Destination of apyrene sperm following migration from the bursa copulatrix in the monandrous swallowtail butterfly Byasa alcinous

Konagaya, Tatsuro; Idogawa, Naoto; Watanabe, Mamoru

doi:10.1038/s41598-020-77683-x

Cited by 8 publications

(10 citation statements)

References 30 publications

(61 reference statements)

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“…Previous studies on E. kuehniella show that adult males increase the apyrene-eupyrene ratio in response to the presence of rivals [10] but male larvae reduce the ratio after exposed to larval cues [19]. These may be ascribed to the fact that spermatogenesis of apyrenes and eupyrenes occurs at different stages of insects [53,73] and they have different functions in reproduction [56][57][58][59][60], allowing adults to increase investment in apyrene and larvae to trade-off apyrene for more eupyrene. However, the current study on pupae demonstrates that the apyrene-eupyrene ratio was about 5:1 with no significant difference between treatments.…”

Section: Discussionmentioning

confidence: 96%

“…Apyrenes may function to delay female remating [55,56] protect eupyrenes in female reproductive tract [57] or enable eupyrenes to migrate to the spermatheca [58]. More recent studies suggest that the role of apyrenes may be completed after both types of sperm arrive at the spermatheca [59,60]. The apyrene to eupyrene ratio remains consistent under the food shortage during the larval stage [61] or environmental stress during the larval [62] and pupal stages [63].…”

Section: Introductionmentioning

confidence: 99%

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Pupal Cues Increase Sperm Production but Not Testis Size in an Insect

Liu

Zheng

et al. 2021

Preprint

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Theoretic and empirical studies show that social surroundings experienced by male insects during their larval or adult stage can influence their testicular investment in diverse ways. Although insect pupae do not feed and crawl, they can communicate using sex-specific and/or non-sex specific cues. Yet, it is unknown, in any insect, whether and how male pupae can fine-tune their resource allocation to sperm production and testis size in response to socio-sexual environment. We investigated this question using a moth, Ephestia kuehniella, which produces fertile eupyrene sperm and unfertile apyrene sperm. We held male pupae individually or in groups with different sex ratios, and dissected adults upon eclosion, measured their testis size, and counted both types of sperm. We demonstrated that after exposure to conspecific pupal cues regardless of sex, male pupae increased production of eupyrenes and apyrenes at the same rate but kept testis size unchanged. We suggest that testis size is fixed after pupation because most morphological traits are formed during the larval stage, allowing little room for pupae to adjust testis size. Like adults, male pupae with fully grown testes have sufficient resources to produce more sperm of both types according to the perceived increase of sperm competition risk.

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Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Pupal Cues Increase Sperm Production but Not Testis Size in an Insect

Liu

Zheng

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Previous studies on E. kuehniella show that adult males increase the apyrene-eupyrene ratio in response to the presence of rivals [10] but male larvae reduce the ratio after being exposed to larval cues [19]. These may be ascribed to the fact that spermatogenesis of apyrenes and eupyrenes occurs at different stages of insects [53,73] and they have different functions in reproduction [56][57][58][59][60], allowing adults to increase investment in apyrene and larvae to trade-off apyrene for more eupyrene. However, the current study on pupae demonstrates that the apyrene-eupyrene ratio was about 5:1 with no significant difference between treatments.…”

Section: Discussionmentioning

confidence: 96%

“…Apyrenes may function to delay female remating [55,56], protect eupyrenes in the female reproductive tract [57], or enable eupyrenes to migrate to the spermatheca [58]. More recent studies suggest that the role of apyrenes may be completed after both types of sperm arrive at the spermatheca [59,60]. The apyrene-to-eupyrene ratio remains consistent under food shortage during the larval stage [61] or environmental stress during the larval [62] and pupal stages [63].…”

Section: Introductionmentioning

confidence: 99%

Pupal Cues Increase Sperm Production but Not Testis Size in an Insect

Liu

Zheng

et al. 2021

Insects

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Theoretic and empirical studies show that social surroundings experienced by male insects during their larval or adult stage can influence their testicular investment in diverse ways. Although insect pupae do not feed and crawl, they can communicate using sex-specific and/or non-sex specific cues. Yet, it is unknown, in any insect, whether and how male pupae can fine-tune their resource allocation to sperm production and testis size in response to socio-sexual environments. We investigated this question using a moth, Ephestia kuehniella, which produces fertile eupyrene sperm and unfertile apyrene sperm. We held male pupae individually or in groups with different sex ratios, and dissected adults upon eclosion, measured their testis size, and counted both types of sperm. We demonstrated that after exposure to conspecific pupal cues regardless of sex, male pupae increased production of eupyrenes and apyrenes at the same rate but kept testis size unchanged. We suggest that testis size is fixed after pupation because most morphological traits are formed during the larval stage, allowing little room for pupae to adjust testis size. Like adults, male pupae with fully grown testes have sufficient resources to produce more sperm of both types according to the perceived increase in sperm competition risk.

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“…The fact that most of these components are unavailable in the adult diet adds to their importance for female fitness and explains, in some extent, the ubiquity of polyandry in this group ( Drummond III, 1984 ; Eberhard, 1985 ; Simmons, 2001 ; Sanchez, Hernandez-Baños & Cordero, 2011 ; Cannon, 2020 ). However, intriguingly, in Lepidoptera there are some monandrous species ( Drummond III, 1984 ; Eberhard, 1985 ; Walters et al, 2012 ; Caballero-Mendieta & Cordero, 2013 ; Konagaya, Idogawa & Watanabe, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Atypical functioning of female genitalia explains monandry in a butterfly

Xochipiltecatl

Baixeras

Cordero

2021

PeerJ

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Monandrous species are rare in nature, especially in animals where males transfer nutrients to females in the ejaculate. The proximate mechanisms responsible for monandry are poorly studied. In butterflies and moths, the male transfers a nutritious spermatophore into the corpus bursae (CB) of the female. The CB is a multifunctional organ that digests the spermatophore and has partial control of the post-mating sexual receptivity of the female. The spermatophore distends the CB and the post-mating sexual receptivity of the female is inversely proportional to the degree of distension. The CB of many butterfly species has a muscular sheath whose contractions mechanically contribute to digest the spermatophore. As the contents of the CB are absorbed, the degree of distension decreases and the female recovers receptivity. We studied the monandrous butterfly Leptophobia aripa (Boisduval, 1836) (Pieridae) and found that females do not digest the spermatophores. We investigated the structure of the CB and found that a muscular sheath is absent, indicating that in this butterfly females lack the necessary “apparatus” for the mechanical digestion of the spermatophore. We propose that female monandry in this species is result of its incapability to mechanically digest the spermatophore, which results in a constant degree of CB distension after mating and, thus, in the maintenance of the sexually unreceptive state of females. Hypotheses on the evolution of this mechanism are discussed.

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Destination of apyrene sperm following migration from the bursa copulatrix in the monandrous swallowtail butterfly Byasa alcinous

Cited by 8 publications

References 30 publications

Pupal Cues Increase Sperm Production but Not Testis Size in an Insect

Pupal Cues Increase Sperm Production but Not Testis Size in an Insect

Pupal Cues Increase Sperm Production but Not Testis Size in an Insect

Atypical functioning of female genitalia explains monandry in a butterfly

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