Sunday, July 28, 2013

100,000 Pageviews!

A threesome of three-lined potato beetles, Lema daturaphila. Click. 

The Urban Wildlife Guide just hit 100,000 pageviews. I'm taking the day off to bask in the glow...

Sunday, July 21, 2013

Atlantic Ghost Crab

Atlantic ghost crab, Ocypoda quadrata. Click to enlarge. 
I met this little crab on a beach in Cape May, New Jersey. It's Ocypoda quadrata, called a ghost crab or sand crab.

The Latin name Ocypoda means "fast-footed," and quadrata describes the rectangular shape of its carapace, or back. It is pale like a ghost, and camouflaged to blend with the sand. It is famous for hunkering down and covering itself with sand very quickly, seeming to disappear before your eyes.

Ghost crabs live in burrows in the sand above the high water line. They don't go far from the ocean; females lay their eggs in the water.   The crabs are mainly nocturnal, but they come out in the day. They hunt at the water's edge, running after the retreating surf to pick up bits of food like sand fleas, clams, mole crabs, turtle eggs, detritus, and vegetation. Ghost crabs are common on Atlantic coastal beaches from Rhode Island south to Brazil.

Ghost crabs have eyes on long stalks that let them see 360 degrees around; there's no sneaking up on a ghost crab!

Sunday, July 14, 2013

Growing Caterpillar

A black swallowtail butterfly caterpillar. Click to enlarge. 
For the past few weeks, I have been watching black swallowtail caterpillars in a nearby stand of fennel plants. Like many butterfly species, black swallowtails are picky about what they eat. They prefer host plants in the carrot family, Apiaceae, which includes parsley, fennel, dill, Queen Anne's Lace, and of course, carrots.

Fennel smells like licorice candy. It is delightful to look for caterpillars on fennel plants, because as I brush the lacy fronds, they release a sweet licorice smell. I usually wonder in passing what it's like to live on an exclusive diet of fennel.

Adult females lay eggs on the plants. A tiny caterpillar hatches right on its food and starts to eat. It eats and eats until it grows to the maximum size its external skeleton will allow. Then it sits quietly while its skin splits; it emerges larger and ready for the next growth stage. Each stage is called an instar. Black swallowtails have five instars.

Today, as I was taking a walk, I found the caterpillar pictured above. It was sitting very still. I learned later that it was about to change its skin. After walking in the neighborhood for a few hours, I stopped at the fennel plant to look again.  The picture below shows what I saw -- a new instar, feasting on its old skin. The caterpillar was efficiently recycling its resources. I could not help thinking that it probably tasted like licorice.

A newly emerged black swallowtail caterpillar, eating its old skin. 

Sunday, July 7, 2013

A Baby Wheel Bug !

I found a tiny assassin sitting on a yellow flower in Brooklyn Bridge Park last week. It's an immature, or nymphal, stage of an assassin bug.

Assassin bugs are predatory insects in the family Reduviidae. They have long downward-facing beaks that unfold forward. Assassin bugs capture other insects and pierce them with their sharp beaks. Then they inject enzymes to paralyze and dissolve. Then they suck out the victim's liquified insides.

Click to enlarge. You can see the bug's developing little beak. 
The orange and black nymph pictured above overwintered in an egg that its mother laid on a plant last fall. It hatched this spring and will pass through five nymphal stages until it is a fully grown adult some time this summer.

And it's not just any assassin bug, it is Arilus cristatus -- a wheel bug!

When it is fully grown, it will look like this adult wheel bug. Get a load of the beak on this! 
The wheel bug is one of the largest terrestrial bugs in North America. Adults are about an inch and a quarter long. It is named for the cog-shaped armor on the adult's back.

If you get a chance, check the foliage around the Pier 1 entrance to the Squibb Park Pedestrian Bridge this summer. At least one great big wheel bug will be hunting there.