Graduate Research Course
Insect Biophysics & Biochemistry
From metamorphosis to the pollinator crisis — flight mechanics, sensory systems, silk and venom, social organization, and the biochemistry of the most diverse animal group on Earth.
Key Equations of Insect Biophysics
Tracheal Diffusion Limit
\( J = -D_{\text{O}_2}\frac{\partial C}{\partial x}, \quad L_{\max} \sim \sqrt{\frac{2D C_0}{\dot{V}_{\text{O}_2}}} \)
Wing Loading Scaling
\( W/S \propto M^{1/3}, \quad f \propto M^{-1/4} \)
Ecdysone-JH Ratio
\( \text{Molt type} = f\!\left(\frac{[\text{20E}]}{[\text{JH}]}\right): \text{larval} \to \text{pupal} \to \text{adult} \)
Bombardier Beetle Reaction
\( \text{H}_2\text{O}_2 + \text{C}_6\text{H}_4(\text{OH})_2 \xrightarrow{\text{catalase}} \text{H}_2\text{O} + \text{C}_6\text{H}_4\text{O}_2 + \Delta T \)
Silk Tensile Stress
\( \sigma = E\,\varepsilon + \eta\,\dot{\varepsilon}, \quad \sigma_{\text{UTS}} \approx 0.5\text{--}1.3\;\text{GPa} \)
Insect Decline Rate
\( \frac{dN}{dt} = rN\!\left(1 - \frac{N}{K}\right) - \mu(c)\,N, \quad \mu \propto [\text{neonicotinoid}] \)
About This Course
Insects comprise over one million described species — more than all other animal groups combined. They have conquered every terrestrial habitat, evolved powered flight 150 million years before pterosaurs, and developed social systems of staggering complexity. Yet insect biomass is declining at roughly 2.5% per year worldwide, threatening ecosystems that depend on pollination, decomposition, and nutrient cycling.
This course applies rigorous physics and chemistry to understand insects at every scale: the fluid dynamics of tracheal gas exchange, the nonlinear aerodynamics of flapping flight, the endocrine cascades driving metamorphosis, the materials science of silk and cuticle, the explosive thermochemistry of bombardier beetle defense, and the information theory of pheromone communication.
Every module includes MathJax derivations, SVG diagrams, and computational models. Cross-links to our Bee Biophysics and Ant Biophysics courses provide deep dives into specific eusocial lineages and their unique adaptations.
Nine Modules
M0
Physical Foundations
Scaling laws at insect scale, tracheal gas exchange, exoskeleton mechanics, and chitin-cuticle composite materials.
M1
Flight Mechanics
Unsteady aerodynamics, wing-beat kinematics, leading-edge vortices, and the biomechanics of hovering versus forward flight.
M2
Metamorphosis & Development
Hormonal control of molting cycles, ecdysone-juvenile hormone interplay, imaginal disc patterning, and holometabolous body remodeling.
M3
Sensory Systems
Compound eye optics, mechanosensory halteres, infrared pit organs, electroreception, and antennal olfactory biophysics.
M4
Silk, Venom & Defense
Silk fibroin self-assembly, spider-silk comparisons, venom cocktail biochemistry, and the bombardier beetle explosion mechanism.
M5
Social Organization
Eusociality origins, caste determination, pheromone-mediated colony regulation, termite mound climate engineering, and division of labor.
M6
Aquatic Insects
Surface tension locomotion, plastron breathing, gill adaptations, and the fluid mechanics of diving beetles and water striders.
M7
Insect-Microbe Symbiosis
Gut microbiome function, endosymbiont biochemistry, bioluminescence in fireflies, and fungus-farming in leaf-cutter ants.
M8
Decline & Conservation
Quantifying the insect apocalypse, neonicotinoid neurotoxicity, habitat fragmentation modeling, and pollinator network resilience.
Recommended Textbooks
- [1] Chapman, R.F. (2013). The Insects: Structure and Function, 5th ed. Cambridge University Press.
- [2] Gullan, P.J. & Cranston, P.S. (2014). The Insects: An Outline of Entomology, 5th ed. Wiley-Blackwell.
- [3] Nation, J.L. (2016). Insect Physiology and Biochemistry, 3rd ed. CRC Press.
- [4] Klowden, M.J. (2013). Physiological Systems in Insects, 3rd ed. Academic Press.