Evolution of the honey bee: the long way to Europe

In many places, the western honey bee (

has practically become a pet: humans provide the shelter and not only harvest honey and beeswax for it.

Because honey bees diligently visit flowers and pollinate them, they also play an important role in agriculture.

Where the western honey bee originally came from has been a matter of debate.

An international group of researchers has found out with genome analyzes that there is a high probability that it comes from Asia, where the eleven other species of the genus Apis also live.

The western honey bee probably evolved in Southeast Asia from honey bees that already built their nests in tree cavities.

The common ancestors of all modern variants apparently lived in western Asia.

The biologists led by Kathleen A. Dogantzis from York University in Toronto included 251 bees from Europe, Africa and Asia in their study.

They were able to confirm five known evolutionary lineages: two European, two Asian and one African.

In addition, they discovered two other African lineages in Egypt and Madagascar, and they list eleven subspecies in total.

However, seven other suspected subspecies turned out to be more or less colorful mixtures of the different groups.

Family trees based on changes in individual base pairs in the DNA double helix indicate that the

species began to split in this way around six million years ago, the researchers write in Science Advances.

The honey bees, which are obviously extremely keen on migrating, then populated new continents several times on different routes: An evolutionary lineage probably advanced on a northern route to northern and central Europe and then further west to the Iberian Peninsula.

Another later conquered southern and south-eastern Europe from western Asia.

In doing so, it may have pushed the honey bees, which had long since arrived in Europe, out of part of its range.

They were able to confirm five evolutionary lineages: two European, two Asian and one African.

In addition, they discovered two new African lines of development in Egypt and Madagascar.

In total, they list eleven subspecies.

On the other hand, seven other putative subspecies turned out to be more or less colorful mixtures, created by contacts between different evolutionary lineages.

Differences are mainly found in genes

Irrespective of this, Africa has been colonized by Western honey bees, probably also twice: bees originating from Egypt turned out to be closely related to those native to Yemen.

Genetically, they differ significantly from an evolutionary lineage that is otherwise widespread throughout Africa, from which a branch lineage found exclusively in Madagascar also descends.

The fact that the populations in Europe and western Asia were drastically decimated by the last glacial period of the Ice Age probably explains the far greater genetic diversity of African honey bees.

Differences between the evolutionary lineages are mainly found in genes relevant for development from embryo to adult insect and for behavioral traits.

Often these are genes that primarily influence workers.

Although they usually remain childless, they still play an important role in the evolution of honey bees.

Because it depends on their skills whether a bee colony can reproduce successfully.

So whether there will be many young queens and drones that will pass their genes on to the next generation.

The genome analyzes suggest that the adaptation to different living conditions from the temperate latitudes to the tropics is mainly due to the evolution of the worker bees.

African honey bees are notorious for being much more aggressive in defending their nest than their European relatives.

Apparently, well-fortified bees had an advantage when it came to defending the honey and bee brood in the combs against a wide range of different attackers.

From the point of view of the beekeepers, who regularly tamper with the combs, such aggressive bees are undesirable.

Peaceful colonies that deliver high honey yields are in demand.

However, the genetic diversity of honey bees of different origins could also contain variants

which prove useful for breeding.

For example, when it comes to better arming bee colonies for heat waves or against pathogens.