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.[42] 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. Eyespots on wings of Speckled Wood, Pararge aegeria, appear to distract predators from attacking the head. The left hind wing has been badly damaged by birds, but the insect is alive and able to fly. Cryptic coloration is found in many butterflies. Some like the oakleaf butterfly are remarkable imitations of leaves.[43] 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.[

4] Eyespots and tails are found in many lycaenid butterflies. It is thought that their function is to 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.[45] A butterfly's hind wings are thought to allow them to take swift, tight turns to evade predators. A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host. Thus parasitoids are similar to typical parasites except in the more dire prognosis for the host. Camouflage is a set of methods of concealment that allows otherwise visible animals, soldiers, military vehicles, or other objects to remain unnoticed by blending with their environment or by resembling something else. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly. Camouflage is a form of visual deception; the term probably comes from camouflet, a French term meaning smoke blown in someone's face as a practical joke.[1] Camouflage can be achieved in what may seem opposite ways. Mimesis means being seen, but resembling something else, whereas crypsis means being hidden.[2] But in both cases, camouflage is achieved by not being noticed. A third approach, dazzle, means confusing the predator or enemy by moving a conspicuous pattern. The prey or target is visible but hard to hit.