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The biomechanics of bloated bloodsuckers
Dave Ellerby, Wellesley College
Understanding
Animal
Movement
Energy, Performance and Fitness
Muscle and movement
…muscles move skeletal elements to transfer power
Muscle and movement: hydrostatic skeletons
Rowlerson & Blackshaw (1991), J. Exp. Biol 157: 299.
Muscle and movement
Muscle and movement
…segmental shape changes drive movement
Neural and neurochemical control
Behavior also influenced by
neurotransmitters/ hormones
Friesen & Kristan (2007), Curr. Op. Neur 17: 704.
Soft robots
Harvard University
‘Starfish’ - Harvard
Chembot – iRobot
GoQBot – Tufts University
Crawling
…extreme changes in body shape
Swimming
…totally different movement, same motor
…still the same motor, plus massive change in size
Dimensional changes during movement
Gerry SP and Ellerby DJ (2011). Biology Letters 7, 885-888.
Structural simplicity – functional flexibility
Swimming
Crawling
Feeding
How is this achieved?
Evolutionary implications?
Don’t swim after eating…
…not a hydrodynamically favorable shape!
…crawl instead?
Recovering mobility after feeding
Slow swimming
recovery, crawling
barely impaired.
Muscle and expansion
Serotonin added
No serotonin
Vertebrate muscle
Muscle and expansion
Vertebrate cross-striated muscle
Obliquely striated muscle
Hormonal modulation of muscle contraction
No serotonin
Serotonin added
…integration of behavioral and mechanical effects
Evolution of blood feeding
Apakupakul et al. (1999). Mol.
Phylo. Evol. 12, 350-359..
Blood
feeding is
the ancestral
state
The biomechanics of bloated bloodsuckers
•Structural simplicity but functional flexibility
•Supported by muscle mechanical properties
•Neurochemicals integrate behavior and biomechanics
Acknowledgements
Shannon Gerry
Amanda Hitchcock
Johanna Ascher
Karin Darakananda
Kara Feilich
Malika Hayashi
Cataia Ives
Janet Jeong
Grace Jung
Arbor Quist
Jessica Liao
Allison Robbins
Michelle Vogelzang
Jasmine Wang