Bug Day (23)
It’s been almost a year since our last Bug Day. For shame! Here we try to catch up, starting with this beautiful Tiger Swallowtail by Jutta Burger.
This butterfly is a Western native, seen as far south as northern Baja California and as far north as southern British Columbia. They live on both sides of the Sierra Nevada and the Rocky Mountains, as far east as the Dakotas and south to New Mexico. They spend the cold winter months in a chrysalis that looks like a dead twig, and emerge as beautiful butterflies as soon as it gets warm enough for them. The female sips nectar from a variety of plants. She will lay about 100 eggs one at a time under the leaves of various plants. The caterpillars aren’t picky about what they eat, either. That’s part of the secret of their survival.
This Harvestman (Opiliones sp.) looks like a spider but is only distantly related. It has a single apparently fused body, where spiders have two segments with a thin and visible connector. It has only two eyes that can’t form images, where spiders usually have three or four pairs of eyes with sharp, complex vision. Harvestmen also lack venom glands so a bite would not be dangerous. They also lack silk glands and can’t spin webs. They do have jaws that allow them to swallow solid food, whereas spiders can only ingest liquids. The males also have a penis, unlike any spider. Most species reproduce through copulation, and may guard territories. The females lay eggs, sometimes within minutes, sometimes months later. In many species the males clean and guard the eggs, whether his own or another male’s. A frequent threat to the eggs is egg-eating females. There are nearly 7,000 species of opiliones, and that may be an underestimate. Some of them haven’t changed much in eons. Fossils that are 400 million years old are practically identical to what we may find in our yard today. You and I are very recent arrivals on earth compared to this long-legged little critter.
I saw these two beetles four days apart. Or rather, my sharp-eyed wife saw the first one and pointed it out to me. They look very similar, but one has long shallow ridges on its body and the other doesn’t. I’ve asked the ever helpful experts at bugguide.net for an identification but they’re so swamped with requests I haven’t got a response yet. So I went web-hunting and I’m fairly sure they’re Darkling Beetles. There are about 20,000 known species worldwide, but only about 150 species are native to the U.S. Which species these are is just a guess: Coelocnemis californica, based on a similar photo on one of the beetle websites (yes, there are several!). Generally, they are crawlers. They can’t fly, no wings. Mostly nocturnal. Garden pests that chew young plant stems and leaves. They are frequent prey of birds, lizards and rodents. If they survive, they may live for 20 years. That’s ancient for a bug!
I poked my nose into a fresh fennel bush growing by the water on the east side of the park to see what might be lurking there, and was immediately rewarded with what I thought was a ladybug (Hippodomia convergens). But when I got the photos (left) home and wondered about the lack of spots, some of the sources warned that my bug was not the familiar European ladybeetle but the Asian variety, said to be a much nastier customer. The Asian ladybug (Harmonia axyridis) was imported here by well-intentioned agriculturists as early as 1916 because it has a voracious craving for aphids, scale insects, and other bugs. The resident ladybug eats the same diet but with a more moderate appetite. The Harmonia variety may also bite people, causing minor irritation, and it has the habit of entering people’s basements and wall spaces in late fall to shelter for the winter. A few days later I checked the same bush again and saw what I think is the same bug, and persuaded it to walk on my fingers so that I could get a better picture. On closer inspection, It had at least two spots, rather faint ones. It did not have a certain white “M” shape on its neck that some sources say flags the Asian variety. It did not bite me. Bottom line, I’m guessing that this is the traditional variety that just hasn’t made growing its spots a priority yet. And why should it?
Snails aren’t bugs in anybody’s book, not even by the widest stretch of the term. But since we’ve been talking about garden pests, they fit right into the topic. I saw these, dozens of them, on a stand of Wild Radish (Raphanus raphanistrum) on the north side of the park. These particular plants looked rather peaked, very likely as a result of the snails’ work. It surprised me a bit to find them. Thousands of Wild Radish plants populate the park, but very few have snails on them. I wonder what it was about these particular half-dozen plants that made them a gastropod magnet. Nature seems so simple but is amazingly complicated. I look, and what I see is only the first few inches of surface on a deep, deep sea.
