The Impact of Sunlight on Bees
Sunny days diminish as summer gives way to fall. As the sun sets, the bees retire for the night. Bees, with their unique orientation to light, use the sun for direction and navigation. Besides their prominent compound eyes for vision, they possess three simple eyes, or ‘ocelli,’ arranged triangularly on the tops of their heads. These ocelli are light sensors. This video, shared by postgraduate student Hamish Symington, features bees examined by Kristina Buch in the University of Cambridge’s botanical garden. Notably, the ocelli are situated between the compound eyes.
An intriguing video circulating online reveals bees in a laboratory enclosure. When the researcher dims the lights, the bees instantly plummet, indicating they won’t fly sans light. This behavior mirrors what’s observed in nature when clouds sporadically block the sun. On sunny days, plants buzz with pollinator activity. Yet, when shadows loom, bees vanish. As days become colder and shorter, pollinators become a rarer sight. However, warm October afternoons might still bring bees out, scavenging for winter reserves. Late-season flowers such as goldenrod, Douglas aster, and California poppy continue to nourish these bees during this transition.
Pictures by Mallory Mead showcase:
- Triepeolus bee.
- Aster viola and goldenrod in a natural meadow.
- A long-horned bee and a sweating bee on black-eyed susan (Rudbeckia hirta).
- A green metallic sweat bee on Scabiosa.
Types of Bees and Their Late-season Activities
1. Social Bees:
- Honey Bees: They hustle to accumulate enough honey before winter renders foraging impossible.
- Bumble Bees: The late summer and fall seasons usher in an influx of bumblebee queens. Post breeding in underground hives during summer, new queens emerge in late season to mate and forage, while the rest of the colony fades away. For regional bumblebee details, consult this western US guide.
2. Solitary Bees:
- By season’s end, many solitary bees conclude their nesting activities, laying the foundation for their species’ next generation. Those with garden nesting boxes should remember to bring bees inside and cleanse their cocoons for the season. Visit here for more on mason bee care.
- Most adult solitary bees, after nesting, reach their lifecycle’s end. However, female Ceratina bees, or small carpenter bees
- , are a unique exception. These resilient females linger as deep into the cold season as possible, primarily to safeguard their nests. These maternal warriors are diligent in repelling any threats such as predators, pests, and parasitoids that attempt to breach the safety of their nests.
- Breathtaking Imagery by Mallory Mead:
- Close-up of a nest built with leaves, mud, and petals, all prepared and sealed for winter.
- Intricately designed bamboo petal nest.
- A Final Glimpse of the Season’s Bees
- As autumn progresses, we eagerly seek those last, fleeting glimpses of the year’s buzzing inhabitants. Observing their activities, from rapid foraging to diligent nest protection, serves as a poignant reminder of nature’s cycles and the importance of these vital pollinators. With winter approaching, these bees, whether social or solitary, complete their seasonal tasks and prepare for the challenges ahead.
- This article marks the end of our series delving into the seasonal intricacies of bee life in the Willamette Valley. We’re grateful for your engagement on this enlightening journey through the complex and captivating lives of bees. Their actions, behaviors, and sheer determination remind us of nature’s wonders and the interconnectedness of life.
- Source Cited:
- Danforth, B. N., Minckley, R. L., & Neff, J. L. (2019). The solitary bees: Biology, evolution, conservation. Princeton University Press.
