With regard to photoperiod, USNO (2015) records indicate that daylength
was shorter from October to February and longer from March to September.
I was fascinated when I learned about subjects as diverse as animal thermoregulation and how daylength
controlled avian reproduction.
Pharmacological doses of thyroxine simulate the effects of increased daylength
and thyroidectomy decreased daylength
, on the reproductive system of European starlings.
Another important factor working in the early hunter's favor is extreme daylength
extends for more than 13 hours, providing some evening work time.
Although temperature is important, daylength
also is likely a contributing factor, so spawning might occur in cooler temperatures during abnormally cool springs and vice versa in springs that warm early.
Effect of Daylength
, Photon Flux Density, Night Temperature and Day Temperature on the Yield and Composition of Peppermint Oil.
Effects of daylength
and hopper density on reproductive traits in a Japanese population of Locusta migratoria L.
The paper "Diurnal and Seasonal Mood Tracks Work, Sleep and Daylength
Across Diverse Cultures" claims that positive tweets were seen in abundance on Saturdays and Sundays, with the morning peaks occurring about two hours later in the day, implying that people awaken later on weekends.
Budde (1983) claims that daylength
and lack of moonlight is important in triggering puberty, as well as ovulation activities, in female white-tailed deer (Odocoileus virginianus).
and photon flux density influence the growth regulator effects on morphogenesis in epicotyl segments of Troyer citrange.
Mineral concentrations in four tropical forages as affected by increasing daylength