Defense

Butterflies are threatened in their early stages by parasitoids and in all stages by predators, diseases and environmental factors. They protect themselves by a variety of means.
Chemical defenses are widespread and are mostly based on chemicals of plant origin. In many cases the plants themselves evolved these toxic substances as protection against herbivores. Butterflies have evolved mechanisms to sequester these plant toxins and use them instead in their own defense. These defense mechanisms are effective only if they are also well advertised and this has led to the evolution of bright colours in unpalatable butterflies. This signal may be mimicked by other butterflies. These mimetic forms are usually restricted to the females.

Cryptic coloration is found in many butterflies. Some like the oakleaf butterfly are remarkable imitations of leaves.As caterpillars, many defend themselves by freezing and appearing like sticks or branches. Some papilionid caterpillars resemble bird dropping in their early instars. Some caterpillars have hairs and bristly structures that provide protection while others are gregarious and form dense aggregations. Some species also form associations with ants and gain their protection (See Myrmecophile).
Behavioural defenses include perching and wing positions to avoid being conspicuous. Some female Nymphalid butterflies are known to guard their eggs from parasitoid wasps.
Eyespots and tails are found in many lycaenid butterflies and these divert the attention of predators from the more vital head region. An alternative theory is that these cause ambush predators such as spiders to approach from the wrong end and allow for early visual detection.
A butterfly's hind wings are thought to allow the butterfly to take swift, tight turns to evade predators

Notable species

 

• Swallowtails and Birdwings, Family Papilionidae
  • Common Yellow Swallowtail, Papilio machaon
  • Spicebush Swallowtail, Papilio troilus
  • Lime Butterfly, Papilio demoleus
  • Ornithoptera genus (Birdwings; the largest butterflies)
• Whites and Yellows, Family Pieridae
  • Small White, Pieris rapae
  • Green-veined White, Pieris napi
  • Common Jezebel, Delias eucharis
• Blues and Coppers or Gossamer-Winged Butterflies, Family Lycaenidae
  • Xerces Blue, Glaucopsyche xerces (extinct)
  • Karner Blue, Lycaeides melissa samuelis (endangered)
  • Red Pierrot, Talicada nyseus
• Metalmark butterflies, Family Riodinidae
  • Duke of Burgundy, Hamearis lucina
  • Plum Judy, Abisara echerius
• Brush-footed butterflies, Family Nymphalidae
  • Painted Lady, or Cosmopolitan, Vanessa cardui
  • Monarch butterfly, Danaus plexippus
  • Morpho genus
  • Speckled Wood, Pararge aegeria
• Skippers, Family Hesperiidae
  • Mallow Skipper, Carcharodus alceae
  • Zabulon Skipper, Poanes zabulon

http://en.wikipedia.org/wiki/Butterfly