REVEALED: Strange Link Between Bad Weather, Bug Behavior

David Freeman
(Photo: )
(Photo: )

Sex may feel electrifying, but insects may avoid the naughty act when they detect storms are coming, a new study suggests.

As the climate changes, insect sex and other activity may shift as well, the research also suggests.

Insects are the most abundant and most diverse group of animals on Earth; scientists know of more than a million different insect species. However, their size and frailty make them vulnerable to storms' strong winds and heavy rains, which could easily kill the creatures. [Gallery: Dazzling Photos of Dew-Covered Insects]

"For an aphid, a raindrop is something like what a refrigerator would be like falling on us," said researcher Jeremy McNeil, an entomologist and chemical ecologist at the University of Western Ontario in Canada.

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Sexy scents

Preliminary research from McNeil and others found that insects apparently changed how they emitted and responded to pheromones — scents linked with sex — depending on the weather. To learn more about how insects survive the perils regularly presented by storms, McNeil and his colleaguesinvestigated the mating behavior of three very different insects: the cucurbit beetle, the true armyworm moth and the potato aphid. They focused on how sex among the insects varied depending on weather conditions such as falling, stable and increasing air pressure.

Falling air pressure is linked with high rains and winds. When atmospheric pressure naturally fell due to weather conditions, male cucurbit beetles were attracted significantly less toward sources of female pheromones, the researchers found. In addition, when air pressure dropped, nearly two-thirds of male cucurbit beetles in the lab rushed through sex with females, instead of engaging in foreplay activities, such as touching females with their antennae, and the females did not take part in any rejection behaviors, as they normally do.

"Insects are forecasting weather for their own lives just like we do," McNeil said. "We have weather forecasts that we use to not plan a picnic on a day where rain is announced, and since insects can't listen to the news, they have evolved their own ways of evaluating weather and modifying behavior in ways that are beneficial to their survival."

Stormy sex

In the study, when scientists lowered the air pressure in chambers containing insects, female armyworm moths released sex pheromones less often. However, female potato aphids showed less courtship behavior both when the researchers decreased the air pressure and when they increased it.

"The question is, why is there this difference?" McNeil asked.

The difference lies in aphid biology, and the fact that both rising and falling atmospheric pressure are linked with winds. Female aphids emit pheromones by crawling to the edge of a leaf and lifting their back two legs to the air.

"It's wingless, and it's clinging to life at the edge of a leaf with four of its six legs — so if there's wind, there's a chance that it might get blown away to its death," McNeil said. Female armyworm moths, by contrast, are much larger and can resist winds better — and also have wings to fly, so they may not fall to their deaths if they are blown off surfaces. [7 Amazing Bug Ninja Skills]

Future research could investigate how insects detect changes in the weather. The researchers speculated that insects might have mechanical sensors on their exoskeletons to detect faint air movements, or that changes in the size of bubbles in the guts of some beetles could help them detect fluctuations in atmospheric pressure.

McNeil also noted that the researchers concentrated on insect communication via scents. "It'd be interesting to see how other insects with different communications respond to weather — for instance, crickets, that communicate with sound," he said.

The researchers also would like to explore the effects of life span on insects' responses to weather. "The insects we looked at are fairly short-lived as adults," McNeil said. "Would insects with relatively long lives respond in the same way to weather? Crickets may live for three months — maybe young adults might shut down their behavior when cues indicate bad weather is coming, but might older individuals with a shorter life expectancy go take a risk?"

As the globe proceeds to warm, these findings suggest climate change" might change the behavior of insects as well — not only of pests, but also of beneficial insects," McNeil said.

The scientists detailed their findings online Oct. 2 in the journal PLOS ONE.

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Assassin bug

<em>Triatoma infestans </em> Look out for it in: Mexico, Central and South America Why you should fear it: Assassin bugs transmit Chagas disease, a long-term, chronic disease that can ultimately cause serious cardiac and digestive problems. Notorious victim: Charles Darwin met one on his first trip to Argentina.
Triatoma infestans Look out for it in: Mexico, Central and South America Why you should fear it: Assassin bugs transmit Chagas disease, a long-term, chronic disease that can ultimately cause serious cardiac and digestive problems. Notorious victim: Charles Darwin met one on his first trip to Argentina.

Fire caterpillar

<em>Lonomia obliqua </em> Look out for it in: Brazil, Argentina, and neighboring countries Why you should fear it: The caterpillars release a powerful toxin that can cause internal bleeding and massive organ failure. Notorious victim: A young Canadian tourist walked barefoot through a resort and stepped on five. Although local hospitals carried an antivenin, she didn't seek treatment until she returned home--a mistake that cost her her life.

Biting midge

<em>Culicoides spp. </em> Look out for it in: Everywhere. Why you should fear it: Also called no-see-ums, biting midges are a serious annoyance in the Scottish Highlands--so much so that tourists check the Biting Midge Forecast before heading out for a round of golf or a trek to a distillery. In Brazil and around the Amazon, they transmit Oropouche fever. Notorious victim: According to a community study, the biting midge broke up marriages in Hervey Bay, Australia, presumably because couples were forced to spend more time indoors together.

Paederus beetle

<em>Paederus sp. </em> Look out for it in: Most of the world. Why you should fear it: The beetle lands on the skin but doesn't bite. People tend to want to slap it, which releases a nasty poison called pederin that causes horrible blisters and welts. Notorious victim: Our troops stationed in Iraq. The beetles tend to swarm around the bright lights at military bases.

Asian giant hornet

<em>Vespa mandarina japonica</em> Look out for it in: Japan, China, Taiwan, Korea Why you should fear it: Stings deliver a powerful neurotoxin that could be fatal. Notorious victim: Dr. Masato Ono, the world's leading expert on the giant hornet, said the sting felt like "a hot nail through my leg."
Vespa mandarina japonica Look out for it in: Japan, China, Taiwan, Korea Why you should fear it: Stings deliver a powerful neurotoxin that could be fatal. Notorious victim: Dr. Masato Ono, the world's leading expert on the giant hornet, said the sting felt like "a hot nail through my leg."

Pork tapeworm

<em>Taenia solium </em> Look out for it in: South America, Africa, Asia, and parts of Europe and North America Why you should fear it: While modern livestock management here at home has practically eliminated tapeworm-infested pork, the tapeworm eggs can be spread directly from one infected person to another. How? Let's just say that it's really, really important to wash hands after going to the bathroom-- and leave it at that. Notorious victim: A woman in Arizona went into surgery thinking she had a brain tumor, and woke up later to learn that the cause of her problems had been a tapeworm, not a tumor.

Deer tick

<em>Ixodes scapularis </em> Look out for it in: Eastern United States (other species that transmit Lyme are found in the West and in Europe) Why you should fear it: The nymphs transmit the miserable and difficult-to-treat Lyme disease Notorious victim: Polly Murray, a resident of Lyme, Connecticut, battled the disease for decades and led the fight to get it properly identified, diagnosed, and treated.

Chigoe flea

<em>Tunga penetrans </em> Look out for it in: Tropical beaches in Latin America, the Caribbean, India, and Africa. Why you should fear it: Tiny fleas burrow under toenails and lay eggs, creating awful sores and possible infection Notorious victim: Members of Christopher Columbus' crew were made so miserable by chigoe fleas that they cut off their own toes to get rid of the bugs.

Scorpion

<em>Centruroides sp. </em> Look out for it in: Southern United States, Central and South America Why you should fear it: The venom can cause severe pain, difficulty breathing, and can be fatal to small children. Notorious victim: A little boy vacationing with his family in Mexico stepped on a scorpion in his shoe. He was flown to a hospital in San Diego, placed on life support, and did survive.

Bed bugs

<em>Cimex lectularius</em> Look out for it in: Your bed Why you should fear it: After hearing about all these other nasty creatures, you aren't still worried about bed bugs, are you? Bed bugs may be annoying, but they are not known to transmit disease. They may cause a dreadful allergic reaction, but you'll survive. Bed bugs have always been around; overuse of toxic pesticides drove them away for a few decades, but fortunately, we now realize that the chemicals were far more dangerous than the bugs. Notorious victim: You.

This article originally appeared on HuffPost.