NONLETHAL IMAGING TECHNIQUES FOR CRAB SPERMATHECAE

Techniques for collecting information on spermathecae without dissecti on were evaluated on the giant crab Pseudocarcinus gigas. Techniques t ested were: biopsy, ultrasound, conventional x-radiography, computeriz ed tomography (CT) scans, and magnetic resonance imaging (MRI). Attemp ts at biopsy and ultrasound imaging were unsuccessful. Spermathecae we re imaged by x-radiography, although resolution was poor. suggesting t hat it can be applied only to gain general information such as determi ning whether mating has occurred. High resolution images were produced with CT and MRI. Resolution by MRI is of such detail that internal st ructure of spermathecae is imaged. Nonlethal techniques allow animals to be used repeatedly, which permits monitoring of changes during mati ng, sperm storage, and extrusion.