It’s that time of year again when fruit flies spontaneously appear in your kitchen. Where did they come from? How do you make them go away?
Fruit flies or “vinegar flies” (Drosophila melanogaster) love moisture and the vinegar smell of fermenting, rotting fruit. They and their eggs cling to fresh fruits and vegetables. They even squeeze through your screens to get to their goal.
One fruit fly becomes one hundred in a matter of days as we learned to our dismay when they invaded our office in 2012.
Back in 2008 a team of scientists made an amazing discovery: the western conifer-seed bug uses infrared sensors to find his favorite food.
The western conifer-seed bug (Leptoglossus occidentalis) is a North American sucking beetle that resembles a stink bug, though he’s not in the stink bug family. Ornately marked and 1/2 to 3/4 inch long (16-20 mm), he feeds on the sap of developing pine cones. This causes the seeds in the cones to wither which is only a minor problem in western forests but a big deal at pine seed orchards.
The seed bug used to be confined to temperate forests of the Pacific coast but has naturally expanded his range all the way east to Nova Scotia. In the past 20 years he’s been accidentally imported into Europe, Chile, and Japan so there’s international interest in how this bug finds pine cones at a distance.
Pine cones emit infrared light because they’re warmer than the rest of the tree by almost 60 degrees F. These photos from the study, taken in normal and infrared light, explain: “The temperature bar to the right of the paired images reveals that cones are up to 15°C warmer than foliage under high-cloud conditions.”
To prove that the bug is attracted to infrared, researchers set up infrared emitters shaped like pine cones (photos below). Did the bug approach them? Yes, it did. Could the bug find the cones when his IR sensors were experimentally blocked? No he could not.
As the study explains:
Here, we show that the western conifer seed bug, Leptoglossus occidentalis Heidemann (Hemiptera: Coreidae), a tissue specialist herbivore that forages during the photophase and feeds on the contents of seeds within the cones of many conifers (Blatt & Borden 1999; Strong et al. 2001), uses IR radiation from developing cones as a long-range foraging cue. We present data revealing that (i) cones are warmer and continuously emit more near-, mid- and long-range IR radiation than needles, (ii) seed bugs possess IR receptive organs and orient towards experimental IR cues, and (iii) occlusion of the insects’ IR receptors impairs IR perception.
Apparently the world looks very different to a western conifer-seed bug. For him the pine cones really stand out while the rest of the world is boring.
postscript: NOTE that the western conifer-seed bug (Leptoglossus occidentalis) is not the scourge of our western pine forests. The forests are being killed by a completely different native bug — the mountain pine beetle (Dendroctonus ponderosae) — whose larvae make galleries under the bark and kill the tree from inside. Below: Pines killed by the mountain pine beetle, Galleries under the bark, and the mountain pine beetle.
photo credits: Click on the captions to see the originals. * Infrared images from study at Royal Society 2008.0742, Creative Commons license * Western conifer-seed bug photos from Wikimedia Commons * Mountain pine beetle row of photos: #5540352: Kill at Deadman Road, CO, William M. Ciesla, Forest Health Management International, Bugwood.org, #UGA1254003, Galleries, William M. Ciesla, Forest Health Management International, Bugwood.org, #UGA1306005, mountain pine beetle, Dendroctonus ponderosae, Ron Long, Simon Fraser University, Bugwood.org
Magicicada on a small tree next to the parking lot in Moon Twp, PA, 9 June 2019 (photo by Kate St. John)
Holes left by magicicadas Brood VIII as they emerged in 2019
Exoskeletons shed by magicicadas Brood VIII, 9 June 2019 (photo by Kate St. John)
Exoskeleton shed by magicicada Brood VIII, 9 June 2019 (photo by Kate St. John)
Magicicada on a small bush near the parking lot in Moon Twp, 9 June 2019 (photo by Kate St. John)
"You can't see me" Cicada mostly hidden by a twig (and out of focus), 9 June 2019 (photo by Kate St. John)
Not dead, just stuck on its back. It rolled over and flew away (photo by Kate St. John)
For many years I’ve anticipated the return of Brood VIII of the 17-year cicadas, Magicicada sp. They were stunning at the west end of Nichol Road in Raccoon Creek State Park in 2002 so I stopped by that location two weeks ago. What a disappointment! There were almost none.
Consequently when I heard them in Moon Township yesterday I followed the sound and ended up here, right next to the center pindrop labeled “AMC Settlement Services.” (center of satellite image)
Cicadas were calling, flying, mating and oviposting in that narrow arc of trees surrounded by parking lots. My photos include the holes they emerged from beneath the trees, their discarded exoskeletons, cicadas perched on knee-high bushes, and a cicada on its back on the asphalt. It wasn’t dead. It bounced off my leg, landed on its back, and couldn’t fly again until the wind rolled it over and freed its wings.
Cicada activity in this small woodlot was in stark contrast to the lack of cicadas elsewhere. Clearly the Brood VIII population is smaller than it used to be.
In 2002 this generation burrowed underground and waited to mature in 2019. Meanwhile bulldozers cleared land, pavers laid asphalt. Cicadas that survived the bulldozers were trapped under pavement. They will die this year without reproducing.
Why aren’t there more Magicicadas in Moon Township, PA? They can’t get out.
(cicada photos by Kate St. John, screenshot of Google satellite map of Moon Twp PA; click on the caption to see the original)
Have you encountered incredibly energetic earthworms in your garden that thrash violently when you touch them or break off their own tails? If so, your garden is probably home to a new invasive species: the Asian jumping worm (Amynthas spp).
The jumping worms’ lifestyle causes problems. They move fast, writhe and thrash, reproduce prolifically, and can live in higher densities than European earthworms. Instead of mixing the soil they live on the surface, devouring all the leaf litter and flooding the soil with nutrients that quickly wash away. When they invade the forest, the soil becomes barren and no plants grow. This 3-minute video shows why Asian jumping worms are so bad in our forests.
Asian jumping worms are in the Pittsburgh area but most of us don’t realize it. I remember finding crazy writhing earthworms while weeding my front garden several years ago and watching robins struggling to hold them. I didn’t know the worms were something new until Master Gardener Dianne Machesney gave a presentation about them at Wissahickon Nature Club.
As awareness grows about Asian jumping worms, garden clubs have stopped sharing plants in the traditional way. Dianne told us that her own garden club and the Master Gardeners Plant Sale specified that donated plants must be cleansed of dirt and re-potted in store bought soil.
Does your garden have these worms? Penn State Extension describes how to find out:
How do you know if you have Asian earthworms? Scratch the upper surface of the soil in your garden. If you uncover many worms writhing and twisting like snakes, you most likely have Asian earthworms. These worms, which can reach 6 inches in length, are much more active than European earthworms.
The clitellum–the prominent band around the body of the earthworm–is also different. On a jumping worm, the band completely encircles the body and is creamy white to light gray. In comparison, the clitellum of European earthworms does not wrap entirely around the body and is slightly raised.
I remember a time in Pennsylvania when we could bushwhack through dense brush or lie down in a meadow without worrying about black-legged ticks and Lyme disease. In retrospect it seemed like Eden.
Nowadays we have to be careful, especially in May-August when the tiniest freckle-sized nymphs are active. Our best defense is to prevent ticks from getting on our skin. I’ve stopped bushwhacking and I don’t lie down in meadows to look at the sky.
Eden is over. These stanzas from Mark Doty’s poem, Deep Lane (Into Eden Came The Ticks), describe it perfectly:
Into Eden came the ticks, princes of this world, heat-seeking, tiny, multitudinous …
A week ago I received a message from the USA National Phenology Network that hemlock woolly adelgids would hatch very soon in Pittsburgh and the southern Appalachians. This is worrisome because the nymphs are the active phase of this forest pest.
Originally from Japan, hemlock woolly adelgids (Adelges tsugae) kill eastern hemlocks in 4-20 years by locking on where the needle meets the stem and sucking the lifeblood out of the tree (closeup at top).
The adults are sedentary, attached to a tree. The nymphs, however, are tiny and mobile. They blow on the wind and hitchhike on clothes, equipment, birds and animals. They spread very easily just after they’ve hatched.
The message above says “You should see active nymphs” but you won’t. At 1/100th of an inch they’re smaller than a grain of sand, almost microscopic. And yet, their effect is devastating.
Hemlock woolly adelgids have already killed up to 80% of the hemlocks on parts of the Blue Ridge Parkway and in Shenandoah National Park. They are eating their way through the Great Smoky Mountains, shown below, and they’re killing hemlocks in Pennsylvania.
We won’t know how far they’ve spread this spring until they reveal their presence next fall when the females deposit woolly egg sacs on the undersides of hemlock branches.
Nature uses unusual colors to warn of danger. We do too. The blue and red crop seeds above are warning us that they’re coated with a poisonous nerve agent. Though not as dangerous to humans as to insects, the label says handlers should wear long pants, long sleeves, and chemical-resistant waterproof gloves. “Caution: Harmful if swallowed or absorbed through the skin.”
The picture above tells us more. The rows are actually bar graphs from a Penn State study. The blue soy at top and reddish corn at bottom show the percentage of neonic-treated soy and corn grown in the United States in 2015. 30% of soy was neonic-treated, 92-95% of corn. The percentage is increasing. You’d be hard pressed to find U.S-grown corn that isn’t imbued with neonicotinoids. That’s where bees come in.
April and early May is corn planting time in the lower Great Lakes region. Tractors like this are in the fields of Ohio and Indiana. I see them as I drive to Magee Marsh.
The seed hoppers contain neonic-treated corn, pinkish red below. (Oh my! The farmer isn’t wearing long sleeves and gloves.)
Meanwhile insects are waking up to forage, fruit trees bloom and honeybees are enlisted to pollinate crops. By 2012 beekeepers noticed large bee die-offs during corn planting season.
The Purdue study concluded that 42% of Indiana is exposed to neonicotinoids during crop planting, but 94% of honeybees are affected because of their location. “Nearly every foraging honey bee in the state of Indiana will encounter neonicotinoids during corn planting season.” Purdue’s video shows why.
Ironically, the Purdue study found that the benefit of neonicotinoids is declining or negligible. “The common seed treatments produced no improvement in crop yield.” Despite these findings neonics are still in use.
Monarch butterflies are famous for migrating long distances from North America to Mexico but they’re not the only butterfly that travels far. Red admirals migrate, too.
Red admirals (Vanessa atalanta) occur in Europe, Asia and North America. Though the European population can hibernate, red admirals on this continent migrate south to places where their favorite host plant — stinging nettle — grows throughout the winter. In eastern North American they spend the winter in south Texas.
Over the winter a new generation of red admirals matures to fly north and repopulate the continent. We usually don’t notice them but in the spring of 2012 hot weather came so fast that red admirals passed through Presque Isle State Park in a couple of days on mass migration.
On Throw Back Thursday read about the amazing number of red admirals in 2012 in this vintage blog: Mass Migration.
Why don’t we see them migrating more often? Perhaps they’re traveling high above our heads. According to Wikipedia: “During migration, the red admiral flies at high altitudes where high-speed winds carry the butterfly, requiring less energy.” Oh my!
(photo from Wikimedia Commons; click on the caption to see the original)
Today is April Fools Day but here’s no joke. Now’s the time to spray your outdoor clothes with permethrin to repel black-legged ticks that carry Lyme disease.
Black-legged ticks (Ixodes scapularis), sometimes called deer ticks, are tiny blood-sucking arachnids that transmit the parasite that causes Lyme disease from small rodents to us.
Lyme disease is debilitating and if not stopped early can ruin your life for a very long time. If you live in Pennsylvania you probably know someone who’s had Lyme disease, maybe even yourself. Pennsylvania has the most Lyme disease cases per year in the U.S. — 10,001 of them in 2018 according to this PennLive report.
The predictions for 2019 say Lyme disease will be even worse in Pennsylvania this year. Black-legged ticks need moisture to survive and the past year has been wet. There will be lots of ticks. Watch out!
So how do we avoid getting Lyme disease?
Stay away from places where black-legged ticks live,
Keep ticks off your skin,
Check your body daily for any ticks that got through those defenses.
Unfortunately most of us can’t stay away from tick habitat. It’s in our own backyards.
Black-legged nymphs live in moist leaf litter or at the edge of wooded areas. Many people catch Lyme disease while gardening. Have you been moving damp leaves lately?
Don’t fool yourself that you’re completely safe in city parks. A 2017 study of Pittsburgh’s regional parks — Highland, Schenley, Riverview and Frick — found infected ticks in all of them. Highland was the worst. Download the study here.
The best defense is to keep ticks off your skin.
Stay on-trail as much as possible. (Not possible when gardening!)
Wear light-colored clothing so you can see ticks if they get on your clothes.
Wear long pants and long sleeves. Before you step off trail, pull your socks over your pant bottoms.
To really keep ticks away spray your outdoor clothes — pants, shirts, socks, shoes, jacket, hat — with permethrin. The repellent lasts through six washings. It works really well for me.
And as always, take a shower shortly after coming indoors and check your body for ticks every day. Read more about tick prevention and daily checks at these links.
Get ready for a bad tick year.
Today is Spray Your Clothes Day.
(photos by Kate St. John, map from CDC.gov, black-legged tick diagram from Wikimedia Commons; click on the captions to see the originals)
(*) Note: The CDC map of Lyme disease shows reported cases, not all cases. Western Massachusetts & the Adirondacks look Lyme-free because of a difference in reporting.