Carcinus maenas Ecdysteroids

Tomaschko, K.H., Ecdysteroids from Pycnogonum litorale (Arthropoda, Pantopoda) act as a chemical defense against Carcinus maenas (Crustacea, Decapoda), J. Chem. Ecol., 20, 1445, 1994. 

From the observation that the common shore crab (Carcinus maenas, Crustacea, Decapoda) rejects ecdysteroid-containing food, Tomaschko et al. [206] developed an in vivo oesophagus dilation assay, capable of comparing ecdysteroid analogues 20E (EC50 = 1.8 x 10 jVI) and 20E22AC (4.6 x 10 4M). 

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