Tropical rock lobster (Panulirus ornatus) uses chemoreception via the antennular lateral flagellum to identify conspecific ecdysis

Abstract

The tropical rock lobster, Panulirus ornatus, is a commercially important aquaculture species exhibiting complex social interactions in laboratory culture, including cannibalism of moulting conspecifics. Cannibalism of soft-shelled post-moult stage individuals is a major limitation during the juvenile stage of culture. Not limited to P. ornatus, cannibalism is widespread across farmed decapods, limiting stocking densities in crab, freshwater crayfish, and prawn species. To understand the mechanisms driving this behaviour and reduce its prevalence, we have investigated the role of chemoreception via the aesthetasc-bearing region of the lateral antennular flagellum, in the recognition of conspecific moulting cues. Differential expression analysis of several tissues in P. ornatus shows an upregulation of 70 ionotropic receptor isoforms, including co-receptors (IR25a and IR93a) and divergent receptors (IR4, IR7, and IR21a) in the aesthetasc-bearing region of the antennules. Deafferentation of the aesthetascs via deionised water exposure prevents juveniles from responding to conspecific moulting cues in a two-current choice flume, suggesting chemoreception, possibly olfaction, plays a role in identifying moulting juveniles. This is the first step in understanding the mechanisms via which cannibalism is triggered in juvenile P. ornatus culture. Further work in this area will help discover means to limit cannibalism in laboratory and commercial culture.

Evidence of the Existence of Site-Specific Female Contact Pheromones Involved in the Sexual Interaction Behavior of the Pacific Whiteleg Shrimp Penaeus vannamei

“…Although there has been previous research on crustacean pheromones [ 4 , 6 , 7 ], these studies have paid little attention to the potential applications of these molecules, covering only preliminary attempts to incorporate pheromones as feed attractants or their use to facilitate the capture of wild broodstock [ 8 , 9 ]; however, the use of pheromones in aquaculture and fisheries has great potential [ 10 , 11 , 12 ]. Pheromones have the potential to solve several current problems in the captive breeding of crustaceans, either by substituting current techniques or by complementing them to increase their efficiency.…”