Data from: Single and multiple mating reduces longevity of female dumpling squid (Euprymna tasmanica)

For many species, mating is a necessary yet costly activity. The costs involved can have an important influence on the evolution of life histories and senescence. Females of many species mate multiply and this behaviour can inflict a longevity cost. Most studies investigating the effects of multiple mating on female survival have been conducted on insects and the effects in other taxa are largely unknown. We investigate the effects of both a single mating and a second mating on longevity in female dumpling squid (Euprymna tasmanica), a species in which both sexes mate multiply. Through comparing the longevity of virgin, once-mated and twice-mated females, we found that a single mating reduced female lifespan by 15 days on average. A second mating resulted in an additional 8 day (on average) longevity cost, despite no difference in total clutch mass, number of clutches, single egg mass or number of eggs per clutch between once-mated and twice-mated females. This demonstrates a cost to multiple mating which may be independent of the cost of egg production. Furthermore, total clutch mass and female lifespan were positively correlated, whilst female lifespan decreased with increasing average water temperature. The presence of an additive effect of reproduction on longevity suggests that multiple mating in cephalopods may have benefits that outweigh these costs, or that there is a conflict in optimal mating frequency between males and females.

对于多数物种而言，交配是一项必要却代价高昂的生命活动。此类代价对生物生活史的演化与衰老进程具有重要影响。诸多物种的雌性个体存在多次交配行为，该行为会对其寿命造成损耗。目前针对多次交配对雌性存活影响的研究大多以昆虫为对象，其他动物类群中的相关效应尚不明晰。本研究以两性均存在多次交配行为的饺子乌贼（Euprymna tasmanica）为研究对象，探究单次交配与二次交配对雌性个体寿命的影响。通过对比处女雌性、单次交配雌性与两次交配雌性的寿命，我们发现单次交配可使雌性平均寿命缩短15天；二次交配则会额外带来平均8天的寿命损耗，尽管单次交配与两次交配雌性的总产卵团质量、产卵批次数量、单卵质量以及每批次产卵数均无显著差异。这一结果证实，多次交配存在独立于产卵成本之外的繁殖代价。此外，总产卵团质量与雌性寿命呈正相关，而雌性寿命则随平均水温升高而降低。繁殖对寿命存在累加效应，这表明头足类动物的多次交配或许存在能够抵消此类代价的进化收益，或是雌雄个体间存在最优交配频率的演化冲突。