Ejaculate allocation in Brachyura: What do males of Metacarcinus edwardsii respond to?

Pardo, Luis Miguel; Riveros, Marcela; Chaparro, Óscar R.; Pretterebner, Katrin

doi:10.3354/ab00693

Cited by 12 publications

(4 citation statements)

References 40 publications

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“…On its side, males evolved gonopods with varied species specific morphological features (Becker et al ., 2012) likely aimed to prevent sperm competition and the intensity of polygyny (Pretterebner et al ., 2022). They also have the ability to deposit their spermatozoa encapsulated in spermatophores that provide nutrition and protection to the cells, allocate the volume of ejaculates based on the socio-sexual context, and even sequentially ejaculate sperm and seminal fluid that hardens within the seminal receptacle in order to isolate or displace sperm masses previously deposited by competing males (Sainte-Marie, 2007; Pardo et al ., 2016, 2018). The patterns of male sperm delivery and female storage of P. meridionalis , as well the structure of the female reproductive tract, resembles partially that described in D. sayi (Swartz, 1976) and provides further support for the hypothesis of a coercive mating system and strong sexual antagonistic coevolution at play.…”

Section: Discussionmentioning

confidence: 99%

Opposites attract: Multiple evidence of sexual antagonistic coevolution driving extreme male-biased sexual size dimorphism inPanopeus meridionalis

Farias,

Ribeiro,

Lancia

et al. 2024

Preprint

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Explanations for the evolution of male-biased size dimorphism (MBSSD) traditionally focus on male competition and female choice, overlooking the alternative that larger males may be better at coercing females into mating. While displaying considerable diversity, ‘true crabs’ (Eubrachyura) share common traits that theoretically should promote the evolution of coercive mating strategies. Despite this, there is a conspicuous lack of studies investigating this aspect. We investigated several reproductive and life history traits ofPanopeus meridionalis(a mud crab that exhibits extreme MBSSD) to assess whether the specific set of characters is consistent with the hypothesis of sexual antagonistic coevolution at place. We found that the high MBSSD is likely driven by sexual conflict, where males use their size to coerce females into mating. Experimental matings involved male aggression towards females. Females first resist male attempts, but are ultimately subdued. Mating is relatively brief and there is no evident pre or post copulatory guarding. The female reproductive tract lacks complex structures for long-term sperm storage or manipulation, and given the small size of seminal receptacles related to male sperm load capacity, it is unlikely for females to store sperm from multiple partners. All considered, the evidence suggests that females have limited control over paternity and support the existence of an intrinsically coercive mating system inP. meridionalis. We propose this species as an interesting model for studying the resolution of sexual conflict through antagonistic coevolution and selection in the highly diverse group of true crabs.

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Section: Discussionmentioning

confidence: 99%

Opposites attract: Multiple evidence of sexual antagonistic coevolution driving extreme male-biased sexual size dimorphism inPanopeus meridionalis

Farias,

Ribeiro,

Lancia

et al. 2024

Preprint

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“…The left vas deferens was used for biochemical analyses and the right vas deferens was used to determine the dry weight to relate the quantity of each biochemical component to it. Normally both vasa deferentia have similar weight 67 . Dry weight was determined by oven drying the right vas deferens for 4 days at 70 °C and weighing it to a precision of 0.00001 g. Total dry weight of paired vasa deferentia (i.e.…”

Section: Methodsmentioning

confidence: 96%

Influence of mating strategies on seminal material investment in crabs

Pretterebner

Pardo²,

Paschke³

et al. 2022

Sci Rep

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Reproduction involves high energetic costs which are related to behaviour and gamete production. In females energy allocation to gamete production has been well documented. However, estimations of male investment in seminal material are scarce. The present study aims to assess and compare male investment in four brachyuran species by determining biochemical substrates present in the vasa deferentia to subsequently estimate energetic investment during the reproductive cycle. We identified two groups with contrasting energy investments. Two species, Homalaspis plana and Romaleon setosum, showed high investment due to significant quantities of proteins and lipids. Both species are characterised by large and complex vasa deferentia, and the formation of a remarkably large sperm plug deposited to the female after copulation as a sperm competition avoidance strategy. In contrast, Metacarcinus edwardsii and Taliepus dentatus invested little energy in their smaller-sized and simpler vasa deferentia. Morpho-functional traits may play a key role in determining the investment, which may also be influenced by mechanisms (i.e. mating tactics) to prevent sperm competition and the intensity of polygyny. This study emphasises the high amount of energy males invest in seminal material and highlights the diversity of mating strategies in Brachyura, which are reflected even on the physiological level.

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“…The left vasa deferentia were used to estimate their dry weight (seminal material) and to calculate the vasosomatic index (VSI, n = 4). The VSI has been suggested as an indicator of the reproductive condition of males [8,15,38]. The VSI (expressed as a percentage) was calculated: VSI = (2 × VDW/BDW) × 100, with VDW being the dry weight of the left vasa deferentia (oven dried for 5 days at 70°C and weighed to a precision of 0.0001 g) and BDW being the dry weight of the complete body (oven dried for 5 days at 70°C and weighed to a precision of 0.01 g).…”

Section: Methodsmentioning

confidence: 99%

Temperature-dependent seminal recovery in the southern king crab Lithodes santolla

2019

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Male-biased fishery management can provoke depletion of seminal reserves, which is the primary cause of sperm limitation. Therefore, identifying factors which contribute to the vulnerability to depletion of seminal reserves is a priority. The present study aimed to determine the effect of temperature on the recovery rate of sperm and seminal reserves after their depletion in Lithodes santolla , an important fishery resource in southern Chile. Sperm and seminal reserves were not fully recovered within 30 days. Temperature significantly affected seminal recovery: after 30 days the recovery index increased to 40% and 21% at 9°C and 12°C, respectively. The twice as fast seminal recovery at 9°C may be explained by the zone of origin of the individuals in this study (northern distributional limit), and 12°C may be close to the threshold of temperature tolerance. Lithodes santolla populations subject to intense male-only fisheries may be vulnerable to depletion of seminal reserves and a climate change scenario could additionally aggravate the risk of seminal depletion in L. santolla in its northern distributional limit.

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Ejaculate allocation in Brachyura: What do males of Metacarcinus edwardsii respond to?

Cited by 12 publications

References 40 publications

Opposites attract: Multiple evidence of sexual antagonistic coevolution driving extreme male-biased sexual size dimorphism inPanopeus meridionalis

Opposites attract: Multiple evidence of sexual antagonistic coevolution driving extreme male-biased sexual size dimorphism inPanopeus meridionalis

Influence of mating strategies on seminal material investment in crabs

Temperature-dependent seminal recovery in the southern king crab Lithodes santolla

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