2/28/2011

The Insects of Jennifer Angus: Leaf Mimics

“Arranging Nature”, the insect art installation by Jennifer Angus has been drawing a lot of interest around the museum. Guests have been asking about what species of insects are used in this art exhibit. We’ve already covered cicadas and grasshoppers used in the exhibit, so now onto the really neat bugs: leaf mimic insects!

Leaf mimic insects exist in a vast array of colors and patterns and exhibit an extreme sort of camouflage. Camouflage is a type of crypsis (hiding) which allows a visible creature to blend into their environment and thus become difficult to see. Tigers have stripes that help to break up their overall form and modern soldiers wear a camouflage print that has the same effect. By utilizing colors similar to their environment, counter-shading, patterns, the eye of a human or predator is tricked

Phyllium giganteum: The walking leaf insect uses an incredible blend of color and shape crypsis. From Malaysia, this insect’s curious outline and green coloring render it mostly invisible among foliage. Males of this species are very rare and females can breed by parthenogenesis. This process allows a female to produce eggs or embryos that do not require fertilization by a male. These eggs will develop The resulting brood of insects will each be a clone of their mother.

Heteropteryx dilatata: The Thorny Stick comes to us from Malaysia.DSCN0128 Males and females of the species are very different in appearance.  The male is mottled brown and looks like a thorny stick, thus the name. The female is large with a wide green body and tiny wings that make her incapable of flight. In the wild, females of the species are very aggressive. They will hiss and thrash their legs at any creatures that approaches.

The Art of Camouflage: There are four main strategies of camouflage: cryptic (or blending), disruptive (or dazzle), mimicry, and countershading.

  • Cryptic camouflage involves colors and patterns that help an organism blend into their surroundings and become invisible to the eye. The dead leaf butterfly has the coloration and shape of a dead leaf and becomes nearly invisible on the forest floor. The walking leaf insect, mention above, utilizes shape and color to blend into foliage
  • Disruptive camouflage dazzles the eye by providing visual cues that override the characteristics of creature. The eyespots found on many butterfly and moth species create an image of large, circular eyes often similar to the eyes of predators. Octopus ink is another sort of disruption that catches the eye and disrupts smell and sight to allow the octopus to escape.
  • Mimicy camouflage allows one organism to present itself likeLeaf Mimic Insect another organism, often a dangerous or toxic creature. A species of snake from Asia, the False Cobra (Malpolon moilensis), mimics the hooded head of the Cobra to scare off predators. Learn more about mimicry in the butterflies of Florida in this post from our BioWorks Butterfly Garden blog.
  • Countershading mimicry utilizes coloration to override the normal cues of depth perception. This mimicry employs light coloration in places where dark colors are normally found and dark colors where light ones are normally found. In nature, most animals are lit from above by the sun and thus have a shadow on their undersides. The bright white bellies of many sharks or of salmon are shadowed so that in the wild the become nearly the same color as the darker top side of the animal. This same principle is used in camouflage makeup for the military where light colors are used in the normally shadowed parts of the face like around the eye and darker colors are used for the normally well lit, protruding parts of the face such as the nose. This swap of visual cues for depth perception tricks the eye into seeing a textured face as flat.

No comments:

Post a Comment