Phylogenetic Patterns of Parental Care in Calidridine Sandpipers

We examined the sequence of parental-care evolution in calidridine sandpipers by mapping parental-care characters onto the two trees produced by a maximum-likelihood and parsimony analysis of molecular data. Our analysis indicated that asymmetric biparental care (male incubates and cares for young, female incubates) is plesiomorphic for the group. This state has been maintained in at least 10 of the 22 species investigated. There have been four changes from the ancestral condition: (1) three to four increases in female care coupled with a complete loss of male care; (2) an increase in female care with the maintenance of male care, producing symmetric biparental care; (3) an increase in female care followed at a later date by three independent losses of male care in Calidris melanotos, C. fuscicollis,and Tryngites subruficollis; and (4) a decrease in female care in C. pusilla.