Transcriptomic analysis of crustacean neuropeptide signaling during the moult cycle in the green shore crab, Carcinus maenas

SUMMARY1. The period of survival in distilled water is shortest with post-moult crabs, longer with pre-moult, and longest with inter-moult.2. Further, a relatively constant percentage of salts is lost, irrespective of size; hence one of the determining factors in survival is the rate of loss of these salts. The other factor is the rate of osmosis of water, causing œdema.3. With regard to the moult cycle, the concentration of the blood and the structure of the membranes are seemingly little altered, but the amount of calcium in the latter varies with moult-age, being least in post-moult and most in inter-moult membranes.4. It is concluded, that the higher the percentage of calcium, the less permeable are the membranes and the longer is the duration of survival.5. Œdema and loss of salts naturally disturb the tonicity equilibrium of the body fluid, and thus cause death.

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A pheromone bouquet controls the reproductive behaviour of the male shore crab, Carcinus maenas

Aquatic Ecology ◽

10.1007/s10452-021-09930-w ◽

2021 ◽

Author(s):

Nichola Fletcher ◽

John A. Terschak ◽

Helga D. Bartels-Hardege ◽

Ralf Bublitz ◽

Paula Schirrmacher ◽

...

Keyword(s):

High Performance ◽

Sex Pheromones ◽

Mating Behaviour ◽

Physiological State ◽

Carcinus Maenas ◽

Sympatric Species ◽

Shore Crab ◽

Moult Cycle ◽

Uridine Diphosphate ◽

Female Urine

AbstractThe reproduction of many brachyuran crustaceans involves the formation of mating pairs often around the time of the female moult with attraction of a sexual partner and mating behaviour controlled by sex pheromones. In shore crabs, Carcinus maenas, females produce sex pheromones that are released in the urine. High Performance Liquid Chromatography analysis (HPLC) of female urine shows that the pheromone, identified as the nucleotide uridine diphosphate (UDP), elutes as an unresolved peak with structurally related nucleotides. We examined female urine samples over the moult cycle and detected UDP as well as uridine triphosphate (UTP). Bioassays were conducted to establish the possibility of a blend of nucleotides forming a sex pheromone bouquet in C. maenas. Whilst UDP induced the male mate guarding behaviour (cradling), a mixture of the two nucleotides at a ratio of 4:1 UDP:UTP elicited an even stronger mating response than either UDP or UTP individually. The urine concentration and composition of these nucleotides changes over the moult period pre and post ecdysis, providing evidence that a pheromone bouquet composition is not always constant. The change of the bouquet is related to the physiological state of the sender, here the moult cycle. Our study unravels the functionality of reaction-specific molecules in a pheromone bouquet. Whilst UDP is the mating signal, UTP acts as an attractant and combined they maximise the reproductive response. The use of bouquets provides species-specificity, potentially enabling reproductive isolation of sympatric species, and contains valuable information on the physiological state of the sender.

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