Valorisation of the Effects of Bioactive Compounds of the Ethanolic Extract of Ramalina Farinacea (Ramalinaceae) on the Development, Eating and Pupation Behavior of Drosophila Melanogaster (Diptera: Drosophilidae)

Plants are rich in bioactive chemical secondary metabolites and have proven insecticidal activity by killing or repelling insects. In this work, we aim to evaluate the direct and delayed effects of ethanolic plant extracts on the vinegar fly (Drosophila melanogaster). The treatment was performed by ingestion on second instar larvae (L2) to evaluate the impact of the ethanolic extract on development for 15 days and subsequently on the feeding behavior of the larvae. The results of this study indicate a slowing down of pupal growth until the adult stage, at the three concentrations (0.25 µg/ml, 0.5 µg/ml, 1.5 µg/ml, 2 µg/ml) used. The results also showed that after three days of treatment, third instar D. melanogster larvae lost the ability to detect the odors of their nutrient environments. Other numbers of larvae (34 %) do not make a choice in the different tests performed. This study indicates that the ethanolic extract of Ramalina farinacea has a neurotoxic property our results confirmed the presence of toxic secondary metabolites which have bioinsecticidal activities in this extract.

Pupation site preference selection in Drosophila jambulina

Larvae of Drosophila jambulina belonging to montium subgroup were tested for pupation site preference in relation to temperature. At higher temperature (30 °C), larvae preferred to pupate on food whereas at lower temperature (21 °C) pupation occurred on the cotton. Genetic basis of larval pupation behavior was studied by conducting reciprocal crosses for 30 generations on food-selected and on cotton-selected larvae. Results from genetic analysis between food-selected and cotton-selected strains suggested a single gene responsible for the pupation site preference, with F1 progeny pupated on cotton and F2 (F1×;F1) larvae pupated on both food as well on cotton. Although we found no change in morphological traits in food vs. cotton selected population, significantly different growth rate (body weight) between the two strains was observed. These results suggest that pupation site preferences can affect life-history traits in D. jambulina.