"Evening" - what is it, definition of the term
The dusk period, occurring after daylight diminishes and before full nightfall, generally covers the hours between late afternoon and the onset of darkness; it is marked by reduced solar illumination, cooler temperatures, and a shift in both natural processes and human activities toward nocturnal patterns.
Detailed information
Twilight marks a transition in temperature and humidity that influences the activity of many ectoparasites. As daylight wanes, ambient moisture often rises, creating favorable conditions for questing ticks. These arachnids ascend vegetation and await a passing host, relying on the cooler, damp air to reduce desiccation risk. Their peak questing period typically aligns with the early hours of nightfall, when host movement increases and visual detection is limited.
Biting insects also adjust their behavior to the dimming light. Many species, such as certain sand flies and midges, become most active during the dusk interval, exploiting reduced predator visibility. Their feeding cycles concentrate within the first two hours after sunset, when host skin temperature remains elevated from daytime exposure, facilitating blood extraction.
Lice, being obligate ectoparasites of mammals and birds, do not depend on external light cues for feeding. Nevertheless, host grooming frequency often declines during the night, providing a window of reduced disturbance. This period allows lice to complete blood meals and reproduce with minimal interference, contributing to rapid population growth in densely populated colonies.
Fleas exhibit heightened activity at the onset of darkness. Their jumping mechanics benefit from lower ambient light, which diminishes the effectiveness of visual predators. Flea larvae develop within the host’s environment, but adult fleas emerge and seek hosts primarily during the early night hours, attracted by carbon dioxide and heat signatures that remain strong after sundown.
Key environmental factors influencing these arthropods at this time include:
- Increased relative humidity, which slows water loss in ticks and insects.
- Lower ambient temperature, reducing metabolic stress.
- Diminished host grooming and vigilance, offering uninterrupted feeding opportunities.
- Elevated carbon dioxide concentrations near sleeping hosts, acting as a strong attractant for fleas and ticks.
Control measures tailored to this period focus on interrupting host–parasite contact:
- Apply topical acaricides and insecticides before the onset of darkness to ensure coverage during peak activity.
- Use bed nets or screened sleeping areas to block flea and tick access.
- Maintain low indoor humidity levels through ventilation, reducing favorable conditions for questing behavior.
- Implement regular grooming and inspection routines during daylight to lower parasite loads before the night‑time surge.