Nicotiana Glauca Graham (Solanaceae) Bioactivity and Toxic Effects on Mor ects on Mortality, Feeding Beha eeding Behavior and Pupation Choice of vior and Pupation Choice of Drosophila Melanogaster Lar osophila Melanogaster Larvae (Dipter ae (Diptera: Drosophilidae) osophilidae)

Abstract

Nicotiana glauca is a medicinal plant used by traditional healers as antibacterial, antifungal, antiviral and anti-inflammatory medicines. The leaves of N. glauca are very rich in indolic alkaloids which give it a larvicidal power which allows us to use it as a bio-insecticide.In the present study we were perfomed in the direct (mortality) and indirect (food attractiveness and pupation) toxic effects of the aqueous extract of N. glauca on the mortality and feeding behavior of the fruit fly Drosophila melanogaster. The treatment was administered to 2nd instar larvae (L2) and the mortality rate was monitored for 15 days. Similarly we treated the 2nd instar larvae (n=50) with a sub-lethal concentration of 25µg/ml. Two days after the treatment the third instar larvae of D. melanogster are exposed to two nutrient media (control and treated with N. glauca) and the choice of the larvae is noted during one hour of time.The findings show that after 15 days of treatment, mortality rates in D. melanogaster larvae can reach 50%, as we observed a disruption in olfactory and gustatory signals, with both control and treated larvae preferring the food preparation mixed with the aqueous extract of N. glauca Graham and losing their ability to smell their control medium. This indicates that the bioactive chemicals isolated from this poisonous plant are mostly appealing allelochemical substances.

Keywords

• drosophila melanogaster
• nicotiana glauca
• mortality
• feeding behavior
• pupation.