Toxic effects of Drimia maritima (Asparagaceae) ethanolic

 Elevage des insects

Drosophila melanogaster was described by Johann Wihelm Meigen in 1830. Its reproduction is very fast. Its life cycle is very short and includes three larval instars and a pupal stage from which an adult emerges that can fly and reproduce. A wild strain harvested from rotten apples in Annaba region (Algeria), was used. The culture was carried out in vials (250 ml) capped with a foam pad and containing an agar-based nutrient medium of cornmeal and brewer’s yeast. The culture was maintained at 25±1 °C, a humidity of 70 to 80%, and a 12-hour scotophase. 

Drimia maritima (Asparagaceae)

It is a bulbous plant, which grows in the Mediterranean region. The main properties of this plant considered in traditional medicine are dropsy, cough and respiratory diseases, jaundice, skin problems, leprosy, baldness, gastric disorders, cancer, epilepsy, joint pain, and use as an antidote (Stannard 1974; Aliotta et al 2004). The D. maritima bulbs had significant insecticidal activity against several species (Pascual-Villalobos and Fernandez 1999; Metin and Burun 2010). For the present study the plant is collected in the region of Seraïdi (Annaba, Algeria) (36°54’27.02″ north latitude, 7°39’49.95″ east longitude). 2.3. Preparation of the ethanolic extract of D.maritima For the extract, we macerated the dry bulb powder (300g) in ethanol (250 ml at 70%) for 24 hours in laboratory conditions and on the shade. After filtration using Whatman filter paper, the liquid obtained was evaporated using a magnetic stirrer heated to 45 °C to remove ethanol. The 10g leg recovered was stored at 4 °C until use. 2.4. Treatment of larvae with D. maritima extract We prepared three different concentrations 0.12 µg/ml, 0.25 µg/ml, and 0.5 µg/ml. The treatment is done by ingestion; each concentration is mixed with food (40g) which will be distributed in four different tubes. In these tubes, 20- second instar larvae (L2) from the mass rearing are placed. In a fifth tube containing no treatment, 20 larvae are placed as a control. The monitoring of mortality and larval development is done for 15 days (time needed to finish development).

Effect of the plant extract on sexual behaviour

Sexual parade in fruit flies is an eventful behavior (Clynen et al 2011; Chardonnet 2013), goes through six essential, predetermined and invariable steps (Terhzaz 2003; Dickson 2008; Revadi et al 2015) and requires many sensory signals, of which chemical signals (cubic hydrocarbon pheromones) play an important role (Greenspan and Ferveur 2000; Sokolowski 2001). The male first walks up to a potential female and taps her on the cuticle with his front legs; if the female moves, the male follows and vibrates a wing. Then, when the female stops, the male runs in circles around her, lick her genitals with his proboscis, and tries to hang her up until mating (Revadi et al 2015). In this work, we treated the larvae group with the sublethal concentration of D. maritima extract (0.12 µg/ml) and then recovered the adults as soon as they emerged. 48 hours after emergence, these adults were used for sexual behaviour tests where we note the time and number of contacts, the time and number of wing vibrations, the time and number of licks, the time and number of mating attempts as well as the time and duration of mating if successful. These tests are carried out according to four types of crossings: control male X control female, treated male X treated female, control male X treated female and treated male X control female. 2.6. Effect of the plant extract on oviposition behaviour and reproduction: To the purpose of determining the egg-laying site choice, we observed mated females and we noted the site eggs hatching, as well as eggs and larval numbers. 2.7. Data analysis The toxicological parameters (LC50%, LC90%, LT50%, and LT90%) were calculated according to Finney’s mathematical methods (Finney 1971). Regarding sexual and oviposition behavior tests, results were analyzed statistically by descriptive metric methods then an analysis of variance (ANOVA) was performed on XLSTAT 2009 software (Addinsoft, New York, NY).