Fatty acid methyl esters extracted from the cuticular surface of Artemia franciscana (Kellogs, 1906) (Crustacea: Anostraca) increase the swim speed of conspecific males

Abstract

Previous researches have established that the swim speed of some microcrustaceans is influenced by chemical compounds emitted by conspecifics. We examined the hypothesis that cuticular compounds present on the body surface of A. franciscana, the most widespread member of Artemia genus, play a role in the swim speed of conspecific males. The movements (swim) of one male confronted to a sponge soaked with female or male cuticular extract, were recorded during 30 minutes and the swim speed was determined using a behavioral tracking software (Ethovision 3.1, Noldus Technologies). As a control, the movements of one male confronted to a sponge soaked with salty water or with a mixture of the solvents used in the extraction (chloroform-methanol), was recorded. The results showed that cuticular compounds from either female or male increase 1.5 (ca.) times the swim speed of males in comparison with the controls treatments salty water and the solvents. There was no a significant difference between the controls (salty water and chloroform-methanol). Chemical characterization was developed by sterification of the cuticular extracts and analyses by GC-FID and GC-MS. Four saturated fatty acid (myristic acid, palmitic acid, estearic acid, arachidic acid) and five insaturated fatty acids (oleic acid, linoleic acid, linoleic acid 3n3, cis-11-eicosanoic acid, euric acid) were identified. Myristic acid was found in female cuticular extract, but not in male cuticular extract. Results suggest that chemical compounds present in the cuticular surface of A. franciscana females could have an important role in the intra-specific recognition in this specie.