The Urban Pantheist

Until the drought killed them, our nasturtiums were a food source for many. This bejeweled true bug (hemiptera) is unidentifiable, but was probably drinking plant juice.


Likewise these candy-stripe leafhoppers were using their beak-like mouthparts to jab holes in the plant and sip its fluid.


And then underneath the leaves these black aphids were also settled in to drink.


Enter the cavalry: ladybeetle larvae specialize on soft-bodied plant-feeders like aphids.


Off they go to eat some aphids--ultimately the plant succumbed to the combined stress of drought and bugs, but it was fun to record the events.

Charlie and I were at Turtle Pond. I noticed a water lily leaf decorated with specks, like someone had shaken pepper over it. "Oh boy! I can get some springtails into my project," I thought. But when I got the leaf close enough to examine, the specks didn't move--springtails would have jumped all over the place.


The specks turned out to be water lily aphids Rhopalosiphum nymphaeae* which are slow and flightless. They start out living on plants in the Prunus group (cherries and plums) in the spring. Then some of the population is born with wings--these fly to water plants and live out the summer there. Later they migrate back to the fruit trees, where the eggs will overwinter.

*Club-tubed water-lily eater.

Yesterday we held the May Urban Nature Walk despite the technicality that it was June first. We went to Cutler Park, a 600 acre marsh on the Charles River. We had more participants than any previous walk, I suspect, although it's hard to tell because some people arrived later and some left early! There were three small children, one teenager, and two dogs. All present were enthusiastic nature lovers, including people who knew a lot about plants, reptiles, birds, insects, mushrooms, and so on. These photos are mostly about the people--I can't wait to see everyone's pictures of all the cool creatures we found.

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Hey look, it's Whitey! She's the most skittish of our hens, so it was nice that I got this shot of her as I scattered a little cracked corn.

( flies and the Cosmos )

The following photos have nothing to do with one another except that they bring me joy. I hope you can like one or two of them.


Jim likes to bring back the frisbee!


And he puts it down like a good boy. Again, again!


When I get that tickly sensation on my leg hair, I don't react by swatting, I reach for my camera. Most of the insects that land on you to eat you come with anaesthetic saliva, so you can't even feel them biting you. This is just a little green aphid, probably caught on the breeze and disappointed to be on a tree made of animal instead of plant.


And a rare outdoor capy snap! We have five capybaras at the zoo now, so there's more chance you'll find them in an outdoor exhibit, looking handsome in the sun. My brother insists they are most noble of beasts.

The tuliptree to the right of the giraffe slide has aphids. I'll explain why that's important later.

We've been to this place twice, both times in weather in which most people wouldn't walk around the block. Yesterday: about 40 degrees, cold drizzle.

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Photos by urbpan. Location: common milkweed plant on the shore of Leverett Pond, Boston.

Urban species #310: Oleander aphid Aphis nerii

There are a few species of aphids which are generalists, feeding on a range of different plants. Most, however, drink the juices of a small subset of similar plants, such as the lettuce aphid (which feeds primarily on lettuce, but may also feed on artichoke and petunias) and the oleander aphid. The oleander aphid is thought to have originated in the Mediterranean, but has now spread worldwide, having been exported along with its host plant. Of course, oleander is a subtropical plant, so in order for the oleander aphid to spread to northern regions, it needed to find an alternate host. It has found that milkweed plants serve quite nicely. In places where oldeander will not grow, this insect may be called "milkweed aphid."

One thing that oleander and milkweeds have in common is that they are both quite toxic, bearing chemicals called cardenolides. Oleander aphids are able to take this poison from their host plant and store it. When a predator attacks, cardenolides are emitted from "cornicles," which are appendages on the top of the insect's abdomen. Usually this repels the predator, but if not, the poison does its dirty work. In an aphid predator such as a lacewing or ladybug, the poison can render the insect sterile, or interfere with wing development. The aphid presents a fair warning in its coloration: bright yellow-orange with contrasting black appendages. This caution sign combination works for all kinds of bees as well as the monarch butterfly (another milkweed feeder that uses cadenolides in defense).

Oleander aphids are thought to be all female, reproducing through parthenogenesis. Generation of wingless daughters and granddaughters are born and spread until they reach a point when the plant can support no more of them. Then a generation of winged aphids is born and they fly to new host plants. Like many other aphids, oleander aphids produce honeydew as excrement, but their honeydew contains the same poison they use to protect themselves. Some species of aphid are protected ("tended") by ants, who consume the honeydew. The giant milkweed we examined in Antigua had both aphids and ants; are there certain ants that can cope with the poison? Or since worker ants are both wingless and sterile, is the poison's effect moot? I hope this question is explored in the entomological literature, but I could not find it. It does seem that while the aphid causes little harm to the host plant, the uneaten honeydew accumulates and grows a fungus called "sooty mold," which is considered unsightly.

Oleander is a widely planted ornamental in cities throughout the tropical and subtropical world. Milkweeds such as butterflyweed are likewise planted, in temperate cities and suburbs. And common milkweed and giant milkweed survive in roadsides, parks, and vacant lots everywhere. Wherever these plants are, they are accompanied by their aphids.

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