Category Archives: Insects

Invasive Wasp Has Unusual Social Life

European paper wasp (photo by Andrew Butko via Wikimedia Commons)

European paper wasps (Polistes dominula) are nothing new. Since their arrival in Massachusetts in the late 1970’s they expanded across eastern North America in just 20 years and reached California by 2001 or 2002. Along the way they displaced native species and were deemed invasive. If you live in an urban setting, this is the paper wasp you’re most likely to see.

To tell these apart from our native yellowjackets, Polistes dominula are larger, have orange antennae, very thin “waists” and trail their long legs behind them in flight.

European paper wasps, legs trailing in flight (photo from Wikimedia Commons)

Also unlike our yellowjackets which nest in holes in the ground, European paper wasps build nests of chewed wood (paper) mixed with saliva that they attach to sheltered spots. The cells open downward.

European paper wasp nest on a metal fence (photo from Wikimedia Commons)

Polistes dominula wear their dominance on their bodies. Dominant females have more black spots in the yellow region above their mouths (the clypeus). Dominant males have smaller, elliptically shaped, yellow abdominal spots on their backs (dorsal) compared to subordinate males.

These outward signs can be useful as they navigate their unusual social life.

Most social insects live only with their relatives and will reject — sometimes to the point of death — unrelated individuals in the nest, but European paper wasps will join unrelated established nests as the season progresses.

… in P. dominula, 35% of the nest mates are unrelated. In many other species, unrelated individuals only help the queen when no other options are present. In this case, subordinates work for unrelated queens even when other options may be present. No other social insect submits to unrelated queens in this way.

European paper wasp, Wikipedia

Related or not, European paper wasps attack if you get too close to their nest. Sometimes you won’t see the nest — only the wasps — as in this unusual location in DC.

Watch out!

(photos from Wikimedia Commons; click on the captions to see the originals. video from Capital Naturalist)

Don’t Step Near That Hole!

Yellowjacket guarding nest hole entrance in Ewing, NJ (photo from Wikimedia Commons)

18 August 2020

Yellowjacket wasps are very active in late summer but you might not realize where they come from. These members of the Vespidae family build papery nests underground that they guard with all the stinging power they possess.

Yellowjacket wasp on a leaf (photo from Wikimedia Commons)

I learned about yellowjacket nests years ago — the hard way — when a person hiking near me stepped on a nest hole. The wasps poured out of the nest and attacked everyone. I ran but was stung anyway, just once. I was lucky. Individual yellowjackets can sting multiple times.(*)

Last Sunday I wasn’t paying attention to insects when I discovered a yellowjacket nest near a large rock at Moraine State Park. Fortunately I was standing well away from the hole and noticed the wasps going in and out.

As you can see, the hole was surrounded by weed-whacked grass that must have been cut the week before. Despite the surrounding debris the entrance was clear. I imagine the wasps moved the debris after stinging the person who held the weed whacker.

Don’t step near that hole!

(photos from Wikimedia Commons; click on the captions to see the originals. video by Kate St. John)

(*) Honeybees die after only one sting.

The Secret Lives of Lacewings

Green lacewing outside my window in Oakland, 11 Aug 2020 (photo by Kate St. John)

Last week a beautiful green bug perched on a window at our new home in Oakland. My bug expert friend, Monica Miller, told me its identity and some amazing facts about its lifestyle.

This green lacewing is probably in the Chrysopa or Chrysoperla genus, both of which are very common in North America. The species are so similar that some have been reclassified back and forth from one genus to the other.

Green lacewing, Chrysopa sp.(photo from Wikimedia Commons)

The bugs themselves have no trouble figuring out who is who. According to Wikipedia, Chrysoperla courtship “songs” are so different that individuals of one species will not react to the other’s vibrations.

After they mate, lacewing females lay their eggs on the tips of stalks which form from the silk they exude with each egg. The egg stalks remind me of the flowers on Solomon’s seal (Polygonatum). Watch her lay eggs in this video.

The adults are beautiful but the real appeal of lacewings is that a single larva can eat up to 400 aphids per week. Often called aphid lions some species drape their backs with debris as a disguise.

Green lacewing larva eating aphid + lacewing larva disguised by debris (photos from Wikimedia Commons)

Lacewings grab the aphids with their pincers and then …

Green lacewings are so good at biological pest control that you can buy them online.

I wonder … was my green lacewing the offspring of eggs-in-the-mail?

(top photo by Kate St. John, remaining photos from Wikimedia Commons; click on the captions to see the originals)

p.s. Seven years ago I wrote about aphid lions. Check out this vintage blog with Aphid Lions video.

Crazy Beetle Names

Festive tiger beetle (photo of museum specimen from Wikimedia Commons)

Festive, blowout, dispirited, punctured, sexguttata. Tiger beetles can have crazy names as I learned when Ted Floyd tweeted his daughter’s photo of a blowout beetle. Who knew!? Here’s what five of these crazy beetles look like.

The festive tiger beetle (Cicindela scutellaris) is irisdescent and often two-toned as shown above and below. Sometimes they are completely indigo blue which would surely confuse me.

Festive tiger beetle in the wild (photo from Wikimedia Commons)

Blowout tiger beetles (Cicindela lengi) occur in the West, including Colorado. See Ted Floyd’s tweet.

Punctured tiger beetles (Cicindela punctulata) are found in much of North America including Pennsylvania. Also called sidewalk tiger beetles you’ll probably see one on a hard surface.

Punctured (or sidewalk) tiger beetle (photo from Wikimedia Commons)

After a blowout when your tire is punctured you might be dispirited or depressed. There’s a tiger beetle for that …

Despite their name dispirited tiger beetles (Cicindela depressula) seemed pretty lively when Ken-ichi Ueda photographed this one at Lassen Volcanic National Park in August 2013. He wrote at bugguide.net, “These little guys were all over the path running southwest from the King’s Creek picnic area.”

Dispirited tiger beetle (photo by Ken-ichi Ueda via Flickr, Creative Commons license)

And finally, a very common tiger beetle whose species name is “sexguttata”. In Latin that means “six drop.” The six-spotted tiger beetle (Cicindela sexguttata) is found eastward from Minnesota and south to Kentucky. They occur in Pennsylvania.

There are over 850 species of tiger beetles so I’m sure I’ve missed a lot of crazy names. Leave a comment to tell me about another one.

(photos from Wikimedia Commons and Ken-ichi Ueda on Flickr; click on the captions to see the originals. Tweet embedded from Ted Floyd, ABA)

This is a Cocoon

30 July 2020

Seven years ago I wrote an article that’s rediscovered every summer when people find unusual “pine cones” hanging from their trees.

Though the structures are coated in plant material they aren’t part of the tree. They’re the cocoons of evergreen bagworm moths (Thyridopteryx ephemeraeformis) whose larvae are disguised by vegetation while they eat the tree. Here’s one that’s sticking its head out.

Evergreen Bagworm – Thyridopteryx ephemeraeformis, Woodbridge, VA (photo from Wikimedia Commons)

Pesticides don’t work on these bag-covered bugs. Find out what to do in this vintage article: These Are Not Pine Cones!

(photos from Wikimedia Commons; click on the captions to see the originals)

Ants Know When To Quarantine

Black garden ants (photo from Wikimedia Commons)

One of the biggest challenges facing the U.S. during the coronavirus pandemic is our poor ability to quarantine to stop the spread. This summer’s COVID-19 surge in Pittsburgh was sparked by travelers who returned from vacation (Myrtle Beach, Hilton Head, Florida, Raleigh, Nashville) but did not quarantine for 14 days.

Perhaps we could learn from ants. An April article in Treehugger described how social species avoid each other to stop the spread of disease. This includes black garden ants.

Ants are very social creatures, always working together to feed and protect the colony. Nurse ants stay inside the nest and tend the larvae; workers forage outside for food. A study of black garden ants found that when workers contract a fungal infection they know to stay outside the nest and avoid contact with other ants. Meanwhile nurse ants move the larvae deeper inside the nest to avoid infection. Ants basically quarantine themselves.

We could learn a lot from ants.

Read more at “How other species handle social distancing when someone is sick.”

p.s. The article also describes other species that practice social distancing including bees, mice, monkeys and bullfrog tadpoles.

(photos from Wikimedia Commons; click on the caption to see the original)

Tiny Jumping Beans

Jumping oak galls, Neuroterus saltatorius (photo by Donald Owen, California Department of Forestry and Fire Protection via bugwood.org)

24 July 2020

There’s a cool thing happening in California right now that we never see in Pennsylvania. In neighborhoods with white oaks there are tiny “jumping beans” in the gutters.

Here’s that they look like, recorded a week ago by Mary K Hanson.

They’re even better in slow motion, recorded by Mark Eagleton in Woodland, California.

Though they resemble the moths called “Mexican jumping beans” (Cydia deshalsiana) these galls are the agamic (asexual) second generation of tiny Neuroterus saltatorius wasps that mature on white oak leaves and fall to the ground.

Neuroterus saltatorius 2nd generation galls on back of oak leaf (photo by Steve Katovich via bugwood.org)

The larvae are tightly packed inside the galls so when they move the galls jump up to 3 cm. That’s 30 times the size of the gall!

In the fall the larvae become adult wasps inside the galls and overwinter to emerge next spring.

Neuroterus saltatorius are native to western North America from Texas to Washington state and up to Vancouver Island, Canada. That’s why we don’t see them in Pennsylvania.

Learn more at the University of Florida’s Department of Entomology: Neuroterus saltatorius.

(photos from Wikimedia Commons and bugwood.org; click on the captions to see the originals. videos embedded from YouTube)

Just One Cicada Makes A Lot Of Noise

19 July 2020

At dusk in July scissor-grinder cicadas (Neotibicen winnemanna) sing from the trees in Pittsburgh. Like birds the male cicadas sing to attract females. Their pulsating drone rises to a crescendo, then drops to a buzz and falls silent. Are they singing in unison? How many are there?

Male scissor-grinders pulse their abdomens as they sing. At close range a single cicada makes a zipper sound. Click here to see another example.

When I’m able to follow the sound I’m often surprised that it’s coming from just one bug who fooled me into thinking a multitude was singing in unison.

Loudness matters. Female scissor-grinder cicadas apparently choose the loudest males.

A single cicada makes a lot of noise.

p.s. Have you heard a different cicada sound in the Pittsburgh area? This article can help you figure out which one: What’s That Sound? Cicadas.

(photo by Kate St. John, embedded videos from YouTube)

Flowers, Fruit and Frogs

American bellflower, Duck Hollow, 13 July 2020 (photo by Kate St. John)

This week brought lavender flowers, green fruit and an overabundance of frogs.

I found American bellflower (Campanula americana) blooming along the Duck Hollow trail with some plants reaching six feet tall. My close-up, above, shows how the pistils avoid being fertilized by their own pollen.

American bellflower, Duck Hollow, 13 July 2020 (photo by Kate St. John)

Wild bergamot (Monarda fistulosa) always has a bad hair day. At Schenley Park a long-legged insect stopped by for a sip (top right of flower).

Wild bergamot, Schenley Park, 12 July 2020 (photo by Kate St. John)

In July the unripe fruits of white fringetree (Chionanthus virginicus) are green. This fall they’ll turn dark blue.

Fringetree fruits, Schenley Park, 12 July 2020 (photo by Kate St. John)

At Panther Hollow Lake and the Westinghouse Memorial pond, pickerelweed (Pontederia cordata) is blooming …

Pickerelweed, Schenley Park, 16 July 2020 (photo by Kate St. John)

… and there’s a serious overabundance of bullfrogs. Here are just a few examples.

Young bullfrogs, Schenley Park, Panther Hollow lake, 17 July 2020 (photo by Kate St. John)
Young bullfrog with tail, Panther Hollow lake, 17 July 2020 (photo by Kate St. John)
Young bullfrog in a wavelet, Panther Hollow lake, 17 July 2020 (photo by Kate St. John)
How many bullfrogs can you count? Panther Hollow Lake, 17 July 2020

Herons don’t nest at Schenley Park but may visit for some easy prey. Where’s a great blue heron when you need one?

(photos by Kate St. John)

Insects Seen and Unseen

Aphids on Helianthus, Schenley Park, 9 July 2020 (photo by Kate St. John)

12 July 2020

It’s easy to find insects in July.

Aphids in Schenley Park are expanding from plant to plant along the gravel trails, sucking the juice out of Jerusalem artichokes (Helianthus tuberosus).

Yellow hawkweeds (Pilosella caespitosa) are attracting bee-like insects.

Wasp or bee on hawkweed, Schenley Park, 6 July 2020 (photo by Kate St. John)

And some insects are unseen but have left evidence behind. Can you see two kinds of insect evidence on this crabapple tree?

Insect evidence on crabapple, Schenley Park, 9 July 2020 (photo by Kate St. John)

(photos by Kate St. John)