Natures wonders: Aquatic insects builld shelters (Introduction)

by David Turell , Monday, February 01, 2016, 01:09 (3217 days ago) @ David Turell

This is very important protection in the larval form. They remain inside until pupation:-http://www.sciencedaily.com/releases/2016/01/160128081431.htm-" Larvae of caddisfly, aquatic insects of the order Trichoptera, using substrate particles, build tiny tubes where they protect their fragile bodies and carry out the metamorphosis which will transform them in adults. Researchers unveil a curious secret of Nature, unknown until now. When the time for pupation comes, larvae modify the architecture of their shelters, balancing their two halves by means of adding weight to both ends. The goal is that the tubes in which they stay captive until pupation can rest horizontally on the shallow banks of the streams, given that, in case of staying in vertical position, the probability of being exposed to the air would be too high and they could die of desiccation. -***-"Intrigued by this fact, professor Alba-Tercedor carried out a research on this aquatic insect using microtomography. The first images showed this double structure and, in addition, they showed that the larva had put additional grains of sand or gravel in both ends before pupating. These grains, which in the images looked like big rocks, were put in the inner or the outer side.-***-"With that change, the tiny tubes can lay horizontally in the shallow banks of the streams where, at the end of the summer, the larvae stay enclosed for several weeks until they complete their transformation and emerge as flying adults.-"'During this time, the streams' volume of water decrease a lot and there remain some poodles in which the larvae, enclosed in their tiny tubes, stay submerged. During this time, if the tubes were in a vertical position, the probability of part of them being exposed to the air would be very high and, therefore, the animal would die out of desiccation," the professor of Zoology from the UGR stresses.-***-"The results confirmed the hypothesis: the weight of the two halves was exactly the same thanks to the re-balancing work that they make by themselves adding new substrate particles to both ends.-***-"Such a tiny larva, whose length is only a little more than one centimeter, is capable of being an expert architect building the tubes and adding the exact amount and volume of grains in both ends to balance the weight as in a scale, afterwards. The survival of the species depends on this. Evolution has selected the ones that built the right way," professor Alba-Tercedor concludes."-Comment: From my viewpoint, this is too complex to have developed by trial and error.