DIFFERENCE IN CUTICLE COMPONENT AND IMMUNOCOMPETENCE IN NURSE AND FORAGER WORKER HONEYBEE (APIS MELLIFERA L)

The aim of this work is to study the difference of physiology between the workerbee nurse and forager (Apis mellifera intermissa). The chosen physiologicalcharacteristics were the component of the cuticle (protein-chitin content) and themeasure of the efficiency of immune system (the total number of haemocytes(THC), the normal haemocytes and the relative mass of fat body). The THC iswidely used as an indicator of cellular immunocompetence of insects. The normalhaemocytes, also referred to immunocytes, indicate the integrity of cellularimmune system. The fat body is an indirect measurement of induced humoralimmunocompetence. The THC and the normal haemocytes were determined by themethod described by Amdam et al., (2004). For the estimation of the cuticularabdominal protein-chitin content, the method described by Berghiche et al., (2007)was employed. The relative mass of fat body was determined using an etherextraction method according to Doums et al., (2002) and Wilson-Rich et al.,(2008).The results show that a considerable percentage of a cuticular protein and adecrease of chitin was observed in nurse compared to forager. The older beesexhibited a strong reduction in the immun parameters

Repellency and toxicity of the crude ethanolic extract of Limoniastrum guyonianum against Tribolium castaneum. Acheuk, F., Belaid, M., Lakhdari, W., Abdellaoui, K., Dehliz, A., and Mokrane, K. (Algeria/Tunisia)

In nature, the interaction between plants and insects has led to the production of a set of secondary compounds. Many plant secondary metabolites have significant insecticidal activity. The aim of this study is to evaluate the repellent and insecticidal effect of the crude ethanolic extract of Limoniastrum guyonianum against adults of the red flour beetle Tribolium castaneum. For the insecticidal activity, five doses (100, 200, 400, 600, and 800 µg/insect) were tested and were topically applied onto insect thorax. An area preference method was adopted to assess the repellent activity. A phytochemical study and measurement of two enzymatic biomarkers: acetylcholinesterase (AChE) and gluthatione Stransferase (GST) were made to understand the mechanisms of toxic action of the tested extract. Phytochemical study showed the presence of various groups of natural products. The plant is rich in flavonoids, tannins, alkaloids, and glycosides. Low amount of saponins was noted. The study also showed that this plant does not contain iridoids. For repellent activity, the results showed that the highest dose (800 µg/insect) exhibited obvious repellent effect against T. castaneum. The repellency percentage was 90.14 ± 2.5% after 4 h of exposure. The crude extract was found to be toxic to T. castaneum and the corresponding LD50value was 218.3 μg/insect. Moreover, the extract inhibits the activity of the acetylcholinesterase (IC50: 205.7 µg/insect)