Category Archives: Insects

First Monarch Butterflies Have Arrived in PA

Insects, Migration
Male monarch butterfly, 2008 (photo by Marcy Cunkelman)

14 May 2025

Monarch butterflies (Danaus plexippus) are migrating north and, happily, the first few have arrived in Pennsylvania within the past two weeks.

As of this morning there are 11 monarch butterfly sightings on Journey North’s 2025 spring migration map. Here are six of the 11 including the very first one on 30 April in Philadelphia.

  • Philadelphia, Philadelphia County, 4/30/2025
  • Pittsburgh, Allegheny County, 5/5/2025
  • McKees Rocks, Allegheny County, 5/10/2025
  • Pennsylvania Furnace, Centre County, 5/10/2025
  • Gettysburg, Adams County, 5/11/2025
  • York, York County, 5/12/2025

These sightings were gleaned from the Journey North Monarch (Adult) First Sighting map, shown below in a screenshot frozen in time on 14 May 2025.

screenshot of Journey North Monarch (Adult) First Sighting map as of 14 May 2025

Ideally we’ll see a handful more monarchs this year compared to last because …

In March the World Wildlife Fund reported that December 2024’s count of eastern monarch butterflies wintering in Mexico showed the eastern population had nearly doubled since the prior year. This is good news in the very short term but is tempered by a sober look at World Wildlife Fund’s Annual Count graph, embedded below. (Purposely small so that you click here to see the full size graph at WWF.)

Annual graph of acreage in Mexico containing wintering monarch butterflies (graph embedded from World Wildlife Fund)

The graph shows healthy large populations from 1993-1994 through 2003-2004, then acreage drops off to the worst year of only 1.66 acres (in red) in 2013-2014.

This year’s 4.42 acres (2024-2025) is nearly twice last year’s 2.22 but both are still among the five lowest levels in 32 years. There’s a lot of work to do both here and in Mexico to continue the monarchs’ turnaround. (*)

Meanwhile, watch monarch butterfly migration at the Journey North 2025 monarch map. Click the Play button on the map’s control panel (screenshot below) to see their progress.

Report the ones you see to put them on the map.

Control panel from monarch sightings map 2025

(*)For information on the monarchs’ plight see July 2024’s blog: Have You Seen Any Monarchs This Year? and Christine Rickabaugh’s comment about the situation in Mexico.)

Ick! It’s Tick Season!

Books & Events, Insects
A vial full of newly hatched black-legged ticks! April 2025 (photo by Anita Colyer Graham used by permission)

10 April 2025

We haven’t thought about black-legged ticks (Ixodes scapularis) for months but their life cycle continues and the most dangerous time for Lyme disease is here. It’s time for Spray Your Clothes Day.

The next 6-8 weeks will witness an explosion of ticks on the landscape though they’ll be too tiny to see. Each engorged female that sipped on deer (and our) blood last fall spent the winter in the leaf litter and has or will soon lay an egg mass of 1,500-2,000 eggs. Then she’ll die.

What does it look like when those eggs hatch? They’re in the vial in the top photo, held by Anita Colyer Graham. These larvae are not yet infected with Lyme disease because they haven’t sucked blood yet, but they will if they get out!

Anita describes how they got there.

A couple of months ago, I pulled a huge, engorged tick off LGK [Little Gray Kitty] on our front porch. My husband took the fat tick and stuck it in a plastic vial, put the vial atop a shelf in the bathroom, and forgot about it. Yesterday, while looking for something, he picked the vial up, and he handed it to me. YUCK!

— Anita Colyer Graham’s blog, There Must Be Magic: Welcome to Tickville, U.S.A.!!!!

Here’s a closer look through Anita’s magnifying glass. They’re all alive despite the lack of water and the limited oxygen in the vial. Yikes!

Closeup of black-legged tick larvae, April 2025 (photo by Anita Colyer Graham used by permission)
Closeup of black-legged tick larvae, April 2025 (photo by Anita Colyer Graham used by permission)

And here’s their mother — or a mother just like theirs.

Engorged adult female black-legged ticks (photo by Anita Colyer Graham used by permission)

Lyme disease is a debilitating illness that has taken over the Mid-Atlantic, Northeastern and Upper Midwest. Since you can only catch it from an infected black-legged tick, the blue color is basically a map of infected ticks. Watch out PA!

Read more about the ticks in the vial and Lyme disease in Anita Colyer Graham‘s article: Welcome to Tickville, U.S.A.!!!!

And don’t forget to Spray Your Clothes! Here’s what to do …

It’s time for Spray Your Clothes Day

U.S. Butterflies Declined 22% in Only 20 Years

Insects, Musings & News
West Virginia white (Pieris virginiensis) in 2008 (photo from Wikimedia Commons)

11 March 2025

A new study published last week in the journal Science analyzed butterfly surveys from 2000 to 2020 to determine the population status of each species in the continental U.S. The results were sobering.

Total butterfly abundance (all individuals of all species) decreased across the contiguous US at a rate of 1.3% annually, for a cumulative 22% decline in overall abundance between 2000 and 2020.

— Science: Rapid butterfly declines across the United States
during the 21st century

The only region of the continental US that didn’t suffer was the Pacific Northwest where the total population remained stable and the highly irruptive California tortoiseshell (Nymphalis californica) surged on and off as expected.

The study found that declines were common and increases rare.

Over our two-decade study period, 33% of individual butterfly species (114 of 342) showed significantly declining trends in abundance. Conversely, only 3% of species increased.

— Science: Rapid butterfly declines across the United States
during the 21st century

For instance, the West Virginia white (Pieris virginiensis), above, declined each year by nearly 20%, in part because they are fooled into laying eggs on invasive garlic mustard that kills their caterpillars. By now 98% of them are gone.

And in southern Texas and south Florida the Soldier butterfly (Danaus erisemus), a relative of the monarch, declined about 15% per year, which means about 96% of them gone.

Solider or Tropical Queen butterfly (Danaus erisemus), Loxahatchee, Florida, 2016 (photo from Wikimedia Common)

Learn more about the study and see the graphs of declining species in Science.

Meanwhile, what can we do to save butterflies? In some cases it simply means planting the butterfly’s host plant. The zebra swallowtail returned to Pittsburgh after an absence of 87 years(!) because many people planted its host plant, the pawpaw tree.

Do Spotted Lanternflies Taste Good? Yes, Says a Vireo

Bird Behavior, Insects, Migration, Spotted Lanternflies
Blue-headed vireo eating insect in Missouri (photo from Wikimedia Commons)

25 October 2024

This week a migrating blue-headed vireo visiting New York City decided that spotted lanternflies taste pretty good.

If you don’t see the video above, click here: pic.twitter.com/t41vaByIp9

Though the current distribution of spotted lanternflies overlaps part of the blue headed vireo’s breeding range, an individual vireo might never have seen a lanternfly before he reached Central Park. This particular bird might be taking his first taste.

Spotted lanternflies at Herrs Island, Pittsburgh, 3 August 2024 (photo by Kate St. John)

How can a blue-headed vireo be naive about spotted lanternflies? It’s easy if he hatched this year. Let’s compare three maps.

1. This map of spotted lanternfly (Lycorma delicatula) distribution shows there are no lanternflies in the Adirondacks, Vermont, New Hampshire. Nor are they in Canada yet.

Spotted lanternfly U.S. distribution as of 12 Sep 2024 (map by Cornell CALS via New York State Integrated Pest Management)

2. Blue-headed vireos (Vireo solitarius) breeding north of NYC nest in Canada, New England and New York state. The vast majority of hatch year blue-headed vireos were born north or outside of the lanternfly’s distribution.

Range map of blue-headed vireo (from Wikimedia Commons)

3. Were these naive birds in Central Park this week? This eBird slideshow of blue-headed vireo abundance for the weeks of 18 and 25 October shows that most vireos have left Canada and are moving rapidly out of New York and New England. The bird in Central Park on 22 October was probably born outside the spotted lanternfly zone.

slideshow of blue-headed vireo abundance from eBird Status and Trends

By now blue-headed vireos have already left southwestern PA and this week they’ll depart from eastern Pennsylvania. Their help with spotted lanternflies will have to wait until next year.

Tick Season Returns — On Birds

Insects, Migration
Connecticut warbler banded at Hays Woods with engorged tick above eyering, 8 October 2024 (photo by Nick Liadis, Bird Lab)

9 October 2024

Yesterday while Bird Lab was at Hays Woods, Nick Liadis captured and banded a Connecticut warbler! I was not there to see this rare bird (alas) but Nick sent me a photo. Notice that the warbler has an engorged tick at top right of his eye-ring.

Tick season has returned with a vengeance after a low period during August and September’s drought. Because they cannot live without moisture ticks hang out in humid vegetation, but there was very little available during the drought. All that has changed with the recent rains and black-legged ticks are now active for their mating season which they conduct on the bodies of deer. I was reminded of this yesterday when I saw a deer in Schenley Park with three engorged ticks on its face. (Ewwww!)

Birds that forage on the ground are likely to encounter ticks so its no surprise that the Connecticut warbler and this song sparrow acquired them.

Song sparrow with engorged tick below its eye
(photo from Scott, & Clark, Kerry & Coble, & Ballantyne,. (2019). Detection and Transstadial Passage of Babesia Species and Borrelia burgdorferi Sensu Lato in Ticks Collected from Avian and Mammalian Hosts in Canada. Healthcare. 7. 155. 10.3390/healthcare7040155)

Birds, in fact, are an integral part of the tick’s life cycle. Notice the robin in the Summer section of the CDC diagram below.

Black-legged tick life cycle (diagram from CDC enhanced with lifeform names)

I used to say that deer were the black-legged ticks’ long distance transport system but I’ve changed my mind. It’s birds. A 2015 study found that 3.56% of the songbirds migrating north into Texas in the spring are carrying tick(s), most of which are native to Central and South America.

The bird-tick transport system works both ways. A 2019 tick-host-pathogen study in Canada found that some birds carry ticks with pathogens on fall migration.

Poor birds! They need all the strength they can get to complete their migration. It doesn’t help when ticks are sucking their blood.

Meanwhile, be careful about ticks out there! Lyme disease, transmitted by ticks, is terrible. Check your clothing while you’re in the field and thoroughly check your body for ticks when you return home. Click here for ways to prevent infection by keeping ticks off your clothes and body.

p.s. Support Nick Liadis’ efforts with a donation at Bird Lab’s GoFundMe site.

Busy Bees in Early October

Insects, Phenology
Bumblebee at grape leaf anemone; honey bee arriving, 1 Oct 2024 (photo by Kate St. John)

6 October 2024

With fewer flowers, nectar and pollen available, bees are quickly eating what they can in early October. Though it looks like the honey bees and bumblebees are doing the same thing they have different strategies for dealing with winter.

Honey bee workers are still busy gathering nectar and pollen to support their hive and queen through the winter. We see them foraging when the temperature is at or above 55°F (13°C).

Honey bee and bumblebee at grape leaf anemone, 1 Oct 2024 (photo by Kate St. John)

Bumblebees, on the other hand, are very busy but their lives are short. Only their queen will survive the winter. After she mates with the available males she will retreat underground to wait for spring.

Bumblebee alone at grape leaf anemone, 1 Oct 2024 (photo by Kate St. John)

The flowers they love are grape leaf anemone in a garden near Carnegie Library and Museum.

Bumblebees coming and going at grape leaf anemone, 1 Oct 2024 (photo by Kate St. John)
Bumblebees at grape leaf anemone, 1 Oct 2024 (photo by Kate St. John)

Let Your Garden Sleep In

Insects, Phenology, Plants & Fungi
Monarch butterfly on salvia (photo from Wikimedia Commons)

3 October 2024

On Tuesday I saw a monarch butterfly fly past my 6th floor window on its journey south. Every night that butterfly it will rest in sheltering vegetation and feed on flowers the next day. But what if those amenities aren’t available?

On Wednesday I noticed landscaping staff clearing a garden in front of an Oakland office building. Monthly gardening schedules, sometimes based on pre-climate change temperatures, call for clearing the garden or changing the plants in October. Salvia looks “leggy” now. Perhaps they were going to plant chrysanthemums.

Fortunately Saving Monarchs sends this helpful Facebook reminder for all gardeners. Take a break and let your garden sleep in!

This is a tiny screenshot. Click here to see the full Saving Monarchs post on Facebook!(*)

About the sign, Saving Monarchs says:

Some have messaged me asking if they can buy the sign, yes, they’re available for purchase. The large aluminum signs measure 18”x 12” are 50 plus shipping. I also make them in pvc size 9” x 11.5” and are 25 plus shipping. No extra shipping if you purchase more than 1. Obviously, due to shipping costs no posts are included, just the signs. Message [Saving Monarchs on Facebook] if you’re interested.

Read more about the benefits of leaving the leaves for insects, pollinators, birds, and even salamanders.

Leave The Leaves

(*) p.s. I used a screenshot of the Saving Monarchs sign because Facebook’s embedded posts do not display on mobile devices.

The Triangle Fly

Insects
Triangle fly on our window, 30 Aug 2024 (photo by Kate St. John)

31 August 2024

After yesterday evening’s rainbow a “triangle fly” landed on our dining room window and spun its body slowly like a top. Google Lens identified it as genus Rhagoletis, a member of the fruit fly family Tephritidae.

There are about 25 species of Rhagoletis native to North America, each with its own host fruit. Those who eat the fruits we grow commercially, such as cherries and walnuts, are considered agricultural pests.

Since my photo shows the bug’s underside, Google Lens picked up on the yellow body and identified it as the walnut husk fly, Rhagoletis completa, though it may have been a different species such as the closely related Rhagoletis suavis. There are black walnuts in Pittsburgh’s parks so these species are possibilities.

Here’s a topside view of Rhagoletis completa.

Rhagoletis completa, the walnut husk fly (photo from Wikimedia Commons)

Adult female Rhagoletis inject their eggs into the host fruit so that the larvae have something to eat when they hatch. If you open an infested fruit it looks like it has maggots. Here’s a walnut husk (yes, it’s a fruit) with R. completa larvae in it.

A walnut infested with Rhagoletis completa (photo from Wikimedia Commons)

Perhaps that’s why we occasionally see rotting black walnut husks on the ground.

A walnut infested with Rhagoletis suavis (photo from Wikimedia Commons)

Rhagoletis are preyed upon by jumping spiders!

Some species mimic jumping spiders. The wing-waving apparently deters the approach of jumping spiders, important predators of the flies. Other species have brightly-patterned bodies, and may mimic wasps.(3)

“Spider predation has been intense enough to mold the evolution of prey characteristics: predation by salticids (jumping spiders) has shaped the morphology and behavior of some tephritid flies. Their wing markings resemble the pattern of the legs of jumping spiders; the flies also wave their wings in a fashion that appears to mimic the agonistic behavior of salticids – making them ‘proverbial sheep in wolf’s clothing’.”(8)

— bugguide.net: Rhagoletis account

Could this native North American jumping spider be a predator of our Rhagoletis flies? Do you see a resemblance between its angled legs and the pattern on the fly’s wings?

Jumping spider native to North America, Phidippus audax (photo from Wikimedia Commons)

The triangle fly has opened a whole new area of inquiry.

Seeing More Spotted Lanternflies Lately?

Insects, Spotted Lanternflies
Spotted lanternfly on my window on 2 Aug 2023 (photo by Kate St. John)

28 August 2024

I was beginning to think we were safe this year but now I’m not so sure. After surprisingly few spotted lanternflies (Lycorma delicatula) in July and August, there are suddenly more of them in the air and on buildings and trees. Uh oh!

Have you seen more spotted lanternflies, too? I think I know why.

  • Their peak population was in September last year so we probably haven’t reached the peak yet. But it’s coming.
  • Spotted lanternflies love heat and it has been hot this week. Yesterday’s high was 94°F –> 13° above normal.
  • Why do I see them fly by my 6th floor windows? They love height as well.

Last year I mused on their love of height and heat. I sure hope their population doesn’t get so bad this year!

Spotted Lanternflies Love Height and Heat

Appalachia’s Mango Ripens Next Month

Insects, Phenology, Trees
Pawpaw fruits on the tree (photo from Wikimedia Commons)

27 August 2024

I came up with today’s slightly inaccurate title when I heard WESA’s piece on Pennsylvania’s secret tropical fruit, the pawpaw or “hillbilly mango.” In fact, pawpaws are not mangoes — they just taste like it — and their range is much wider than Appalachia. However it is true that they ripen in September.

Pawpaw range map from Wikimedia Commons

Pawpaws (Asimina triloba) are the quintessential wild fruit for browsing animals that eat the only ripe fruit on the branch and then move on. The fruit tastes like mango and has the consistency of banana. But don’t eat the seeds. They are poisonous.

Pawpaw cut open to show the fruit and seeds (photo from Wikimedia Commons)

Pawpaws defy commercial agriculture.

  • The skin is thin and bruises easily so they cannot be shipped.
  • Pawpaws don’t ripen all at once. You must come back later for the next batch because …
  • If you pull a hard, unripe fruit from the tree it will never ripen.
  • Pawpaw fruits lose their flavor if you heat them.
  • The bark, leaves, fruit and seeds of pawpaw trees contain the disabling and potentially lethal neurotoxin annonacin so …
  • Do not dry or cook down the fruit because that concentrates the compound that — fortunately — makes you vomit. (see more in the WESA article).

However, the neurotoxin is a benefit for zebra swallowtails (Eurytides marcellus) whose only host plant is the pawpaw tree. Zebra swallowtail caterpillars eat pawpaw leaves, become toxic themselves and are protected from predators.

Zebra swallowtail in spring (photo from Wikimedia Commons)
Pawpaw Festivals in September

If you want to eat a pawpaw and learn more about them, your best bet is at an upcoming Pawpaw Festival. The complete schedule of 12 festivals plus additional events are at Heppy.org: 2024 Pawpaw Festivals and Events. Here are a few close to Pittsburgh on the Heppy.org list in order of occurrence.

  • Ohio Pawpaw Festival in Albany, Ohio, 13-15 Sept
  • Paw Paw Festival in Duncansville, PA, 22 Sept, 9a-4p
  • West Virginia Pawpaw Festival, Core Arboretum, Morgantown, WV, 28 September
Pittsburgh has two notable pawpaw enthusiasts:

Andrew Moore wrote the book on pawpaws in 2015. Pawpaw: In Search of America’s Forgotten Fruit. If you want to know about pawpaws this is the book to read!

Book cover. Pawpaw: In Search of America’s Forgotten Fruit by Andrew Moore

Gabrielle Marsden is restoring zebra swallowtail butterflies to southwestern PA by planting pawpaw trees and encouraging others to do the same. Her YouTube channel is here. She also has two upcoming events:

Pawpaw Pathways poster (image from Wikimedia Commons)

Still curious about pawpaws? Learn more at this vintage blog.

Eat Pawpaws in September

p.s. Thanks to John English for pointing out the WESA article.