Fishing for hosts: Larval spurting by the endangered thick-shelled river mussel, Unio crassus

Abstract

[Excerpt] Understanding the life-history characteristics of endangered species is crucial to their conservation, management, and predicting their responses to environmental change (Stark et al., 2004). Host specificity is central to the evolutionary diversification and conservation of the Unionida (Barnhart et al., 2008; Modesto et al., 2018). In the North American mussels of the Ambleminae subfamily, specificity toward a restricted host fish range that shares the same microhabitat as the mussel has resulted in remarkable morphologies and behaviors that dramatically increase the likelihood of attachment and successful transmission of larvae (glochidia). This includes modification of mantle flaps into lures and packaging of glochidia into conglutinates that resemble insect larvae upon which the host fishes preferentially feed (Barnhart et al., 2008). [...]