September 12, 2015 | David F. Coppedge

Insects Worth Respecting

Most six-legged creatures are small and we give them little notice. Here are surprises that entomologists are discovering in some very special insects.

Brazilian wasp venom kills cancer cells by opening them up (Science Daily): Will a cure for cancer come from a wasp? An entirely new class of anticancer drugs is being derived from wasp venom.

Insect Mothers Control Their Egg Colors (Current Biology): This paper is categorized under “evolutionary ecology,” but sounds more like good design: “a new study in Current Biology by Abram et al. shows not only that egg coloration in an insect seems to be adaptive in protecting embryos from harmful ultraviolet (UV) light, but also that mothers can selectively control egg appearance depending on where the eggs are laid, and hence risk of UV exposure.” That’s about all the author, Martin Stevens, had to say about evolution: the trait is adaptive.

Butterfly wings help break the status quo in gas sensing (PhysOrg): A beautiful Morpho butterfly like the one on Illustra’s DVD cover, Metamorphosis, graces the top of this article about biomimetics. “The unique properties found in the stunning iridescent wings of a tropical blue butterfly could hold the key to developing new highly selective gas detection sensors,” the article begins. How?

Amazing FactsTiny tree-like nanostructures in the scales of Morpho wings are known to be responsible for the butterfly’s brilliant iridescence. Previous studies have shown that vapour molecules adhere differently to the top of these structures than to the bottom due to local chemistry within the scales. This selective response to vapour molecules is the key to this bio-inspired gas sensor.

Professor Pete Vikucic (U of Exeter) says, “Bio-inspired approaches to the realisation of new technologies are tremendously valuable.

Nocturnal, compass-guided insects have a sense for turbulence too (Science Daily): A moth migrating in a stiff breeze seems in a bad way. They manage, this article says, by keeping track of the direction of wind gusts. “Turbulence cues” add to their “internal compass” equipment to keep them on course.

How termite mounds ‘breathe’ (Science Magazine): Commenting on a paper in PNAS, “Termite mounds harness diurnal temperature oscillations for ventilation,” the AAAS reporter gives a nice summary of this clever air-conditioning system built by collective action:

Here’s how it works: Inside the hill is a large central chimney connected to a system of conduits located in the mound’s thin, flutelike buttresses. During the day, the air in the thin buttresses warms more quickly than the air in the insulated chimney. As a result, the warm air rises, whereas the cooler, chimney air sinks—creating a closed convection cell that drives circulation, not external pressure from wind as had been hypothesized. At night, however, the ventilation system reverses, as the air in the buttresses cools quickly, falling to a temperature below that of the central chimney. The reversal in air flow, in turn, expels the carbon dioxide–rich air—a result of the termites’ metabolism—that builds up in the subterranean nest over the course of the day, the researchers report online this week in the Proceedings of the National Academy of Sciences.

Ant communication: Secrets of the antennae (Science Daily): If ants are invading your kitchen, look before you spray. See how they touch antennae as they meet? What are they communicating? They share chemical odors like pheromones in a “complex social communication” system, but what they are doing with the information is a work in progress. Researchers at Kobe University have identified olfactory genes that are expressed in the antennae.

Supersniffing Ants Smell Things Humans Can’t (Live Science): It seems unfair that tiny ants can smell things humans cannot, like low volatility hydrocarbons. Although people can train their sense of smell, “human noses are not up to the standards of ant antennae,” the article says, rubbing it in. “In fact, most animals would not be able to detect the hydrocarbons in the study as a smell at all,” a specialist at UC Riverside says. These chemical cues allow ants to tell the difference between a queen, a major worker, a minor worker, and other castes in the colony. Because the chemicals are not highly volatile (vaporizing), the ants can read each individual neighbor without getting confused by a cloud of smell.

Honey bees rapidly evolve to overcome new disease (Science Daily): Because bees are such important pollinators for agriculture, perhaps you’ve been worried about the hive collapse disease caused by mites that has drastically reduced some honeybee populations. This article says that some bees are “evolving” resistance, but doing it much faster than thought. “One of the most interesting changes in the bee population was in a gene related to a dopamine receptor known to control aversion learning,” the article explains. “Another study has suggested this receptor is involved with bees grooming themselves to get rid of the mites by chewing them up.” Is this really natural selection in action? There may be a programmed response at work; “we see how evolution happens as compared to how we think it happens,” a researcher said. Even if this is natural selection, it is only enhancing an existing trait, not inventing a new trait or organ. Nothing was said about random mutation. Normal genetic variation that occurs in any population appears sufficient to enhance the existing defensive traits.

Deforestation in Mexico butterfly reserve more than triples (PhysOrg): We end on a sad note: the habitat for Monarch butterflies continues to dwindle because of illegal deforestation. The Mexican government appears unable to defend the Monarch sanctuary (a World Heritage Site) from local farmers and outside loggers who are sometimes armed. This means that the heroes of Illustra’s film Metamorphosis: The Beauty and Design of Butterflies face a double threat: shrinking wintering grounds in Mexico and decreasing milkweed availability in the United States. The problem involves multiple governments and differing economic pressures. Readers may wish to join efforts to at least raise awareness and put pressure on the destroyers.

Before stepping on every insect you see, try to understand it. You might find a natural solution to a problem, get a bright idea, and make a lot of money.




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