The diversity of butterflies image: By Charlesjsharp – from Sharp Photography
The Diversity of Butterflies – Article By Bisaso Edward Esau
Butterflies, which are believed to have existed before man, are a diurnal group of insects of order Lepidoptera, under the phylum Anthropoda, which comprise of about 16500 species (sburdoni and ferestiero, 1985)
Butterflies of Uganda
Family Papilionoidea (swallow tails): A large family of tropical butterflies having larvae with osmateurium. Some species are strikingly polymorphic; the pupae are variable in form.
Family Pieridae (whites and yellows): This is a group of butterflies with normal legs usually white or yellow in color. The family is equally well represented in the tropics and temperate region.
Family Lycaenidae (small to medium sized butterflies): The predominant color of the upper surface of the wings is metallic blue or coppery brown, hind wings often have delicate “tails”, all legs are functional. It is present in most regions, and sexes often exhibit distinct sexual dimorphism.
Family Nymphalidae (four-footed butterflies): This group of butterflies is most dominant family of butterflies and one of the largest in all Lepidoptera, forelegs of both sexes are reduced in size, usually folded on to the thorax and functionally impotent, Male forelegs are always clawless.
This family has several sub families:
Sub family Satyrinae (Brown and Ringlets): This sub species is easily recognized by the somber colors and the developments of the eye spots on the under side of all four wings. (Nirhout, 1985).
- Sub family Danainae (milk weed butterflies/ Danaids): Members are generally large with a similar wing shape but color patterns differs from genera to genera being orange in Danaus, dark brown and blue in Tirumals, and black and white in Amauris, (Acrkry and Vane Wright, 1984).This sub family is found in all tropical areas, and can occur in temperate zones.
- Sub family Charaxinae: Many species are large and beautiful, with extremely powerful wings. These butterflies are often localised and scarce.
- Sub family Nympalinae (Nymphlids): A large cosmopolitan tribe, medium sized to large butterflies with often powerful flight. Many have colorful patterns of great beauty.
- Sub family Acraeinae (the Acraeas): These are chiefly African butterflies with rounded wings and tough bodies, color patterns in orange or black spots, occasionally black and white are toxic. Acrae and family Libytheidea; (Wright R et al 1984)
Super family Hesperoidea (skippers): This family is widely distributed, somewhat intermediate between butterflies and moths, and considered more primitive than the true butterflies. They are called skippers because of their darting flight. The body is stout, the antennae have a gradual expanding club often ending in a hook, wings are proportionally smaller than in most butterflies and often held partly open at rest. Their larvae are often concealed in foliage where leaves are joined together with webs of silken threads.
Another important feature of butterflies is their role in the pollination of forest trees and plants, their presence is prominently used in selection of sites for conservation (New, 1992). Butterflies are also used in scientific research, this is due to their manageable size, and the fact that most are readily identifiable, even on the wing, they are also relatively easy to rear in captivity, and they can be used commercially in fine art designs and decorations.
Butterfly species have freely interacted with components of the environment and these have a direct influence on their diversity and abundance;
There are symbiotic relationships between the butterflies and the flowering plants, where the plants provide nutritional resources to the animals both in the nectar form for adult butterflies, and plant tissues such as leaves, and soft stems for the caterpillars, the plants also provide shelter from predation a factor which increases butterfly diversity and abundance.
The distribution of these nutritional resources have also influenced the mating behavior of the butterflies, where the males either patrol and seek females through an active search of habitats, or wait for females in the locations where they are encountered, this avoids male to male sexual interactions(Sburdoni and Ferestiero, 1985)
However the population of butterflies is attacked at all stages by a wide range of predators, eggs are searched and eaten by beetles and ants, the pupae are attacked by rodents, and adults are subjected to broad range of predators including the praying mantis, hunting spiders, chameleons, lizards, birds, and parasitoids (hymenoptera and diptera)
They are also attacked by diseases caused by number of pathogens such as viruses like hedrosis, bacteria, fungi, and protozoa.
Although they have little opportunity to learn to cope with enemies and diseases, butterflies have devised some defenses in order to be in equal equilibrium with the environment;
There is a great diversity in the arrangement of eggs, sometimes they are deposited in a confused mass, but in most cases they are arranged in an orderly and systematic manner. This means that the larvae, which hatch from the upper end of the egg, will not disturb the adjoining eggs.
Also butterflies don’t lay their eggs loosely, so that they can be driven by wind from place to place, or washed away by rain; butterflies glue the eggs onto a plant which will also be the appropriate food for the caterpillars.
Whilst in the growing stage caterpillars produce a variety of toxic chemicals (mustard oil, glycosides, histamines, and acetylcholine like substances,) other defenses include unpleasant taste, protective silk webs, and possession of body hairs, also mimicry and color camouflage. This ensures certain levels of survival by driving off the predators and parasitoids (Cott, 1940)
Some butterflies have deflective markings, designed to direct a predator to attack a non-vulnerable part of the butterfly, for example the marginal eye spot of the family Satyrinae and Nymphalidae. These groups are exposed to predators when they land. A lizard or a bird will rush in and has to make a split-second decision about where to strike, often choosing the eye spot as they know that the eyes are good targets. This means the butterfly can fly safely away with just a bit of wing missing. (Nijhour, 1985)
Butterflies also use camouflage, where their patterns merge with the background, or with other inanimate objects, an example of this is the larvae of the Charaxes, which look like pinnate leaves, skippers roll up, hidden, in the tubes of grasses, others are furry, or spiny to discourage the predators.
The dispersal of butterflies is favored by their excellent flying mobility, which is often extremely fast, and erratic, this means predators like birds find it extremely difficult to follow and intercept them. Dispersal may be activated by changes in the environment, such as deterioration of the climate, and thus is often an adaptive response to unfavorable environmental conditions. (Wright and Acrey, 1984)
Nocturnal and diurnal partitioning of the environment is another factor which has shaped defensive adaptation in the butterflies; adults of most species enjoy relative freedom from nocturnal predators because they are normally active and dispersed during the day and are totally inactive at night.
The diversity of Butterflies in Uganda – Conclusion:
Man greatly interferes with the ecology of the earth, often in ignorant and with total disregard for the consequences resulting from habitat disturbance.I feel scientists should devote themselves, to studying the origin, and the dynamics of all environmental change respondent organisms, such as butterflies, moths, and dragon flies. I hope that this understanding will help us to co-exist with nature in a good way. Let us combine our efforts and resources to conserve the biodiversity, including butterflies – long live butterflies!
The writer is a student at the Makerere University’s Institute of Environment and Natural Resources.
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Bisaso Edward Esau
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