|
Butterflies
of the World - Lifecycle, Ecology, Taxonomy, Conservation,
Photography, Butterfly Holidays, Photo Galleries, Book Reviews and
more.........
Butterfly Study Holidays
Trip Reports
Butterfly Diary - latest sightings
Where to find butterflies Frequently Asked Questions Test Your Knowledge Strange but true ! Taxonomy & Evolution Anatomy Lifecycle Ecology Survival Strategies The Enemies of Butterflies Migration & Dispersal Habitats in Britain Rainforests World Butterfly Census Butterfly Books Butterfly Art Gallery Butterfly photography Butterflies of the British Isles Butterflies of the French Alps Butterflies of Amazonia Butterflies of the Andes Butterflies of Malaysia & Borneo Butterflies of West Africa Species index Subject index Glossary
Text and photographs
protected by Copyright © Adrian Hoskins
2007, and must not be published
in part or in whole elsewhere without prior written permission from the
author.
|
![]() | |
|
Strategies for
Survival
PAGE 1
Butterflies
occur in an incredible variety of sizes, shapes, colours and
patterns. Each design serves a dual role. Firstly it must act as a
"badge", identifying the butterfly to potential mates.
Secondly, and perhaps more importantly,
it must function to protect the butterfly from predators, either by
using camouflage, warning coloration, mimicry or transparency.
PAGE 1 - MATE RECOGNITION
PAGE 2 - CAMOUFLAGE and
DISGUISE
PAGE 3 - APOSEMATIC
COLOURATION
PAGE 4
- MIMICRY
PAGE 5
- SEXUAL DIMORPHISM
PAGE 6 - ROOSTING BEHAVIOUR
Mate recognition
Butterflies generally have short lives, and need to be able to quickly locate potential mates. Many species lose their attraction to the opposite sex within a day or two of emergence because their pheromones become exhausted. Rapid mate recognition is therefore vital. The first stage in the recognition process consists of intercepting any flying object of roughly the same size and colour as their own species - in the neotropics for example it is easy to attract Morpho butterflies by waving a piece of blue foil in the air. Many of the more conspicuously coloured species such as Whites and Sulphurs can detect each other from several metres away, but the smaller and duller species need to be much closer - perhaps within one or two metres.
Purple Emperor Apatura
iris, male
In many genera such as Apatura, Morpho and Doxocopa the wings of males have an extremely reflective blue sheen, whereas the females are sombre in colour. During flight the wings of the males glint brilliantly in the sunshine, and probably play a major role in mate location and recognition. Once initial contact has been made, a combination of olfactory and visual factors hold the interest of both sexes as a precursor to the courtship ritual. Visual stimuli include holding the wings or body at particular angles, flicking the wings, or simply displaying the patterns by opening the wings. It is difficult to know how a butterfly perceives or interprets pattern, as the compound eyes produce an image totally different from that of mammalian or avian eyes, but biologists speculate that they might be able to build up a composite image by means of "flicker vision" During the courtship process a series of exchanges take place during which olfactory and visual stimuli trigger a particular response. A "wrong" response might indicate that the potential mate was not of the same species, or was unwilling to mate - females of many Pierids for example signal an unwillingness to mate by raising their abdomen and angling their outspread wings downwards. These are clearly visual signals. A "correct" response invariably triggers an array of further visual, olfactory and tactile stimuli, each leading to a "set" response which confirms that both butterflies are of the same species, of the opposite sex, and willing to mate. In some species this process is very brief, but in others such as the Small Tortoiseshell Aglais urticae, it is protracted and may take several hours during which the male doggedly follows the female from place to place, "persuading" her to copulate.
Small Tortoiseshell Aglais urticae
Male
butterflies will usually intercept both sexes of their own
species. The purpose of male-male sorties is usually to oust an
intruding male from the "territory" of another, and thus increase
the territory owner's chances of success with any female that
passes by.
Males also
"know" that they can often find food by following other males :
In tropical
regions males of many species need to imbibe mineralised water,
from which they obtain vital salts that they pass to females
during copulation. Normally just one or two males locate suitable
feeding spots, largely by chance. Other butterflies flying past
seem able to recognise their brethren on the ground, and swoop
down to join them. The bright patch of colourful butterflies
quickly becomes a magnet to every passing male of the same
species.
Dryas iulia,
Peru. A single male on the ground quickly attracts others of the
same species.
Urania leilus,
Peru. An assemblage of day-flying Urania moths.
More information about courtship, feeding and other
forms of adult behaviour can be found on the
Lifecycle and
Anatomy
pages, and in the individual
species accounts.
NEXT >>
|