I paid a visit to the Arnold Arboretum on Sunday, the first day after the end of our long heat wave. Insect life was abundant.
I found five species of butterflies, three of them skippers. A least skipper (Ancyloxypha numitor) was roaming near the meadow. This skipper is mostly orange with thick black borders on its hindwings.
I initially saw this silver-spotted skipper (Epargyreus clarus) on a purple loosestrife flower. At first glance, the wing looks broken, but that’s the silver spot that gives this skipper its name.
The third skipper I found is the Northern Broken Dash (Wallengrenia egeremet). Note the triangular yellow spots on its wings that were missing from the wings of the least skipper. This guy is also on the thicker side.
This eastern tailed-blue (Everes comyntas) looked white from a distance. As I got closer, I noticed the orange “eyes” on the back of its wings. Closer still and I could see its double tail.
Finally, our most common butterfly, the cabbage white (Pieris rapae). The two spots on its wings gives this one away as a female.
On to the dragonflies and damselflies. I’ve seen plenty of eastern forktail damselflies (Ischnura verticalis) near the ponds, and did so again today, but this is my first photograph of a young female forktail.
A male twelve-spotted skimmer (Libellula pulchella) came to rest on a twig. With three dark spots on each of their four wings, this dragonfly can be identified from a distance.
Much more difficult to tell apart are the meadowhawks. I’m guessing that the female below is an autumn meadowhawk. I’m not even going to guess on the male that comes after it.
The cicada-killer wasps (Sphecius speciosus) love to build their nests near the sidewalks around the ponds. Look for their reddish wings and legs, and the black abdomen with three broken yellow rings around it. These wasps generally don’t bother humans, but annual cicadas have much to fear. The wasp will sting a cicada to paralyze it, drag it underground, and then lay an egg on it. The larva will eat the paralyzed cicada while it is still alive. [Update: Arbotopia has some good information on these insects.]
Here is a potential victim, an annual cicada. Actually, it’s the shell the cicada left behind after it molted. The cicadas were singing, quite loudly at times, but they were too high in the trees for me to spot any.
A hoverfly came to rest on a plant near the linden collection. Although its abdomen is skinnier, I think this is the same species I saw on the Cape, Toxomerus geminatus. Maybe it will fatten up over time.
Nearby, I almost missed this small tumbling flower beetle (Mordellidae). Judging from this photograph, it is probably the species Paramordellaria triloba. Thanks to bugguide user josephfortier for help with the ID.
This black wasp with black-and-white legs was identified by bugguide user Bob Carlton as belonging to the genus Cratichneumon. Browsing through photos, I think it most resembles Cratichneumon sublatus. According to Forest Pest Insects of North America, this wasp preys on the caterpillars of the saddled prominent moth.
I saw this large fly with black-and-white wings resting on a rock near one of the ponds. It looked like an overgrown deer fly and I feared that I was soon going to be donating a lot of blood. Turns out this is a tiger bee fly (Xenox tigrinus), whose larvae feed on carpenter bees.
That previous link is from Julie Feinstein’s New York City Urban Wildlife Guide, which I highly recommend.
Sometimes I come across an insect so odd that I can scarcely believe it’s real. This leafhopper nymph (Coelidia olitoria), yellow with an upcurved abdomen and green eyes, looks unreal. Thanks to Charley Eiseman of bugguide for the ID. As the photos on his site Bug Tracks show, this nymph comes in many wild colors.
I also highly recommend Bug Tracks. Charley’s entomological knowledge is impressive.
The final insect I encountered is another killer, a robber fly (thanks to bugguide user josephfortier for the ID). Robber flies chase and jump on insects that come near them, injecting them with saliva that paralyzes the insect and digests its insides. The robber fly will then suck out the contents. Tasty, I’m sure. [Update: this one has been identified by Herschel Raney as Efferia aestuans.]
The wildflowers and other creatures I saw will have to wait for another post.