Criterios de nuliparidad y de paridad en Lutzomyia townsendi (Ortiz, 1959) del occidente de Venezuela

Abstract

Lutzomyia townsendi (Ortiz, 1959) es un flebótomo antropofílico con concordancia gonadotrófica, en las zonas endémicas de Leishmania brasiliensis y L. garnhami en el occidente de Venezuela. Mediante el estudio de hembras colonizadas en el laboratorio, nuliparas o paridas, de hembras silvestres alimentadas sobre voluntarios y de hembras silvestres mantenidas con sacarosa, se establecen criterios de nuliparidad con un 56,6% de confianza. En cambio, signos de paridad aparecen en un 82% de las hembras consideradas como tales. La digestión de un ingesta sanguínea inicia un ciclo gonadotrófico con oogénesis abortiva y acumulación de fosfolípidos en las células epiteliales del estómago y en las glândulas accesorias. La ovoposición completa produce un calix ovárico grueso e irregular con restos de oocitos abortivos y acumulación de pigmentos. Estos caracteres son suficientes para precisar un criterio de paridad. La presencia de fosfolípidos en el estómago y en las glândulas accesorias de hembras nulíparas es una indicación de ingesta incompleta de sangre.<br>Lutzomyia townsendi (Ortiz, 1959) is the main anthropophilic sandfly in endemic places for Leishmania braziliensis and L. garnhami in Western Venezuela. The study of laboratory bred females, nulliparous or parous and, wild females fed on man as well as wild females maintained with sucrose, allowed to establish a criterion of nulliparity with 56.6% of confidence for those captured in field conditions. In the same wild females, parity can be assessed with 81.5% of confidence. After blood digestion of full-engorged females a gonotrophic cycle is completed. Abortive oogenesis and accumulation of phospholipids in midgut epitelial cells and into accessory glands are observed. The ovoposition produces a thick and irregular ovaric calix with rests of abortive oocytes and accumulation of a melanin-like black pigment. All these changes are enough for identification of a parous fly. The presence of phospholipids in the stomach and accessory glands of a nulliparous sandfly is indicative of digestion of an incomplete blood meal

Comparison of three methods for age‐grading of female Neotropical phlebotomine sandflies

“…unfed or fed on sugar or blood, mated or not, parous or notthe ovarian appearance was the only completely reliable character for distinguishing nullipars from parous females. The latter had yellow ovaries with looser ovarioles, whereas the former had paler ovaries with more tightly packed ovarioles (Marquez & Scorza, 1982). However, this method cannot be applied to gravid females.…”

“…Theoretically nullipars were expected to lack residual secretions in the AG (clear), to have tightly-packed ovarioles in the OV, and to have no creases at the edges of the GA armature. Parous flies were expected to show opacity due to yellow granulated secretions in the AG, to have loosely-packed ovarioles in the OV, and a creased GA (Marquez& Scorza, 1982;Aiiezetal., 1994;Tang &Aiiez, 1996). For the wild caught flies examined, the criterion forjudging them Age-grading female Neotropical phlebotomine sandflies 5…”

“…The small size of sandfly ovaries makes it difficult or impossible to determine accurately how may times a female has laid eggs by counting the number of follicular relics in the ovarioles. The observer, in the best of cases, may be able to distinguish only between parous and nulliparous flies (Marquez & Scorza, 1982;Ready et al, 1984).…”