Category Archives: Insects

Harvestmen

Insects
Close up of “daddy longlegs” Phalangium opilio (photo by Mehran Moghtadai on Wikimedia Commons)

28 November 2011

Last weekend in southern Virginia I saw a troop of six daddy longlegs exploring the edge of a hiking trail. What were they doing?

I searched the Internet for information and though I didn’t find that answer I learned some fascinating things — and their real name.

I call them daddy longlegs but their real name is harvestmen. They’re very ancient and diverse bugs with more than 6,400 species on earth that date back to the Devonian era 400 million years ago.  Compared to humans who reached our present form 200,000 years ago, this bug goes way back!

Harvestmen are arachnids but they’re not spiders (Araneae), they’re Opiliones.

Unlike spiders their bodies look like a single oval because the segments are joined broadly.  They can’t make silk, they have no venom, no fangs and are completely harmless to people.

Harvestmen can eat solid food (spiders have to liquefy their food and suck it in) and they’re omnivorous, willing to ambush prey or scavenge the dead.  They’ll even eat bird dung.

The bird connection works both ways.  Birds eat daddy longlegs but the longlegs have a decoy system.  A harvestman can lose a leg and it’ll continue to twitch because of  a “pacemaker” at the end of the first segment (the pacemaker is useful in controlling such a long leg).  The twitching distracts the predator while the other seven legs carry the bug to safety.  At least one of the bugs I watched last weekend was missing a leg.

And what were so many of them doing together?  Apparently some species of harvestmen are gregarious and will congregate in groups of 200 to 70,000 individuals.

Maybe the six of them were having a small party.

(photo of Phalangium opilio by Mehran Moghtadai from Wikimedia Commons.  Click on the photo to see the original.)

p.s. In this blog I’m using the word “bug” loosely.  True bugs are insects (six legs) with a chitinous (hardened) wing cover. Harvestmen are not really bugs; stink bugs are.

Monarchs on the Move

Insects, Migration


Every year at this time I blog about monarch butterfly migration. I hope you don’t tire of it.  It’s just so amazing to me that this butterfly migrates as much as 2,500 miles to spend the winter in Mexico — and we can see it happening.

Years ago people suspected the butterflies were migrating but didn’t know where they went.  After 40 years of tagging and tracking monarchs, Dr. Fred Urquhart found their wintering site in 1976 in the mountains of Mexico.  At first the locations were kept secret because there are so few of them, but nowadays they are eco-tourist destinations where visitors can observe millions of monarchs in the Oyamel fir trees.

Right now the butterflies are on their way.  Yesterday afternoon at the Waterfront Shopping Center I was loading my car when I saw a monarch fly by.  I paused and looked up and counted 10 monarch butterflies flying southwest over the parking lot.  The wind was calm, the air was warm and all of them were fluttering in the exact same direction, each bug on its own long journey.  Wow!

Monarchs are on the move across the country.  You can watch their progress on the Journey North website or in your own neighborhood.  In southwestern Pennsylvania you can know a monarch butterfly is migrating by these three things:

  1. It’s the right time of year —  September is prime time.
  2. The butterfly is fluttering or gliding in one direction without pausing to eat.
  3. It’s flying southwest.  

It’s easy to see them.  Keep looking up.

(photo by Marcy Cunkelman)

p.s.  This monarch is male.  You can tell because he has dots on his hind wings.  The females don’t have them.

Look Before You Drink!

Insects, Phenology
Yellowjacket on a soda can (photo from Wikimedia Commons)

20 September 2011

Watch out!  At the end of summer you might find a yellowjacket in your soda can!

All summer long we’ve been able to eat outdoors without being plagued by yellowjacket wasps, but now it’s downright dangerous to put the can to your lips unless you’ve guarded it from these invaders.

Why do they do this?

Yellowjackets are members of the Vespidae family (wasps) who build papery nests underground.  Last spring a single fertilized female, the queen, came out of the crevice she hid in all winter.  She built a few papery cells underground, laid some eggs, tended the nest and fed the larvae.  Within 30 days her eggs became sterile female workers. The colony was born. 

From that point forward the queen merely laid “worker” eggs and her growing population of sterile females did all the work.  They tended the nest and collected insect prey (meat) to feed the larvae.  They weren’t interested in sweets.

But in late summer a change occurs.  Instead of sterile worker eggs, the queen lays eggs containing males and fertile females. When they hatch and mature they leave the colony to mate.  As soon as that’s done, the queen stops laying eggs and colony social life breaks down.  The workers stop tending the remaining larvae and leave the nest to go roaming, looking for sweets — fallen apples and your can of sweet soda.

Yellowjackets are somewhat aggressive but don’t worry they’ll disappear soon. By late fall they will all die and the newly fertilized queens will retreat to their crevices to wait out the winter and restart the cycle next spring.

Coincidentally, we stop eating outdoors by that point so we don’t notice the yellowjackets are gone.

.

p.s.  Do you have a yellow jacket story?  Leave a comment to share it with us.

(photo from Wikimedia Commons in the public domain.  Click on the photo to see the original.)

Also Comes in Green

Insects, Schenley Park


Though our gardens have been awash in brown marmorated stink bugs I found some green ones last week in Schenley Park.

Are these the same species as the annoying, invasive stink bugs from Asia?  No.

Green stink bugs are native to North America.  Just like the brown marmorated stink bug they eat a wide variety of plants so they’re considered an agricultural pest.

In Schenley Park I first noticed them when I saw a green stink bug (at right) perched on yellow jewelweed.  This is the adult.

Out of curiosity I checked the rest of the jewelweed for more insects and found a Japanese beetle and the small, round, ornately marked bug at left.   The left-hand bug is not to scale. It’s actually half the size of the bug on the right.

At first I was sure that the small, ornate bug was a unique and wonderful species … until I looked it up.  The left-hand bug is a green stink bug nymph (young).

Since there’s more than one species of green stink bug in North America, I might not have identified the bugs I saw in Schenley Park correctly, but these photos look like what I saw. They are Acrosternum hilare photographed by Susan Ellis at bugwood.org.

(photos of green stink bugs, nymph and adult by Susan Ellis at bugwood.org)

He Jumped Out of His Skin

Insects


On my way to work the other day I found this scissor-grinder cicada shell clinging to an oak.

Cicadas live most of their lives as nymphs in the soil under trees but when they’re ready to become adults they crawl out of the soil, climb up a tree, hang on and… jump out of their skins!

Click here to watch the process.

It looks like this happened fast but in fact it takes about two hours for the adult to emerge and dry off.  During that time its body is soft, like a softshell crab, and it’s quite vulnerable to predation.

When the adult’s wings and body have hardened, the adult flies away leaving his old skin behind, including his legs and the covers of his eyes.

No need to be afraid of this bug.  He’s just a shell of his former self.

.

For more information on cicada molting see this informative page at Massachusetts Cicadas.

(photo by Kate St. John)

The “Famous” Moth

Insects


Earlier this month Tim Vechter found this Polyphemus moth on a tree trunk in the city’s Shadyside neighborhood. 

Finding such a huge moth — with a wingspan of 6″ — is always amazing but even more so in the city where we don’t expect to see wildlife.

It probably likes Shadyside’s habitat.  Polyphemus don’t eat when they’re moths but as caterpillars they feed on a wide variety of deciduous trees including oak, maple, hickory and beech.  Shadyside’s tree-lined streets provide a nice selection of mature host plants.

When Pittsburgh was a smoky city the moths probably weren’t here but all it took was one female to make the leap back to town.  The males’ bushy antennae can detect female pheromones from miles away and they’ll fly that far to mate with them.

Polyphemus moths are noticeable because of their huge size and the purplish eyespots on their hind wings.  Those two traits gave them their name. 

Polyphemus was the one-eyed giant who ate six of Odysseus’ men.  He was well known among the Cyclops.  His name means “famous.” 

(photo by Tim Vechter)

Coming Soon to a Tree Near You

Insects, Trees


If you haven’t seen these webs in the trees, you will soon.

These are the communal webs of fall webworm caterpillars (Hyphantria cunea).

Their mother laid a mass of eggs on a deciduous tree, preferably a cherry, apple, ash or willow.  A week later the eggs hatched into tiny caterpillars and they began to build their web, mostly at night.

The caterpillars live inside the web, molting as they grow, and extending it to surround the leaves they’re eating.  The web can become as much as three feet long but it’s very different from the tent webs we see in the spring.

Tent caterpillars build in the forks of branches and come out of their nest to eat.  Fall webworms build at the tips of branches and stay inside to eat, only emerging on very hot days (too hot to stay inside!) or when they’ve reached their final instar and are ready to pupate.

Hyphantria cunea overwinter in the pupal stage under loose bark or debris on the ground.  When they emerge in the spring they look like this with a 2″ wingspan:

Unless you have an infested orchard, fall webworms aren’t that bad for trees and they’re quite good for birds.

The caterpillars don’t permanently harm the trees because they’re eating the leaves at the end of the growing season when the trees would drop them anyway.

And they’re an important food source for birds.  Migrating warblers see the webs as huge advertisements:  “Come eat!  Good protein inside!”

When you see fall webworms in the trees, think “happy warblers.”

(Web photo by G. Keith Douce, University of Georgia, Bugwood.org.  Moth photo from Wikimedia Commons.  Click on each photo to see its original.)

What’s That Sound?

Insects
Angle-wing Katydid (Microcentrum) in Texas (photo from Wikimedia Commons)

10 August 2011

Ticking, whirring, grating, droning.  August is Bug Noise month.

Nature is loud right now.  During the day there’s a chirping and buzz-saw whine; at dusk, a grinding, droning chorus and a faint whirring sound.  Marianne Atkinson, who lives in Clearfield County, Pennsylvania, says “a loud, 2 part, harsh sound, repeated quickly, sort of like saying hello” starts up at twilight near her home.

What makes these sounds?

I searched the web for an answer and found this helpful page on the Music of Nature website:  Thumbnail Guide to species (with sounds).

Just for fun I listened to a few of the recordings and they solved an old mystery.

Years ago, before Duquesne Light cut back the trees across the street, we heard a ticking sound at night in the summer.  The bug that made that sound is pictured above, a greater angle-wing katydid.  It actually made two mystery sounds:  the ticking and a periodic “dzit.”

When we had the greater angle-wing katydid in our neighborhood I never saw it among the leaves.  If it had perched on a lawn chair, as this one did in Texas, I would certainly have noticed it!

Listen to the Songs of Insects and you might find the one that puzzles you.

(photo in the public domain from Wikimedia Commons.  Click on the photo to see the original.)

p.s. June 2021. Identify trilling possibilities in southwestern PA that I can still hear (less than 6000 hertz) listed by frequency (hertz). See thumbnails + recordings here.

Only the beginnings of a list …

Bug on a Pogo Stick

Insects

Three weeks ago I hiked along Hell Run down to Slippery Rock Creek and paused by the stream to eat lunch.

It was cooler by the creek so I stayed a while and watched the water striders patrolling the quiet pools.  Eventually a dragonfly flew over the creek, then hovered above the riffles and began to bounce her tail in the moving water over and over again.  It looked like she was riding a pogo stick.

What was this?

My bug knowledge is almost non-existent so I asked Chuck Tague and he put me in touch with Ben Coulter.  Ben told me I saw the typical ovipositing behavior of a female spiketail. Though I couldn’t describe the bug well enough to identify the species, it was in the Cordulegaster genus.

Yes, the dragonfly was laying eggs.

To show you how strange this looked I found two videos on YouTube.  The first, above, is a good illustration of the pogo-stick behavior even though the bug in the movie is not native to North America.  (The golden-ringed dragonfly lives in Britain.)

The second, below, is an award-winning video I’m sure you’ll enjoy — and it shows dragonflies native to Pennsylvania.

David Moskowitz studied Tiger spiketail (Cordulegaster erronea) mating behavior by suspending fake female look-alikes from fishing poles to see if they could attract a mate.   When the fake females did not bounce, the males were uninterested.  When the “females” looked as if they were ovipositing, the males tried to mate with them.  Notice how the male rushes over and grabs her!

Turn up your speakers; you’ll like the music.  (Sorry about the ad a few seconds into it.)

And don’t miss David Moskowitz’ Bug Addiction website.

(videos from YouTube)

Metamorphosis

Insects
Royal Walnut or Regal Moth (photo by Marcy Cunkelman)

5 August 2011

This amazing creature with beautiful orange and yellow accents is a regal or royal walnut moth (Citheronia regalis), the largest moth north of Mexico with a wingspan of up to six inches.

He didn’t always look like this.

As a caterpillar he molted five times, becoming bright green with scary horns and “about the size of a large hot dog,” according to the Bug Guide.  He preferred to feast on hickory and walnut trees, earning him the name hickory horned devil.

In his final instar, when he’d eaten his fill, the hickory horned devil turned a beautiful turquoise color and searched the ground for a suitable place to burrow 5-6 inches under the soil and spend the winter pupating.

Marcy Cunkelman captured this process, beginning in August last year, when the man who services her furnace brought her a hickory horned devil caterpillar.   She marked the place where the caterpillar burrowed and brought him above ground at various stages to see what he looked like.

He shed his skin, turned a beautiful color, then became dark and emerged as a moth early this summer.

Here he is just before he flew away, destined to live only a week.  Regal moths have no mouths and cannot eat.  Their only purpose is to reproduce.

Watch Marcy’s photos of the metamorphosis in the slideshow below. Click on any image to see the slideshow in a lightbox.

  • Hickory Horned Devil caterpillar

(photos by Marcy Cunkelman)