Glochidial Mortality in Freshwater Mussels

摘要: A crucial factor in the reproduction of parasites is rate successful host infection. In most parasitic species subtle mechanisms for effective transmission infectious stages have evolved. These include vector transmission, highly mobile propagules that are able to locate and infect new hosts actively, attraction hosts, extremely resistant may spend an extended dormant period “waiting” a suitable host, or parasite by direct contact between individuals (Anderson 1981; Begon et al. 1988). The precise mode infection must be considered important evolutionary constraint (Calow 1983). Except African South American families Mutelidae Mycepodidae, which produce larvae with specific morphology (Wachtler al., Chap. 6, this Vol.; Hoeh 14, Vol.), Unionoidea, achieved via unique larval stage, glochidium. Glochidial anatomy well adapted efficient attachment epithelia aquatic vertebrates (Lefevre Curtis 1910; Arey 1924a). Three morphological types glochidia can distinguished based on number shape hooks their ventral apex. common (e.g. genera Margaritifera, Quadrula, Elliptio) form hookless, referring absence spined hook projecting inward from edge each valve present hooked Anodonta, Unio, Lasmigona). third (axe-head) distinctly flared margins carrying double known North genus Proptera 1910).