RESUMO
The family Nemesiidae was once among the most species-rich of mygalomorph spider families. However, over the past few decades both morphological and molecular studies focusing on mygalomorph phylogeny have recovered the group as paraphyletic. Hence, the systematics of the family Nemesiidae has more recently been controversial, with numerous changes at the family-group level and the recognition of the supra-familial clade Nemesioidina. Indeed, in a recent study by Opatova and collaborators, six nemesiid genera were transferred to the newly re-established family Pycnothelidae. Despite these changes, 12 South American nemesiid genera remained unplaced, and classified as incertae sedis due to shortcomings in taxon sampling. Accordingly, we evaluate the phylogenetic relationships of South American nemesioid species and genera with the principle aim of resolving their family level placement. Our work represents the most exhaustive phylogenomic sampling for South American Nemesiidae by including nine of the 12 genera described for the continent. Phylogenetic relationships were reconstructed using 457 loci obtained using the spider Anchored Hybrid Enrichment probe set. Based on these results Nemesiidae, Pycnothelidae, Microstigmatidae and Cyrtaucheniidae are not considered monophyletic. Our study also indicates that the lineage including the genus Fufius requires elevation to the family level (Rhytidicolidae Simon, 1903 (NEW RANK)). In Pycnothelidae, we recognize/delimit five subfamilies (Diplothelopsinae, Pionothelinae (NEW SUBFAMILY), Prorachiinae (NEW SUBFAMILY), Pselligminae (NEW RANK), Pycnothelinae). We also transfer all the 12 South American nemesiid genera to Pycnothelidae: Chaco, Chilelopsis, Diplothelopsis, Flamencopsis, Hermachura, Longistylus, Lycinus, Neostothis, Prorachias, Psalistopoides, Pselligmus, Rachias. Additionally, we transferred the microstigmatid genus Xenonemesia to Pycnothelidae, and we propose the following generic synonymies and species transfers: Neostothis and Bayana are junior synonyms of Pycnothele (NEW SYNONYMY), as P. gigas and P. labordai, respectively (NEW COMBINATIONS); Hermachura is a junior synonym of Stenoterommata (NEW SYNONYMY), as S. luederwaldti (NEW COMBINATION); Flamencopsis is a junior synonym of Chilelopsis (NEW SYNONYMY), as C. minima (NEW COMBINATION); and Diplothelopsis is a junior synonym of Lycinus (NEW SYNONYMY), as L. ornatus and L. bonariensis (NEW COMBINATIONS). Considering the transferred genera and synonymies, Pycnothelidae now includes 15 described genera and 137 species. Finally, these results provide a robust phylogenetic framework that includes enhanced taxonomic sampling, for further resolving the biogeography and evolutionary time scale for the family Pycnothelidae.
Assuntos
Aranhas , Animais , Filogenia , América do Sul , Aranhas/genéticaRESUMO
Locomotor and physiological performance of ectotherms are affected by temperature. Thermoregulation is achieved by changes in behavior and the selection of micro-habitats with adequate temperatures to maintain the body temperature (Tb) within a range of preference. Apart from this temperature dependence at spatial scales, ectotherms are also affected by temperature at temporal scale. For instance, ectotherms can only be active some months of the year, particularly in temperate environments. Tarantulas are ectotherms that live in burrows most of their life. Nevertheless, after the sexual maturation molt, males leave their refugia and start a wandering life searching for females to mate. The reproductive period varies among species. In some species walking males are seen in late spring or early summer, while in other species males are only seen during fall or winter. Apart from the differences in lifestyles after maturation, tarantulas exhibit sexual dimorphisms in longevity and body mass, having smaller, shorter-lived males. Thus, to optimize energetic budgets, decreasing thermoregulation costs, we hypothesize and examine a putative correlation between an individual's preferred body temperature (Tpref) and the environmental temperature during the reproductive period. Hence, we characterize Tpref in seven tarantula species and analyze which factors (i.e., time of day, body mass, and sex) correlated with it. Furthermore, we assess putative correlated evolution of Tpref with ambient temperature (minima, mean, and maxima) during the reproductive period by means of phylogenetic independent contrasts. We did not find differences in thermal preferences between sexes; and only one species, Acanthoscurria suina, exhibited diel differences in Tpref. We found evidence of correlated evolution between Tpref and minimum temperature during the reproductive period among all seven species studied herein. Our results show that the reproductive period is constrained by thermal preferences, dictating when males can start their wandering life to mate.
Assuntos
Aranhas/fisiologia , Aclimatação , Animais , Temperatura Corporal , Regulação da Temperatura Corporal , Ecossistema , Feminino , Masculino , Filogenia , Reprodução , Aranhas/genética , TemperaturaRESUMO
Biological corridors are connections which link habitats in a regional scale, allowing the gene flow between populations. The Uruguay River comprises riverside and insular riparian forests along subtropical to temperate zones passing through different biogeographic provinces. The aim of this study was to characterise the spider fauna from the Uruguay River islands highlighting their connection role for the spider community of riparian forest. Spiders were studied from surveys in a fluvial island of the southern course of the river with nine campaigns being carried out from September 2007 to September 2009. Three complementary collecting methods were used: G-Vac, night hand collecting and pitfall traps. A total of 58 samples were taken in each campaign. A total of 33 families, 145 species/morphospecies and 8 guilds were registered. Theridiidae and space web weavers showed the highest abundance and species richness. Web weavers were predominant in the spider community evidencing the importance of the forest vegetation heterogeneity in spider diversity. Fifteen species have been recorded for the first time for Uruguay. Additional data of previous surveys in the northern islands of the river were analysed and compared. Several species confirm the role of the Uruguay River as a biological corridor from the upper to lower course of the river. The riparian forests from the islands constitute a southernmost intromission of Paranaense biota between Chaco and Pampa regions along the river. The results obtained are an important input for the conservation of these areas. Knowing the biodiversity, as well as its dynamics and the flow of biota that exists in these environments, would allow planning the management from a regional point of view.
RESUMO
El traumatismo accidental de los dientes es considerado una afección bucodental y quizás uno de los accidentes más dramáticos que le suceden a un individuo, y su frecuencia en la clínica odontológica es cada día mayor. Con el propósito de identificar la frecuencia de traumatismos dentarios en adolescentes con dentición permanente, se realizó un estudio observacional, descriptivo y transversal, cuyo universo comprendió 1 065 estudiantes de las escuelas secundarias básicas Héroes del Moncada y Armando Mestre, del área de salud de Milanés, de la ciudad de Matanzas, en el curso escolar 2008-2009. De ellos se encontraron afectados por algún tipo de trauma dentario un total de 187 estudiantes entre las edades de 10 y 15 años. Los resultados permitieron identificar que el sexo masculino (52,9 %) y el grupo de edad de 14 a 15 años fueron los más representados (35,8 %); los dientes más afectados por traumas fueron el 11 y el 21, y la lesión traumática más encontrada fue la fractura no complicada de la corona (26,2 %).
The accidental trauma of the teeth is considered a oro-dental disease and may be one of the most dramatic accidents happening to people; its frequency in the dentist clinic increases every day. With the purpose of identifying the frequency of the dental trauma in teenagers with permanent dentition, we developed an observational, descriptive, cross-sectional study, which universe was formed by 1 065 students of the junior high schools Heroes del Moncada and Armando Mestre, of the health area Milanés, Matanzas city, in the school year 2008-2009. A total of 187 students aged from 10 to 15 years were affected for some dental trauma. The results allowed identifying that the male gender and the age group 14-15 years were the most represented ones (35,8 %); the most affected by trauma teeth were the 11 and the 21 ones, and the most traumatic lesion found was the non-complicated crown fracture (26,2 %).
RESUMO
When two similar species co-occur in time and space, strong mechanisms isolating them from each other are expected. Acanthoscurria suina Pocock, 1903 and Eupalaestrus weijenberghi (Thorell, 1894) are two sympatric and synchronic tarantulas that inhabit burrows in Uruguay's meadows. Here we test how and when reproductive isolation operates between these species. We exposed females of each species simultaneously to two males: either one male of each species, or two males of the same species. Males courted females of both species. Contrary to expectations, however, females of A. suina responded more effusively to heterospecific than to conspecific males, whereas females of E. weijenberghi only responded to conspecific males. Clasping (prelude of mating) was only recorded for couples of the same species. Females of A. suina at first seem to prefer the stronger body vibrations performed by heterospecific courting males than by males of their own species.
RESUMO
When two similar species co-occur in time and space, strong mechanisms isolating them from each other are expected. Acanthoscurria suina Pocock, 1903 and Eupalaestrus weijenberghi (Thorell, 1894) are two sympatric and synchronic tarantulas that inhabit burrows in Uruguay's meadows. Here we test how and when reproductive isolation operates between these species. We exposed females of each species simultaneously to two males: either one male of each species, or two males of the same species. Males courted females of both species. Contrary to expectations, however, females of A. suina responded more effusively to heterospecific than to conspecific males, whereas females of E. weijenberghi only responded to conspecific males. Clasping (prelude of mating) was only recorded for couples of the same species. Females of A. suina at first seem to prefer the stronger body vibrations performed by heterospecific courting males than by males of their own species.
RESUMO
When two similar species co-occur in time and space, strong mechanisms isolating them from each other are expected. Acanthoscurria suina Pocock, 1903 and Eupalaestrus weijenberghi (Thorell, 1894) are two sympatric and synchronic tarantulas that inhabit burrows in Uruguay's meadows. Here we test how and when reproductive isolation operates between these species. We exposed females of each species simultaneously to two males: either one male of each species, or two males of the same species. Males courted females of both species. Contrary to expectations, however, females of A. suina responded more effusively to heterospecific than to conspecific males, whereas females of E. weijenberghi only responded to conspecific males. Clasping (prelude of mating) was only recorded for couples of the same species. Females of A. suina at first seem to prefer the stronger body vibrations performed by heterospecific courting males than by males of their own species.
RESUMO
The road tarantula Eupalaestrus weijenberghi shows a strongly female-biased sex ratio since adult females live several years while adult males live only for 2 months. In this scenario selective males could be expected. However, several factors such as the rates of reproduction of each sex, degree of sexual selectivity and synchronicity of female receptiveness determine the operational sexual ratio and mating system of the species. Our objective was to determine the mating rates and mating tactics for females and males of E. weijenberghi and their variation throughout the reproductive period. Four hundred sexual encounters among 20 females and 20 males in all possible pair-wise combinations were carried out during 29 days, a brief but intense experimental period, as it also occurs in the field. Mating success differed strongly between sexes. Females mated once: five females mated at the first attempt, eight initially rejected males and copulated in subsequent attempts. Half of the males did not copulate and the others copulated 1-3 times. Mated females actively rejected males. Results indicate a mating system with monogamous females and polygamous males. Not all the females were receptive in every reproductive season. We suggest that female monogamy drastically affects the operational sex ratio, since several females were unreceptive after a single copulation, directly diminishing the male potential reproductive rate. This is the first experimental approach to estimate tarantula mating systems, their determinants and the consequences of the strategies shown by each sex.
Assuntos
Preferência de Acasalamento Animal/fisiologia , Reprodução/fisiologia , Comportamento Sexual Animal/fisiologia , Aranhas/fisiologia , Animais , Feminino , Longevidade , Masculino , Razão de MasculinidadeRESUMO
Las setas especializadas que las tarántulas presentan en los segmentos proximales de los apéndices han sido relacionadas con la producción de sonidos (estridulación), utilizados en defensa o comunicación sexual. La estructura superficial de las setas llamadas estridulatorias en Acanthoscurria suina Pocock, 1903 fue estudiada mediante microscopía electrónica de barrido. Tres patrones morfológicos de setas fueron reconocidos y al menos dos de ellos podrían estar involucrados en la estridulación. Su rol en la comunicación sexual fue estudiado mediante remoción experimental. Los resultados no mostraron diferencias en el éxito sexual entre individuos sin setas e individuos control. Consecuentemente, parece más probable una función defensiva que sexual para dichas setas.
Specialized setae placed on proximal segments of appendages in tarantulas have been related to sound production (stridulation), used in defense or sexual communication. The surface structure of called stridulatory setae of Acanthoscurria suina Pocock, 1903 was studied by SEM. Three morphological types of setae were recognized and at least two of them could be involved in stridulation. Their role in sexual communication was tested by experimental removal. Our results showed no differences in the sexual success between the setaeless and control individuals. Consequently, a defensive function for stridulatory setae seems to be more likely than a sexual function.
RESUMO
Las setas especializadas que las tarántulas presentan en los segmentos proximales de los apéndices han sido relacionadas con la producción de sonidos (estridulación), utilizados en defensa o comunicación sexual. La estructura superficial de las setas llamadas estridulatorias en Acanthoscurria suina Pocock, 1903 fue estudiada mediante microscopía electrónica de barrido. Tres patrones morfológicos de setas fueron reconocidos y al menos dos de ellos podrían estar involucrados en la estridulación. Su rol en la comunicación sexual fue estudiado mediante remoción experimental. Los resultados no mostraron diferencias en el éxito sexual entre individuos sin setas e individuos control. Consecuentemente, parece más probable una función defensiva que sexual para dichas setas.
Specialized setae placed on proximal segments of appendages in tarantulas have been related to sound production (stridulation), used in defense or sexual communication. The surface structure of called stridulatory setae of Acanthoscurria suina Pocock, 1903 was studied by SEM. Three morphological types of setae were recognized and at least two of them could be involved in stridulation. Their role in sexual communication was tested by experimental removal. Our results showed no differences in the sexual success between the setaeless and control individuals. Consequently, a defensive function for stridulatory setae seems to be more likely than a sexual function.