How Do Bees Reproduce Sexually

Trilobites

Scientists Detect Genes That Allow These Bees Reproduce Without Males

Researchers studied the genomes of a population of honeybees in South Africa, Cape bees, that often reproduce without males.

Credit... Mike Allsopp

June 9, 2016

The female person Greatcoat bee is a renegade. She breaks all kinds of rules and disregards orders. In this isolated subspecies of dear bees from South Africa, female worker bees can escape their queen'south control, take over other colonies and reproduce asexually — with no need for males. Scientists identified the genes well-nigh likely to take instigated this unusually powerful worker bee behavior, according to a study published Thursday in PLOS Genetics.

The typical story of reproduction is that males and females of an animal species do information technology sexually. Generally, that's what honeybees do, also. Sperm from a male drone fertilizes a queen's eggs, and she sends out a chemic signal, or pheromone, that renders worker bees, which are all female, sterile when they detect it.

But the Cape honeybee, a subspecies that lives in the Fynbos ecoregion, a unique surface area of incredible diverseness along the southwestern tip of South Africa, evolved a workaround where, in some cases, female workers tin get something similar a queen and produce offspring of their ain.

Similar all honeybees, some Cape bee colonies also take male person drones. But female workers tin start laying their own eggs in their home colony when a queen dies. These females will also invade colonies of other honeybee subspecies and lay eggs in some cases, and they can enter undetected past bees that would normally kick them out.

"The Greatcoat bees will take over the strange colonies and start eating up all the honey," said Matthew Webster, a geneticist at Uppsala University in Sweden, who led the study. This behavior is called social parasitism.

To understand what was driving this beliefs, researchers compared the whole genomes of 100 honeybee subspecies with those of 10 Cape honeybees. Unsurprisingly, the genomes were very similar: The bees wait and deed the same in every way except for the egg-laying quirk. But a few select areas of the genome were unique on the Greatcoat honeybee genome.

"Normally that doesn't cause really big differences," said Dr. Webster. But in this item bee, the workers lay eggs that self-fertilize and get female person workers in their abode colonies or the hives they invade.

Genetic differences likely made social parasitism possible by selecting for bees that could develop ovaries to a greater extent than other worker bees, lay eggs prepackaged with two sets of chromosomes, and possibly emit a chemic betoken to mask their presence while laying eggs, said Dr. Webster.

This asexual tendency may sound weird, just information technology's not unheard-of in biology. A variety of species of ants, wasps and bees tin can switch between sexual and asexual reproduction. And scientists have documented virgin births in turkeys, chickens, sharks and reptiles.

During a process called thelytoky, ii of the Cape bee's girl cells fuse together to make a unmarried prison cell with both sets of chromosomes — just like Thelma the snake, a reticulated python known for her virgin births. Normally, honeybee eggs split during meiosis into four daughter cells with just one gear up of chromosomes. Those turn into male drones without a begetter to contribute the other set to make them female person.

What scientists oasis't sorted out is why there might be an evolutionary advantage for a female being able to reproduce without a male. In farthermost situations with no males, information technology could mean the survival of her species. But then over again, self-fertilization, the paradigm of inbreeding, could exit her offspring more than vulnerable to disease and other threats.

Dr. Webster hopes to elucidate why this adaptation on the Cape honeybee genome survived.

"Why doesn't it have over the whole world, and why doesn't it die out?" wondered Dr. Webster. "There's no really good answer to that."