Autumn Revelations

Just this week, the leaves here began to turn in a marked way. And, finally, biology and urban naturalism are coming together. Leaves change color because of triggers such as length of light, temperature, and amount of precipitation, maybe things we already knew or could guess. But, what I learned is that these factors cause elements of the light-absorbing green pigment chlorophyll to degrade, allowing other pigments that were already present to show through. The stronger green now makes way for the orange and red (carotenoids) and yellow (xanthophylls), no longer masking the brilliant variety of color. 

Fruit Flies Revisited

I’m taking a biology class, which I believed would provide me with a wealth of information about the natural world and help me understand urban wildlife. Instead, I’m mired in the chemistry and physics of individual cells—electrons, ions, ATP, ADP, and etc.— which if I were less tired and thus more perceptive, I might be able to translate into acute and stunning observations about the world around me. I did read an interesting article related to biology in today’s New York Times science section about a scientist, Michael Dickinson, who studies fruit flies, those creatures about whom I was so flippant just two posts ago. As it turns out, fruit flies are one of the “most important laboratory animals in the history of biology, often used as a simple model for human genetics or neuroscience.” The article focused more, though, on how different the fruit fly is from us, for example, in its ability to fly and to taste with its wings. Although studied widely, Dickinson says, “we’re still fundamentally ignorant about the many features of its [the fruit fly’s] basic biology…” 

The Hummingbird Moth

During the last week or two acquaintances and friends have been exclaiming over the tiny hummingbird-like creatures they were seeing. When you first notice hummingbird moths, you really aren’t sure if they are hummingbirds or not. Their behavior and size can cause momentary confusion. They feed off of deep-lobed flowers, have a strong wing beat, and hover while feeding. A Calliope hummingbird measures 3.5 inches in length, whereas hummingbird moths can measure three inches or more in length. They are also called sphinx or hawk moths. We’re probably seeing what are named whitelined sphinx (Hyles lineata), with clear white lines marking their wings. Unlike other hornworms, which as moths fly at night, these are most active in late afternoon and dusk. Although the pupae are grossly impressive in size, shape, color, and texture, they are only pests and do not significantly damage plants. I don’t have a photo, but please look up a picture of a moth in flight and feeding on a flower—I think you’ll be impressed at how strongly they resemble hummingbirds.

Fruit Flies (Drosophila melanogaster)

We have had oodles of fruit on our counter ever since the farmer’s market opened in late June. And, with fruit comes fruit flies. Or, as one entomologist wrote, “time flies like the wind and fruit flies like bananas.” Although not a particularly felicitous piece of writing, it’s undeniable that the little creatures do like bananas, as well as tomatoes, raspberries, melons, and anything else that’s ripe and tasty. Even though their swarms can be unappetizing, to me they do not have the connotations of filth that houseflies have for me. In fact, I have a hard time taking them seriously, perhaps because they are so small. Also, their ability to appear out of nowhere amuses me. Now you see them, now you don’t. Or vice versa, once you put out a deliquescent pear. Although a nuisance pest, they can purportedly contaminate fruit with bacteria. Fruitflies.org, which I would have presumed to be a pro-fruit fly site promoting understanding and tolerance, has the tagline, “Fruit flies are nasty … learn how to get rid of them.” But, how to control them short of tossing anything that’s ripe or reducing the flavor of a peach by refrigeration? The Purdue extension author quoted above estimates that within a week, 500 fruit flies can mature, mate, and reproduce, with each of the resulting females laying 500 eggs of her own. All I can say is that I’ve never known anyone to get an illness attributable to a fruit fly, but I’m open to the possibility. In the meantime, I’ll take my chances, knowing that any fruit they find delectable, I will too.

Not For The Squeamish

They land on the rim of my cup, in my tea leaves, stick in my hair. Musca domestica. The housefly. It’s gotten colder outside, and they fly languidly. They hardly care when I wave them away. I’ve been taught that everything has its place in the ecosystem. I know they must exist for a reason, but I still shudder when they touch me and gag when they vomit on the edge of my cup. So, I typed beneficial flies into a search engine, and the following are some findings, none of them favorable. This quote pretty much sums it up: “Common household pests, they visit dumps, sewers and garbage heaps, feeding on fecal matter, discharges from wounds and sores, sputum, and all sorts of moist, decaying matter such as spoiled fish, eggs and meat. Flies regurgitate and excrete wherever they come to rest and thereby are ideally suited to mechanically transmit disease organisms. House flies are suspected of transmitting at least 65 diseases to humans.” Cornell University asserts that house flies can transmit over 100 human and animal disease-causing organisms. Texas A&M Agrilife Extension adds a whole other dimension, revealing that larvae can damage seeds and seedlings. I was surprised that these scientific sites all placed these “filth flies” firmly in the category of pest. Is it possible that the flies serve no useful function, or at least not one that outweighs the harm they cause, not to mention they annoyance they create?

Ladybug, Ladybug, Fly Away Home

I was drinking Sencha at my favorite teashop, watching a ladybug crawl along the windowsill instead of doing my work. I, like many people I think, have affection for ladybugs or ladybirds, which don’t seem like “bugs” at all in the sense of causing fear or feelings of squeamishness, although there is a phobia regarding them named coccinellidaephobia.

While eyeing this beetle (in the order of Coleoptera), a man with a child in his arms walked up, and I thought I overheard him say, “There, you can tell it’s a boy ladybug, because it’s orange.” I had never heard such a thing (It could have been completely true, as far as I knew). Whether you think it’s unmannerly to eavesdrop or not, I couldn’t help but hear, so I asked him to elaborate. He explained that what he really said was that the orange ladybugs are from Asia, and the red ones are from North America. He further told me that the orange are cheap imports taking over the native species. I just thought the orange ones were an anemic-looking variant.

Agreement among websites seems universal that the orange ones hail from Asia and the red ones from North America. The orange ones are about one-third longer than natives, and have nineteen, yes, exactly nineteen, spots on their backs. Counting the spots is one way of identifying which ladybug you’re looking at. The Department of Agriculture helped introduce exotics, as non-native species are called, in an attempt to control aphids. They eat fifty aphids a day.

Over four hundred species of ladybug exist in North America. Can everyone coexist, or are the Asian ladybugs outcompeting the natives, as the man at tea told me? A Canadian website, The Local Gardener, claims that  they are, to the extent that they are becoming pests. They even bite humans—maybe a ladybug phobia isn’t so farfetched. This informative and readable site includes a ton of (well, ten) interesting facts about ladybugs, including the statement that they bleed reflexively to repel predators.

The Lost Ladybug Project points out that non-native beetles have increased at the same time that natives have decreased, but doesn’t hypothesize a reason. The project collaborates with Cornell University and seems like yet another worthwhile and reputable citizen scientist endeavor in which to participate. If you take better photos than I do, you may find yourself a valuable addition to the project and even become, in their punny (that really is a word!) parlance, a “superspotter.”

They're Gone...

And I helped them leave. We packed the trailer on Saturday morning, said goodbye on Saturday night, and would have waved goodbye on Sunday morning if we had gotten out of bed in time. Alison and Jerry have left for Seattle. This may not seem like it is a nature post, but it is because it brings back so many memories of the urban nature we saw together over years as we ran miles and miles training for our half marathons. On Thursday evenings, we also ran together, after which we would return to our home for Indian food prepared by my husband, and for Alison and I anyway, the vice of reality tv. On our runs we saw a mink in the creek, oodles of bird species, including waterfowl, kingfishers and countless hawks. Some birds were alive and others were dead, especially after this winter’s late spring snowfall. We saw foxes, a skunk perambulating in the twilight, and several evenings a beaver swimming in a holding pond. We leapt over goose poop in spring and summer, and avoided squishing unidentified insects that traversed the trail. We ran past wild asparagus and wildflowers. Leaves changed color, fell, and then the trees leafed out in spring. The trees shaded us in summer and, when they lost their leaves, allowed the sun to warm us in winter. In keeping with our philosophy of running, and of course relieved for an excuse to rest even if momentarily, we would stop and watch the beaver, the hunting fox, the ducks. When we ran separately, we always reported back to each other what we had seen—a raccoon swimming in the river and disappearing into the rushes lining the creek, a dead baby raccoon, seemingly unmarked, and the three baby mink that Alison saw. My husband and I still plan on running, and nature will continue to cross our path, but we’ll miss seeing it with Alison and Jerry.