Movement of spermatozoa in the reproductive tract of adult male Spodoptera litura: daily rhythm of sperm descent and the effect of light regime on male reproduction

R K Seth, D K Rao, S E Reynolds

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Abstract

Sperm production and movement from the fused testes into the male reproductive tract of the common cutworm Spodoptera litura were studied in insects maintained in a 12 h: 12 h light dark (LD) regime. Two types of sperm bundles, eupyrene (nucleated) and apyrene (anucleate) were present in the adult testes. Eupyrene bundles constituted about 25% of the total. Descent of spermatozoa from the testes into the upper vas deferens (UVD) first occurred about 24-30 h before adult eclosion. On entering the reproductive tract, eupyrene spermatozoa remained in bundles while apyrene bundles became dissociated before they reached the UVD. Downward movement of both eupyrene and apyrene spermatozoa within the male tract occurred in a daily rhythm. Sperm descent from the testes into the UVD occurred during the early scotophase, followed by their further descent into the seminal vesicle (SV) during the photophase. Spermatozoa remained in the SV for only a short duration, whence sperm quickly passed through the lower vas deferens into the duplex, which acted as the main sperm storage organ until mating was initiated. During mating 80% of sperm left the duplex, but mating did not influence the number of sperm bundles that subsequently descended into the duplex or the rate of their descent. There was no evidence of sperm reflux. Rearing in constant light (LL) and in constant dark (DD) reduced the number of eupyrene sperm present in the testes of adults that emerged in LL and DD compared to controls (LD), although there was no significant effect on the number of apyrene sperm in the testes. The rhythmic pattern of sperm descent was suppressed in both LL and DD regimes, and the number of sperm in the duplex was adversely affected, with a marked impact in LL reared insects. Male longevity, mating behaviour, oviposition and fertility were found to be more severely affected in LL than in DD. (C) 2002 Elsevier Science Ltd. All rights reserved.
Original languageEnglish
Pages (from-to)119-131
Number of pages13
JournalJournal of Insect Physiology
Volume48
Issue number1
Publication statusPublished - 2002

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Spodoptera
Spodoptera litura
Reproduction
Spermatozoa
photoperiod
spermatozoa
Light
Testis
Sperm Count
Vas Deferens
testes
Seminal Vesicles
Insects
seminal vesicles
Oviposition
cutworms
insects
storage organs
Fertility
scotophase

Cite this

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title = "Movement of spermatozoa in the reproductive tract of adult male Spodoptera litura: daily rhythm of sperm descent and the effect of light regime on male reproduction",
abstract = "Sperm production and movement from the fused testes into the male reproductive tract of the common cutworm Spodoptera litura were studied in insects maintained in a 12 h: 12 h light dark (LD) regime. Two types of sperm bundles, eupyrene (nucleated) and apyrene (anucleate) were present in the adult testes. Eupyrene bundles constituted about 25{\%} of the total. Descent of spermatozoa from the testes into the upper vas deferens (UVD) first occurred about 24-30 h before adult eclosion. On entering the reproductive tract, eupyrene spermatozoa remained in bundles while apyrene bundles became dissociated before they reached the UVD. Downward movement of both eupyrene and apyrene spermatozoa within the male tract occurred in a daily rhythm. Sperm descent from the testes into the UVD occurred during the early scotophase, followed by their further descent into the seminal vesicle (SV) during the photophase. Spermatozoa remained in the SV for only a short duration, whence sperm quickly passed through the lower vas deferens into the duplex, which acted as the main sperm storage organ until mating was initiated. During mating 80{\%} of sperm left the duplex, but mating did not influence the number of sperm bundles that subsequently descended into the duplex or the rate of their descent. There was no evidence of sperm reflux. Rearing in constant light (LL) and in constant dark (DD) reduced the number of eupyrene sperm present in the testes of adults that emerged in LL and DD compared to controls (LD), although there was no significant effect on the number of apyrene sperm in the testes. The rhythmic pattern of sperm descent was suppressed in both LL and DD regimes, and the number of sperm in the duplex was adversely affected, with a marked impact in LL reared insects. Male longevity, mating behaviour, oviposition and fertility were found to be more severely affected in LL than in DD. (C) 2002 Elsevier Science Ltd. All rights reserved.",
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T1 - Movement of spermatozoa in the reproductive tract of adult male Spodoptera litura: daily rhythm of sperm descent and the effect of light regime on male reproduction

AU - Seth, R K

AU - Rao, D K

AU - Reynolds, S E

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N2 - Sperm production and movement from the fused testes into the male reproductive tract of the common cutworm Spodoptera litura were studied in insects maintained in a 12 h: 12 h light dark (LD) regime. Two types of sperm bundles, eupyrene (nucleated) and apyrene (anucleate) were present in the adult testes. Eupyrene bundles constituted about 25% of the total. Descent of spermatozoa from the testes into the upper vas deferens (UVD) first occurred about 24-30 h before adult eclosion. On entering the reproductive tract, eupyrene spermatozoa remained in bundles while apyrene bundles became dissociated before they reached the UVD. Downward movement of both eupyrene and apyrene spermatozoa within the male tract occurred in a daily rhythm. Sperm descent from the testes into the UVD occurred during the early scotophase, followed by their further descent into the seminal vesicle (SV) during the photophase. Spermatozoa remained in the SV for only a short duration, whence sperm quickly passed through the lower vas deferens into the duplex, which acted as the main sperm storage organ until mating was initiated. During mating 80% of sperm left the duplex, but mating did not influence the number of sperm bundles that subsequently descended into the duplex or the rate of their descent. There was no evidence of sperm reflux. Rearing in constant light (LL) and in constant dark (DD) reduced the number of eupyrene sperm present in the testes of adults that emerged in LL and DD compared to controls (LD), although there was no significant effect on the number of apyrene sperm in the testes. The rhythmic pattern of sperm descent was suppressed in both LL and DD regimes, and the number of sperm in the duplex was adversely affected, with a marked impact in LL reared insects. Male longevity, mating behaviour, oviposition and fertility were found to be more severely affected in LL than in DD. (C) 2002 Elsevier Science Ltd. All rights reserved.

AB - Sperm production and movement from the fused testes into the male reproductive tract of the common cutworm Spodoptera litura were studied in insects maintained in a 12 h: 12 h light dark (LD) regime. Two types of sperm bundles, eupyrene (nucleated) and apyrene (anucleate) were present in the adult testes. Eupyrene bundles constituted about 25% of the total. Descent of spermatozoa from the testes into the upper vas deferens (UVD) first occurred about 24-30 h before adult eclosion. On entering the reproductive tract, eupyrene spermatozoa remained in bundles while apyrene bundles became dissociated before they reached the UVD. Downward movement of both eupyrene and apyrene spermatozoa within the male tract occurred in a daily rhythm. Sperm descent from the testes into the UVD occurred during the early scotophase, followed by their further descent into the seminal vesicle (SV) during the photophase. Spermatozoa remained in the SV for only a short duration, whence sperm quickly passed through the lower vas deferens into the duplex, which acted as the main sperm storage organ until mating was initiated. During mating 80% of sperm left the duplex, but mating did not influence the number of sperm bundles that subsequently descended into the duplex or the rate of their descent. There was no evidence of sperm reflux. Rearing in constant light (LL) and in constant dark (DD) reduced the number of eupyrene sperm present in the testes of adults that emerged in LL and DD compared to controls (LD), although there was no significant effect on the number of apyrene sperm in the testes. The rhythmic pattern of sperm descent was suppressed in both LL and DD regimes, and the number of sperm in the duplex was adversely affected, with a marked impact in LL reared insects. Male longevity, mating behaviour, oviposition and fertility were found to be more severely affected in LL than in DD. (C) 2002 Elsevier Science Ltd. All rights reserved.

M3 - Article

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SP - 119

EP - 131

JO - Journal of Insect Physiology

JF - Journal of Insect Physiology

SN - 0022-1910

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ER -