Crab libidos can be curbed by shipping traffic, according to preliminary research that deployed crustacean sex dolls to see if noise pollution threw male green shore crabs off their game. The dolls were pheromone-soaked sponges that were convincing enough to get the crabs on board, but exposure to ship noise proved to be enough to turn the amorous crabs off.
Anthropogenic noise is known to be a pollutant capable of disrupting the lives of marine animals, but past research typically hasn’t focused on how it affects crustaceans. A 2022 paper decided to change this, exploring how male green shore crabs’ (Carcinus maenas) mating game was affected by recordings of ship noise.
Dummy females were then presented to the male crabs, made up of a sponge soaked in the female sex pheromone uridine diphosphate and skewered with a few cocktail sticks for extra sex appeal. “Sight is not the most important sense for the crabs when mating,” lead author Kara Rising told Hakai Magazine, “but they do like a nice pair of gams.”
The male crabs’ behavior indicated they approved of the pheromone-soaked dolls, but when the recordings of ship noises started, things got more complicated. Compared to when the mating arena was quiet, male green shore crabs were significantly less likely to try and copulate with the doll decoy.
“We found a significant, negative effect of noise on the occurrence of mating behaviour compared to no noise conditions, though no significant effect of noise on the time it took for a crab to respond to the pheromone,” wrote the study authors.
“Such effects suggest reproductive impairment due to anthropogenic noise, which could potentially contribute to decreased crustacean populations and subsequent ecological and economic repercussions.”
As for why, it’s possible that noise acts as a distraction that takes the crabs’ attention away from the chemical cues that help them mate successfully. Alternatively, they may be freaked out that a predator is approaching, or simply stressed out by the extra sensory information.
They conclude that further studies using larger sample sizes and a double-blind set up in a controlled environment could bolster the preliminary findings, but these little dolls have done their bit in demonstrating how an unnaturally noisy ocean environment could be harming marine ecosystems.
One small doll for crabs’ sex lives, big news for crab kind.
The study is published in PLOS ONE.
Source Link: Crabs Given Crabby Sex Dolls Reveal Ship Noise Kills The Crustacean Mood
