Spermatophores: The Mode of Insemination of Chiggers (Acarina: Trombiculidae)

Abstract

Stalked spermatophore of 7 spp. of trombiculid mites were noted. Trombicula (Entrombicula) splendens was used in the experimental studies, and the spermatophore of this and another American chigger, Hannemania sp., is described and figured. Spermatophores were also noted for 5 spp. of Korean chiggers; Trombicula (Leptotrombidium) pallida and T (L) n. sp. are described and figured, T. (L) orientalis, T (L) palpalis and Euschangastia kitajimai were observed. Four groups of virgin females (reared in isolation) were included in the experimental results: Group A, paired with males, Group B, remained in isolation 50 days (no egg laid) then exposed to a single spermatophore; Group C, exposed to 10 spermatophores; and Group D, remained in isolation. Females of each of Groups A, B, and C, laid viable eggs; Group D females laid no eggs. Observations were made on the method, behavior and rates of deposition by males, and method of insemination and related behavior pattern of the females. First deposition by the male did not require the presence of the female, nor was the presence of the male required in insemination. Insemination was required for egg deposition and there was no evidence for parthenogenesis.