Two new bee species are mysterious pieces in the Panama puzzle

Can these tiny bees unlock history of tectonic plate movements?

October 2011: Two new, closely related bee species: one from Coiba Island in Panama and another from northern Colombia have been discovered by Smithsonian scientists. 

NEW SPECIES: The new bee from Panama's Coiba Island has fuzzy yellow hairs on its abdomen. Picture: STRI

Both species descended from of a group of stingless bees that originated in the Amazon and moved into Central America, the ancestors of Mayan honeybees.

The presence of one of these new species on Coiba and Rancheria Islands, and its absence from the nearby mainland, is a mystery that may ultimately shed light on Panama's history and abundant biodiversity.

At almost 200 square miles, Coiba Island is the largest offshore island along the Pacific coast of Latin America. Rancheria Island is a much smaller neighbour. The species name, insularis, of the new bee from Coiba, means ‘island'. This is the first species in its group to be found on islands near the mainland.

These bees have a small range
‘These forest bees have a small range over which they can establish new nests and colonies,' says David Roubik, staff scientist at the Smithsonian Tropical Research Institute. ‘They can't establish a new nest across more than a short stretch of open water because workers from the original nest have to build and supply the new nest before the new queen moves in.'

Either several entire tree-cavity nests arrived on Coiba and Rancheria in floating mats of vegetation or a land connection existed between the island and the mainland before the bees disappeared from the mainland.

Sea level has risen and fallen dramatically in the past. During ice ages, sea level dropped in Panama. Five other stingless bee species on Coiba are widespread on the mainland and on many little islands that were connected to the mainland during glaciations.

Panama land bridge could have arisen millions of years earlier than thought
Those bees are relative newcomers that may have arrived during past drops in sea level when the islands were reconnected to the mainland.

But even if a drop in sea level explains how the bees got from the mainland to the island, their discovery that the bees had already established in Central America around 17 million years ago spurs an ongoing debate about the age of the connection between North and South America. Traditionally, geologists think that the Panama land bridge arose by tectonic and volcanic action to connect the two continents about three million years ago.

‘Our studies of the genetic relationships between these bees tells us that they originated in the Amazon about 22 million years ago and that they moved north into Central America before three million years ago,' said Roubik. ‘This actually agrees with new evidence that geologists working in the earthworks created by the Panama Canal expansion project are finding. We think that a land bridge may have formed as early as 12 million years ago.'