The characteristics of the insect spine and eye that I have recently investigated give considerable strength to my theories regarding infrared and microwave communication among insects, and are: (1) Application to spines of the formula for determining resonant radiation modes indicates the infrared or microwave region for moths and the visible light region for small mites. (2) Waxy substances such as cover the insect cuticle have thermoelectret properties. Beeswax is one of the most efficient thermoelectret substances yet discovered. Under certain conditions of an electrical field and heat, such waxy substances can be polarized or depolarized with both heterocharges and homocharges. The insect exoskeleton is, without doubt, an efficient thermoelectret. (3) Insect waxes have a dielectric constant lying somewhere between 2.5 and 3.0, the constant most expected for an efficient dielectric waveguide design within the infrared region. (4) The refractive index of the exoskeleton is 1.5; for hollow dielectric waveguides with this refractive index, the HE_n mode exhibits the lowest attenuation. (5) The directivity of a dielectric aerial of optimum design is proportional to the tube length. If its wall thickness is slight (as in insects), such an aerial has a single lobe radiation pattern of a value such that it excites only the HE_n hybrid mode, the most likely for dielectric insect spines. (6) The main lobe of the radiation pattern of a dielectric rod is more directive and the side lobes are smaller if the rod is tapered toward the free end. The taper formula fits that of insect spines, most of which are tapered. (7) Insect spines differ from the remainder of the insect exoskeleton in having a uniform consistency throughout; the hardness of the spines makes them tubular dielectrics. (8) The insect antenna loses its sensing ability under conditions of extremely high humidity; insects attempting to clean the antennae indicate a loss of aerial gain caused by excessive moisture.

For the reasons listed I conclude that insect spines are dielectric antennae with inherent thermoelectret properties. The very fact that they occur in arrays on the antenna indicates a radiation configuration. Transmission of infrared radiation through the outer corneal lens of moth eyes matches the transmission windows of the atmosphere. The corneal lens has 3 IR windows at 1–2.5 μ, 3–6 μ and 7–14 μ. Moth-wing scale patterns are highly infrared reflective and iridescent.