Editing Caterpillar (section)

=== Appearance ===

[[File:Hairy caterpillar (Costa Rica).jpg|thumb|[[Costa Rica]]n hairy caterpillar. The spiny bristles are a self-defense mechanism]]

The appearance of a caterpillar can often repel a predator: its markings and certain body parts can make it seem poisonous, or bigger in size and thus threatening, or non-edible. Some types of caterpillars are indeed poisonous or distasteful and their bright coloring [[Aposematism|warns predators of this]]. Others may [[Mimicry|mimic]] dangerous caterpillars or other animals while not being dangerous themselves. Many caterpillars are [[crypsis|cryptically]] colored and resemble the plants on which they feed. An example of caterpillars that use camouflage for defense is the species ''[[Nemoria arizonaria]]''. If the caterpillars hatch in the spring and feed on oak catkins they appear green. If they hatch in the summer they appear dark colored, like oak twigs. The differential development is linked to the tannin content in the diet.<ref>{{cite journal|last1=Greene|first1=E|year=1989|title=A Diet-Induced Developmental Polymorphism in a Caterpillar|journal=Science|volume=243|issue=4891|pages=643–646|bibcode=1989Sci...243..643G|doi=10.1126/science.243.4891.643|pmid=17834231|url=http://courses.biology.utah.edu/feener/5445/Readings/Lecture%2018/Greene%201989.pdf|citeseerx=10.1.1.462.1931|s2cid=23249256|access-date=2017-10-27|archive-date=2017-08-10|archive-url=https://web.archive.org/web/20170810102937/http://courses.biology.utah.edu/feener/5445/Readings/Lecture%2018/Greene%201989.pdf|url-status=live}}</ref> Caterpillars may even have spines or growths that resemble plant parts such as thorns. Some look like objects in the environment such as bird droppings. Some [[Geometridae]] cover themselves in plant parts, while [[bagworm]]s construct and live in a bag covered in sand, pebbles or plant material.