Archive for the 'Insects, Fish, Frogs' Category

Sep 20 2017

Webs in the Trees

In the spring we saw tents in the trees.  Now we see webs. Though similar in concept, the structures aren't made by the same species.

The springtime tent, located in the crotch of a tree, is made by eastern tent caterpillars (Malacosoma americanum) who emerge from their tent to eat young leaves as they unfurl.  The webs, located on the branches, are made by fall webworms (Hyphantria cunea) who hide in the web and eat leaves that will fall off in a month or two.

Since late summer female moths have been laying egg masses on deciduous trees.

Fall webworm moth (photo from Wikimedia Commons)

Fall webworm moth (photo from Wikimedia Commons)

After a week the eggs hatch into tiny caterpillars who build a web to completely enclose themselves and their food.  As they eat, they build the web larger to enclose more leaves.

Fall webworms avoid coming out of the web until they're ready to pupate. Then they hide their cocoons under flaps of bark to overwinter and emerge next year.

Though the webs look ugly they don't harm the trees because the leaves will drop soon anyway.

See webworms in action in the video above from The Capitol Naturalist in D.C.  Read more in this vintage article from 2011:  Coming Soon To A Tree Near You

 

(photo of fall webworm moth from Wikimedia Commons; click on the image to see the original)

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Sep 13 2017

In Hot Water

Two men holding an Atlantic sailfish caught off the coast of Port St. Lucie, Florida (photo from Wikimedia Commons)

Two men holding an Atlantic sailfish caught off the coast of Port St. Lucie, Florida, 2010 (photo from Wikimedia Commons)

The warming ocean has been in the news lately as the most powerful Atlantic hurricanes ever recorded -- Harvey's rain and Irma's wind -- slammed into Texas, the Caribbean, and Florida.  The ocean is hotter now than any time since record keeping began in the 1880's and, though hotter water doesn't cause hurricanes we've learned it makes them worse.  Uh oh!

There's another sign the ocean is warming.  Fish are on the move.  A wide variety of species including sole, haddock, herring, and black sea bass have left places too warm for them and migrated to cooler water.

For example an enormous Atlantic sailfish (Istiophorus albicans), normally off the coast of Florida above, was caught in the Cape Cod Canal in August 2013.  It was the first Massachusetts record.

It's not just temperature that makes fish move.  Warm water has less oxygen, so it's harder to breathe, and more carbon dioxide so it's more acidic.  Acidic water holds less calcium carbonate, the building block of sea shells including those of tiny copepods.  With fewer tiny organisms there's less food all the way up the food chain.

Fish swim away from these "deserts" but some animals can't move very far. Think of lobsters, now gone from Long Island Sound.

The changes in species affect both fishermen and nesting seabirds.  The old catch limits refer to fish that can't be found because they've moved north, and baby puffins starve because the new species are too big for them to swallow.

From more powerful hurricanes to fish leaving home, we're in hot water!

 

Read more in this article from Yale e360: Feeling the Heat: How Fish Are Migrating from Warming Waters

(photo from Wikimedia Commons; click on the image to see the original)

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Sep 11 2017

The Zig Zag Web

Published by under Insects, Fish, Frogs

Yellow garden spider female with prey (photo by Kate St.John)

Yellow garden spider female with prey, Virginia Beach, 5 Sept 2017 (photo by Kate St.John)

Last week in Virginia Beach my mother said, "Come see my spider."  We stepped out the front door and there she was, an impressive yellow garden spider with a zig zag web.

Yellow garden spiders (Argiope aurantia) are very common orb weavers but we rarely notice them until late summer when the females have reached full size, about an inch long.   At this point their webs are also large with conspicuous vertical zig zags(*) giving them this alternate name in Virginia: the sewing machine spider.

My mother's spider hid behind her web which in turn was camouflaged by the light colored brick behind it.  (Click here to see a more obvious zig zag.)  In these photos the spider is packaging prey in gauze or perhaps eating it.

Yellow garden spider with prey (photo by Kate St.John)

Yellow garden spider with prey (photo by Kate St.John)

My mother pointed out a smaller web nearby with a smaller spider in it, only 0.2 to 0.3 inches.  It was the male who will eventually come courting, but he has to be very careful and quick.  His goal is to deliver both sperm packages without being attacked.  After delivering the second one he dies a natural death.  Then the female eats him.

Soon the female will lay 500 to 1,000 eggs in a small brown sac which will overwinter and hatch in early spring.  The tiny spiderlings are cannibals, too, but those who survive will play out the same story next year.

If you find a yellow garden spider you can enjoy it in peace.  Even though the females are large, they won't bite unless you grab them (egads!) and their venom is harmless to humans.

Read more about these and other Pennsylvania native spiders in this fact sheet from Penn State.

 

(photos by Kate St. John)

(*) The zig zag is called a stabilimentum.

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Aug 31 2017

How Do You Know It’s A Moth?

Published by under Insects, Fish, Frogs

Antennae of an Agreeable Tiger Moth (photo by Chuck Tague)

Antennae of an Agreeable Tiger Moth (photo by Chuck Tague)

What's the difference between a moth and a butterfly?

The best clue is their antennae.

Moths have feather-like antennae with many branches.  Butterflies have smooth antennae with a knob at the end.

The feathery antennae above are on an Agreeable Tiger Moth photographed by Chuck Tague.  Yes, the moth is agreeing to have his picture taken and yes, that's really his name!  Agreeable Tiger Moth (Spilosoma congrua).

The knobs on the antenna below are on a Pearl Cresent butterfly (Phyciodes tharos).

Pearlcresent butterfly (photo by Kate St. John)

Pearlcresent butterfly (photo by Kate St. John)

 

For more differences between moths and butterflies see this vintage article from August 2010:  How Do You Know It's a Moth

 

(photo of Agreeable Tiger Moth by Chuck Tague. photo of Pearl Crescent Butterfly by Kate St. John)

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Aug 29 2017

Green Eggs On Nettle

Green eggs on stinging nettle leaves (photo by Kate St.John)

Green eggs on stinging nettle leaves (photo by Kate St.John)

Today, a quiz.

I found green eggs on stinging nettle on August 9 at Wolf Creek Narrows, Butler County, PA.

Are they eggs or something else?

And who laid them?

Post a comment with your answer.

I'll reveal their identity later today.

 

THE ANSWER:  29 August, 3:15pm
This was a tricky quiz because the structures really do look like eggs. I thought they were butterfly eggs but they are too smooth. The likely butterflies lay very wrinkled eggs.  For instance, click here to see the eggs of the small tortoiseshell butterfly.

Mary Ann Pike correctly identified the green "eggs" as nettle galls of (probably) Dasineura investita.  The galls are the plant's defenses against the larvae inside them.  The larvae are from midges so tiny that I can't find photographs of the adult insects though these three photos may give you an idea.

Caterpillars of the Sordid Hypena moth (Hypena sordidula) eat these galls.  Click here to see it.

 

(photo by Kate St. John)

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Aug 27 2017

Today’s Outing at Schenley Park

Schenley Park outing, 27 August 2017 (photo by Kate St. John)

Schenley Park outing, 27 August 2017 (photo by Kate St. John)

This morning's outing at Schenley Park was great for birds!

Though we saw only 26 species, plus a silent Empidonax flycatcher, we had good looks at some birds we don't see every day including wood thrushes and a young Baltimore oriole.

Best Bird was a male pileated woodpecker, the first bird of the day.  😉

Best Insect -- the one that got me excited -- were some tiny flatid planthoppers, gray with blueish spots. To my untrained eye they looked like this, Metcalfa pruinosa, an insect native to North America.

Citrus flatid planthopper (Metcalfa pruinosa), photo from Wikimedia Commons

Citrus flatid planthopper (Metcalfa pruinosa), photo from Wikimedia Commons, Creative Commons Attribution-Share Alike 4.0 International license.

Click here for today's eBird checklist, also listed below.

Mourning Dove (Zenaida macroura)
Chimney Swift (Chaetura pelagica)
Ruby-throated Hummingbird (Archilochus colubris)
Red-bellied Woodpecker (Melanerpes carolinus)
Downy Woodpecker (Picoides pubescens)
Hairy Woodpecker (Picoides villosus)
Northern Flicker (Colaptes auratus)
Pileated Woodpecker (Dryocopus pileatus)
Eastern Wood-Pewee (Contopus virens)
Empidonax species (Empidonax sp.)
Red-eyed Vireo (Vireo olivaceus)
Blue Jay (Cyanocitta cristata)
Carolina Chickadee (Poecile carolinensis)
Tufted Titmouse (Baeolophus bicolor)
White-breasted Nuthatch (Sitta carolinensis)
Wood Thrush (Hylocichla mustelina)
American Robin (Turdus migratorius)
Gray Catbird (Dumetella carolinensis)
Cedar Waxwing (Bombycilla cedrorum)
Chipping Sparrow (Spizella passerina)
Eastern Towhee (Pipilo erythrophthalmus)
Northern Cardinal (Cardinalis cardinalis)
Rose-breasted Grosbeak (Pheucticus ludovicianus)
Baltimore Oriole (Icterus galbula)
Common Grackle (Quiscalus quiscula)
House Finch (Haemorhous mexicanus)
American Goldfinch (Spinus tristis)

 

(group photo by Kate St. John. Insect photo from Wikimedia Commons via Creative Commons Attribution-Share Alike 4.0 International license.)

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Aug 19 2017

More Monarchs Than Last Year

Published by under Insects, Fish, Frogs

Monarch butterfly on a zinnia (photo by Kate St.John)

Monarch butterfly on a zinnia (photo by Kate St.John)

It feels like a miracle.  After years of almost no monarch butterflies I've seen more in Pittsburgh this summer than I have for a long time.

Their relative abundance reminds me of the "old days" in 2011 when they were so plentiful.

Have you noticed more monarchs this year than last?

 

(photo by Kate St.John)

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Aug 17 2017

Listening To The Temperature

Published by under Insects, Fish, Frogs

Male fall field cricket (photo from Wikimedia Commons)

Male fall field cricket (photo from Wikimedia Commons)

On Throw Back Thursday:

There's a Rule of Thumb that says you can tell the temperature --in Fahrenheit! -- by listening to a cricket's chirp.

Here's how:  Read about the Thermometer

 

(photo of a fall field cricket (Gryllus pennsylvanicus) from Wikimedia Commons; click on the image to see the original)

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Aug 14 2017

Boogie-Woogie Aphids

Published by under Insects, Fish, Frogs

Beech blight aphids, 9 Aug 2017 (photo by Kate St. John)

Beech blight aphids, Butler County, PA, 9 Aug 2017 (photo by Kate St. John)

Last week Andy Zadnik and volunteer Tom Koehler from the Western PA Conservancy showed us amazing aphids on a beech tree at Wolf Creek Narrows.

Beech blight aphids (Grylloprociphilus imbricator) are nicknamed "boogie-woogie aphids" because they waggle their bodies when disturbed.  A puff of wind or a jolt to the branch will start them waving to ward off predators.  My photo is out of focus because the aphids would not stand still when I got close!

Like all aphids these suck the juice of their host, the beech tree, but their scary name (blight) is misleading.  Beech blight aphids rarely hurt the tree and are easily knocked off by a stream from a garden hose. Once on the ground the nymphs can't fly up because they have no wings, though their mothers do.

Beech blight aphid colonies are sought by ants, wasps and a fungus for their sweet honey dew.  They're also sought by predators that they mesmerize with their dance or sting with their tiny mouth parts too small to hurt mammals.

This video by the Capital Naturalist shows how they dance.

What's the boogie-woogie all about?

Click on these links to see what really scares these aphids:  Harvester caterpillar eating aphids, Harvester butterfly ventral view (wings closed) and dorsal view (wings open).

 

(photo by Kate St. John)

 

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Aug 13 2017

Primrose Moths

Primrose moths on a primrose, Allegheny County,PA, 6 Aug 2017 (photo by Kate St.John)

Primrose moths on a primrose, Allegheny County,PA, 6 Aug 2017 (photo by Kate St.John)

Last Sunday I found a crowd of pink and yellow moths head down in a common evening primrose.  Bob Machesney identified them as primrose moths (Schinia florida).

I should have guessed their name.

Moths are often named for their host plant and so are these. Primrose moth caterpillars eat evening primrose, biennial gaura and other members of the Evening-primrose family (Onagraceae).  In July and August the adult moths fly at night and spend the day resting on their host plants.  That's why there were so many on one flower.

Keep an eye out this month for beautiful pink moths on primrose and biennial gaura.  Here's a common evening primrose (Oenothera biennis) without a moth in it.

Common evening primrose (photo by Kate St. John)

Common evening primrose (photo by Kate St. John)

Click here to see biennial gaura whose flowers are actually quite small.

And here's what the primrose moth looks like in a museum, mounted to show all its features.  Amazingly its antennae are pink.

Primrose moth specimen, mounted (photo from Wikimedia Commons)

Primrose moth specimen, mounted (photo from Wikimedia Commons)

 

(primrose photos by Kate St. John. photo of mounted primrose moth from Wikimedia Commons; click on the image to see the original)

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