The Sublethal Effects of the Entomopathic FungusLeptolegnia chapmaniion Some Biological Parameters of the Dengue VectorAedes aegypti

Abstract

The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti.

Infectivity of housefly, Musca domestica (Diptera: Muscidae) to different entomopathogenic fungi

“… 40 Moreover, decreased survival and fecundity with increasing doses of entomopathogenic fungi have been reported. 41 , 42 The results are similar in the current research; housefly longevity and fecundity were both reduced after exposure to a sublethal dose (1 × 10 6 spores/mL) of different entomopathogenic fungi compared to controls. The differences in housefly longevity and fecundity might be due to the virulence potential of the fungus and/or the susceptibility of houseflies.…”

Toxicity of microbial insecticides toward the non‐target freshwater insect Chironomus xanthus

“…demonstrated that both B. thuringiensis ‐ and B. bassiana ‐based formulations were slightly to moderately toxic to honey bees. Sublethal effects on female Aedes aegypti fertility and wing length were shown after exposure to the entomopathogenic fungus Leptolegnia chapmanii, similar effects may be expected with B. bassiana infection.…”

EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS

“…aegypti ) and tested groups (treated and control) were randomly aspirated and maintained in separate cages. Then, all the individuals were anesthetized with 60% alcohol and the right wing of each individual was detached from the thorax and the length from the axial vein to the outmost extreme of the R1 vein 50 was measured using a stereomicroscope (100×) ( Fig. 3 ).…”