In the past week I’ve noticed many monarch butterflies in flight and they’ve all been heading south.
When you see a monarch, pay attention to the direction it’s heading. Right now is the peak period for them to pass through Pittsburgh on their way to Mexico.
Monarch butterflies are on the move!
(photo from Wikimedia Commons; click on the caption to see the original)
For some reason millipedes give me the creeps. A worm with a thousand legs? No way would I hold one!
However, this video of a millipede’s shadow made me take a look. (*)
TIL: millipedes prance. pic.twitter.com/PBifC3CooP
— Dick King-Smith HQ (@DickKingSmith)August 22, 2019
Who knew that millipede bodies move vertically as they walk? Who knew that their antennae tap in time to their steps?
Diplopoda or millipedes are a class of 12,000 arthropods with two pairs of jointed legs on most of their body segments. Though mille means a thousand, Wikipedia says that none of them have that many legs. The record is 750.
Millipedes are susceptible to drying out so they live where it’s cool and moist, especially under leaf litter. They’re active at night but you might see them at dusk or on a very damp day when they come out to forage for decaying leaves, decaying plants or fungi.
They can’t bite or sting so their only defense is to curl in a ball and, when really irritated, release a stinky liquid.
Millipedes are harmless to us and our houses but can surprise us when they come indoors. As Penn State’s Dept of Entomology explains:
At certain times of the year millipedes become restless and migrate from their normal living places; they [may] appear in window wells, basements, garages and other places where they become an annoyance.”
Penn State Extension Insect Advice: Millipedes
This restlessness usually has to do with mating. The crowd was looking for a cool damp place and made a mistake.
Don’t be alarmed. It’s too dry for them indoors. Penn State says, “Since millipedes do not live for more than a few days indoors, treatment inside the home is not necessary. Vacuum or sweep millipedes into a dust pan for removal.”
Did you know that you can identify male millipedes because they’re missing legs on their 7th body ring? That’s where they have gonopods for transferring sperm to the female.
Of course, you’d have to get really close to a millipede to see this.
I’m not ready for that yet.
(photos from Wikimedia Commons; click on the captions to see the originals. Video shared on Twitter by @DickKingSmith; video originally by Crystal Albright a.k.a. Chris Dull on FB)
p.s. The photos in this article are of a single species found in eastern North America, the American “giant” millipede, Narceus americanus. I’ve seen them in Pennsylvania.
This moth can remember what it learned as a caterpillar.
In 2008, scientists at Georgetown University exposed late-stage tobacco hornworm caterpillars (Manduca sexta) to a specific scent and trained them to avoid it with a mild shock. The caterpillars got the message.
Scientists had thought that metamorphosis changed the brain so much that moths would not remember their caterpillar past. However, the caterpillars that learned about the scent in their last instar remembered the scent when they became moths — and they avoided it.
I wonder if other butterflies and moths remember their final days as caterpillars. Perhaps this is how females know to lay eggs on their host plant. “Hmmm,” says the butterfly, “This smells like the plant where I was feeding before I could fly.”
Read more at this article in Science Daily.
(photos from Wikimedia Commons; click on the captions to see the originals)
All bugs are insects but not all insects are true bugs. Is this cicada a true bug? The answer is complicated.
According to Ask A Biologist, true bugs are insects with:
Cicadas have these characteristics so they and 50,000 to 80,000 other insects are in the “true bug” Order Hempitera. This tiny green flatid planthopper is too.
But their status is more complicated. These two are true bugs but not true “True Bugs.”
Within Hempitera there’s a suborder of really True Bugs called Heteroptera. Cicadas, planthoppers, spittlebugs, aphids, and adelgids aren’t in this suborder. (See taxonomic chart from bugguide.net below.)
Encyclopedia Britannica says you can recognize Heteroptera by the X shaped design on their backs. Here are three true True Bugs I’ve seen in Pittsburgh this month.
This green and brown shield bug (probably Elasmostethus artricornis) is native to North America. I found several perched on American spikenard in Schenley Park.
The invasive brown marmorated stinkbugs are mating this month. I found this pair at Washington’s Landing.
And finally, I think this is a leaf-footed bug because of the swollen leaf-like segments on his hind legs.
Wondering if a bug is true? It’s a safe bet that it isn’t. Most insects are not, including dragonflies, bees, wasps, grasshoppers, butterflies, moths, flies and fleas.
(photos by Kate St. John)
In case you missed it, a monarch butterfly migration study published in the Proceedings of the National Academy of Sciences in June 2019 has troubling news for those who rear monarchs indoors.
Eastern monarch butterflies, famous for their autumn migration from North America to Mexico, have declined 80-90% in the last 20 years. To help the butterflies many people collect eggs and caterpillars in the wild and captive-raise them to increase their chances of survival. Unfortunately this well-meaning act can damage the insect’s ability to migrate.
Researcher Ayse Tenger-Trolander at Univ. of Chicago stumbled upon this when she purchased captive-bred butterflies for her monarch migration study. To measure their autumn migratory drive she placed them in a flight simulator and noted the dominant direction they wanted to fly. Wild migratory monarchs orient South. The captive-bred monarchs chose random directions, unlikely to migrate.
To further test the butterflies, Tenger-Trolander collected wild monarchs and raised a new generation indoors, mimicking outdoor autumn conditions. Here’s what she found.
Furthermore, rearing wild-caught monarchs in an indoor environment mimicking natural migration-inducing conditions failed to elicit southward flight orientation. In fact, merely eclosing(*) indoors after an otherwise complete lifecycle outdoors was enough to disrupt southern orientation.
Contemporary loss of migration in monarch butterflies, PNAS
Chip Taylor, Director of Monarch Watch, pointed out on NPR that some captive-bred monarchs do make it to Mexico, but added that “The real reason for raising monarch butterflies is for the enjoyment, the education. [T]he idea of individuals saving caterpillars as “monarch rescue” is misguided. “That’s simply not going to work as a way to boost the population,” says Taylor. “What we really need to do is to improve the habitat.”
We’re learning that monarch migration is complex and very fragile. It’s easy to break it in a single generation.
(photo by Kate St. John)
(*) “eclosing” means emerging from the chrysalis.
Perhaps you already know this but it was news to me: Cinnamon repels ants.
Cinnamon comes from the dried inner bark of a tropical evergreen, the cinnamon tree (Cinnamomum sp.). Ants would eat these trees alive if they could but the cinnamon genus evolved a very effective defense: two chemicals, Cinnamaldehyde and Cinnamyl alcohol, that are toxic to ants. Ants stay away from cinnamon.
In this 9-minute video, the guy from You Can Science It shows that even swarming, warring ants will drop what they’re doing when confronted with cinnamon. He theorizes that it changes their messaging from “Kill the other colony” to “Oh no! It’s cinnamon!” (video begins where he starts discussing cinnamon. Click here for the full video.)
Yes, cinnamon repels ants but it has to be fresh and you have to use a lot of it.
Read more about this experiment and the research behind it in this 2015 blog post at You Can Science It.
(photo and illustration from Wikimedia Commons, video from You Can Science It on YouTube)
Seven years ago I found a flock of moth-shaped insects clinging to yellow jewelweed stems in Schenley Park.
A closer look revealed they were big-eyed bugs wearing white capes.
On Throw Back Thursday, learn who they really are at These Are Not Moths.
Last week I saw two caterpillars and a butterfly that teased me: Who am I?
1. While taking closeups of Japanese snowball fruit (Viburnum plicatum) I saw the tiny green insect above looking at me from the corner of a leaf.
iNaturalist suggests he’s a moth in the genus Isa, a slug moth. However none of the photos show a caterpillar with a tiny black eye. He seems to be saying, “Who am I?” UPDATE, 24 July 2019: Monica Miller says he’s a planthopper, one of many confusing species.
2. On Lower Riverview Trail I paused where lots of tiny caterpillars were dropping to the ground on thin silk filaments. Were they a type of tussock moth? “Who am I?” UPDATE, 24 July 2019: Monica Miller confirmed my guess that these are hickory tussock moth caterpillars.
And in Schenley Park on the Greenfield Bridge I found an emperor. A hackberry emperor? A tawny emperor (Asterocampa clyton clyton). Thanks to Bob Machesney for the ID!
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.
On Throw Back Thursday, here’s the story of how we got rid of them: Trapping Very Small Game.
(photo by Kate St. John)
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.
The 2008 study led by Stephen Takács, Infrared radiation from hot cones on cool conifers attracts seed-feeding insects, found that pine cones emit infrared light at all levels and the western conifer-seed bug can “see” it.
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.
— Infrared radiation from hot cones on cool conifers attracts seed-feeding insects, Stephen Takács et al, Royal Society Publishing
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
This topic was inspired by a 2008 article from Nature’s Crusaders blog: Pine Beetle Uses Infrared to Find Next Meal