Sperm transfer during mating, movement of sperm in the female reproductive tract, and sperm precedence in the common cutworm Spodoptera litura

Abstract

Abstract. Mating behaviour, sperm transfer and sperm precedence were studied in the moth Spodoptera litura (Fabr.) (Lepidoptera: Noctuidae). There existed a rhythmic, diel pattern of mating behaviour of this moth during the scotophase, presumably set with respect to an endogenous activity rhythm. Approximately 30 min after copulation had started, the formation of the corpus of the spermatophore began in the bursa copulatrix of the female moth, but full inflation of the corpus was not completed until 45–60 min after mating had started. The mature spermatophore contained about 350 eupyrene sperm bundles and a large number of individual (loose) apyrene spermatozoa. The mating status and the age of the male insect influenced the number of sperm transferred to the female within the spermatophore, and also affected the consequent fertility. There was no evidence of sperm reflux within the male tract. Within the female, dissociation of eupyrene sperm bundles was evident within the spermatophore less than 15 min after the completion of mating. Spermatozoa began to move from the bursa (in which the spermatophore is lodged) into the spermatheca 30–45 min after the end of the copulation, and the quantity of sperm in the spermatheca reached a plateau at 90 min after mating. Apyrene sperm reached the spermatheca first, followed by eupyrene sperm. Examination of total (apyrene plus eupyrene) sperm in the female tract showed that 86% of mated females received an apparently normal amount of total sperm from the male. Examination of eupyrene sperm alone showed that 81% of matings resulted in an apparently normal transfer of eupyrene sperm. A small proportion (approximately 8%) of the matings, however, were identified as transferring a clearly subnormal quantity of eupyrene sperm to the spermatheca. The eggs produced as a result of such pairings displayed much reduced fertility (about 43%) compared to those from matings confirmed to have transferred normal quantities of sperm, which showed about 92% fertility. This shows that the availability of eupyrene sperm in the spermatheca may be an important constraint on fertility in normal populations of insects. In the laboratory, S. litura females exhibited multiple matings. Of the females, 93% mated, and the mean frequency of mating was 1.69. Mating with a fertile male led to the oviposition of an increased number of eggs. This effect continued even when the female subsequently mated with an infertile male. Displacement of sperm from previous matings is known to be an important factor in the evolution of multiple mating strategies. Our results on sperm utilization by S. litura indicated that after a second mating, the sperm utilized for subsequent fertilization were almost exclusively from the last mating with little mixing. The proportion of eggs fertilized by sperm from the second mating (P2) was calculated as 0.95, indicating almost complete sperm precedence from the last mating.

Influência da temperatura na freqüência de cópula de Anticarsia gemmatalis Hübner e Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

“…4). Seth et al (2002) observaram a transferência do espermatóforo e a transferência de espermatozóide durante a cópula de S. litura (F.) e verifi caram que 30 min. após a cópula, a parte tubular do espermatóforo ainda estava parcialmente dentro do aparelho genital do macho.…”

“…Porém, tais parâmetros podem ser afetados não somente pela freqüência de cópulas (Opp & Prokopy 1986), mas também pela idade (Delisle & Bouchard 1995, Roggers & Marti 1996, Seth et al 2002 e o tamanho dos adultos (Bergstrom et al 2002), além do processo de maturação do ovário que, por sua vez, pode ser afetado pela temperatura (Taufer et al 2000, Crema & Castelo Branco 2004 e/ou por fatores nutricionais (Jervis et al 2001, Jervis et al 2005.…”

A Z-linked sterility locus causes sexual abstinence in hybrid females and facilitates speciation inSpodoptera frugiperda

“…Only during successful copulation is a spermatophore formed inside the female's genital pouch, the bursa copulatrix (Takeuchi and Miyashita ; Amaldoss and Hsue ; Seth et al. ). As the spermatophore persists after the sperm has been transported to the spermatheca (the final sperm storage organ in the female; Takeuchi and Miyashita ; Seth et al.…”

“…As the spermatophore persists after the sperm has been transported to the spermatheca (the final sperm storage organ in the female; Takeuchi and Miyashita ; Seth et al. ), absence of a spermatophore cannot be due to resorption. The finding that most RC hybrid females did not mate successfully confirms the behavioral observations of Schöfl et al.…”

Microscopic organization of the sperm storage tubules in the oviducal gland of the female gummy shark (Mustelus antarcticus), with observations on sperm distribution and storage

“…Sperm storage has several advantages including (1) reduction of the dependence of finding appropriate mates; (2) reduction in predation due to the reduced number of times for copulation; (3) ensuring a supply of sperm where there is temporal separation of reproductive events or geographical separation of gender groups; (4) preventing loss of valuable sperm; (5) the protection of sperm; (6) maintenance of viability, motility, and fertilizing capabilities of sperm; (7) allowing for a delay in fertilization and embryonic development until better environmental conditions occur; and (8) permitting multiple inseminations. Multiple inseminations are advantageous as they may increase (1) mate choice; (2) the chance of fertilization; (3) genetic diversity of offspring; (4) fitness, quality, and survival of offspring; and (5) sperm competition (Fox, 1956(Fox, , 1977Howarth, 1974;Saint-Girons, 1975;Zweifel and Dessauer, 1983;Schuett and Gillingham, 1986;Schwartz et al, 1989;Hunter et al, 1991;Watson, 1991;Birkhead and Moller, 1993;Taggart, 1994;Murphy-Walker and Haley, 1996;Blackburn, 1998;Gist and Congdon, 1998;Olsson and Madsen, 1998;Sever and Brizzi, 1998;Suarez, 1998;Crichton, 2000;Potter and Kramer, 2000;Feldheim et al, 2001;Pearse and Avise, 2001;Pearse et al, 2002;Saville et al, 2002;Seth et al, 2002;Sever, 2002;Madsen et al, 2005).…”