Antônio Fernando de Souza Leão Veiga

Histological description of the midgut and the pyloric valve of Tropidacris collaris (Stoll, 1813) (Orthopetera: Romaleidae)

The present research describes the histology of the midgut, gastric caeca, and pyloric valve of Tropidacris collaris (Stoll, 1813), (Orthopetera: Romaleidae). We used light microscopy, staining (Gomoris trichrome and periodic acid-Schiff (PAS)), and a routine histological analysis method (hematoxilin-eosin). The insects were obtained from, and also bred in, the Laboratory of Entomology, Department of Biology, of the Rural Federal University of Pernambuco (UFRPE). The collected material was fixed in alcoholic Botüin and embedded in paraplast. The results demonstrated that the midgut wall is composed of an inner epithelial layer and two outer layers of striate muscles: one internal (circular) and the other external (longitudinal), with connective tissue between the muscle fibers. The epithelium is single-layered, with two cell types: regenerative and elongated columnar. The gastric caeca presents muscle layers similar to those of the midgut. Simple columnar epithelium lines the gastric caeca, which presents villi and projects towards the lumen. The pyloric valve is of striate muscle tissue, covered by a single epithelial-cell layer.

Preferência alimentar e desempenho de Brontocoris tabidus Signoret (Hemiptera, Pentatomidae) em plantas hospedeiras

The choice between cotton, Gossypium hirsutum L. (Malvaceae), green bean, Phaseolus vulgaris L. (Fabaceae) and pigweed, Amaranthus lividus L. (Amaranthaceae) and its relationship as first feeding, weight gain and biological performance of the predator Brontocoris tabidus (Signoret) (Hemiptera, Pentatomidae) adults were studied. Adults of the predator were allowed to choose between plants and, immediately paired and reared on the same selected plants plus prey. Furthermore, nymphal development and adult stage were obtained on the same plants plus prey. The results show that B. tabidus do not exhibit host plant preference among tested plants. Likewise, feeding period (106 to 115 minutes) and weight gain (28 to 30% of body weight) were statistically equal among plants. However, predators at adult stage only or nymphal and adult stages maintained on young green bean plants plus prey exhibited lower performance compared to the other plants. Nymphs feeding exclusively on plants lived, on average, up to 6.5 days but did not reach adult stage and lived longer on cotton plants and pig weed. The results indicated that adults of the predator B. tabidus do not exhibit selection on host plant to feed although different results in its life history was attained among the studied plants with better results for cotton and pigweed.

Patogenicidade de Metarhizium anisopliae var. anisopliae e Metarhizium anisopliae var. acridum sobre Nasutitermes coxipoensis (Holmgren) (Isoptera: Termitidae)

A acao de Metarhizium anisopliae var. anisopliae e Metarhizium anisopliae var. acridum sobre o cupim de monticulo Nasutitermes coxipoensis (Holmgren) e a producao de conidios sobre os insetos mortos foram estudadas em laboratorio. Doses infectivas foram determinadas atraves do contato direto dos insetos com a cultura fungica apos 12 dias de crescimento e quantificacao dos conidios em câmara de Neubauer. Foram utilizadas as doses 0,5 x 106 e 1,6 x 107 conidos/ml, para M. anisopliae var. anisopliae, e 1,4 x 105 e 1,8 x 106 conidios/ml para M. anisopliae var. acridum, nominadas dose A e dose B, respectivamente. As doses corresponderam a 3 min. e 15 min. de contato direto de 20 cupins com a cultura fungica. A producao de conidios foi avaliada utilizando-se insetos inoculados com o fungo, 10 dias apos a morte. Os bioensaios foram realizados em triplicata. Os percentuais de mortalidade acumulada de N. coxipoensis tratados com M. anisopliae, no terceiro dia apos a inoculacao, foram: controle, 15,7%; dose A 95,7% e dose B 100%; para M. anisopliae var. acridum foram: controle, 13,3%; dose A 66,4 e dose B 88,8%. A media da producao de conidios foi mais elevada para M. anisopliae var. anisopliae do que para M. anisopliae var. acridum. Os resultados mostraram que M. anisopliae var. anisopliae apresentou maior potencial para o controle biologico de N. coxipoensis.

Mecanismos de ação de himenópteros parasitóides sobre Megastes spp. (Lepidoptera: Pyralidae) em agroecossistema de batata-doce (Ipomoea batatas L.)

The presence and action of Hymenoptera parasitoids in agroecossystems of sweet potato (Ipomoea batatas L.) in Pedra de Fogo county - PB, Brazil, on Megastes spp. complex were studied, with the objective of identifying parasitoids species and to describe the main aspects on parasitism action on Megastes grandalis Guenee and Megastes pusialis Snellen. On direct evaluation 14% of plants had females of ectopasitoids belonging to the Braconidae family. The indirect evaluation showed the occurrence of 22% of worms attacked by parasitoids. The emergence of parasitoids adults of seven species belonging to the Braconidae, Chalcididae and Ichneumonidae families has been observed. It was concluded that the presence of parasitoids in sweet potato agroecossystem is diversified and important to suppress the insect pest.

Morfologia do ovo e das formas imaturas de Zagloba beaumonti Casey (Coleoptera, Coccinellidae)

Optical microscopy and scanning electron microscopy technics were aplied in order to describe, for the first time, the immature stages of Z. beaumonti Casey, 1899 reared on its prey, Diaspis echinocacti (Bouche, 1833) (Homoptera, Diaspididae), the unique pest of Opuntia ficus-lndica Mill and Nopalea cochenillifera (L.) Salm-Dick (prickly-pear, Cactaceae), an impportant alternative food source for the cattle on drought areas of Northeast of Brazil. Yellow eggs layed inside the scales, caraboid larvae without wax processes and pupae partially protected by the last exuvia presented the Scymninae pattern.