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The long and short of honey bee tongues

Some sources say honey bees are “long-tongued” and some say they are “not long-tongued.” So, which is it? After spending a couple of hours with Google and a stack of books, I’ve come to a conclusion, but it’s not crystal clear.

According to a paper by R. P. Hawkins called “Length of tongue in a honey bee in relation to the pollination of red clover” (1969), a honey bee can extend its proboscis about 7 mm (0.27 inches) into the corolla of a red clover flower. A different source said a honey bee tongue “can extend 1/4-inch.” Those are pretty consistent, so let’s say a honey bee tongue is 7 mm—a length, by the way, that is insufficient for red clover.

My “go to” reference for all things bee, Bees of the World by O’Toole and Raw claims that the tongues of short-tongued bees, which include Hylaeus, Colletes, and Andrena species, are 0.5–3 mm long. Medium-tongued bees, which include Melitta, Dasypoda, Halictus, and Lasioglossum species, are about 3.5–5.5 mm. That part is pretty easy.

But they don’t follow up with a range for long-tongued bees. Instead, they begin writing about certain species of long-tongued bees, including bumble bees with tongues that range from 9–18 mm and Anthophora with tongues that range from 9–20 mm.

Reading between the lines, then, I’m going to assume that anything with a tongue longer than 5.5 mm is a “long-tongued bee.” But honey bees are on the short end of long, if you will, because their tongues are certainly nowhere near as long as some Bombus and Anthophora species, and they are not even long enough to nectar on red clover. Honey bees are more or less intermediate between medium-tongued and long-tongued bees.

Like many shorter-tongued bees, honey bees are known for robbing when they can’t reach down into a corolla to reach a nectar source. They will either drill holes through a petal or prize the petals apart in order to reach the nectar, a maneuver that results in no pollination for the flower since the pollen is left undisturbed.

So there you have it: a honey bee is a long-tongued bee with a mediumish tongue. No wonder I couldn’t figure it out.


Nectar robbing
Carpenter bee robbing nectar from the base of flower. Wikimedia photo by Alvesgaspar.



Persian beekeeping


Actually, the terms “long tongued” and “short tongued” bees are for an evolutionary grouping rather than the actual length of the tongue (annoying, I know). The bee families Apidae and Megachilidae are a monophyletic group of “long tongued bees”. All the other bees fall into a loose, less well determined group of “short tongued bees”. That includes Halictidae, Melittidae, Andrenidae, and Stenotritidae. There’s a good paper by Hedtke et al 2013 on this but I don’t know if it’s open access:


I forgot Colletidae! Also short tongued!


Yes, I agree. But my readers are not evolutionary biologists not do they want to be. The take home message for them is that various tongue lengths exist in the bee world and that tongue length influences foraging choice. How they got that way is not as important, especially in the incipient stages of learning about bees. My mission here it to encourage people to explore the world of bees—to become aware of them—not to be the definitive authority. I couldn’t do that in any case.

For those who want to read the Hedtke paper, it’s freely available for download.

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