Variation of sperm allocation with male size and recovery rate of sperm numbers in spiny king crab Paralithodes brevipes

Sato, Taku; Ashidate, Masakazu; Jinbo, Tadao; Goshima, Seiji

doi:10.3354/meps312189

Cited by 55 publications

(32 citation statements)

References 46 publications

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“…Bukowski & Christenson (1997) also showed that sperm stored inside the female's spermatheca were on the order of 1 3 10 4 . However, sperm counts in scorpions more closely resembled ejaculates of other arthropods (e.g., Brown & Knouse 1973;Swallow & Wilkinson 2002;Sato et al 2006;Vahed 2006;Dallai et al 2009;Aron et al 2016). Similar to what happened with scorpions' seminal vesicles, Snow & Andrade (2004) also reported a correlation between the number of spermatozoa in the right and left pedipalps.…”

Section: Discussionsupporting

confidence: 55%

From storage to delivery: sperm volume and number of spermatozoa inside storage organs and ejaculates in males ofTimogenes elegans(Scorpiones: Bothriuridae)

Vrech

Olivero

Mattoni

et al. 2018

Journal of Arachnology

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Abstract. Sperm competition influences the evolution of many reproductive traits such as gonads, sperm or genitalia. Many sperm competition analyses concentrate in testes and ejaculates. Among arachnids, scorpions constitute an intriguing taxon for examining sperm production and usage. For example, in the family Bothriuridae the females of Timogenes elegans Mello-Leitão, 1931 accept more than one male per reproductive season and males produce spermatozoa continuously, storing them inside two elastic storage organs (i.e., two seminal vesicles plus two deferent ducts) before inseminating females, using a sclerotized spermatophore. In this study, we analyzed the sperm storage organs and the ejaculate volume transferred by T. elegans. We described the volume and number of spermatozoa at storage sites and in ejaculates, and investigated ejaculate volume and concentration in remating experiences. Storage organs varied in total size. Inside the spermatophore, the volume of the sperm drop represented 38% of the volume of both sperm storage sites. The remaining space around the sperm drop is filled with a gel-like substance. The ejaculate volume and spermatozoa number did not vary significantly between consecutive matings. Timogenes elegans stored abundant sperm inside the seminal vesicles. Available sperm was divided equally between both storage organs, and ejaculates were diluted in the spermatophore, presumably, with the gel stored in the trunk. There was no effect of body condition over any of the variables analyzed. Male sperm storage and ejaculate production are discussed considering the sperm depletion hypothesis and the sperm competition theory.

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Section: Discussionsupporting

confidence: 55%

From storage to delivery: sperm volume and number of spermatozoa inside storage organs and ejaculates in males ofTimogenes elegans(Scorpiones: Bothriuridae)

Vrech

Olivero

Mattoni

et al. 2018

Journal of Arachnology

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“…The size-dependent reproductive potential in males resulted from the num- ber of sperm in the vasa deferentia of smaller males being smaller than for larger males. In other crabs, larger males had more abundant sperm than smaller males (Sapelkin & Fedoseev 1986, Jivoff 1997, Sato et al 2005b and passed larger ejaculate to each mate than did small males (Jivoff 1997, Sato et al 2006. Also in H. dentata, a decrease in ejaculate size with increasing mating frequency would differ between male size classes, which may result in differences in the degree of decrease in reproductive success of females with increasing male mating frequency between male size classes.…”

Section: Discussionmentioning

confidence: 98%

Impacts of male-only fishing and sperm limitation in manipulated populations of an unfished crab, Hapalogaster dentata

Sato¹,

Goshima²

2006

Mar. Ecol. Prog. Ser.

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“…Several studies have shown that males adjust the number of sperm released based on the expected number of eggs available (e.g. males release more sperm when mating with larger females; Marconato & Shapiro 1996, Sato et al 2006. In loliginid squid, the fertilization success of head-to-head copulation events might not dramatically increase with an increase in sperm number due to a limited availability of eggs, and strategic allocations of sperm to more than a single female might be adaptive for small males.…”

Section: Most Alternative Mating Tactics Involve Dimorphism In Secondmentioning

confidence: 99%

Threshold dimorphism in ejaculate characteristics in the squid Loligo bleekeri

Iwata

Sakurai²

2007

Mar. Ecol. Prog. Ser.

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Male dimorphism has been thought to correlate with alternative reproductive behaviors. Alternative reproductive behaviors promote asymmetry in sperm competition, and the differences in fertilization success could promote adaptations in ejaculate characteristics in relation to each reproductive behavior. Using allometric analysis, we show that ejaculate dimorphism clearly exists in males of the squid Loligo bleekeri, a cephalopod species with body size-related alternative mating behaviors. A morphological switch point was detected for internal characters: larger individuals produced discontinuously longer spermatophores than did smaller individuals, although no switch point was detected for external characteristics (fin length, fin width, head width, mantle width, tentacle length and hectocotylus length) except for bimodal body size. This clear internal switch point could be an adaptation to the characteristic alternative mating behaviors of loliginid squid, in which males use different mating tactics to pass spermatophores to different sperm storage sites in and on the females. Our results indicated that alternative reproductive behaviors can result in morphological adjustment in internal characteristics. KEY WORDS: Male dimorphism · Sperm competition · Alternative reproductive behavior · Squid · Loligo bleekeri Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 345: [141][142][143][144][145][146] 2007 squid, however, have 2 distinct sperm storage sites (the seminal receptacle near the mouth and the opening of the oviduct within the mantle cavity), which corresponds to alternative mating behaviors (Hanlon & Messenger 1996). Loliginid squids form dense spawning aggregations on coastal spawning grounds, and males pair temporarily with females in order to mate (Hanlon & Messenger 1996). These spawning aggregations usually tend to have more males than females and the mating behaviors that males use correlate with their body size: large males pair with females and copulate in the male parallel position by attaching spermatophores to the female's oviduct in the mantle cavity, and small sneaker males mate in the head-to-head position by attaching spermatophores near the mouth of females that have already paired with other males (Hanlon et al. 1997(Hanlon et al. , 2002. Sneaker males fertilize fewer eggs than paired males do (Iwata et al. 2005). This suggests that sperm stored near the oviduct have an advantage, perhaps because they are stored closer to the eggs being spawned than are sperm stored in the seminal receptacle near the mouth. These size-dependent alternative mating behaviors and the differences in fertilization success could promote strategic ejaculation in males specializing on different sperm-passing sites. Furthermore, loliginid males pass sperm as spermatophores, enclosing the spermatozoa within a hard shell, and males store several hundred spermatophores when they mature. Therefore, the ejaculate characteristics associated with a male's status c...

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Variation of sperm allocation with male size and recovery rate of sperm numbers in spiny king crab Paralithodes brevipes

Cited by 55 publications

References 46 publications

From storage to delivery: sperm volume and number of spermatozoa inside storage organs and ejaculates in males ofTimogenes elegans(Scorpiones: Bothriuridae)

From storage to delivery: sperm volume and number of spermatozoa inside storage organs and ejaculates in males ofTimogenes elegans(Scorpiones: Bothriuridae)

Impacts of male-only fishing and sperm limitation in manipulated populations of an unfished crab, Hapalogaster dentata

Threshold dimorphism in ejaculate characteristics in the squid Loligo bleekeri

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