Snow crabs, Chionoecetes opilio (O. Fabricius, 1788) (Crustacea: Majidae) have two types of spermatophore: hypotheses on the mechanism of fertilization and population reproductive dynamics in the southern Gulf of St. Lawrence, Canada

Abstract

Observations on the structure of spermatophores stored in the median vas deferens of the snow crab, Chionoecetes opilio (O. Fabricius, 1788), revealed two different morphological types: one with an extremely wrinkled spermatophoric wall found mainly in adolescent and adult males with soft or new carapace, and the other with smooth and thin spermatophoric wall mainly found in adult males with hard and older carapace. Wrinkled spermatophores had extremely low rates of dehiscence in the seminal fluid extracted from females, but a rapid dehiscence within 40 min upon contact with seminal fluid was observed for the latter type of spermatophores. The observations of the spermathecae of both primiparous and multiparous females after the mating season revealed that they contained only the spermatophores with wrinkled spermatophoric walls. Based on these findings, we hypothesize that the spermatophores with smooth and thin spermatophoric walls are used for immediate fertilization of oocytes at copulation, while the spermatophores with wrinkled spermatophoric walls are stored in the spermathecae.

Keywords :

• Snow crab
• Majidae
• Chionoecetes opilio
• morphology
• dehiscence
• spermatophore
• sperm competition
• reproductive potential