Not called the "kill zone" for nothing, a patch of bare ash on the side of a volcano in Nicaragua that is frequently exposed to highly acidic gas is the last place you’d think of looking for life. So imagine the surprise when an entomologist climbed to the top of the volcano to find a little insect buzzing about. Just meters from the opening of the active volcano, where the vent continuously ejects ash and volcanic bombs as the magma relentlessly bubbles, a tiny species of bee has made its home.
Burrowing into the ash on the side of a volcano where temperatures can soar to 42°C (108°F), not only do the tenacious little insects have to deal with the threat of the entire mountain going off and smothering their burrows in ash and lava, but they also have to contend with the occasional downpour of acid rain caused by the sulfur dioxide fumes emitted by the thing. The conditions are so extreme, in fact, that there is no other visible life clinging to the top of the mountain, not even any plants.
How the bees manages to survive living on the barren slopes of the caldera is therefore a bit of a quandary. But by studying the dogged insects over three years, a team of researchers have been able to answer some of the bees’ mysteries. The bee in question, Anthophora squammulosa, is actually quite a widespread species, found right along the Central American seaboard, though this is by far the most punishing location it has ever been discovered living in.
Area of Masaya volcano in Nicaragua on the slopes that the bees make their home. Erenler 2015
In fact, this is thought to be the most extreme volcanic environment any species of bee has ever been found to live and forage in, to the extent that the researchers had to wear gas masks and protective clothing in order to study it. The paper, published in The Pan-Pacific Entomologist, estimates that there are around 1,000 to 2,000 bees calling the slopes home, where the insects maintain a burrow around 30 centimeters (11.8 inches) deep, at the bottom of which it lays its eggs.
They found that an incredible 99 percent of all pollen collected by the bees was from a single species of plant, Melanthera nivea, which can withstand volcanic conditions, including acid rain. This is in stark contrast to bees that live in other locations, as they are usually known to be generalists that feed on a wide variety of plants. It seems that in ferocious conditions, the bees have to rely on the one plant that can survive alongside it, and the plants the one pollinator.
But that still doesn’t explain why the bees have decided to set up camp here. The researchers think that it is possibly related to the simple fact that few predators or parasites can survive living just meters from an active volcano, and who can blame them. Not only that, but the lack of plants might also be an advantage to the bees, as it means that it doesn’t have to negotiate roots when constructing their burrow.
Despite being found across much of Central America, it is thought that A. squammulosa is on the brink of extinction due in part to habitat destruction, and if the extreme habits of this population are anything to go by, they may not be helping themselves much either.
The bees only feed on one species of plant, which can also withstand the harsh volcanic ecosystem. Erenler 2013/ Erenler et al. 2015