title: A tale of two antennules: the performance of crab odour-capture organs in air and water.
abstract: Odour capture is an important part of olfaction, where dissolved chemical cues (odours) are brought into contact with chemosensory structures. Antennule flicking by marine crabs is an example of discrete odour capture (sniffing) where an array of chemosensory hairs is waved through the water to create a flow-no flow pattern based on a narrow range of speeds, diameters of and spacings between hairs. Changing the speed of movement and spacing of hairs at this scale to manipulate flow represents a complicated fluid dynamics problem. In this study, we use numerical simulation of the advection and diffusion of a chemical gradient to reveal how morphological differences of the hair arrays affect odour capture. Specifically, we simulate odour capture by a marine crab (Callinectes sapidus) and a terrestrial crab (Coenobita rugosus) in both air and water to compare performance. We find that the antennule morphologies of each species are adaptions to capturing odours in their native habitats. Sniffing is an important part of odour capture for marine crabs in water where the diffusivity of odorant molecules is low and flow through the array is necessary. On the other hand, flow within the hair array diminishes odour-capture performance in air where diffusivities are high. This study highlights some of the adaptations necessary to transition from water to air.
authors.affiliation: Applied Mathematics Unit, School of Natural Sciences, University of California, Merced, CA 95343, USA.|Department of Biology, New Mexico Institute of Mining and Technology, Socorro NM 87081, USA.
authors.forename: Lindsay D
authors.identifier: 0000-0001-5708-2789
authors.initials: LD
authors.lastname: Waldrop
authors.affiliation: Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.|Department of Mathematics, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Miller
authors.affiliation: Applied Mathematics Unit, School of Natural Sciences, University of California, Merced, CA 95343, USA skhatri3@ucmerced.edu.
authors.forename: Shilpa
authors.identifier: 0000-0002-0848-5925
authors.initials: S
authors.lastname: Khatri
mesh_terms: D000388:Air; D000818:Animals; D033381:Anomura / Q000033:anatomy & histology / Q000502:physiology*; D057506:Arthropod Antennae / Q000033:anatomy & histology / Q000502:physiology*; D003386:Brachyura / Q000033:anatomy & histology / Q000502:physiology*; D055696:Olfactory Perception / Q000502:physiology*; D014867:Water
chemical_list: D014867:Water
keywords: Callinectes; Coenobita; advection diffusion; biofluids; mathematical model; terrestrialization