title: Mouthpart conduit sizes of fluid-feeding insects determine the ability to feed from pores.
abstract: Fluid-feeding insects, such as butterflies, moths and flies (20% of all animal species), are faced with the common selection pressure of having to remove and feed on trace amounts of fluids from porous surfaces. Insects able to acquire fluids that are confined to pores during drought conditions would have an adaptive advantage and increased fitness over other individuals. Here, we performed feeding trials using solutions with magnetic nanoparticles to show that butterflies and flies have mouthparts adapted to pull liquids from porous surfaces using capillary action as the governing principle. In addition, the ability to feed on the liquids collected from pores depends on a relationship between the diameter of the mouthpart conduits and substrate pore size diameter; insects with mouthpart conduit diameters larger than the pores cannot successfully feed, thus there is a limiting substrate pore size from which each species can acquire liquids for fluid uptake. Given that natural selection independently favoured mouthpart architectures that support these methods of fluid uptake (Diptera and Lepidoptera share a common ancestor 280 Ma that had chewing mouthparts), we suggest that the convergence of this mechanism advocates this as an optimal strategy for pulling trace amounts of fluids from porous surfaces.
authors.affiliation: Department of Biological Sciences, Kent State University at Stark, North Canton, OH 44720, USA mlehner1@kent.edu.
authors.forename: Matthew S
authors.identifier: 0000-0003-1999-196X
authors.initials: MS
authors.lastname: Lehnert
authors.affiliation: Department of Biological Sciences, Kent State University at Stark, North Canton, OH 44720, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bennett
authors.affiliation: Department of Biological Sciences, Kent State University at Stark, North Canton, OH 44720, USA.
authors.forename: Kristen E
authors.initials: KE
authors.lastname: Reiter
authors.affiliation: Department of Mathematical Sciences, Clemson University, Clemson, SC 29634, USA.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Gerard
authors.affiliation: Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
authors.forename: Qi-Huo
authors.initials: QH
authors.lastname: Wei
authors.affiliation: Department of Biological Sciences, Kent State University at Stark, North Canton, OH 44720, USA.
authors.forename: Miranda
authors.initials: M
authors.lastname: Byler
authors.affiliation: Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
authors.forename: Huan
authors.initials: H
authors.lastname: Yan
authors.affiliation: Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Wah-Keat
authors.initials: WK
authors.lastname: Lee
mesh_terms: D000825:Animal Structures / Q000033:anatomy & histology*; D000818:Animals; D002080:Butterflies / Q000033:anatomy & histology*; D005247:Feeding Behavior; D009036:Moths / Q000033:anatomy & histology*
keywords: Diptera; Lepidoptera; capillarity; liquid bridges; nanoparticles