An ice age is not a great time for most living things. Periods of extreme cold have a habit of spelling the end of animals that can't find a way to either adapt or relocate. This would be especially true, you'd think, of insects. After all, how many bugs do you know of with a layer of fur or blubber to keep warm?
And yet, a newly-discovered bug in a limestone cave on Vancouver Island may be an Ice Age insect survivor. Either that, or it walked there from Japan.
Sorry, come again?
Bug background check
Let's begin with a description. Haplocampa wagnelli (say HA-ploh-kam-pah wehg-NEH-lee) is blind, tiny (only about 4 millimetres long) and appears nearly see-through. This translucence and blindness is common among many cave-dwelling animals, as there is no need for pigment or eyesight when you live in total darkness.
In short, it is fairly easy to determine that this species has spent a long time living underground. Except ...
The H. wagnelli (named for its discoverer, Craig Wagnell) doesn't have the extremely thin, elongated body that most cave-living insects tend to. This makes scientists wonder: How long has this species been living down there? Was it there 26,500 years ago, when its current cave home was covered by the Cordilleran Ice Sheet? Or did it arrive later?
International Bug of Mystery
Then there is the fact that H. wagnelli shares a number of physical traits with similar insects in Japan and Siberia. Today these places are separated by an ocean, but they were, as recently as 11,000 years ago, connected by the Bering Land Bridge, which once ran between Siberia and Alaska.
So how did this insect come to live in the cave in Vancouver Island? Here are the three most likely candidates...
- Ice age insect: H. wagnelli has lived in these caves for many thousands of years, including during the last ice age, when its cave system was under ice.
- Mighty migrant: H. wagnelli is the descendent of a species that migrated from Japan and Siberia somewhere between 26,000 and 11,000 years ago (when the land bridge still existed).
- Not quite-as-might-migrant: H. wagnelli is the descendent of a species that migrated from somewhere in the southern United States after the last ice age ended.
If it really is an ice age insect, this would make it the farthest north that scientists has discovered an animal that lived underground during this time. Which is quite extraordinary.
What answer do you think is correct? Mysterious bugs are the best!