Study: Ancient bees were both specialists and generalists

BONN, Germany, Nov. 12 (UPI) -- New evidence suggests ancient bees were both generalists and specialists when it came to foraging for pollen.

Researchers from Germany and the United States analyzed the pollen found on the bodies of several bees specimens trapped in amber. The bees comprised six different species from the extinct tribe Electrapini -- relatives of modern bee species -- all dated between 44 to 48 million years old.

While a wide variety of flower pollen was found on the bees' bodies, a types of pollen found on their legs was more limited. Bees use their hind legs to collect pollen and deposit it into attached feeding sacs, used to feed their young.

"Pollen retrieved by the second, specialized mode represented flowers that were considerably more morphologically stereotyped than the first mode and originated from only three or four major taxa of plants, unlike the considerably greater, more diverse spectrum of plants of the generalist mode that formed the pollination mutualism," Torsten Wappler, a researcher with the University of Bonn, said in a press release.

Bees presence in the fossil record extend back almost 100 million years. Researchers, whose work was published in the journal Current Biology, say dual foraging strategies may be as old as bees themselves.

"If this is the case, then the controversy as to whether the earliest bees were generalist or specialist pollen collectors may be moot: the earliest bees during the mid-Cretaceous may have been simultaneously generalists and specialists!" said Conrad Labandeira, a researcher with the Smithsonian Institution.

The new findings also suggest the generalist foraging approach is likely common throughout pollinator lineages. Those species that form specialized relationships with plant species -- yucca moths and fig wasps, for example -- are likely exceptions to the rule.