Here where I live in southern California we get a lot of spiders, including black and brown widows that seem to thrive outside. On the plus side, we rarely have to deal with any kind of bugs coming inside the house. But there’s one exception to that rule. Maybe once or twice a year we get a sudden influx of ants.

This seems to happen not just at random but usually when it’s particularly hot and dry and the ants find a way into the house looking for a source of water. We had one invasion about a month ago where the ants found their way to two different showers in the house. My bug service (they spray for spiders once a quarter) gave me some bait traps and after about 24 hours we had no more ants in the house.

And as bug problems go here in SoCal that’s about it. I once had a hive of bees move into my chimney about 10 years ago. That was exciting. Fortunately the glass door on my fireplace kept most of them outside as I was trying to get my kids off to school before they noticed what was happening and started screaming. But other than that one freak incident, it’s just ants looking for something to drink.

All of this came to mind today when I read this story about some scientists who have made a best estimate of the total number of ants that currently exist on the planet. It turns out it’s a lot, significantly more than previous estimates.

Ants aretiny in size but not in number. There are about 20 quadrillion ants on the Earth at any given time, a new study has estimated. That’s 20,000 trillion individuals.

The estimate is two to 20 times higherthan previous ones, according to the study, published in the journal Proceedings of the National Academy of Sciences on Monday.

“We were very surprised about the large number of ants we found,” Sabine S. Nooten, an insect ecologist and temporary principal investigator at the University of Würzburg in Germany, told CNN Tuesday. Nooten was a co-lead author of the study…

…the research team of this latest study based the new estimate on observational evidence from an extensive data set of globally distributed ant samples. The authors identified and assessed 465 suitable studies, encompassing 1,306 sampling locations, covering all continents and major biomes where ants live…

“This new study, based on nearly 500 studies across the world, gives us the best answer yet to this tricky question. The astounding thing is not just the overall number, but the proportion of biomass that ants represent — a fifth of the biomass of all humans. It really underlines just how important ants really are,” he added.

The Washington Post did the math and came up with this skin-crawling factoid: “For every person, there are about 2.5 million ants.”

So this new study is less of a guess than previous estimates but the authors say it’s still probably “conservative” because there are parts of the world where they still don’t have any good estimates. But basically anywhere on earther except the very coldest of climates, there are lots of ants.