Fossil moths show their true colors

Wednesday, November 16, 2011
(A?C) Light micrographs of specimen MeI12269 with details of areas indicated (B, C). (D?J) Scanning electron micrographs of scales. (D) Surface showing longitudinal ridges and transverse crossribs and microribs. (E) Two overlapping scales showing windows, perforations, and internal laminae of the upper, fractured, scale. Arrow indicates densely packed bead- to rod-like spacers in the uppermost internal lamina. (F, G) Windows and perforations in proximal (F) and distal (G) parts of a scale. (H) Oblique fracture through scale showing successive internal laminae. (I) Surface of internal lamina showing perforations and bead-like spacers. (J) Horizontally fractured scale showing trabeculae (fractured and lying parallel to the scale surface) and reticulate basal lamina with, inset, intact vertically orientated trabeculae. Scale bars: (A), 5 mm; (B, C), 1 mm; (D, E, H, J) (including inset), 2 ?m; (F, G, I), 1 ?m. Credit: McNamera et al. PLoS Biol

The brightest hues in nature are produced by tiny patterns in, say, feathers or scales rather than pigments. These so-called "structural colors" are widespread, giving opals their fire, people their blue eyes, and peacocks their brilliant feathers. Many animals use this type of color for communication, notably butterflies and moths (Lepidoptera), which display the biggest range of structural colors and put them to uses from advertising their toxicity to choosing the best mates.

This is the first evidence of structurally colored scales in fossil lepidopterans. The fossil moths came from the Messel oil shale in Germany, a site famous for exquisite fossil preservation.

Although the original colors of the fossil moths were not preserved, the researchers were able to reconstruct them because the tiny color-producing patterns in the moth scales were intact. "The level of detail preserved in the scales of the fossil moths is just spectacular", said McNamara. The fossil moths owe their color to a stack of layers inside the scales. These layers form a fossil multilayer reflector, which usually produces iridescent colour that changes depending on viewing angle. But other details of the fossil scales suppressed this effect, producing instead muted colors. "The moths basically wanted to appear the same colour from different angles ? they didn't want flashy iridescence" said McNamara.

Today, the front wings of the ancient moths look mostly blue, presumably because the chemistry of the cuticle was altered during the process of fossilization. The researchers reconstructed the original colors via mathematical analysis of the scale ultrastructure, revealing that the wings had actually been yellow-green when the moths were alive. Modern butterflies and moths use bright, contrasting colors to communicate with each other, and muted greens to camouflage themselves in leafy habitats. This makes it likely that the fossil moths used their yellow-green wings to blend in with leaves, suggesting that this strategy for hiding in plain sight had evolved as early as 47 million years ago amongst lepidopterans.

The fossils are thought to be from extinct relatives of today's forester moths, which feed on flower nectar. If this was also true of these ancient moths, their yellow-green wings would have stood out while feeding. The researchers suggest that being easy to see on flowers could have served as a warning to predators. Modern forester moths can synthesize cyanide, making them taste bad, and their ancestors may have already developed this capability.

These findings shed light on the evolution of tactics for predator avoidance and deterrence in forester moths. In addition, by showing that the original structural colors of fossil moths can be reconstructed, this works leads the way toward finding the origins of the many ways butterfly and moth species use this type of color to communicate amongst each other as well as with predators. "Reconstructing the original colors of ancient animals gives us really good insights into their behaviour" said McNamara. "These moth fossils hint that we can even do this for fossils that don't have obvious color".

###

McNamara ME, Briggs DEG, Orr PJ, Wedmann S, Noh H, et al. (2011) Fossilized Biophotonic Nanostructures Reveal the Original Colors of 47-Million-Year-Old Moths. PLoS Biol 9(11): e1001200. doi:10.1371/journal.pbio.1001200

Public Library of Science: http://www.plos.org

Thanks to Public Library of Science for this article.

This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.

This press release has been viewed 19 time(s).

Source: http://www.labspaces.net/115219/Fossil_moths_show_their_true_colors_

vitiligo los angeles weather portia de rossi portia de rossi herman cain for president herman cain for president pumpkin bread