Molecular identification of alarm cues in the defensive secretions of the sea hare Aplysia californica
نویسندگان
چکیده
Prey species possess numerous strategies to reduce predation. One tactic is to respond with antipredator behaviours when conspecific alarm cues are detected. The sea hare Aplysia californica defends itself from predators in many ways, one of which is releasing ink and opaline upon attack. Previous work showed that a mixture of ink and opaline from A. californica causes conspecifics to respond with antipredator behaviours such as moving away and/or ‘galloping’. We examined the specificity of the alarm response, including identifying the molecules mediating it. Either ink or opaline alone evokes the full alarm response, but conspecific mucus, conspecific haemolymph, odour from predatory spiny lobsters, or odour from algal food do not. Thus, the defensive secretions, ink and opaline, specifically act as alarm cues to nearby conspecifics. We isolated and identified the alarm cues in ink as the base uracil and the nucleosides uridine and cytidine. Each of these molecules individually elicits frequencies of alarm behaviours as great as ink. Ink without its alarm cue molecules does not elicit a significant frequency of alarm behaviours. Thus, these three molecules together are necessary and sufficient to produce alarm responses. Aplysia californica antipredator behaviours are also elicited by ink from the congener Aplysia juliana or Aplysia dactylomela. Furthermore, ink from the squid Lolliguncula brevis or the octopus Octopus bimaculoides also elicits antipredator behaviours by A. californica, owing to the presence of uracil and uridine. Thus, these alarm cues may be common among inking molluscs.
منابع مشابه
Molecular Identification of the Persian Gulf Sea Hare (Aplysia sp.) Based on 16s rRNA Gene Sequence
Background: Sea hares of the Aplysia genus are among the mollusks of interest for various researchers to study their phylogeny, bioactive compounds and the nervous system. These mollusks are herbivorous and produce chemical compounds (ink) to defend themselves. The present study provided molecular identification of the Persian Gulf (Bushehr city) sea hare using 16s rRNA gene sequence. Materials...
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Sea hares of the genus Aplysia rely on an array of behavioral and chemical defenses, including the release of ink and opaline, to protect themselves from predation. While many studies have demonstrated that ink and opaline are repellent to predators, very little is known about which components of these secretions are active against predators. Ink was previously shown to facilitate the escape of...
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