extrapolation into novel environments. European and North American fungus populations show differential use of environmental space, but rather than niche differentiation, we find that changes are best attributed to climatic differences between the two continents. Suitable areas for spread of the pathogen were identified across southern South America; however caution should be taken to avoid underestimating the potential for spread of this pathogen in South America.


Assuntos
Ascomicetos , Quirópteros/microbiologia , Micoses/veterinária , América/epidemiologia , Animais , Ascomicetos/fisiologia , Clima , Ecologia , Modelos Estatísticos , Micoses/epidemiologia , Micoses/transmissão , Análise Espacial
9.
Evolution ; 68(4): 1082-93, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24372193

RESUMO

The distribution of genetic diversity within and among populations in relation to species' geographic ranges is important to understanding processes of evolution, speciation, and biogeography. One hypothesis predicts that natural populations at geographic range margins will have lower genetic diversity relative to those located centrally in species' distributions owing to a link between geographic and environmental marginality; alternatively, genetic variation may be unrelated with geographic marginality via decoupling of geographic and environmental marginality. We investigate the predictivity of geographic patterns of genetic variation based on geographic and environmental marginality using published genetic diversity data for 40 species (insects, plants, birds, mammals, worms). Only about half of species showed positive relationships between geographic and environmental marginality. Three analyses (sign test, multiple linear regression, and meta-analysis of correlation effect sizes) showed a negative relationship between genetic diversity and distance to environmental niche centroid, but no consistent relationship of genetic diversity with distance to geographic range center.


Assuntos
Variação Genética , Geografia , Distribuição Animal , Animais , Evolução Biológica , Aves , Ecossistema , Insetos , Invertebrados , Mamíferos , Dispersão Vegetal , Plantas
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