{"id":23331,"date":"2020-12-12T05:21:49","date_gmt":"2020-12-12T05:21:49","guid":{"rendered":"https:\/\/www.lifeandnews.com\/articles\/?p=23331"},"modified":"2020-12-13T23:31:46","modified_gmt":"2020-12-13T23:31:46","slug":"bitter-battles-between-stinkbugs-and-carnivorous-mice-could-hold-clues-for-controlling-human-pain","status":"publish","type":"post","link":"https:\/\/www.lifeandnews.com\/articles\/bitter-battles-between-stinkbugs-and-carnivorous-mice-could-hold-clues-for-controlling-human-pain\/","title":{"rendered":"Bitter battles between stinkbugs and carnivorous mice could hold clues for controlling human pain"},"content":{"rendered":"

Lauren Koenig<\/a>, Michigan State University<\/a><\/em><\/p>\n

It\u2019s hard to appreciate the value of pain when we feel it, but most living things would not survive without it. Pain is a signal that something is causing harm to your body and that you need to take action<\/a>.<\/p>\n

One way to learn about pain receptors is by studying species in which these receptors seem to be absent. As an example, many animals regularly eat toxic food without suffering reactions that would cause pain in other species. Goats will happily browse on poison ivy without developing itchy rashes<\/a>, while garter snakes feed on poisonous newts<\/a> with no persistent effects.<\/p>\n

I have a long-standing appreciation for bizarre biology, so my Ph.D. research led me to study one of the most specialized predators in the animal kingdom: the grasshopper mouse (Onychomys torridus<\/em>)<\/a>. These tiny rodents have a big appetite for prey that other mice prefer to leave alone because of their quarry\u2019s chemical defenses. Understanding how grasshopper mice can consume noxious food may provide insights into pain pathways and help scientists seeking to find new, nonaddictive treatments for blocking pain signals.<\/p>\n

Mice vs. beetles<\/h2>\n

To learn more about grasshopper mouse predatory behavior, I traveled to the Sonoran Desert in southern Arizona with a small team from Michigan State University. The desert is beautiful but hostile. Many animals there have developed extreme adaptations, including venoms and poisons, that help them catch food and defend themselves from predators. This makes it the perfect natural lab for studying rodents and how they\u2019ve specialized to handle desert life.<\/p>\n

\"Desert<\/a>
The Santa Rita Experimental Range research site in the Sonoran Desert.<\/span>
\nLauren Koenig<\/span>, CC BY-ND<\/a><\/span><\/figcaption><\/figure>\n

My research focused on three related species of mice with different dietary preferences. Deer mice (Peromyscus<\/em>)<\/a> are omnivores, known for supplementing a diet of insects with whatever they find in kitchens all over North America. Peanut-shaped pocket mice (Chaetodipus penicillatus)<\/em><\/a> prefer to eat seeds and grain, but will eat insects as a last resort.<\/p>\n

\"Scorpion<\/a>
Grasshopper mice are fully capable of eating this venomous scorpion, which fluoresces under a blacklight.<\/span>
\nLauren Koenig<\/span>, CC BY-ND<\/a><\/span><\/figcaption><\/figure>\n

In contrast, southern grasshopper mice are voracious carnivores. At sunset they let out long cries, like muted teakettles, that have been described as \u201cwolf howls in miniature<\/a>.\u201d Their stubby legs and tan-and-white patterned coats make them look like tiny corgis, but belie their aggressive nature. Grasshopper mice attack and eat anything that moves, including centipedes, tarantulas, scorpions and even other mice. They have an astounding immunity to scorpion venom<\/a>, which kills deer mice in minutes.<\/p>\n

We wanted to see how grasshopper mice, deer mice and pocket mice ate different types of insects, so we trapped over 80 of them and tested their feeding behavior. We gave each mouse a cricket, which is largely defenseless, and a stink beetle (Eleodes longicollis<\/em><\/a>). These bugs are like the chocolate-covered pretzels of the desert \u2013 high-calorie treats that contain contrasting tastes.<\/p>\n

But to get to the juicy center, a predator must overcome a hard outer shell and a burning, acrid spray that the beetle squirts from its rear end. The spray contains benzoquinone chemicals<\/a>, which release fumes similar to bleach and can damage the eyes, nose, mouth and skin with prolonged exposure. I can personally attest to its bitter, stinging taste and the brown stains it leaves on clothes and skin.<\/p>\n

Taste tests<\/h2>\n

In a typical battle, most grasshopper mice immediately attacked the beetle but were repulsed by a face full of chemical spray. Eyes closed, they would turn to rub their head in the sand, seemingly trying to brush the spray off their fur. But then, remarkably, each mouse returned to bite the beetle\u2019s head until it was subdued. Crunching followed as the mouse held the beetle like a sandwich, working its way down the body until all that remained were six legs and an empty shell.<\/p>\n