The Appearance of Bees to Each Other (Conspecifics) in Ultraviolet Light Part 3

In this article series, we have been exploring how bees see each other in ultraviolet light (UV). I have been using UV at 365 nanometers, which as shown earlier is close to a honey bee’s maximum sensitivity in UV. Seeing bees more like they see each other can bring us closer to understanding their lives. Besides its intrinsic fascination, a more intimate understanding of bees makes us better beekeepers.
For routinely encountered bees in the apiary, I think the two stunning flagship photographs from the previous article were bees with eyes fluorescing in blue (see Figure 1) and scent-fanning bees, their Nasonov glands fluorescing brightly (see Figure 2).
As mentioned in the previous article, the tilted elevation of a scent fanner’s abdomen varies. Some scent fanners hold their abdomens almost too high given what is needed for broadcasting scent. Figure 3 shows one of these scent fanners in the background (behind a scent fanner in a typical position). Around this unusual scent fanner, no other bees are bumping into her from behind and causing her to hold her abdomen higher. It seems the behavior is intrinsic to the bee herself. In UV 365 nm, the ventral (stomach) side of her distended abdomen (filled with honey) is bright in a white fluorescence around the dark areas of pigment. Confused bees flying above would likely not see that white fluorescent display projected at most horizontally, not like an upturned fluorescent Nasonov gland. A flying bee could see the ventral abdominal display, if approaching the scent fanner low enough and somewhere from behind her.
Crawling bees could be more the target audience for this fluorescent abdominal display. Figure 4 shows how crawling bees could see that fluorescent beacon and come to it. Therefore, scent-fanning bees have possibly a third channel to broadcast a location with a somewhat bright fluorescent ventral abdomen held high. The other two would be the fluorescent Nasonov gland and the …