"Light" - what is it, definition of the term
Illumination is electromagnetic radiation detectable by the human visual system, composed of photons that propagate at roughly 299,792 km/s in vacuum, displaying dual wave‑particle behavior, and covering wavelengths between approximately 380 nm and 750 nm, the range identified as the visible spectrum.
Detailed information
Illumination refers to electromagnetic radiation within the visible portion of the spectrum, typically ranging from approximately 380 nm to 750 nm. Photons in this range possess sufficient energy to stimulate retinal receptors, enabling visual perception in most organisms.
Key physical parameters include wavelength, which determines perceived color; frequency, the inverse of wavelength; and intensity, measured in lux or candela, which quantifies luminous flux per unit area. Color temperature, expressed in kelvins, characterizes the hue of a source, influencing both visual comfort and biological responses.
Natural emission originates from the sun, delivering a broad spectrum that peaks near 500 nm. Artificial emitters encompass incandescent filaments, fluorescent tubes, and solid‑state diodes. Each technology presents distinct spectral profiles, efficiency ratings, and thermal outputs, affecting suitability for specific applications.
Interaction with ectoparasites such as ticks, insects, lice, and fleas depends on phototactic behavior and spectral sensitivity. Many species exhibit positive phototaxis toward ultraviolet (UV) wavelengths (300–400 nm), while others respond to blue (450–495 nm) or green (495–570 nm) light. Attraction mechanisms involve vision, heat perception, and circadian regulation.
Practical use of illumination for pest management includes:
- UV‑emitting traps targeting adult flies and mosquitoes.
- Blue‑LED devices positioned near livestock to draw ticks away from hosts.
- Green‑light panels in grain storage to deter stored‑product beetles.
- Low‑intensity red illumination for monitoring louse activity without stimulating movement.
Biological effects extend beyond attraction. Exposure to specific wavelengths can disrupt developmental cycles, inhibit egg hatching, or alter feeding patterns. For example, continuous UV exposure reduces flea larval survival by up to 40 %, while intermittent blue light delays tick molting by several days. Circadian entrainment, mediated by light cues, regulates rhythmic behaviors such as questing in ticks and host‑seeking in fleas.
Effective implementation requires matching spectral output to the target species’ sensitivity, optimizing intensity to avoid repellence, and integrating illumination with complementary control measures such as chemical treatments or environmental sanitation.