Data from: Do wolf spiders' egg-sacs emit tactochemical signals perceived by mothers?

Parent-offspring relationships take many forms. One particular form of parental behaviour is egg care when parents brood their eggs after laying them. Parents of many oviparous vertebrates and terrestrial arthropods brood their eggs. Spiders present a particular interesting form of parental behaviour, enclosing their eggs in a silk sac (or egg-sac) and can care for it until spiderlings emerge. This study investigated proximal cues which stimulate the wolf spider Pardosa saltans (Lycosidae) to care for their egg-sacs, transport it for 30 days and open it to allow spiderlings to emerge. We showed that mothers discriminate between egg-sacs differencing in mass (empty or not) as they do not hang an empty egg-sac but do not discriminate between egg-sacs with viable and nonviable juveniles either when manipulating or when hanging them. However, mothers do not open nonviable egg-sacs but abandon them only at the end of the juvenile development period when spiderlings are due to emerge (30-day-old egg-sacs). We investigated egg-sac silk chemical cues that mothers detected by presenting them egg-sacs washed with different polar solvents or chemical egg-sacs silk extracts. We identified the polar and apolar chemical compounds of lipid extracts of egg-sacs detected by mothers during manipulation. Our results demonstrate that these compounds stimulate maternal care, and mothers detect mobility of juveniles at the end of the post-embryonic period, when juveniles are ready to emerge from a 30-day-old egg-sac indicating that tactochemical stimuli are involved in egg-sac care.

亲子关系存在多种表现形式，其中一类典型的亲本行为为产卵后的护卵行为，即亲本在产卵后对所产的卵进行抚育。诸多卵生脊椎动物与陆生节肢动物的亲本均会开展护卵行为。蜘蛛的护卵行为尤为独特：它们会将卵包裹于丝囊（或称卵囊）中，并持续抚育直至幼蛛孵化。本研究以狼蛛科（Lycosidae）的盐洒狼蛛（Pardosa saltans）为研究对象，探究了刺激其开展卵囊抚育、携带卵囊长达30天，并在幼蛛孵化时开启卵囊的近端触发线索。研究发现，母蛛能够依据卵囊质量（是否为空）进行区分：它们不会悬挂空卵囊，但在操作或悬挂卵囊时，无法区分携带有存活幼体与非存活幼体的卵囊。不过，母蛛不会开启携带有非存活幼体的卵囊，仅会在幼体发育末期，也就是幼蛛即将孵化的30日龄卵囊阶段，才会遗弃此类卵囊。为探究母蛛所感知的卵囊丝状物化学信号，本研究通过为母蛛提供经不同极性溶剂洗涤后的卵囊，以及卵囊丝状物的化学提取物开展实验；同时，我们还鉴定出母蛛在操作卵囊过程中所识别的卵囊脂质提取物中的极性与非极性化学成分。研究结果表明，此类化学成分可激发亲本抚育行为；此外，母蛛能够在胚胎发育末期，即幼蛛即将从30日龄卵囊中孵化时，感知幼体的活动能力，这说明触觉-化学联合刺激共同参与了卵囊抚育过程。