Insect Sperm Battle Inside Colony Queens

When an insect queen ventures onto the mating scene, she certainly makes the most of it, coupling with as many as 90 males each half-hour. That's because during the mating process for "social insects" like ants, bees, and termites, the highly prized queens mate for just one day, collecting enough sperm in that short period of time to last a lifetime. But for males, the contest to get some 'alone time' with the queen can be fierce--and new research is revealing that the battle to reproduce continues long after the deed is done.Seminal Fluid Kills Rival Sperm
According to New Scientist, researchers at the University of Western Australia report that a male's seminal fluid is like a poison to sperm belonging to another--leading to a microscopic battle to determine who has the top-sperm, all from within the queen. In one experiment, researchers observed over half the sperm of one male killed by the seminal fluid of rival in a matter of minutes.

Boris Baer, who spearheaded the study, explains the findings:

The males seemed to use the seminal fluid to harm the sperm.

The research centered on bumblebees and leaf-cutter ants; both species that mate only once in a lifetime and take on multiple partners. With the sperm of so many individuals vying for the position of 'fertilizer' inside the queen, it's no wonder why developing harmful seminal fluid might come in handy to weaken the competition. Still, Baer and his colleagues still find it "weird" that the fluid can distinguish between friendly sperm and that of a rival.

How Does this Help the Queen?
While it might seem disadvantageous for so much of a queen's hard-earned sperm to be lost due to infighting, it turns out that she's capable of stopping it at any time by releasing a fluid of her own. But Baer believes that queens wait a while to let the sperm battle, ensuring that only the strongest survive to fertilize her eggs.

The study offers a surprising peek into the lifecycles of nature's social insects and the complex process by which they reproduce. But for Baer and his colleagues, it's all just part of the job:

In the sperm world you must be prepared for everything.

We'll take his word for it.

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Going Steady: 10 Animals More Monogamous Than Us (Slideshow)

Tags: Biology | Evolution | Insects