Chemical Senses 20: 221-230,
© 1995
research-article |
Endocrine, Gonadal and Behavioral Responses of Male Crucian Carp to the Hormonal Pheromone 17
,20ß-dihydroxy-4-pregnen-3-one
1Department of Zoophysiology, Uppsala University Norbyvàgen 18 A, S-752 36 Uppsala 2Vertebrate Physiology and Behaviour Unit, Department of Limnology, Uppsala University Norbyvägen 20, S-752 36 Uppsala, Sweden 3Department of Zoology, University of Alberta Edmonton, Alberta, Canada T6G 2E9
Correspondence to be sent to: R. Bjerselius, Department of Zoophysiology, Uppsala University, Norbyvägen 18 A, S-752 36 Uppsala, Sweden
The olfactory-mediated responses to the sex hormone 17
,20ß-dihydroxy-4-pregnen-3-one (17,20ß-P) were studied in spermiated and regressed male crucian carp (Carassius carassius L). The position and spontaneous locomotor activity of single male crucian carp were continuously recorded in an artificial stream. 17,20ß-P (final concentration 10–11 M) was supplied to one half and its ethanol carrier to the other half of the test area. Milt volume and gonadotropin (GtH-II) concentration in the plasma were also measured. The smell of 17, 20ß-P significantly increased both the GtH-II concentration in the plasma and the volume of strippable milt in spermiated crucian carp. Behaviorally, the side of the test area scented with 17,20ß-P was significantly avoided by spermiated males. None of the described effects of 17,20ß-P on spermiated males were observed for the regressed crucian carp. In view of the lack of response from regressed crucian carp we suggest that the observed avoidance behavior of 17,20ß-P by spermiated males is a relevant reaction for spawning male crucian carp. The results are well in accordance with responses obtained in the closely related goldfish and gives strong support that the wild male crucian carp use the 17,20ß-P signal from the females to prepare for the coming spawning.