A. L. M. Mesquita

Male orientation to trail sex pheromones in parasitoid wasps: does the spatial distribution of virgin females matter?

We studied male locomotory response to trails and patches of sex pheromone (left respectively by free-ranging females and females constrained to stay on a small area) in the two parasitoids Aphelinus asychis (Hymenoptera: Aphelinidae) and Trichogramma brassicae (Hymenoptera: Trichogrammatidae). Under the hypothesis that the spatial distribution of virgin females differs between these species (scattered among host plants in A. asychis, gregarious at emergence sites in T. brassicae), we predicted that male locomotory response to their sex pheromones should also differ: A. asychis males should follow pheromone trails on plants in order to encounter the females along these trails, whereas T. brassicae males should stay on pheromone patches, at emergence sites, and mate the females on these patches. Using an improved video-tracking system, we found that males of both species respond to conspecific sex pheromone trails and patches, but that the response does not differ much between species. Males released on marked substrates walked in a more convoluted pattern (i.e. higher path fractal dimension and higher number of crossings within tracks) than males released on unmarked substrates. On pheromone patches, males turned persistently in the same direction when leaving the patch, which explains a higher number of visits on marked patches than on unmarked patches, and possibly, higher track convolution on pheromone trails. Contrary to our hypothesis, male A. asychis did not follow female trails more accurately than male T. brassicae, and male T. brassicae did not stay longer on pheromone patches than male A. asychis. We argue that these discrepancies between our predictions and the observed responses originates from discrepancies between the assumed spatial distribution of virgin females and their actual distribution in the wild.

Occurrence and damage of soursop pests in northeast Brazil

Abstract Field studies from 1995 to 1997 in the Paraipaba county state of Ceara, Brazil evaluated the occurrence and potential damage of soursop Annona muricata L. pests. The most important pests were the fruit borer Cerconota anonella and the “irapua” bee Trigona spinips , the maximum fruit damage being 62 and 53%, respectively. The seed borer Bephratelloides maculicollis caused the least fruit damage. Different species of Membracidae, Coccidae, Diaspididae and Aphididae were also evaluated with plant damage that varied from 16 to 20%. The leafminer Prinomerus anonicola was continuously present during the three-year period with plant damage varying from 17 to 22%. Other less important pests were stem borer Cratosomus sp, ants, stink bugs and defoliators that together caused on an average 19–32% plant damage.

Taxonomic identification of lepidopterous species of cashew plant in Brazil

Este trabalho relata a identificacao taxonomica das especies de lepidopteros Thagona postropaea Dyar (Limantriidae), Stenoma cathosiota Meyrick (Stenomatidae) e Anacampsis cf. phytomiella Busck (Gelechiidae) que atacam o cajueiro (Anacardium occidentale L.) no Brasil. Tipos de dano, locais de ocorrencia e niveis de ataque sao citados.

Occurrence of Fulcidax coelestina (Lac.)(Coleoptera: Chrysomelidae: Fulcidacinae) in Barbados cherry Malpighia glabra L.

Desde janeiro de 1996, o crisomelideo Fulcidax coelestina (Lac.), pertencente a subfamilia Fulcidacinae, tem sido encontrado atacando severamente ramos laterais e principal de plantas da acerola Malpighia glabra L. nos municipios de Pacajus e Paraipaba no Estado do Ceara. As larvas fazem o anelamento do ramo principal e dos laterais da planta, provocando o bloqueio floemico com consequente seca dos ramos ou planta. A mortalidade pode chegar a 100% em plantas jovens. Este e o primeiro registro da ocorrencia da praga atacando a aceroleira no Brasil. A presenca continua do inseto nos plantios de acerola tem forcado o uso sistematico do controle quimico para reduzir as populacoes. O adulto apresenta corpo azul metalico com superficie extremamente rugosa. O ultimo estadio larval constroi um envoltorio em forma de coracao utilizando seu proprio excremento onde completa o ciclo.