Intrigued by the lack of sex drive in prawns that are bred in captivity for eating, a researcher found the females were not releasing enough pheromones, and the males were not intersted in the pheromones they were releasing.
Gay Marsden of the life sciences department in Queensland University of Technology (QUT) spent two months filming what prawns got up to when the sun went down.
The Australian prawn aquaculture industry depends on black tiger prawns, Penaeus monodon.
Using infrared cameras, Marsden compared the bedroom behaviour of captive-bred prawns with their wild counterparts.
"Males mate with females after the females moult, when they have lost their shells their bodies are soft and can be implanted with sperm," she said.
"But when I looked at the videos of the captive-reared prawns, when the females moulted, the males weren't interested, indicating pheromones were lacking.
"Their non-reproductive behaviour is normal, so they appear healthy in that regard, but there is a problem, the male and females are not attracted to each other.
"I found it was partly the females fault probably for not releasing many pheromones, but there was also something wrong with the males, they weren't very receptive to what pheromones there were."
Marsden said that for an animal that had a brain the size of a pin head, prawns were surprisingly complex, said a QUT release.
"Their endocrine system is not functioning normally and further research is needed to find out why that is," she added.