Manipulation of fire ant density, Solenopsis spp., for short-term reduction of Diatraea saccharalis larval densities in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comportamento de oviposturas individuais, percentagem de eclosão e peso larval mínimo para pupação em populações de Chrysomya megacephala (F.)

Chrysomya megacephala (F.), a exemplo de muitas outras moscas-varejeiras, utiliza recursos discretos e efêmeros para alimentação e oviposição, tais como carcaças em decomposição. O contexto espacial em que ocorre competição por alimento em C. megacephala caracteriza-se por duas populações: indivíduos adultos dispersando-se e imaturos que são depositados nos substratos pelas fêmeas adultas. O objetivo do estudo foi investigar aspectos da bionomia associados com competição larval por alimento em populações experimentais de C. megacephala, incluindo comportamento de ovipostura e peso mínimo necessário para pupação. Os resultados indicaram que fêmeas depositam parte de seus ovos produzidos, contrastando com estudos anteriores que consideraram apenas ovipostura completa. A percentagem de eclosão de larvas foi alta (90 %) e o peso mínimo necessário para pupação situou-se entre 30 e 32 mg.

LARVAL INSTARS AND IMMATURE DEVELOPMENT OF A BRAZILIAN POPULATION OF PHARAOHS ANT, MONOMORIUM-PHARAONIS (L) (HYM, FORMICIDAE)

The immature development of pharaoh's ant, Monomorium pharaonis, workers was s died in a naturally collected Brazilian population. Three larval instars were confirmed by measuring maximal cephalic widths in cohorts of known age. Minimum egg to adult duration was 25 days, while the maximum duration was 54 days, both of which are larger than those reported for European populations. Larval instar development is cyclical at the colony level, suggesting reproductive bursts followed by lower reproductive activity of the queens.

THE EFFECT OF TUBEROINFUNDIBULAR DOPAMINERGIC-NEURONS ON PROLACTIN AND ALPHA-MELANOCYTE STIMULATING HORMONE-RELEASE

The effect of tubero-infundibular dopaminergic neurons (TIDA) on the release of prolactin (PRL) and alpha-melanocyte stimulating hormone (alpha-MSH) was studied in median eminence-lesioned (MEL) male rats (N = 6-28). Plasma PRL and alpha-MSH levels were significantly elevated 2 (86.1 +/- 19.8 and 505.1 +/- 19.1 ng/ml), 4 (278.7 +/- 15.5 and 487.4 +/- 125.1 ng/ml), 7 (116.2 +/- 16.2 and 495.8 +/- 62.6 ng/ml) and 14 (247.3 +/- 26.1 and 448.4 +/- 63.8 ng/ml) days after MEL when compared to sham-operated control animals (55.5 +/- 13.4 and 56.2 +/- 6.1 ng/ml, respectively). MEL altered plasma PRL and alpha-MSH levels in a differential manner, with a 1.5-to 5.0-fold increase in PRL and an 8.0-to 9.0-fold increase in alpha-MSH. The increase of alpha-MSH levels occurred abruptly and remained constant from days 2 to 14. These observations indicate that TIDA plays an important role in the pituitary release of PRL and alpha-MSH and provide evidence that the release of the two hormones occurs in a differential manner.

LARVAL DISPERSION OF ORMIA-DEPLETA (TOWNS) (DIPT, TACHINIDAE)

The dispersion patterns of the larval planidia of Ormia depleta was studied in circular arenas. After placing 25 larvae in the center of the arena, their angle of distribution and distance travelled was recorded 15 min later. No innate directional orientations were evidenced, nor was evidence found for either positive or negative orientation to point sound and light sources. In all cases, dispersion was bimodal, with most dispersing only 1 cm, and a much smaller peak found at 10 cm. The bimodality of dispersal distances may be a response to the sexual behavior of its host, mole crickets of the genus Scapteriscus.

Oil-soluble dyes for marking Spodoptera frugiperda (Lepidoptera : Noctuidae)

Although various biological aspects of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) have been examined, adult movement and dispersal of this insect pest is not well understood. Release-recapture techniques by using marked insects is a useful approach for dispersal studies; however, the marking technique should not significantly affect insect biology or behavior. Therefore, the effect of different concentrations of oil-soluble dyes (Solvent Blue 35 [C.I. 61554], Sudan Red 7B [C.I. 26050], Sudan Black B [26150], Sudan Orange G [C.I. 11920], and Sudan I 103624 [C.I. 12055]) on development, mortality, and fecundity of S. frugiperda was evaluated. Dyes were added to artificial diet used to feed larvae. Larval and pupal development and mortality, adult longevity, and female fecundity were evaluated. High concentrations (400 and 600 ppm) of all dyes led to longer larval and pupal stages. Adult life span and number of eggs were not affected by the dyes. Sudan Red 7B marked both adults and eggs very well. Solvent Blue 35 marked both adults and eggs, but the blue-marked eggs could not be distinguished from some bluish eggs laid by nonlabeled females. Adults and eggs were not adequately marked by the Sudan Black B, Sudan Orange G, and Sudan I 103624 (a yellow dye).

Larval Contracaecum sp (Nematoda : Anisakidae) in Hoplias malabaricus and Hoplerythrinus unitaeniatus (Osteichthyes : Erythrinidae) of economic importance in occidental marshlands of Maranhao, Brazil

This work describes the presence of Contracaecum sp. larvae (Nematoda: Anisakidae) found in food fish of economic importance captured in occidental marshlands in the State of Maranhao, Brazil. Hoplias malabaricus (Erythrinidae) and Hoplerythrinus unitaeniatus (Erythrinidae), commonly called traira and jeju, respectively, were examined. All H. malabaricus were infected with a mean intensity of 24.6 +/- 38.3 (1-137 parasites per host) while eighty percent of H. unitaeniatus showed a mean intensity of 10.4 +/- 9.2 (2-31) parasites. Nematodes were most similar to larvae of a type 2 described by Moravec, Kohn and Fernandes [Moravec, F., Kohn, A., Fernandes, B.M.M., 1993. Nematode parasites of fishes of the Parana River, Brazil. Part 2. Seuratoidea, Ascaridoidea, Habronematoidea and Acuarioidea. Folia Parasitol. 40, 115-134], but differed in having a longer intestinal caecum and greater caecum/ventricular appendix ratio. Larval measurements and a description of their Brazilian fish hosts are presented. (C) 2004 Elsevier B.V. All rights reserved.

LARVAL DISPERSION IN CHRYSOMYA-MEGACEPHALA, CHRYSOMYA-PUTORIA AND COCHLIOMYIA-MACELLARIA (DIPT, CALLIPHORIDAE)

Horizontal and vertical frequency distribution of larvae in three species of Calliphoridae were studied. Correlation between horizontal and vertical dispersion and larval size was also assessed. The experiment was monitored depositing vials with larvae at one end of a cardboard box covered with wood shavings. Chrysomya megacephala and C., putoria reached 2.9 m from the starting portion of the box. Co. macellaria reached only 2.0 m from the starting portion of the box. The majority of pupae of the three species were found at 4 and 5 cm depth from the surface of the box. Correlation coefficients between pupal size and horizontal and vertical migration were usually very low, and apparently no clear pattern emerges from this data set. This study revealed variation in the dispersion patterns although the two Chrysomya species are more similar in their postfeeding larval behaviour compared to Co. macellaria.

PHARMACOLOGICAL EVALUATION OF THE INHIBITORY EFFECT OF EXTRACTS FROM ANCHIETIA-SALUTARIS ON THE HISTAMINE-RELEASE INDUCED IN THE RAT AND THE GUINEA-PIG

The tea made with leaves and stems of plant Anchietia salutaris is traditionally used in Brazil to treat allergies. We examined the effects of a crude aqueous extract and of purified fractions of this plant on the histamine release induced in rat and guinea pig tissues. The crude extract (3-10 mu g/ml) inhibits the histamine release induced by compound 48/80 (0.5 mu g/ml) and antigen in rat peritoneal mast cells. The inhibition is significant after 10 s of preincubation and is completed after 3 min. The crude extract dissolved in the perfusion fluid (1-30 mu g/ml) also inhibits the histamine release induced in guinea pig heart by cardiac anaphylaxis and in hearts from pretreated animals (10-100 mg/kg i.p.). In pretreated animals, the effect manifests after 3 h, is maximum after 12 h and disappears after 48 h. The histamine release induced in isolated guinea pig heart by ionophore A23187 is inhibited by similar doses as in antigen-induced histamine release. Extraction with solvents concentrated the active principle (s) in the hexane fractions, as demonstrated by the inhibition of the histamine release induced by antigen in isolated cells from guinea pig heart dispersed with collagenase. In subfractions produced by the fractionation of the hexane fraction, the active principle(s) concentrated in the subfractions obtained by extraction with hexane and ethyl acetate, which shows the low polarity of the compound(s). The same subfractions that inhibit the histamine release induced by antigen in cells from guinea pig heart also inhibit pulmonary cells. Our result show that A. salutaris contains low-polarity compound(s) that inhibit the histamine release induced by three different mechanisms in mast cells from two animal species. These facts suggest that the active principle(s) of A, salutaris could be useful in the treatment of allergies and/or as a tool for the study of mast cell secretions.