Nocturnal Bees Forage by Starlight in Australia
Honeybees and other bee species are solar insects. The sun plays a vital role in their navigation systems, and most flowers they pollinate are open and available in the daytime due to sunlight.
Many night-blooming plants, like the cereus flower, are white because they reflect moonlight and that makes them appear to glow in order to attract quality pollinators. They also emit potent scents to lure insects to their nectar. Cacti also bloom at night and have intense scents, large flowers and lots of nectar. So far, night-blooming flowers have always been considered the realm of nocturnal creatures like moths and bats, but not many, if any, bees.
Bees try to get home to the hive before sunset so they won’t get lost, and they don’t emerge for a new day of foraging until after sunrise when the sun warms up their world.
But this post is about Australia. In a new study by Australian scholars published in Journal of Hymenoptera and released on October 30, 2020, exciting new revelations about the secret life of some bees has been revealed. The study is: Morphometric comparisons and novel observations of diurnal and low-light-foraging bees.
Australian bees are known to pollinate plants on sunny days, but this new study has identified two species that have adapted their vision for night-time conditions for the first time. The study by a team of ecology researchers has observed night time foraging behavior by a nomiine (Reepenia bituberculata) and masked (Meroglossa gemmata) bee species, with both developing enlarged compound and simple eyes which allow more light to be gathered compared to their daytime kin.
This unrelated 4:46-minute video by Texas A&M University features Katy Boyd discussing Foraging Behavior in the Honeybee:
These observations are the first regarding Australian bees foraging in low-light conditions, and this is also the first evidence of low-light foraging behavior in the colletid bee subfamily, Hylaeinae. The bee species involved were Reepenia bituberculata on the palms Dypsis lutescens and Licuala ramsayi, and Meroglossa gemmate on Melaleuca leucadendra. These are the first plant records for these bee species confirmed crepuscular foraging behavior for any Australian bee species and some were sighted nearly 90 minutes past sunset as they foraged into the evening twilight, when host plants can only be seen as silhouettes.
These sightings were in November 2019 and in February 2020. This confirms that there are at least these two types of nocturnal bees or star foragers in Australia, whereas almost all bees are considered sun foragers.
Experts agree that more studies are needed regarding bee foraging behavior that is restricted to dim-light conditions in Australia. There are no previously published recordings of Australian twilight-foraging for any species even though there has been much conjecture about low-light adapted bees. Here is another excellent presentation on the findings of this team.
Our main image today is of a beautiful sunset. It fit the theme of nocturnal bees, and it also fits the fact that the sun literally set on the year 2020 tonight. We wish you all things good in 2021. Please stay true to all bees everywhere.
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