5 Ways That Insects Deal With Rain


The other day, there was a terrific thunderstorm which made me wonder how insects cope with giant water boulders suddenly crashing all around them. In ye olden days, I would have to get some insects, Erlenmeyer flasks, distilled water and a centrifuge but fortunately we live in the era of the Internet.

5. Mosquitoes

Mosquitoes are extremely fragile creatures. There’s really not much to them other than legs, wings, a hypodermic needle and a puckish desire to make your life miserable. They’re born in water and usually found near it so rain is clearly something they would have to deal with fairly often. So, what do they do?

The creators of this video published a paper in The Proceedings of the National Academy of Science, as reported here in Smithsonian. They found that if the mosquito is flying along in the rain, one of three things can happen. First, the drop can strike just a glancing blow off of the mosquito’s waterproof body causing it to spin out of the way like a judo master. Second, the drop can hit the mosquito dead on and end up carrying it along for about 10 centimeters before it’s dangling legs and wings catch enough air resistance to pull it back out again. The mosquito absorbs very little energy in either of these two scenarios, not nearly enough to actually damage it.

The final scenario is less fun for the mosquito. If it can’t escape the raindrop before it slams into the ground, then there is a good chance that it will be squashed.

4. Butterflies

Now, butterflies famously cause most of the world’s rain through their insistence on flapping their wings. But do they pay a cost?

Michael Raupp of the University of Maryland dealt with this question in this 2006 article from Scientific American.

Butterflies do not like rain one bit. They cannot move backwards within their own timeline to avoid storms and they have large, fragile wings so rain most definitely can kill them. So, when they feel rain is coming, they seek shelter in the same secluded spots where they normally shelter for the night.

The force of the rain isn’t the only danger. Butterflies need to absorb warmth from the sun in order to power up to fly and get on with their business. The cool rain makes them sluggish and more vulnerable to predators.

3. Beetles and Aphids

When WC Fields heard rain on the roof, it reminded him of the carefree days of childhood. When scientists hear rain on the roof, they wonder if beetles might be screwing. Scientists can be a bit odd.

A 2013 paper in PLoS, reported here in Nature, found that aphids, beetles and moths do not, in fact, like to get it on in the rain. In fact, they find the idea of being pummeled by huge balls of water from the sky a complete turn off.  Even bugs safely living inside laboratories could detect the changes in atmospheric pressure and head for shelter rather than trying to chat each other up.

Now, if the scientists plunked a male beetle right down next to a female, he still made coffee but he didn’t grind the beans fine. There wasn’t any of the usual singing and dancing and other nonsense of courtship. Just a quick wham, bam, thank you, ma’am and scurry off for shelter as quickly as possible.

2. Rain Beetles

There are some beetles, however, who have the completely opposite attitude vis a vis rain and the getting of it on. These would be the rain beetles.

No, these are relatives of scarabs that live on the Pacific coast of North America. Like cicadas, they spend most of their lives as larvae underground. But by the time the first winter rains of October have come around, the adults have burrowed to the surface.

The males brave the rains and take to the air. They’re fairly large (2.5 to 3.0 cm) and remarkably hairy which helps them stay nice and warm against the cold and damp. The males  don’t have functional mouths to feed with so they can go, on average, about 2 hours on their stored fat. The flightless females await them in shallow burrows down on the ground.

Here they are in action.

1. Fire Ants

Now, ants in general are very clever ladies and, as you can imagine, they deal with rain well.

This colony appears to be preparing for the oncoming rains by closing up their entrances and dealing with any pesky videographers still lurking in the area.

Now rain isn’t generally a problem for ants living in the soil unless the ground becomes completely saturated. The water just percolates slowly through their chambers. But, what if things get out of hand and there’s a flood? Well, the fire ant knows how to deal with that.

That’s right, when Zan takes the form of flood waters, Jayna takes the shape of a boat made of fire ants, shortly after stinging the Hell out of Zan’s hand. The workers protect the queen and the young until such time as they either all get eaten by fish or they drift onto dry land. They can also form bridges.

Terrible Simon and Garfunkel covers are just another of the many ways that fire ants can hurt you.