Bugs That Bug
When I last wrote a “Bugs That Bug” post in the mid-2000s, it was West Nile Virus that had everyone concerned. First documented in Wisconsin in 2002, West Nile – an arbovirus that is transmitted by a bite of an infected mosquito – caught the media’s attention and had people brushing up on best practices for avoiding mosquitoes. Now that Zika virus has joined our lexicon and our sleepless night worries, the mosquito’s reputation has dipped lower than loathsome. The same could be said for the much-detested tick. While Lyme disease was first recorded in Wisconsin in 1980, causing much alarm, a new more virulent tick-borne disease, the Powassan virus, has appeared on the scene to heighten our uneasiness. Powassan is carried by the deer tick (like Lyme disease) and causes swelling of the brain. While still quite rare (only 5 documented cases in Wisconsin in 2016), its occurrence is on the rise.
It’s no wonder then, that our relationship with insects and arachnids includes descriptors like “pest,” “vector,” and “infestation.” Indeed, the tiny mosquito bears the huge title of most deadly animal in the world – over snakes and crocodiles (and, by the way, dogs who come in at #3). And while many insects and arachnids are beneficial, and all play a role in a balanced ecosystem, some people contend that mosquitoes and ticks certainly could, even should, be wiped from the face of the earth (more on that in a bit). In the meantime, it’s important to note that not all mosquitoes prey on humans (or even mammals – some prefer frogs!) and not all ticks bear diseases that affect humans. Here’s a bit more information on each species, including ideas on how to avoid encountering them.
Mosquitoes: There are about 50 mosquito species found in Wisconsin, all of which (if female) require a blood meal to nourish their developing eggs. In general, these members of the Order Diptera (flies), feed on nectar and plant juices. Depending on the species, females deposit their eggs in small pools of water or on low ground to await flooding. Once the eggs hatch, the larvae (or “wrigglers”) live underwater, then pupate and emerge several days later as adults. The entire egg-to-adult process takes 10-14 days. The species known to transmit West Nile Virus (the Northern House Mosquito – Culex pipiens) lives and breeds while staying within a 1-3 mile radius so, your best defense against it and other mosquito species is eliminating backyard breeding grounds (i.e. any pool of standing water as small as a bootprint that remains wet for a week or more). Need help selecting the best mosquito repellant? Check out this research published in the Journal of Insect Science. DEET still takes the crown but lemon eucalyptus makes a good showing.
The good news: Scientists studying West Nile Virus have found that only 1% of mosquitoes carry the virus; and if bitten by an infected mosquito, there’s only a 1% chance of severe illness. (Find out more about West Nile, including 2017’s reported activity, from the Wisconsin Department of Health Services.) And mosquitos that carry the Zika virus (the Asian tiger mosquito – Aedes albopictus) are not found in Wisconsin – but UW entomologists are continually tracking their presense or absence.
So, back to the idea of eliminating mosquitoes. We have it pretty easy here, in the Midwest, considering tropical mosquitoes carry much more deadly diseases like malaria, dengue, yellow fever, and encephalitis. Should we eradicate the “most deadly animal in the world?” Would it have a deeper impact than we imagine? Bioethicist, David Magnus, posits on this topic that “we have to make every effort to be humble in recognizing the limits of our knowledge. We ought to be very careful before we do anything that has irreparable consequences.” He further notes, however, that he is on the side of elimination when it comes to Aedes aegypti, the species responsible for spreading Zika, yellow fever, dengue, and other diseases. Read more on the topic from Goats and Soda. Or, check out this video from SciShow:
Ticks: Luckily there are only two species of ticks found in Wisconsin: the deer tick and the American dog or “wood” tick (see a comparison TickEncounter.org). Of the two, only the smaller deer tick is known to carry and transmit Lyme disease and the Powassan virus. Both tick species have a two year life cycle: spring-hatching larvae feed on mice or birds, then overwinter until the following spring when they go through a nymph stage before becoming sesame seed-sized adults. Ticks cannot jump or fly but wait on grasses (at about the height of a deer belly) for a host to happen by. If you find a tick attached to your skin, the best removal process is, using a tweezers, grasp the tick as close to the skin as possible and gently pull it straight out. Most often, 18-24 hours of feeding is required to transmit the spirochete bacteria responsible for Lyme disease, and a much shorter time for Powassan transmission, so early detection and removal is the best defense. To avoid ticks when you’re outdoors, stay on the trails and tuck your pant legs into your socks. Some people suggest wearing light colors so you can spot any offending hitchhikers more easily. Find out more about Lyme disease and the Powassan virus from Wisconsin Department of Health Services.
Did you know…
Truthfully, I can’t stand the title of this post. Neither mosquitoes, nor ticks are bugs. Bugs are an order of insects, Hemiptera, that includes cicadas, aphids, and leafhoppers and are identified by half-membranous wings.
There is hopeful news regarding another detested insect – the wasp. New research shows promise that the toxins in wasp venom can kill cancer cells while leaving healthy cells intact.
To Do This Month:
Listen for 17-year cicadas (brood VI), who began their adult emergence after 17 years underground. Find out more about cicadas from this 2015 Nature Net News.
Check out Discovery Channel’s documentary all about the Mosquito – premiering July 6th.
Try out this homemade bug spray! My personal recipe is much easier: just witch hazel and citronella oil. But I’m going to try lemon eucalyptus oil after reading that report from the Journal of Insect Studies.
Visit the non-pest insects at Olbrich Gardens’ Blooming Butterflies event: July 20-August 13th.
Teaching About Insects
You know it’s going to be good when a Lesson Plan webpage starts out with a joke.
Q: What’s the difference between a fly and a mosquito?
A: A mosquito can fly, but a fly can’t mosquito.
Many educators are likely familiar with EducationWorld.com which provides current news briefs relevant to educators, lesson plans, and app reviews among other things. And lo and behold, they have a page dedicated to insect lesson plans. Ideas include creating “wanted” posters for insect pests, designing bug puzzles that teach anatomy and classification, and exploring the nutritional value of insects as food (which, some people believe will be a necessity as our global population swells).
Here’s an additional tip from their insect-focused page: “If you feel a little squeamish about your lack of bug know-how, you might want to begin your own buggy adventure with a visit to the University of Kentucky Department of Entomology. At Using Insects in the Classroom: A Teacher’s Guide to Six-Legged Science, you’ll learn everything you need to know to introduce your students to the wonderful world of bugs.” Of course, you don’t have to rely on Kentucky. Our own UW Madison has great resources, including the Insect Ambassadors and the UW Insect Diagnostic Lab.
Understanding the insects that may be a threat to our health is important but celebrating insects is equally important. In last summer’s post about Bees & Wasps, I shared a bit about how to build your own Insect Hotel to encourage beneficial insects. Check out this great collaboration between the UW-Milwaukee Art Department and the Department of Natural Resources that resulted in dozens of unique Insect Hotels:
If you want to see one of these creations in person, you can find one at the Aldo Leopold Nature Center. Ask the staff how to find it along the basswood trail.
One more way to celebrate: learn more about local butterflies with the Wisconsin Butterflies website.