AFRICAN MONARCH BUTTERFLY
(Danaus chrysippus)
Conspicuous medium-sized butterfly that is protected from predators by poisonous chemicals obtained from milkweed plants. Its orangish- or reddish-brown wings are bordered with black and white. The apex or tips of the fore wings are black with a white bar and spots. The male has 4 black spots on his hind wings while the female has only 3. Sides of the thorax are black with white spots. Wings are large for the size of the body and the first pair of legs is greatly reduced in size. Cells of both fore and hind wings are closed. There are overlapping scales on the body and wings, multi-segmented antennae with slightly developed clubs, and mouthparts that form a proboscis for taking liquids.
The male and female are alike except the male has a scent patch on each hind wing and scent brushes in the end of the abdomen. The male has a velvety black spot in the middle of each hind wing that consists of a shallow pocket or pouch with a small slit on the upper surface. A thick ridge covered with black scales overhangs this opening. These tiny black scales are oval in shape and different from the scales that cover the rest of the wings. This scent patch or gland is thought to be secretory and produces aphrodisiac scents used in courtship.
Ecology and Behavior |
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Distribution: One of the most widespread butterflies in the world, found from southern Europe to the Cape, and from West Africa to the Far East.
Habitat: Almost all habitats where milkweed plants grow.
Food and Feeding Methods: Larvae feed by day mostly on milkweed plants (family Asclepiadaceae) and their relatives, and the poisons that accumulate in their bodies make them distasteful to predators. Poisons persist into adulthood.
Behavior: Like all unpalatable butterflies, the African monarch butterfly is a slow, lazy flier with frequent gliding; however, when disturbed or migrating, it is capable of rapid, sustained flight. It seldom exerts itself to fly to a treetop and instead, settles frequently on low vegetation. The males patrol in flat areas near the larval food-plants (milkweed) in search of females and interactions occur all day.
Life Cycle: The female monarch normally flies in a leisurely, unhurried manner, but during courtship she adopts a rapid, jerky flight. The male pursues her, flying above, displaying and thrusting out his hair pencils, and induces her to alight by lightly brushing her antennae with them every time an opportunity presents itself. The dust particles of the pheromone from the hair pencils stick to the olfactory receptors of her antennae by means of the compound of alcohol, also from the hair pencils. The pheromone appears to keep the female from escaping by producing a calming effect and in a short time, she settles with the male beside her, facing in the same direction. The male bends his abdomen sideways to reach the female and join with her. If during mating, flight becomes necessary, the male flies, pulling the female with him on their nuptial flight, unlike other butterflies where the female is the active partner.
Females lay eggs singly on milkweed plants belonging to the family Asclepiadaceae. The eggs are white or pale yellow, oval in shape, pointed at the end and flattened at the base. They are ornamented with fine longitudinal ridges connected by broad, lateral cross-ridges. Eggs hatch in about 10 days and the larva is 1/10 inch long on hatching and pale greenish-brown. At the end of the fifth stage or instar, just before it pupates, the larva is 1 ½ inches long. In the larva’s fifth and final stage, it is easily recognizable as a bluish-white caterpillar marked with yellow and black streaks. It has 3 pairs of black threadlike filaments on its back that first start to appear in the second larval stage and are sensory, with the pair on the thorax moveable. They are hardy insects and feed during the day freely exposed with their brightly banded pattern acting as a warning to potential predators of their poisonous properties. When fully grown, the caterpillar hangs itself up by its tail end and changes into a pupa marked by golden spots. In about 2 weeks, the pupa turns black and soon afterwards the adult butterfly emerges.
Members of the subfamily Danaidae are long-lived.
Status: Common throughout Africa, flying nearly year round.
Adaptations: The monarch butterflies derive their unpalatable qualities from the toxic chemical compounds that occur in the milkweed plants they feed on as caterpillars. If a bird eats one, it will immediately start vomiting until the insect is regurgitated and the horrific experience is imprinted on the bird’s mind forever. When some monarch caterpillars were fed on cabbage instead, they were readily eaten by birds.
The adult monarch butterfly’s slow, leisurely flight and its bright colors and patterns are the means by which it warns predators, such as birds and lizards, that it is poisonous. The caterpillars are brightly colored as a warning of their poisonous properties.
Remarks: Monarch butterflies belong to the Danaidae, a subfamily of the family Nymphalidae. This small group of butterflies that are highly unpalatable and some even toxic to predators, are sometimes called milkweed butterflies and are mimicked by many species of other families that avoid predation by evolving similar bright warning colors.
Some species of the Danaidae subfamily are known to take part in migrations. Danaus plexippus, the North American monarch butterfly, is known for its long-distance migrations, the longest extending from Mexico to Canada. The African monarch butterfly has periodic migrations in some regions of Africa but not in the spectacular manner of its American relative.
Wingspan: 3 - 4 in.