What is a butterfly?
 |
Butterflies are widely embraced and celebrated for their beauty and charisma. They make a very valuable contribution to ecosystems worldwide and are important study animals for ecology, evolution, and conservation biology. All butterflies and moths are insects (Class: Insecta). Insects are the most abundant and diverse group of animals, making up over 58% of the world’s known biodiversity. Butterflies and moths belong to the insect Order Lepidoptera, which is a word that comes from the Greek words for “scale” and “wing”. This is because all the patterns and colors on the wings and bodies of butterflies and moths are made up of tiny colored scales. Along with their distinctive coiled proboscis (mouthpart) and big showy wings, these features make butterflies and moths different from all other insects. The order Lepidoptera contains an estimated 150,000 described species (mostly moths) and there are an estimated 18,000 described butterfly species found globally. The earliest known butterfly fossils date to the mid Eocene epoch, between 40–50 million years ago.The wings, bodies, and legs, like those of moths, are covered with dust like scales that come off when the animal is handled. Unlike moths, butterflies are active during the day and are usually brightly coloured or strikingly patterned. Perhaps the most distinctive physical features of the butterfly are its club-tipped antennae and its habit of holding the wings vertically over the back when at rest. The lepidopteran life cycle has four stages: egg, larva (caterpillar), pupa (chrysalis), and adult (imago). The larvae and adults of most butterflies feed on plants, often only specific parts of specific types of plants.
Metamorphosis is a series of major changes in an animal’s body form as it moves through its life cycle. Butterflies and moths undergo a complete metamorphosis, which means there are four separate stages in the life cycle (egg, larva, pupa, and adult). Each stage looks completely different and serves a different purpose in the life of the insect.
Egg Stage: Female Lepidoptera (the group butterflies and moths belong in) often require specific plants, called host plants, on which to lay eggs. A butterfly usually lays 200-500 eggs which vary in shape and size depending on the species. Most species hatch in four to five days, while others may take as long as three weeks.
Larva Stage: When the eggs hatch, tiny caterpillars begin feeding and growing. Its first meal is usually the eggshell, which provides it with important nutrients. Then it will begin eating the host plant. Almost all caterpillars eat leaves but some eat stems, roots, fruits, seeds, seed pods or flowers. They will eat only the host plant and will not move to any adjacent plant of a different species – even if it runs out of food. As they eat and their bodies expand, their skin (an exoskeleton with a limited stretching capacity) becomes tight and eventually splits and sheds, revealing new skin beneath. This is called molting and occurs several times as the larva grows.
Pupa Stage: When the caterpillar has grown enough, it finds a protected spot, molts for the last time, and forms an encasement in which they metamorphose. During this stage, most moth caterpillars spin a silken cocoon while most butterfly caterpillars form a chrysalis. The pupa undergoes tremendous change. The caterpillar releases digestive juices that break down most of its body into a “tissue cell soup” from which it develops four wings, new legs, new eyes, new mouthparts, and genitalia. When the insect emerges, its metamorphosis is complete.
Adult Stage: The fully developed adult splits the pupal case open, crawls out and hangs upside down to facilitate stretching and drying its wings. Its wings are inflated by pumping fluid into the wing veins. At this stage, the wings are very soft and wet and the butterfly/moth must remain suspended while waiting up to two hours for its wings to dry. Once the wings are stretched and dried, the adult flies off to feed, find a mate and begin the cycle again. The average adult lifespan is two weeks but ranges from several days to as long as 11 months.
Butterfly Pollination
Butterflies are very active during the day and visit a variety of wildflowers. Butterflies are less efficient than bees at moving pollen between plants. Highly perched on their long thin legs, they do not pick up much pollen on their bodies and lack specialized structures for collecting it.
Butterflies probe for nectar, their flight fuel, and typically favor the flat, clustered flowers that provide a landing pad and abundant rewards. Butterflies have good vision but a weak sense of smell. Unlike bees, butterflies can see red.
Butterflies typically visit flowers that are:
- In clusters and provide landing platforms
- Brightly colored (red, yellow, orange)
- Open during the day
- Ample nectar producers, with nectar deeply hidden
- Nectar guides present
- May be clusters of small flowers (goldenrods, Spirea)
Many butterflies produce scents that attract the opposite sex. Many of these scents often smell like the flowers that they are attracted to and visit. The scent of these butterfly-pollinated flowers might have evolved as an adaptation that made use of the existing attractiveness of these scents.
No comments:
Post a Comment