Introduction: Nature's Tiny Engineers

• Bugs as extraordinary problem solvers with incredible solutions
• Career studying: spiders using webs as slingshots, worms forming knots, aquatic beetles with scuba gear
• Focus on extraordinary engineers pushing limits of fluid mechanics and bioengineering
• Student Elyuchilida observed tiny insect urinating for hours in Atlanta backyards
• Behavior so quick barely visible to naked eye

Insect Urination Basics

• Almost all insects urinate in some form (closed system: what goes in must come out)
• Protagonist: Homalodisca vitripennis (glassy-winged sharpshooter)
  • Transparent wings give name
  • Specializes in feeding on xylem fluid from plants (sap sucker)
  • Functions as "plant's mosquito"
  • Spreads bacteria into plants causing devastating diseases
  • Major agricultural problem in California: millions of dollars damage to vineyards
  • Compensate small size with massive numbers

High-Speed Camera Discoveries

• Insect forms droplet of pee then flings at extreme accelerations
• 40G forces = 40x faster than cheetah sprint
• Microscope analysis of "business end" reveals "butt flicker" structure
• Evolved springs and latches like catapult for efficient repeated hurling
• High acceleration droplet launching mechanism

Speed Measurement Puzzle

• Measured speed of both droplets and flicker
• Puzzling observation: droplet speed in air faster than flicker speed
• Expected 100% ratio, actual 150-200% faster than flicker
• Counterintuitive example: baseball player throwing 100mph but ball measures 100mph in flight
• Amateur throwing 50mph but ball measuring 100mph would be surprising

Surface Tension Energy Storage Discovery

• Unlike rigid baseball, droplets are squishy due to surface tension
• Aha moment: insect storing energy in surface tension before launch
• Kitchen table lab experiment: droplets on speaker squished at high speeds
• Water at tiny scales behaves differently due to surface tension
• With right timing can store energy and launch at extremely high speeds
• Analogy: child on trampoline
• Built "catapult" or "cat-a-pee" to test timing concept
• Slow droplets don't launch, right speed enables flinging

Mechanism Summary

• Insects use scaffolding structure to store energy in surface tension
• Throw droplets at record-breaking speeds for urination efficiency

Why This Remarkable Ability Evolved

Reason 1: Zero Calorie Diet

• Feeding on xylem fluid from plant roots through soil
• Very poor nutrients: just water and minerals
• Unlike phloem fluid (rich in sugar from photosynthesis at leaves)
• Analogy: human sustaining on diet lemonade
• Constant drinking requires constant urination

Reason 2: Size Constraints

• Insects tiny (smaller than pinky)
• Surface tension enables energy storage but also impediment
• Gravity doesn't matter at this scale
• Surface tension sticks droplets to bodies
• Must actively flick droplets away
• Very difficult for tiny bugs to urinate

Comparison: Cicadas vs Sharpshooters

• Cicadas are cousins, also xylem fluid feeders
• Cicadas urinate in jets (not droplets)
• Video shows cicadas singing and urinating simultaneously after hibernation

Engineering Solutions

• Tiny engineer survives on barely-water xylem fluid
• Evolved catapulting structure for high-speed droplet flinging
• Similar to other engineers on Friday night at bar (drinking/urinating analogy)
• "It's not a bug, it's a feature"

Practical Applications

• Potential future applications: more efficient water ejector systems
• Smartphones, watches, hearing aids could benefit
• Honest admission: not primary motivation for 4-year obsession

True Motivation: Inspiring Curiosity

• Sharing work with kids ignites curiosity
• Insect urination makes children's eyes light up
• Children laugh, run around backyards looking at bugs, asking questions
• Reminds us: can discover marvelous in mundane, even own backyards
• Just need to look closely