Courtship behavior and potential indications for chemical communication in Artemia franciscana (Kellog 1906)
Two behavioral experiments were performed to test that A. franciscana shows specific courtship patterns, which in part, would be governed by semiochemicals released by females. The courtship ethogram, based on 30 adult virgin pairs (1 female v/s 1 male) individually video recorded for 1 hour, revealed that males display four independent activity patterns: 1) approach and touch, 2) swim behind, 3) riding attempt, and 4) riding success. The analysis of the transitions among the observed patterns suggested two ways to achieve riding success, both requiring female touch. In one, males approach and touch females followed by riding attempt (27% probability of occurrence), but if the latter fails, males start over from approach and touch (23% probability of occurrence) to finally achieve riding success (19% probability of occurrence). The alternative route is approach and touch, swimming behind (7% probability of occurrence) and riding success (5% probability of occurrence). The role of semiochemicals released from females was assessed by using the polar solution (PS) extracted from water conditioned with 40 adult virgin females. Virgin males were soaked with PS for obtaining pseudo females. Afterwards, we confronted 1 pseudo female, 1 female, or 1 control male to either 1 male or 5 male. In all cases the behavior was recorded for 1 hour (N=10), and the frequencies of occurrence of each courtship patterns were analyzed. The most important results showed that: 1) virgin female and pseudo female elicited the same frequency of response in 1 male in all four courtship patterns (P˃0.05); b) virgin female and pseudo female elicited the same response when tested against 5 males in approach and touch, swim behind and riding attempt (P˃0.05). The fact that in all the cases control male always elicited the lowest frequency value in each courtship patterns, strongly suggests the possible role of sexual semiochemicals in the courtship behavior of A. franciscana. The combination of behavior and chemical cues suggests an elaborate pre-mating recognition.