Second Blood Meal by Female Lutzomyia longipalpis: Enhancement by Oviposition and Its Effects on Digestion, Longevity, and Leishmania Infection.

C S Moraes,K Aguiar-Martins,P A Bates,F A Genta,R J Dillon,S G Costa

doi:10.1155/2018/2472508

Abstract

Lutzomyia longipalpis is the main vector of visceral leishmaniasis (VL) in America. Physiological and molecular mechanisms of Leishmania infection in sand flies have been studied during the first gonotrophic cycle. There are few studies about these interactions during the second gonotrophic cycle mainly because of the difficulties maintaining sand flies through sequential feeds. Here we standardized conditions to perform the second blood feed efficiently, and our results show that oviposition is an essential factor for the success of multiple feeds. We evaluated the impact of the second blood meal on longevity, protein digestion, trypsin activity, and Leishmania mexicana development within L. longipalpis gut. Mortality of blood-fed females increases after second blood meal as compared to sugar-fed females. Trypsin activity was lower during the second gonotrophic cycle. However, no difference in protein intake was observed between blood meals. There was no difference in the population size of Leishmania in the gut after both blood meals. In this work, we presented an optimized protocol for obtaining sufficient numbers of sand fly females fed on a second blood meal, and we described some physiological and parasitological aspects of the second gonotrophic cycle which might influence the vectorial competence of sand flies.

Highlights

Visceral leishmaniasis (VL) is a severe chronic disease caused by protists belonging to the Leishmania donovani complex [1]
In the Americas, the phlebotomine sand fly Lutzomyia longipalpis is the main vector of VL [3]
We have developed a protocol to evaluate the impact of the second gonotrophic cycle on longevity, protein digestion, trypsin activity, and Leishmania mexicana development within L. longipalpis females

Summary

Introduction

Visceral leishmaniasis (VL) is a severe chronic disease caused by protists belonging to the Leishmania donovani complex [1]. In the Americas, the phlebotomine sand fly Lutzomyia longipalpis is the main vector of VL [3]. Both male and female L. longipalpis adults, after emergence from pupae, feed on sugars from plants and aphids in a regular basis, but only adult females are hematophagous, feeding on a wide range of vertebrates as dogs, chickens, humans, and horses, among others [4]. Female L. longipalpis are anautogenous insects, where egg development occurs only after a blood feed. The oviposition in this species starts 3 days after the blood meal and in general lasts for 6 days [6, 7]. A second blood feed is necessary to start a new cycle of digestion and oviposition [8]

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Discussion

Conclusion