Physical Factors Influencing the Oviposition of Lutzomyia migonei (Diptera: Psychodidae) in Laboratory Conditions

Abstract

To determine the influence of physical factors on oviposition ofLutzomyia migonei (França 1920) is widely distributed in South America (Young & Duncan 1994). This is an important man-biting sandfly and is considered to be the vector of cutaneous leishmaniasis in Venezuela and Brazil (Pessoa & Pestana 1940, Pifano & Ortiz 1952, Feliciangeli 1991, Queiroz et al. 1994.One of the main problems that occur during sandfly colonization is the high mortality of gravid females before or during oviposition. This mortality hampers studies of sandfly biology, the productivity of the colony and experimental studies of transmission on Leishmania (Killick-Kendrick et al. 1977, Endris et al. 1982, Chaniotis 1986. Oviposition in sandflies is controlled through a combination of complex interactions between environmental, physical and chemical factors. Studies on the physical factors showed that temperature and relative humidity were important factors in the regulation of oviposition behavior (Foster et al. 1970, Chaniotis 1986). Furthermore, it was observed that the oviposition substrate stimulates a thigmotropic response in gravid flies (El Naiem & Ward 1992a). El Naiem and Ward (1990Ward ( , 1991 discovered the existence of an oviposition pheromone associated with the eggs of L. longipalpis. This pheromone has been isolated from female accessory glands and is secreted on to the eggs during oviposition (Dougherty et al. 1992). El Naiem and Ward (1992b) also demonstrated oviposition preferences in L. longipalpis for surfaces containing frass, larval rearing medium and rabbit faeces. In our study, we examined the influence of physical factors on oviposition by L. migonei. The study was designed to determine if the female sandfly lays more eggs on irregular surfaces than on flat surfaces, and to determine the effect that physical space has on oviposition in the gravid female. MATERIALS AND METHODSSandflies -L. migonei used in the experiments belonged to a colony initiated in 1993 with flies collected in Shannon light traps in a coffee plantation located at 1360 m above sea level at Ejído, Mérida, Venezuela. The methods for establishing and maintaining the colony in the laboratory were those described by Killick-Kendrick et al. (1977). Larvae and adults were reared in an incubator (Eletrolab) at a temperature of 25°C with 95% RH. Larval food was a powder mixture 1:1 of coffeeleaves and the larval diet was as described by Young et al. (1981).Before use in experiments, females were fed on hamsters anesthetized with a 50 mg/ml solution of sodium pentabarbitone. They were subsequently isolated with equal numbers of males in 15x15x15 cm nylon cages and offered a 50% sucrose solution, in an atmosphere of 25°C, 95% RH, for three days to allow complete oogenesis and defaecation.

Evaluación de conocimientos y prácticas sobre la leishmaniasis tegumentaria en un área endémica de Venezuela

“…Si bien no existe evidencia consolidada del cafetal como un sitio de refugio de los flebotominos, se han criado con éxito especies de Lutzomyia en el laboratorio con alimento a base de hojas de café (38,39 Otros autores también proponen la participación comunitaria como parte complementaria en el control en las zonas endémicas, orientado al vector y a los reservorios (12), y algunos autores resaltan la importancia de concientizar a la población escolar, como lo propusieron Costa et al (46).…”

Techniques to improve the maintenance of a laboratory colony of Nyssomyia neivai (Diptera: Psychodidae)

“…neivai [ 21 , 22 ]. Rough and irregular substrates stimulate a thigmotropic response in gravid flies of L. longipalpis and L. migonei and also provide greater protection, higher humidity and possibly more food for newborn larvae than flat surfaces [ 23 , 24 ].…”

Biology of the first generation of a laboratory colony of Nyssomyia intermedia (Lutz & Neiva, 1912) and Nyssomyia neivai (Pinto, 1926) (Diptera: Psychodidae)

“…Several physical factors may affect phlebotomine biological cycles (Rangel et al 1987, Nieves et al 1997, besides biological factors such as larval diet (Rangel et al 1985, Wermelinger & Zanúncio 2001. Attempts during the present study to maintain colonies of N. intermedia and N. neivai in larger rearing chambers were unsuccessful, since F2 females died just after taking blood meals.…”