Os reduviidae identificados nos sistemas de cultivo algodoeiro (Estato de Mato Grosso, Brasil)

Reduviids are generalist predators bugs, easy to visualize on plants because of their color and size. However, in Brazil, little knowledge have been published on their presence on cropping systems, particularly in Mato Grosso state. Visual observations, and entomological collections with a triangular sweeping net have been done, mainly in the fazenda Mourão, near Campo Verde, in the cotton cropping systems experimental design, during the 2003 and 2004 campaigns. Punctual observations in some other places in the state (Primavera do Leste, Gloria do Oeste, Caceres) were done occasionaly. All the species, identified by J-M. Bérenger, belong to the biggest subfamily Harpactorinae: Apiomerus erythromelas, A. flavipennis, Atrachelus crassicornis, Atopozelus opsinus, Cosmoclopius annulosus, Doldina carinulata, Graptocleptes bicolor, Heza binotata, H. insignis, Montina confusa, Ricolla quadrispinosa, Zelus armillatus, Z. illotus, Z. laticornis, Z. leucogrammus, Z. longipes, Z. ruficeps. Some species from the genus Apiomerus, Repipta and Zelus were not identified. G. bicolor was also found in Caceres. It has a mimetic appearance with a Braconidae. Colors patterns of species from the Zelus genus (as Z. leucogrammus, Z. ruficeps, Z. armillatus) can be very different between dark to bright specimens difficulting the identification. The most common species is Zelus longipes, found almost all over the year, at the immature stage too, on unsprayed cotton, maize, rice, and cover crops plants as Eleusine coracana, Pennisetum, Crotalaria juncea used in the cropping systems. The annual presence is more erratic for the others species, with some species observed more frequently as R. quadrispinosa, D. carinulata, R. quadrispinosa. Preys belong to different groups of pests or natural enemies from the following insect groups: Coleoptera (Chrysomelidae Maecolaspis sp., Diabrotica speciosa, Melyridae Astylus variegatus, Coccinellidae Naemia (Eriopis) conexa) Hymenoptera (bees), Dermaptera (Doru lineare), Diptera (Dolichopodidae, other small flies) and larval instars of Lepidoptera, as Alabama argillacea, the main cotton defoliator. Most of these species were also detected in the Parana state, south of Brazil (Cascavel, Palotina) and in Paraguay. They seem to have a rather large geographical distribution. The proximity of (untreated) secundary host-plants is a good practice to favorize the presence of these predators. (Résumé d'auteur