Mating Activity of the Mammalophilic Blacklies Simulium (Wilhelmia) Lineatum (Meigen, 1804) (Diptera: Simuliidae) Under Laboratory Conditions

Abstract

The diurnal rhythm of mating activity of the blackflies Simulium (W.) lineatum was established: 88–94% of insects were ready to mate during the daytime (6:00 a.m. – 7:00 p.m.), and 29–53% at night-time (9:00 p.m. – 4:00 a.m.). The peak of mating activity is predetermined by the rhythm of adult emergence from pupae with the time lag not longer than 2–3 hours. Until blood feeding, females mate only once while males copulate more times. Virgin blackflies copulated for 5.51 min at 26–28°C and 4.36 min at 29–32°C. When a male mated the 2^nd time in a minute after the 1^st mating, copulation lasted much longer, 12.98 min (at 26–28°C). The duration of both matings was the same with the interval between matings being within 17.3 to 22.5 hours. During copulation only a single spermatophore was transferred to a female. The length and width of the spermatophore transferred during the 1^st copulation was 0.194 and 0.191 mm, respectively. The spermatophore transferred during the second copulation either 1 min or 24 hours after the 1^st one, was significantly smaller in both length and width as compared to those of the 1^st mating.

Keywords:

• Simulium (Wilhelmia) lineatum
• mating activity
• repeated mating
• diurnal rhythm
• duration of copulation
• spermatophore
• sex ratio