DOES BEHAVIOR REFLECT PHYLOGENY IN SWIFTLETS (AVES, APODIDAE) - A TEST USING CYTOCHROME-B MITOCHONDRIAL-DNA SEQUENCES

Swiftlets are small insectivorous birds, many of which nest in caves a nd are known to echolocate. Due to a lack of distinguishing morphologi cal characters, the taxonomy of swiftlets is primarily based on the pr esence or absence of echolocating ability, together with nest characte rs. To test the reliability of these behavioral characters, we constru cted an independent phylogeny using cytochrome b mitochondrial DNA seq uences from swiftlets and their relatives. This phylogeny is broadly c onsistent with the higher classification of swifts but does not suppor t the monophyly of swiftlets. Echolocating swiftlets (Aerodramus) and the nonecholocating ''giant swiftlet'' (Hydrochous gigas) group togeth er, but the remaining nonecholocating swiftlets belonging to Collocali a are not sister taxa to these swiftlets. While echolocation may be a synapomorphy of Aerodramus (perhaps secondarily lost in Hydrochous), n o character of Aerodramus nests showed a statistically significant fit to the molecular phylogeny, indicating that nest characters are not p hylogenetically reliable in this group.