Published online by Cambridge University Press: 05 June 2009
In vitro pairing studies on rediae of Echinostoma trivolvis, E. caproni, Zygocotyle lunata, Ribeiroia sp. and sporocysts from a species of armatae cercaria were undertaken at 22°C in a Petri dish bioassay containing an agar substratum and a Locke's 1:1 overlay. Pairing was arbitrarily defined as larvae in contact or within 1 mm of each other. Intraspecific and interspecific pairing occurred in the bioassay using several larval combinations initially placed 5 or 10 mm apart. Intraspecific pairing occurred with the rediae of Ribeiroia sp. and interspecific pairing was seen between E. trivolvis or E. caproni and Ribeiroia sp. A previous study documented intraspecific and interspecific pairing between rediae of E. trivolvis and E. caproni. Armatae sporocysts did not pair intraspecifically or interspecifically when matched with either E. caproni or E. trivolvis rediae. Intraspecific pairing of Z. lunata or interspecific pairing between Z. lunata rediae and echinostome rediae did not occur. The significance of redial pairing remains unclear.