Morphometry and Maturity of Paired Tanner Crabs, Chionoecetes bairdi , from Shallow- and Deepwater Environments

Crab p a r s , consisting of a male grasping another crab (the graspee), were collected by divers during the first breeding season of female snow crab Chionoecetes opllio Different types of graspees were found and were ranked according to their reproductive value to the male. High-value graspees were pubescent females (close to their terminal matunty molt) and nulliparous females ljust molted and close to oviposition). Postn~olt prirmparous females (clean-soft shell and carrying eggs) also mated and were inseminated by males, but they were of less value than pubescent or nulliparous females as there was only a remote chance that the males' stored sperm would be used to fertilize the next egg clutch. Females copulated with up to 6 different males dunng their first breeding season. Another category of graspees including males and juvenile females provided the grasping male with no fecundity benefit. Pubescent females paired with males u p to 13 d before molting. Males grasping the high-value pubescent and nulliparous females were larger, had a harder shell, and were missing fewer limbs than the males grasping low-value primiparous females, other males or juvenile females and than the overall population of adult males on the mating grounds assessed by trawl. Size-assortative mating by male chela size and female carapace width occurred in the predominant pubescent pairs. Moreover, males with larger chelae were associated with pubescent females missing fewer limbs or having relatively narrower abdomens. Both traits may influence female survivorship and lifetime fecundity. The complex assortative mating pattern of snow crabs apparently denves from mate choice and male sexual competition in the context of prolonged attractiveness of pubescent females to males

Section: Genetic Evidence For Multiple Mating Of Femalesmentioning

confidence: 55%

Section: Phasesmentioning

confidence: 90%

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Multiple choice criteria and the dynamics of assortative mating during the first breeding season of female snow crab Chionoecetes opilio (Brachyura, Majidae)

Sainte‐Marie¹,

Urbani²,

Sévigny³

et al. 1999

“…Despite a wealth of studies on the limits and mechanisms of crustacean reproduction (Gray & Powell 1964, Waddy & Aiken 1990, Paul & Paul 1992, Stevens et al 1993, Sainte-Marie & Lovrich 1994, Prager 1996, Sainte-Marie & Sainte-Marie 1999, few have conclusively demonstrated sperm limitation. This is attributable both to the large number of factors that must be identified to determine if sperm limitation is occurring and to the difficulty of determining the underlying causes.…”

Section: Introductionmentioning

confidence: 99%

Influence of male size and mating history on sperm content of ejaculates of the blue crab Callinectes sapidus

Kendall

Wolcott²,

Wolcott³

et al. 2002

Laboratory experiments were used to determine the influence of male Callinectes sapidus (Rathburn) size (larger vs smaller than the size limit of the hard crab fishery in Chesapeake Bay, which is 127 mm carapace width) and mating history (recently mated males with depleted seminal stores vs those with fully recovered resources) on number of sperm transferred to females. Females mated by males with fully recovered seminal resources received significantly more sperm than those mated with males that had mated once previously, regardless of male size. No significant difference was found between the number of sperm delivered by small and large males with similar mating history. The sperm content of ejaculates from these laboratory experiments was compared to sperm received by females collected in the field. Only 11% of field-collected females received an amount of sperm as large as that delivered by the fully recovered males in our laboratory experiments. Of the field collected females, 77% received much less sperm, similar to or below the number delivered by depleted males in our laboratory experiments.

“…Studies on commercially important species were often undertaken to understand the reproductive biology of a species to avoid over-exploitation, and to estimate the quantitative and qualitative impact of size-selective or gender-selective fisheries on reproductive success (e.g. Stevens et al 1993, SainteMarie & Lovrich 1994, Hankin et al 1997, Moriyasu & Benhalima 1998, MacDiarmid & Butler 1999, SainteMarie et al 2000, Kendall et al 2002.…”

Section: Introductionmentioning

confidence: 99%

Mating behaviour, female receptivity and malemale competition in the intertidal crab Hemigrapsus sexdentatus (Brachyura: Grapsidae)

Brockerhoff¹,

McLay²

2005

Female receptivity and male-male competition were studied in a laboratory population of the New Zealand rock crab Hemigrapsus sexdentatus. Mating only occurred in the few days prior to oviposition, when females had mobile gonopore opercula. After mating, males guarded females constantly and mated with them repeatedly until the females laid eggs. Isolated females remained receptive for significantly longer than females housed temporarily or constantly with males in the laboratory. The duration of female receptiveness can, therefore, vary in relation to the presence of males. Male-male competition was high with frequent attacks on pairs by other males. Large males mated significantly more often than medium and small males, and were more likely to take over a female from another male. However, large and small male H. sexdentatus both adjusted the ejaculate size according to the size of the female; i.e. transferred relatively large ejaculates to large females, and were equally able to transfer ejaculates to small and large females during the first mating in the season. Post-copulatory guarding reduced the risk of sperm competition. Although male-male competition appears to be the dominant factor in pair-formation, the ability of females to extend their receptivity in the absence of males, will have an impact on the operational sex ratio, and on the extent of male-male and sperm competition.