Uma abordagem peptidômica do venedo do escorpião Tityus serrulatus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise estrutural das proteínas da seda da teia da aranha Nephila clavipes por uma abordagem proteômica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Descrição morfo-histológica dos testículos de Amblyomma cajennense em jejum e alimentados

Os carrapatos são ectoparasitas hematófagos de grande importância epidemiológica, pois são vetores de muitos patógenos. Esses animais pertencem ao Filo Arthropoda, Classe Arachnida, Subclasse Acari, são classificados em três famílias: Ixodidae, Argasidae e Nutalliellidae, apresentam ampla distribuição geográfica e podem parasitar grande variedade de vertebrados, inclusive o homem. O carrapato da espécie Amblyomma cajennense, popularmente conhecido como carrapato-estrela, carrapato do cavalo ou rodoleiro, tem grande importância médica por ser vetor da bactéria Rickettsia rickettsii, causadora da febre maculosa brasileira (FMB), que pode levar o hospedeiro a óbito. Apesar das crescentes pesquisas com esses animais, ainda existem lacunas na literatura acerca de alguns de seus processos reprodutivos. Dessa forma, esse trabalho teve por objetivo estudar o desenvolvimento dos testículos dessa espécie por meio da descrição da morfologia e histologia dos testículos de indivíduos em jejum e alimentados, identificando a dinâmica do processo de espermatogênese e se a alimentação influencia nesse processo. Os resultados obtidos mostraram que os testículos são estruturas pares e tubulares arranjadas dorsolateralmente no opistossoma, sendo que a região proximal está conectada às vesículas seminais pelos ductos deferentes, semelhante ao observado em outras espécies de ixodídeos. Associado ao aparelho genital masculino encontra-se um complexo de glândulas acessórias multilobuladas. Foi constatado que a alimentação tem papel fundamental no desenvolvimento do sistema reprodutor, visto que nos indivíduos em jejum as vesículas seminais e o complexo de glândulas acessórias foram menores e menos desenvolvidos do que nos animais alimentados. Além disso, as espermátides alongadas, precursoras dos espermatozoides no trato reprodutor... (Resumo completo, clicar acesso eletrônico abaixo)

Efeitos indiretos das aranhas Peucetia spp. (Oxyopidae) e Misumenops argenteus (Thomisidae) no sucesso reprodutivo de Trichogoniopsis adenantha (DC) (Asteraceae) e no comportamento das guildas associadas à planta

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise citogenética clássica, molecular e ultraestrutural em escorpiões da família Buthidae: um enfoque evolutivo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hypersensitivity induced in dogs by nymphal extract of Amblyomma cajennense ticks (Acari:Ixodidae)

In general, hosts develop resistance to ticks after repeated infestations; nevertheless, several studies on naturally occurring host-tick interactions were unable to detect resistance of hosts to ticks even after repeated infestations. The purpose of this investigation was to study the type of cutaneous hypersensitivity to unfed nymphal extract of A. cajennense in dogs, which, unlike guinea pigs, do not develop resistance. A first, but no second, peak in skin reaction was observed, suggesting that cellular immunity is an important mechanism of resistance to ticks. This may partially explain why guinea pigs, but not dogs, develop resistance against ticks.

Development of resistance to nymphs of Amblyomma cajennense ticks (Acari : Ixodidae) in dogs

Ticks have long been regarded as constraints to humans and domestic animals, but hosts often develop resistance to ticks after repeated infestations. The purpose of this investigation was to study the possible acquisition of immunity in domestic dogs to nymphs of A. cajennense by determining the tick alimentary performance after successive controlled infestations. Mean engorged weight of nymphs was not significantly different among the three infestations; molting rate from nymph to adult ticks, and the percentage of nymph recovery were also very close in all infestations. These results are similar to those obtained in studies of the dog-adult Rhipicephalus sanguineus interface. It is concluded that domestic dogs do not develop resistance against nymphs of A. cajennense ticks.

Estudo citogenético em aranhas (Mygalomorphae e Araneomorphae) com ênfase na evolução dos genes de DNA ribossômico

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Síntese e caracterização de pequenos peptídeos lineares do veneno de Tityus serrulatus (Buthidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mating behaviour, nympho-imaginal development and description of a new Mesabolivar species (Araneae: Pholcidae) from the Brazilian dry forest

A new species of Mesabolivar is described from Brazilian forests: Mesabolivar delclaroi. The mating behaviour, postembryonic development, number of egg sacs and eggs, birth rate, number of instars, developmental time until adulthood, sex ratio and size of cephalothorax (per instar) were recorded. The sexual behaviour was described and categorized into four steps: courtship, pre-copulation, copulation and post-copulation. After hatching, individuals presented five instars until maturity. The mean number of eggs (42 +/- 16.6) and live births (31.5 +/- 3.4) of the first egg sac were significantly greater than that of a second one (23.8 +/- 3.8, and 19.25 +/- 3.9, respectively). The developmental time from birth to adulthood (130.8 +/- 9.6 days) did not differ significantly between egg sacs produced (128.61 +/- 11.1). The size of the cephalothorax did not differ among adults or between sexes. The sex ratio revealed a shift in favour of females (4: 3).

Male dimorphism of a neotropical arachnid: harem size, sneaker opportunities, and gonadal investment

Serracutisoma proximum is a harvestman with alternative male morphs. Large males use sexually dimorphic second legs in fights for the possession of territories on the vegetation, where females oviposit. Small males have short second legs and do not fight but rather sneak into the territories and copulate with egg-guarding females. We investigated the presence of male dimorphism across 10 populations of S. proximum, compared gonadal investment between male morphs, and assessed if the distribution of the sneakers is influenced by harem size. In all populations, there was male dimorphism, indicated by the bimodal distribution of the leg II length/body length. Gonadal investment did not differ between morphs and was not affected by male size, second leg length, and morph relative frequency in the populations. We found 361 territories, 90.0% containing 1 male, 9.7% containing 2 males (dyads), and 0.3% containing 3 males. The probability of encountering dyads increased with the number of females present in the territories. Moreover, the proportion of sneakers in territories containing dyads was higher than would be expected by chance. One possible reason for the ubiquity of alternative morphs in S. proximum could be the high mating opportunities experienced by sneakers in spatially structured populations with a resource defense polygyny system. Additionally, the high frequency of successful invasions by sneakers and hence the high sperm competition risk for both morphs may explain the similarity in gonadal investment between male morphs.

Maternal Care in the Soft Tick Antricola marginatus

Among spiders, scorpions, and whip spiders, a common type of maternal care consists of females carrying newly hatched offspring on their body for a few days until they are able to live independently. While this maternal care has been suggested to occur in different argasid tick species, it has been recorded only once, for Antricola marginatus in Cuba; however, this earlier record only superficially mentioned the occurrence of this behavior, with no further details. Here we report the occurrence of maternal care in the argasid tick A. marginatus under natural conditions in a cave at Yucatan. Mexico, where 8 A. marginatus females, while walking on bat guano, had their body entirely covered by a mean number of 305 +/- 112 conspecific unfed larvae (range: 105-466). Larvae covered the entire idiosoma of the female tick, where they were motionless or displayed just slight movement. This result substantially expands the number of unique characters that have been found only in Antricola spp, ticks, when compared to the other tick genera. Our findings also indicate that maternal care evolved independently in different taxa of Arachnida, since it has been reported for species of Araneae, Scorpiones, and Amblypygi, and here for an Acari species.