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2.
Ecol Lett ; 23(2): 221-230, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31733032

RESUMO

Many interspecifically territorial species interfere with each other reproductively, and in some cases, aggression towards heterospecifics may be an adaptive response to interspecific mate competition. This hypothesis was recently formalised in an agonistic character displacement (ACD) model which predicts that species should evolve to defend territories against heterospecific rivals above a threshold level of reproductive interference. To test this prediction, we parameterised the model with field estimates of reproductive interference for 32 sympatric damselfly populations and ran evolutionary simulations. Asymmetries in reproductive interference made the outcome inherently unpredictable in some cases, but 80% of the model's stable outcomes matched levels of heterospecific aggression in the field, significantly exceeding chance expectations. In addition to bolstering the evidence for ACD, this paper introduces a new, predictive approach to testing character displacement theory that, if applied to other systems, could help in resolving long-standing questions about the importance of character displacement processes in nature.


Assuntos
Evolução Biológica , Territorialidade , Agressão , Reprodução , Simpatria
3.
Gen Comp Endocrinol ; 285: 113250, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31445009

RESUMO

Seasonally breeding animals initiate gonadal recrudescence when mechanisms that suppress reproduction give way to mechanisms that stimulate it. However, knowledge of mechanistic changes in hormonal regulation during this transition is limited. Further, most studies of reproductive timing have focused on males, despite the critical role of females in determining breeding phenology. Closely related populations that live in the same environment but differ in reproductive timing provide an opportunity to examine differences in mechanisms during the transition from the pre-reproductive to reproductive state. We studied closely related migrant and resident populations of dark-eyed juncos (Junco hyemalis) that reside in the same environment in spring but differ in breeding phenology. Residents initiate breeding earlier than migrants, which do not breed until after they have migrated. To directly study differences in the hypothalamic mechanisms of reproduction, we captured 16 migrant and 13 resident females from the field on March 25-April 11. We quantified expression of mRNA transcripts and show that resident females had higher abundance of gonadotropin-releasing hormone transcripts than migrant females, indicating greater reproductive development in resident than migrant females living in the same environment. We also found higher transcript abundance of estrogen receptor and androgen receptor in migrant than resident females, suggesting that negative feedback may delay reproductive development in migrant females until after they migrate. These differences in hypothalamic mechanisms may help to explain differences in reproductive timing in populations that differ in migratory strategy.


Assuntos
Migração Animal/fisiologia , Sistemas Neurossecretores/metabolismo , Estações do Ano , Aves Canoras/fisiologia , Simpatria/fisiologia , Animais , Feminino , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Modelos Lineares , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
4.
Acta Trop ; 201: 105188, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31545949

RESUMO

Triatoma petrocchiae is the newly member of the Triatoma brasiliensis species complex. This species overlaps with T. brasiliensis in geographic and ecotypic occupation in the sylvatic habitat because both inhabit rocky outcrops in the semi-arid portion of Brazilian northeast. In this region T. brasiliensis is the most important Chagas disease vector because it constantly colonizes domiciles. In contrast, T. petrocchiae is rarely found in peri or intradomiciliary habitats - reason why little is known about this species. Therefore, Here, we present information for the first time on. the T. petrocchiae ecotopes, genetic diversity, Trypanosoma cruzi prevalence/genotyping in comparison to T. brasiliensis. We found T. brasilensis (N = 223) and T. petrocchiae (N = 69) in co-habitation in rocky outcrops in three Districts of Paraíba and Rio Grande do Norte states. Forty-tree T. petrocchiae insects of eleven sampling spots (composing three geographic populations) were genotyped for the mitochondrial Cyt B gene and little geographic structure was observed. Tajima's D test suggested that species is evolving toward a mutation-drift equilibrium in our collection range. Sylvatic T. petrocchiae had 4% (3/68) of infected insects by T. cruzi, whereas T. brasiliensis had 26% (59/223). Fluorescent Fragment Length Barcoding demonstrated that all three T. petrocchiae harbored TcI whereas T. brasiliensis had TcI, but also TcIII, TcII/TcVI and T. rangeli genotype A, sometimes under mixed infections. None of infected T. petrocchiae were carrying mixed infections. However, this result should be confirmed using a larger pool of infected bugs. We here presented the first documentation of T. rangeli infecting T. brasiliensis. The finding of infected T. petrocchiae calls for constant vector monitoring because the epidemiologic scenario is dynamic and sylvatic vectors are progressively found in adaptation to anthropic environments.


Assuntos
Doença de Chagas/transmissão , Insetos Vetores/parasitologia , Simpatria , Triatoma/parasitologia , Trypanosoma cruzi/genética , Animais , Brasil/epidemiologia , Doença de Chagas/epidemiologia , Ecossistema , Variação Genética , Genótipo , Epidemiologia Molecular , Prevalência
5.
Biol Lett ; 15(12): 20190572, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31847747

RESUMO

Phenological differences between host plants can promote temporal isolation among host-associated populations of insects with life cycles tightly coupled to plant phenology. Divergence in the timing of spring budbreak between two sympatric sister oak species has been shown to promote temporal isolation between host plants and their host-associated populations of a cynipid gall wasp. Here, we examined the generality of this mechanism by testing the hypothesis of cascading temporal isolation for five additional gall-formers and three natural enemy species associated with these same oak species. The timing of adult emergence from galls differed significantly between host-associated populations for all nine species and parallels the direction of the phenological differences between host plants. Differences in emergence timing can reduce gene flow between host-associated populations by diminishing mating opportunities and/or reducing the fitness of immigrants due to differences in the availability of ephemeral resources. Our study suggests that cascading temporal isolation could be a powerful 'biodiversity generator' across multiple trophic levels in tightly coupled plant-insect systems.


Assuntos
Insetos , Vespas , Animais , Interações Hospedeiro-Parasita , Plantas , Simpatria
6.
Zootaxa ; 4619(2): zootaxa.4619.2.9, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31716308

RESUMO

Orthoptera from Sandakan, Sabah are relatively understudied compared to some other parts of Borneo, and lack of information of species there can impede our understanding of the origins and biodiversity of orthopterans in Borneo and, in general, Southeast Asia. Based on a recent orthopteran survey in Sandakan, one new species of Lebinthus Stål is described: Lebinthus sandakan sp. nov. The male calling song of this new species is also presented. The calling song of Cardiodactylus borneoe Robillard Gorochov, 2014 is also described for the first time.


Assuntos
Gryllidae , Ortópteros , Animais , Ásia Sudeste , Bornéu , Malásia , Masculino , Simpatria
7.
Zootaxa ; 4565(1): zootaxa.4565.1.9, 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-31716495

RESUMO

Pseudolaryngodus spectabilis gen. et sp. nov., from Little Desert National Park in Victoria, Australia, is described and illustrated. The monotypic new genus superficially resembles the udeocorine genus Laryngodus Herrich-Schaeffer in general facies, and is sympatric with one of the species of Laryngodus. Pseudolaryngodus has some characters that share its tribal placement within both Udeocorini and Myodochini of the family Rhyparochromidae. However, it lacks inner laterotergites on abdomen, making it a Myodochini rather than a Udeocorini. Details of the relationships between these two genera, along with their tribal placements, are discussed.


Assuntos
Hemípteros , Heterópteros , Distribuição Animal , Animais , Simpatria , Vitória
8.
Zootaxa ; 4612(1): zootaxa.4612.1.1, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31717076

RESUMO

I investigate the taxonomy of frogs currently assigned to the single species Callulops doriae, which is unique in the genus for its warty, dark-spotted dorsum and large yellow or orange blotches in the groin and on the hidden surfaces of the thighs. I show that many species are currently encompassed under this single name, I remove Manthophryne neuhaussi from synonymy, and I describe four new species, three of which have long been in museum collections, and one of which is newly collected by me. Each of these new species is most readily distinguished by their unique color patterns, but additional morphological features-primarily morphometric-also serve to distinguish among them. Despite this partition of C. doriae, additional museum specimens cannot be assigned to any of the species treated here and certainly represent unrecognized species. But the poor states of preservation of some of these and the absence of color-pattern information in life preclude describing them until new material of each is available. Three of the six species treated herein, which occur in the southern portion of the Papuan Peninsula, were previously included in a molecular phylogeny, and inferred dates of divergence for them accord well with the geological dynamism of this region created by opening of the Woodlark Rift. In two cases, pairs of species are reported in general sympatry, and elevational data suggest that these species are likely to segregate elevationally where their ranges approach each other. At least four of the species treated herein are known to produce viscous glandular secretions that presumably deter predators, and I describe the defensive display of one of these, which I presume is aposematic.


Assuntos
Anuros , Simpatria , Animais , Cor , Museus , Filogenia
9.
BMC Evol Biol ; 19(1): 187, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31615417

RESUMO

BACKGROUND: Heliopora coerulea, the blue coral, is the octocoral characterized by its blue skeleton. Recently, two Heliopora species were delimited by DNA markers: HC-A and HC-B. To clarify the genomic divergence of these Heliopora species (HC-A and HC-B) from sympatric and allopatric populations in Okinawa, Japan, we used a high throughput reduced representation genomic DNA sequencing approach (ezRAD). RESULTS: We found 6742 biallelic SNPs shared among all target populations, which successfully distinguished the HC-A and HC-B species in both the sympatric and allopatric populations, with no evidence of hybridization between the two. In addition, we detected 410 fixed SNPs linking functional gene differences, including heat resilience and reproductive timing, between HC-A and HC-B. CONCLUSIONS: We confirmed clear genomic divergence between Heliopora species and found possible genes related to stress-responses and reproduction, which may shed light on the speciation process and ecological divergence of coral species.


Assuntos
Antozoários/genética , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Animais , Estudos de Associação Genética , Loci Gênicos , Genética Populacional , Geografia , Hibridização Genética , Japão , Filogenia , Especificidade da Espécie , Simpatria/genética
10.
PLoS Biol ; 17(10): e3000478, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31639139

RESUMO

Genetic data indicate differences in speciation rate across latitudes, but underlying causes have been difficult to assess because a critical phase of the speciation process is initiated in allopatry, in which, by definition, individuals from different taxa do not interact. We conducted song playback experiments between 109 related pairs of mostly allopatric bird species or subspecies in Amazonia and North America to compare the rate of evolution of male discrimination of songs. Relative to local controls, the number of flyovers and approach to the speaker were higher in Amazonia. We estimate that responses to songs of relatives are being lost about 6 times more slowly in Amazonia than in North America. The slow loss of response holds even after accounting for differences in song frequency and song length. Amazonian species with year-round territories are losing aggressive responses especially slowly. We suggest the presence of many species and extensive interspecific territoriality favors recognition of songs sung by sympatric heterospecifics, which results in a broader window of recognition and hence an ongoing response to novel similar songs. These aggressive responses should slow the establishment of sympatry between recently diverged forms. If male responses to novel allopatric taxa reflect female responses, then premating reproductive isolation is also evolving more slowly in Amazonia. The findings are consistent with previously demonstrated slower recent rates of expansion of sister taxa into sympatry, slower rates of evolution of traits important for premating isolation, and slower rates of speciation in general in Amazonia than in temperate North America.


Assuntos
Especiação Genética , Filogenia , Reprodução/genética , Aves Canoras/classificação , Vocalização Animal/fisiologia , Animais , Brasil , Canadá , Feminino , Masculino , Peru , Filogeografia , Aves Canoras/genética , Simpatria , Estados Unidos , Gravação em Vídeo
11.
Nat Commun ; 10(1): 4240, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31534121

RESUMO

Ecological speciation can sometimes rapidly generate reproductively isolated populations coexisting in sympatry, but the origin of genetic variation permitting this is rarely known. We previously explored the genomics of very recent ecological speciation into lake and stream ecotypes in stickleback from Lake Constance. Here, we reconstruct the origin of alleles underlying ecological speciation by combining demographic modelling on genome-wide single nucleotide polymorphisms, phenotypic data and mitochondrial sequence data in the wider European biogeographical context. We find that parallel differentiation between lake and stream ecotypes across replicate lake-stream ecotones resulted from recent secondary contact and admixture between old East and West European lineages. Unexpectedly, West European alleles that introgressed across the hybrid zone at the western end of the lake, were recruited to genomic islands of differentiation between ecotypes at the eastern end of the lake. Our results highlight an overlooked outcome of secondary contact: ecological speciation facilitated by admixture variation.


Assuntos
Especiação Genética , Smegmamorpha/classificação , Smegmamorpha/genética , Simpatria/genética , Animais , DNA Mitocondrial/genética , Fluxo Gênico , Genética Populacional , Genoma/genética , Lagos , Repetições de Microssatélites/genética , Mitocôndrias/genética , Polimorfismo de Nucleotídeo Único/genética , Rios
12.
Oecologia ; 191(2): 359-368, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31473811

RESUMO

Successful territory defence is a prerequisite for reproduction across many taxa, and often highly sensitive to the actions of territorial neighbours. Nevertheless, to date, assessments of the significance of the behaviour of heterospecific neighbours have been infrequent and taxonomically restricted. In this field study, I examined the importance of both heterospecific and conspecific neighbours in a biparental fish, the convict cichlid, Amatitlania siquia. This was done by assessing the colonisation rates of vacant territories, the rates of aggression by the territory holders, and the overall rates of aggression towards intruders, in treatments that controlled the proximity of both neighbour types. Convict cichlid pairs colonised vacant nesting resources (territory locations) at similar rates independent of the proximity of heterospecific (moga, Hypsophrys nicaraguensis) or conspecific neighbours. However, a model of sympatric cichlid intruder was subjected to considerably higher overall levels of aggression when mogas were nearby. In contrast, the proximity of conspecifics did not have a significant effect on the overall aggression towards the intruder. These results suggest that previously demonstrated higher survival of convict cichlid broods in close proximity of mogas may be driven by aggression towards shared enemies. No conclusive evidence was found regarding whether mogas also influence convict cichlids' investment into anti-intruder aggression: the results show a marginally non-significant trend, and a moderately large effect size, to the direction of a lower investment in mogas', but not conspecifics', proximity. More generally, heterospecific neighbours may provide protective benefits in a wider range of ecological settings than commonly considered.


Assuntos
Agressão , Ciclídeos , Animais , Comportamento Animal , Simpatria , Territorialidade
13.
BMC Evol Biol ; 19(1): 166, 2019 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-31434566

RESUMO

BACKGROUND: The Old World insectivorous bat genus Rhinolophus is highly speciose. Over the last 15 years, the number of its recognized species has grown from 77 to 106, but knowledge of their interrelationships has not kept pace. Species limits and phylogenetic relationships of this morphologically conservative group remain problematic due both to poor sampling across the Afrotropics and to repeated instances of mitochondrial-nuclear discordance. Recent intensive surveys in East Africa and neighboring regions, coupled with parallel studies by others in West Africa and in Southern Africa, offer a new basis for understanding its evolutionary history. RESULTS: We investigated phylogenetic relationships and intraspecific genetic variation in the Afro-Palearctic clade of Rhinolophidae using broad sampling. We sequenced mitochondrial cytochrome-b (1140 bp) and four independent and informative nuclear introns (2611 bp) for 213 individuals and incorporated sequence data from 210 additional individuals on GenBank that together represent 24 of the 33 currently recognized Afrotropical Rhinolophus species. We addressed the widespread occurrence of mito-nuclear discordance in Rhinolophus by inferring concatenated and species tree phylogenies using only the nuclear data. Well resolved mitochondrial, concatenated nuclear, and species trees revealed phylogenetic relationships and population structure of the Afrotropical species and species groups. CONCLUSIONS: Multiple well-supported and deeply divergent lineages were resolved in each of the six African Rhinolophus species groups analyzed, suggesting as many as 12 undescribed cryptic species; these include several instances of sympatry among close relatives. Coalescent lineage delimitation offered support for new undescribed lineages in four of the six African groups in this study. On the other hand, two to five currently recognized species may be invalid based on combined mitochondrial and/or nuclear phylogenetic analyses. Validation of these cryptic lineages as species and formal relegation of current names to synonymy will require integrative taxonomic assessments involving morphology, ecology, acoustics, distribution, and behavior. The resulting phylogenetic framework offers a powerful basis for addressing questions regarding their ecology and evolution.


Assuntos
Quirópteros/classificação , Quirópteros/genética , Filogenia , África , Animais , Núcleo Celular/genética , Citocromos b/genética , DNA Mitocondrial/genética , Íntrons , Simpatria
14.
Am J Bot ; 106(7): 1021-1031, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31299090

RESUMO

PREMISE: Closely related species occurring in sympatry may experience the negative consequences of interspecific pollen transfer if reproductive isolation (RI) barriers are not in place. We evaluated the importance of pre- and post-pollination RI barriers in three sympatric species of Achimenes (Gesneriaceae), including ecogeographic, phenological, floral isolation, self-pollination, and hybrid viability (fruit and seed set). METHODS: We recorded geographic distribution throughout species ranges and assessed flowering phenology and pollinator visitation at one site in central Mexico. In the greenhouse, we measured floral traits involved in RI and quantified fruit and seed set for from self, intraspecific, and interspecific crosses. RESULTS: Ecogeographic barriers were important in RI, but under sympatry, phenological and floral barriers contributed more to total RI. Phenological RI varied between species and years, while floral RI was 100% effective at preventing interspecific visitation. Species showed differences in floral morphology, color, and scents associated with specialized pollination systems (A. antirrhina-hummingbirds, A. flava-bees, A. patens-butterflies); heterospecific visitation events were restricted to rare secondary pollinators. Hybrid crosses consistently yielded progeny in lower numbers than intraspecific crosses. CONCLUSIONS: This study indicated that neither autogamy nor early post-pollination barriers prevent interspecific pollen flow between Achimenes species. However, floral isolation, acting through a combination of attraction and reward traits, consistently ensures specificity of the pollination system. These results suggest that selection on floral traits to reduce the costs of hybrid progeny production may have played a role in evolution or maintenance of specialized pollination systems in Achimenes.


Assuntos
Flores/fisiologia , Lamiales , Polinização , Isolamento Reprodutivo , Simpatria , Animais , Abelhas , Aves , Borboletas , Hibridização Genética , Odorantes , Néctar de Plantas/metabolismo , Autofertilização , Açúcares/metabolismo , Compostos Orgânicos Voláteis/metabolismo
15.
PLoS One ; 14(7): e0218899, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31291291

RESUMO

Genetic incompatibilities constitute the final stages of reproductive isolation and speciation, but little is known about incompatibilities that occur within recent adaptive radiations among closely related diverging populations. Crossing divergent species to form hybrids can break up coadapted variation, resulting in genetic incompatibilities within developmental networks shaping divergent adaptive traits. We crossed two closely related sympatric Cyprinodon pupfish species-a dietary generalist and a specialized molluscivore-and measured expression levels in their F1 hybrids to identify regulatory variation underlying the novel craniofacial morphology found in this recent microendemic adaptive radiation. We extracted mRNA from eight day old whole-larvae tissue and from craniofacial tissues dissected from 17-20 day old larvae to compare gene expression between a total of seven F1 hybrids and 24 individuals from parental species populations. We found 3.9% of genes differentially expressed between generalists and molluscivores in whole-larvae tissues and 0.6% of genes differentially expressed in craniofacial tissue. We found that 2.1% of genes were misregulated in whole-larvae hybrids whereas 19.1% of genes were misregulated in hybrid craniofacial tissues, after correcting for sequencing biases. We also measured allele specific expression across 15,429 heterozygous sites to identify putative compensatory regulatory mechanisms underlying differential expression between generalists and molluscivores. Together, our results highlight the importance of considering misregulation as an early indicator of genetic incompatibilities in the context of rapidly diverging adaptive radiations and suggests that compensatory regulatory divergence drives hybrid gene misregulation in developing tissues that give rise to novel craniofacial traits.


Assuntos
Quimera , Especiação Genética , Genética Populacional , Peixes Listrados/genética , Larva/genética , Animais , Cruzamentos Genéticos , Comportamento Alimentar , Feminino , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Fluxo Gênico , Heterozigoto , Peixes Listrados/anatomia & histologia , Peixes Listrados/classificação , Peixes Listrados/crescimento & desenvolvimento , Larva/anatomia & histologia , Larva/crescimento & desenvolvimento , Masculino , Fenótipo , Isolamento Reprodutivo , Crânio/anatomia & histologia , Crânio/crescimento & desenvolvimento , Crânio/metabolismo , Simpatria
16.
Mol Biol Evol ; 36(12): 2682-2697, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31318434

RESUMO

Howea palms are viewed as one of the most clear-cut cases of speciation in sympatry. The sister species Howea belmoreana and H. forsteriana are endemic to the oceanic Lord Howe Island, Australia, where they have overlapping distributions and are reproductively isolated mainly by flowering time differences. However, the potential role of introgression from Australian mainland relatives had not previously been investigated, a process that has recently put other examples of sympatric speciation into question. Furthermore, the drivers of flowering time-based reproductive isolation remain unclear. We sequenced an RNA-seq data set that comprehensively sampled Howea and their closest mainland relatives (Linospadix, Laccospadix), and collected detailed soil chemistry data on Lord Howe Island to evaluate whether secondary gene flow had taken place and to examine the role of soil preference in speciation. D-statistics analyses strongly support a scenario whereby ancestral Howea hybridized frequently with its mainland relatives, but this only occurred prior to speciation. Expression analysis, population genetic and phylogenetic tests of selection, identified several flowering time genes with evidence of adaptive divergence between the Howea species. We found expression plasticity in flowering time genes in response to soil chemistry as well as adaptive expression and sequence divergence in genes pleiotropically linked to soil adaptation and flowering time. Ancestral hybridization may have provided the genetic diversity that promoted their subsequent adaptive divergence and speciation, a process that may be common for rapid ecological speciation.


Assuntos
Adaptação Biológica , Arecaceae/genética , Fluxo Gênico , Especiação Genética , Simpatria , Arecaceae/metabolismo , Hibridização Genética , New South Wales , Isolamento Reprodutivo , Solo , Transcriptoma
17.
Parasitol Res ; 118(7): 2257-2262, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31177405

RESUMO

The New England cottontail rabbit (NEC, Sylvilagus transitionalis) population has decreased dramatically in New York, USA, and the role of parasites in limiting the population has never been examined. The closely related and sympatric eastern cottontail rabbit (EC, Sylvilagus floridanus) was introduced into the range of NEC by humans and is currently thriving. This study aimed to investigate gastrointestinal parasites of the NEC and the EC and compare their parasite communities. Fecal pellets from 195 NEC and 125 EC were collected from the Hudson Valley, New York, in the winter of 2013-2014. Centrifugal fecal floats were performed in Sheather's sugar solution, and parasite ova and cysts were examined microscopically to identify gastrointestinal parasites present. For all pellets combined (n = 320), 91% were found to harbor at least 1 parasite species, with Eimeria species being the most common. Genetic analysis of pellets using microsatellite DNA identified 248 individual rabbits, with parasite prevalence (94%) similar to the prevalence estimate based on all pellets (91%). EC samples had a significantly higher (p < 0.05) parasite species richness (1.73, range 0-4) than NEC (1.20, range 0-3). EC and NEC shared 3 moderate to high (9-89%) prevalence parasites, in which EC prevalence was consistently higher. One parasite species was only found in NEC, and two were only found in EC, but the majority of these were of low abundance, precluding further statistical analyses.


Assuntos
Coccidiose/veterinária , Eimeria/classificação , Enteropatias Parasitárias/veterinária , Repetições de Microssatélites/genética , Parasitos/classificação , Coelhos/parasitologia , Animais , Coccidiose/epidemiologia , Coccidiose/parasitologia , Eimeria/genética , Eimeria/isolamento & purificação , Meio Ambiente , Fezes/parasitologia , Feminino , Geografia , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , New York/epidemiologia , Óvulo , Parasitos/genética , Parasitos/isolamento & purificação , Dinâmica Populacional , Inquéritos e Questionários , Simpatria
18.
Am J Bot ; 106(6): 833-849, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31124135

RESUMO

PREMISE: We take an integrative approach in assessing how introgression and Pleistocene climate fluctuations have shaped the diversification of the core Lentago clade of Viburnum, a group of five interfertile species with broad areas of sympatry. We specifically tested whether flowering time plays a role in maintaining species isolation. METHODS: RAD-seq data for 103 individuals were used to infer the species relationships and the genetic structure within each species. Flowering times were compared among species on the basis of historical flowering dates documented by herbarium specimens. RESULTS: Within each species, we found a strong relationship between flowering date and latitude, such that southern populations flower earlier than northern ones. In areas of sympatry, the species flower in sequence rather than simultaneously, with flowering dates offset by ≥9 d for all species pairs. In two cases it appears that the offset in flowering times is an incidental consequence of adaptation to differing climates, but in the recently diverged sister species V. prunifolium and V. rufidulum, we find evidence that reinforcement led to reproductive character displacement. Long-term trends suggest that the two northern-most species are flowering earlier in response to recent climate change. CONCLUSIONS: We argue that speciation in the Lentago clade has primarily occurred through ecological divergence of allopatric populations, but differences in flowering time were essential to maintain separation of incipient species when they came into secondary contact. This combination of factors may underlie diversification in many other plant clades.


Assuntos
Evolução Biológica , Mudança Climática , Flores/fisiologia , Viburnum/fisiologia , Flores/crescimento & desenvolvimento , América do Norte , Estações do Ano , Especificidade da Espécie , Simpatria/fisiologia , Viburnum/crescimento & desenvolvimento
19.
Genome Biol Evol ; 11(6): 1644-1657, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31124568

RESUMO

The mechanisms of speciation without geographic isolation (i.e., sympatric speciation) remain debated. This is due in part to the fact that the genomic landscape that could promote or hinder species divergence in the presence of gene flow is still largely unknown. However, intensive research is now centered on understanding the genetic architecture of adaptive traits associated with this process as well as how gene expression might affect these traits. Here, using RNA-Seq data, we investigated gene expression of sympatrically speciating benthic and limnetic Neotropical cichlid fishes at two developmental stages. First, we identified groups of coexpressed genes (modules) at each stage. Although there are a few large and well-preserved modules, most of the other modules are not preserved across life stages. Second, we show that later in development more and larger coexpression modules are associated with divergence between benthic and limnetic fish compared with the earlier life stage. This divergence between benthic and limnetic fish in coexpression mirrors divergence in overall expression between benthic and limnetic fish, which is more pronounced later in life. Our results reveal that already at 1-day posthatch benthic and limnetic fish diverge in (co)expression, and that this divergence becomes more substantial when fish are free-swimming but still unlikely to have divergent swimming and feeding habits. More importantly, our study describes how the coexpression of several genes through development, as opposed to individual genes, is associated with benthic-limnetic species differences, and how two morphogenetic trajectories diverge as fish grow older.


Assuntos
Ciclídeos/classificação , Ciclídeos/genética , Animais , Ciclídeos/crescimento & desenvolvimento , Especiação Genética , Lagos , Nicarágua , Locos de Características Quantitativas , Especificidade da Espécie , Simpatria , Transcriptoma
20.
Am J Bot ; 106(6): 788-797, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31131459

RESUMO

PREMISE: Two fundamental hypotheses on herbivore resistance and leaf habit are the resource availability hypothesis (RAH) and the carbon-nutrient balance hypothesis (CNBH). The RAH predicts higher constitutive resistance by evergreens, and the CNBH predicts higher induced resistance by deciduous species. Although support for these hypotheses is mixed, they have rarely been examined in congeneric species. METHODS: We compared leaf constitutive and induced resistance (as leaf polyphenol and tannin concentrations, and as damage level in non-choice experiments) and leaf traits associated with herbivory of coexisting Nothofagus species using (1) a defoliation experiment and (2) natural defoliation caused by an outbreak of a common defoliator of Nothofagus species. RESULTS: In the defoliation experiment, polyphenol and tannin concentrations were similar between deciduous and evergreen species; regardless of leaf habit, polyphenols increased in response to defoliation. In the natural defoliation survey, N. pumilio (deciduous) had significantly higher herbivory, lower carbon/nitrogen ratio and leaf mass per area, and higher nitrogen and phosphorus concentrations than N. betuloides (evergreen); N. antarctica (deciduous) had intermediate values. Polyphenol concentrations and herbivore resistance indicated by the non-choice experiment were lower in N. pumilio than in N. antarctica and N. betuloides, which had similar values. CONCLUSIONS: Higher herbivory in N. pumilio was associated with a higher nutritional value and a lower level of leaf carbon-based defenses compared to both the evergreen and the other deciduous species, indicating that herbivore resistance in Nothofagus species cannot be attributed to only leaf habit as predicted by the RAH or CNBH.


Assuntos
Antibiose , Fagales/fisiologia , Herbivoria , Folhas de Planta/fisiologia , Simpatria/fisiologia , Especificidade da Espécie
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