It Pays to Be Bumpy: Drag Reducing Armor in The Pacific Spiny Lumpsucker, Eumicrotremus Orbis.

Armor is a multipurpose set of structures that has evolved independently at least 30 times in fishes. In addition to providing protection, armor can manipulate flow, increase camouflage, and be sexually dimorphic. There are potential tradeoffs in armor function: increased impact resistance may come at the cost of maneuvering ability; and ornate armor may offer visual or protective advantages, but could incur excess drag. Pacific spiny lumpsuckers (Eumicrotremus orbis) are covered in rows of odontic, cone-shaped armor whorls, protecting the fish from wave driven impacts and the threat of predation. We are interested in measuring the effects of lumpsucker armor on the hydrodynamic forces on the fish. Bigger lumpsuckers have larger and more complex armor which may incur a greater hydrodynamic cost. In addition to their protective armor, lumpsuckers have evolved a ventral adhesive disc, allowing them to remain stationary in their environment. We hypothesize a tradeoff between the armor and adhesion: little fish prioritize suction while big fish prioritize protection. Using micro-CT we compared armor volume to disc area over lumpsucker development and built 3D models to measure changes in drag over ontogeny. We found that drag and drag coefficients decrease with greater armor coverage and vary consistently with orientation. Adhesive disc area is isometric but safety factor increases with size, allowing larger fish to remain attached in higher flows than smaller fish.

[1]  A. Summers,et al.  Sticky, stickier, and stickiest - a comparison of adhesive performance in clingfish, lumpsuckers, and snailfish. , 2022, The Journal of experimental biology.

[2]  J. A. Nyakatura,et al.  Ontogeny of a tessellated surface: Carapace growth of the longhorn cowfish Lactoria cornuta , 2022, Journal of anatomy.

[3]  A. Summers,et al.  Pacific Spiny Lumpsucker armor—Development, damage, and defense in the intertidal , 2021, Journal of morphology.

[4]  R. Blob,et al.  Adhesive force and endurance of the pelvic sucker across different modes of waterfall-climbing in gobiid fishes: Contrasting climbing mechanisms share aspects of ontogenetic change. , 2021, Zoology.

[5]  A. Murat Maga,et al.  SlicerMorph: An open and extensible platform to retrieve, visualize and analyse 3D morphology , 2021, Methods in Ecology and Evolution.

[6]  R. Walter,et al.  Scale performance and composition in a small Amazonian armored catfish, Corydoras trilineatus. , 2020, Acta biomaterialia.

[7]  A. Summers,et al.  Swimming and defence: competing needs across ontogeny in armoured fishes (Agonidae) , 2020, Journal of the Royal Society Interface.

[8]  S. T. Friedman,et al.  Reef-associated fishes have more maneuverable body shapes at a macroevolutionary scale , 2020, Coral Reefs.

[9]  A. Summers,et al.  Ontogeny and potential function of poacher armor (Actinopterygii: Agonidae) , 2020, Journal of morphology.

[10]  C. Kammerlander,et al.  3D printing method for next-day acetabular fracture surgery using a surface filtering pipeline: feasibility and 1-year clinical results , 2020, International Journal of Computer Assisted Radiology and Surgery.

[11]  Andras Lasso,et al.  Polymorph segmentation representation for medical image computing , 2019, Comput. Methods Programs Biomed..

[12]  Adam P. Summers,et al.  Structure and Function of the Armored Keel in Piranhas, Pacus, and their Allies , 2018, Anatomical record.

[13]  Doug M. Boyer,et al.  MORPHOSOURCE: ARCHIVING AND SHARING 3-D DIGITAL SPECIMEN DATA , 2016 .

[14]  E. Stamhuis,et al.  Boxfish swimming paradox resolved: forces by the flow of water around the body promote manoeuvrability , 2015, Journal of the Royal Society Interface.

[15]  J. Altringham,et al.  Hydrodynamics of fossil fishes , 2014, Proceedings of the Royal Society B: Biological Sciences.

[16]  Adam P. Summers,et al.  Stick tight: suction adhesion on irregular surfaces in the northern clingfish , 2013, Biology Letters.

[17]  Wen Yang,et al.  Structure and fracture resistance of alligator gar (Atractosteus spatula) armored fish scales. , 2013, Acta biomaterialia.

[18]  Johannes E. Schindelin,et al.  Fiji: an open-source platform for biological-image analysis , 2012, Nature Methods.

[19]  E. Olevsky,et al.  Battle in the Amazon: Arapaima versus Piranha , 2012 .

[20]  Juha Song,et al.  Threat-protection mechanics of an armored fish. , 2011, Journal of the mechanical behavior of biomedical materials.

[21]  B. Hall,et al.  Comparative morphology and osteology of pelvic fin‐derived midline suckers in lumpfishes, snailfishes and gobies , 2010 .

[22]  M. Boyce,et al.  Materials design principles of ancient fish armour. , 2008, Nature materials.

[23]  George V Lauder,et al.  Ontogeny of form and function: Locomotor morphology and drag in zebrafish (Danio rerio) , 2006, Journal of morphology.

[24]  Morteza Gharib,et al.  Body-induced vortical flows: a common mechanism for self-corrective trimming control in boxfishes , 2005, Journal of Experimental Biology.

[25]  R. Morel,et al.  Shifts in drag and swimming potential during grayling ontogenesis: relations with habitat use , 2000 .

[26]  M. Koehl,et al.  Ecological biomechanics of benthic organisms: life history, mechanical design and temporal patterns of mechanical stress. , 1999, The Journal of experimental biology.

[27]  A. A. Bennett,et al.  THE EVOLUTION OF BONE , 1987, Evolution; international journal of organic evolution.

[28]  R. Lowell,et al.  Selection for Increased Safety Factors of Biological Structures as Environmental Unpredictability Increases , 1985, Science.

[29]  F. Huntingford Do inter- and intraspecific aggression vary in relation to predation pressure in sticklebacks? , 1982, Animal Behaviour.

[30]  B. Kynard Nest Habitat Preference of Low Plate Number Morphs in Threespine Sticklebacks (Gasterosteus aculeatus) , 1979 .

[31]  J. Currey,et al.  DISTINCT BARNACLES, BALANUS BALANUS AND SEMIBALANUS (BALANUS) BALANOIDES (CIRRIPEDIA) , 1978 .

[32]  George S. Arita Sexual Dimorphism in the Cyclopterid Fish Eumicrotremus orbis , 1969 .

[33]  Kirby G. Vosburgh,et al.  3D Slicer: A Platform for Subject-Specific Image Analysis, Visualization, and Clinical Support , 2014 .

[34]  Michael LaBarbera,et al.  ANALYZING BODY SIZE AS A FACTOR IN ECOLOGY AND EVOLUTION , 1989 .

[35]  Paul W. Webb,et al.  Functional Locomotor Morphology of Early Life History Stages of Fishes , 1986 .

[36]  R. M. Alexander Factors of safety in the structure of animals. , 1981, Science progress.