Relating form to function in the hummingbird feeding apparatus

A complete understanding of the feeding structures is fundamental in order to study how animals survive. Some birds use long and protrusible tongues as the main tool to collect their central caloric source (e.g., woodpeckers and nectarivores). Hummingbirds are the oldest and most diverse clade of nectarivorous vertebrates, being a perfect subject to study tongue specializations. T eir tongue ftmctions to intraorally transport arthropods throu h their lon bills and enables them to ex loft the nectarivorous niche by collecting small amounts of liquid, therefore it is of vital importance to study rts anatomy and structure at various scales. I focused on the portions of the hummingbird tongue that ave been s own to be key for. understanding their feeding. mechanisms. I used histo transmission and scanning electron microscopy, microCT, arid ex-vivo experiments in order to advance t e comprehension of the morphology and functioning of the hummingbird feeding apparatus. I found.that hummingbird tongues are composed mainly of thin cornified epithe. liurn, lack papillae, and completely fill the internal cast of the rostra' oropharynge.al cavity. Understanding this puzzle-piece match between bill and tongue will be essential for.th. e study of intraoral transport of nectar. Likewise, I found that the structural composition and tiss.ue architecture of.the tongue groove walls pro cl the rostral porti.on of the tongue. with elasti.c properties that are central to the stuvidy eof tongue-nectar interactions during the feeding process. Detailed studies on hummingbirds set the basis for comparisons with other nectar-feeding birds and contribute to comprehend the natural solutions to collecting liquids in the most efficient way possible.