Experimental studies show that early sensory experience often affects subsequent sensory preference, suggesting that the heterogeneity of sensory cues in nature could induce significant inter-individual behavioral variation, potentially contributing to maintain intraspecific diversity. To test this hypothesis, we explored the behavioral effect induced by variation in the levels of a self-produced chemical, acetoin, and its link with intraspecific diversity. Acetoin is a pheromone-like substance produced by gut-associated microorganisms in Drosophila. Using wild-type Drosophila melanogaster populations producing variable acetoin levels, we (i) characterized factors involved in this variation and (ii) manipulated some of these factors to affect acetoin responses in larvae. We found that increased and decreased variations in acetoin levels were caused by microorganisms associated with the outside and inside of the egg, respectively. Wild-type larvae preferred acetoin-rich food only when they both produced and were exposed to substantial amounts of acetoin. The removal of the outside of the egg or the genetic alteration of olfaction abolished this preference. In contrast, larvae exposed to high doses of synthetic acetoin were repulsed by acetoin. The similar effects obtained with freshly caught wild-type lines suggest that this acetoin “production-preference” link underlies the diversity of acetoin-producing microorganisms among natural D. melanogaster populations.

Spinosad is a biopesticide, derived from fermentation by the soil-dwelling actinomycete, Saccharopolyspora spinosa, which is used to control a variety of insects. Spinosad kills a wide range of insect pests when ingested or topically applied, by overexciting the nervous system, yet is harmless to mammals and many predatory insects. Other modes of action of this insecticide have not been documented. Here, we report that a non-lethal dose of spinosad causes adult male and female German cockroach, Blattella germanica, to exhibit altered responses to their aggregation pheromone as well as to have a changed cuticular hydrocarbon profile.

Nicotiana glauca (N. glauca) (Solanaceae) is an ornamental plant. It has insecticidal properties. However, these uses cannot compensate for the overall negative impacts of this plant. This study was aimed to evaluate the larvicidal effect of the aqueous extract of N. glauca leaves on the 4th stage larva of Culiseta longiareolata (Cs. longireolata). N. glauca leaves were harvested, dried and powdered using an electric mill. Hot aqueous extraction was done with 150 g powdered leaf in 1000 mldistilled water. The dry extract was partitioned in various beakerswith 20 larvae, and the three concentrations 14.85 g / l, 25.66 g / l and 62.4 g / l were determined. The preliminary results showed that used extract has a high efficiency compared to natural substances of plant or microbial origin. This efficiency is expressed by the calculated toxicological parameters which are successively LC50 and LC90, with 26.87 and 55.14g/l, As for lethal times 0.46 and 1 days respectively. N. glauca can be considered among the plants with important insecticidal effects in biological control against mosquitoes. Preliminary toxicity tests on Cs. longireolata have confirmed its toxicity for these vectors.

Drimia maritima is a toxic Mediterranean plant and is considered a commercially important drug by its medicinal values and pharmacological properties. In this work, we seek to evaluate the direct and delayed effects of the ethanol extracts of this plant on vinegar fly (Drosophila melanogaster), an excellent laboratory model. The treatment was carried out by ingestion on second-stage larvae (L2) and then we evaluated the impact of this treatment on mortality, development, sexual behaviour, on female's oviposition choice, fecundity, and fertility of adults. The results showed that mortality rates can reach 100% after 15 days of treatment as we recorded an acceleration of the flies' development. After treatment, we observed incomplete nuptial courtship and a significant decrease in eggs laid number and larvae number of the first generation treated. This study indicates that D. maritima ethanolic extract has a neurotoxic property, our results confirmed the presence of toxic secondary metabolites in the extract studied.

This study aims to investigate the diversity, population dynamics, and distribution of forest cockroaches from the litter of three types of Mediterranean forests (Pinus halepensis, Juniperus phoenicea, Quercus ilex) in Belezma National Park (Northeast Algeria). In every type of forest, blattopteran individuals were hand-collected fortnightly from March 2013 to July 2014. Population dynamics were tested by multivariate analysis of variance for forest types and study months. The capture of 1885 individual forest cockroaches allowed the identification of six species (Loboptera angulata, Dziriblatta stenoptera, Phyllodromica subaptera, Phyllodromica zebra, Phyllodromica cincticollis, and Phyllodromica trivittata). In all studied forests, these species produced two generations per year (spring and autumn), in which the number of females was significantly higher than the number of males. However, P. cincticollis established a single generation in the spring with a balanced sex ratio. L. angulata and D. stenoptera were the most abundant species. The values of individual abundances, species richness, and biodiversity were higher in P. halepensis forest compared to Q. ilex and J. phoenicea.