These insects spend 2-4 years in the ground feeding on sap from tree roots, but due to staggering emergence schedules, some of them come out every late summer. They are green and black in color, in contrast to orange and black periodic cicadas. Annual cicadas are also known as dog-day cicadas due to their arrival coinciding with Sirius, the dog star, being visible at sunrise. Oak Apple Galls are found anywhere there are oak trees.Now, as the annual cicadas emerge with calls as loud as 100 decibels, the outdoors is noisy with insect calls once again. They are green at first, turning brown later. Apple galls have a thin, papery shell and are spongy inside. This very large gall grows up to two inches wide, but is usually golf-ball sized. Oak Apple Gall Wasps are usually identified by their gall. Here is some information to get you going if you decide to do a gall wasp post: I don’t suppose you could write something on wasp galls? Oak tree and wasp eggs – Life in the Undergrowth – BBC Attenborough I have always been interested in galls and this video I found described different oak galls caused by wasps. I’ve never encountered these before and they were neat. I then went on to other Attenborough film clips. But then again, after 17 years, there might be a limit to celibacy. The mating business was interesting especially the bit where the male kept running after David Attenborough. They were all dangling on the tree like shaking earrings on the ears of the leaves. I wonder what chemical signal impels them to emerge? The empty larval cases attached to the trees and below looked like fish scales on the body of the tree. The film illuminating but could not explain the 17 year underground existence. I went immediately to that David Attenborough video and was fascinated by the cicadas emerging like robbers from their underground hideout and rising up the mother tree to emerge like aliens out of their larval cases to their final forms. It’s a different species of cicada, but I expect that it probably works to some degree on other species. In this video clip starting at around 2:30, you can see David Attenborough teasing a male cicada by snapping his fingers to imitate a female. They will then stay there for several years, getting bigger and bigger until one summer they dig back to the surface, split open their backs, and emerge as winged adults. Once the eggs hatch out, the newborn nymphs drop to the ground, burrow into the soil until they find a tree root, and then latch on and start sucking juices. This particular species seems to like to lay eggs in short-needled pines and spruces. Then, after they mate, the female goes off and uses her ovipositor to inject her eggs under the bark of tree branches. The male notices this, and comes over to find her. A female will then make a “clack” noise with her wings that sounds fairly similar to someone snapping their fingers. Meanwhile, the females home in on the screaming males, landing fairly close. These Dog-Day Cicadas typically like to hang out in the tops of fairly tall trees, so it is hard to actually catch them from the ground while they are singing. What normally happens with cicadas, is the males are the ones that make all the noise, sitting in trees and bushes and screaming their heads off. And how could we tell it was a female? Because she had an ovipositor. It looked pretty much like the previous one, except that this one was a female. Then, just a few days later (August 4, 2012), Sam found another one that was already dead. We can also see his white belly with a broad black band running down the middle, which is one of the ID features for the Dog-Day Cicada, Tibicen canicularis. Looking at his underside, we can see his drinking stylet that he used to suck juices from plants. It was a male that was still alive (but dying), Sam found this cicada in the yard on August 1, 2012.
0 Comments
Leave a Reply. |