|Butterfly Farming in Papua New Guinea |
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Planting the Farm
The key to farming butterflies is to establish a garden of the plants the various species need for their life cycles. The ideal farm area is about 0.2 hectares. This is spacious enough for growing food plants for adults and larvae and small enough to keep the plants watered, weeded, pruned, and generally well tended. Such a farm can contain about 500 vines, grown like bean plants on poles or shade trees.
It is important to surround the site with a thick hedge of hibiscus, bougainvillea, ixora, poinsettia, or other nectar-bearing plants whose flowers attract adult butterflies and encourage them to remain in the area. The hedges also keep out pigs and other livestock that may damage the leafy plants inside the farm.
A good way to start a farm is to establish it in a vegetable garden. (Papua New Guinea butterfly farmers often plant butterfly vines between their rows of sweet potato or tarot) By the time the vegetables are ready to harvest, the area already has some thriving butterfly food plants and probably some winged livestock as well.
One of the most successful butterfly food plants in Papua New Guinea is Aristolochia tagala, a vine on which the larvae of more common birdwing butterflies feed. Another is Evodea - a food plant of the large blue ulysses swallowtail and many colorful weevils.
Shade trees also can be food plants for butterflies other than birdwings and for beetles or weevils. Examples are species of Annona (such as soursop), Citrus (such as lemon), Cerbera, and Graptophyllum. Wallace's Longhorn Beetle feeds on breadfruit (Artocarpus communis).
Normally, one area of the farm is kept aside for growing seeds or cuttings. (IFTA sells seed of some suitable species.) In this nursery the butterfly food plants are watered and cared for, and unhealthy ones are easily spotted and weeded out.
A Hedge of hibiscus, ixora, and poinsettia to keep pigs out and provide nectar.
B Fruits trees (such as lemon).
C The aristolochia vine grown on the branches of others trees (such as leucaena), to feed caterpillar larvae.
D Nursery area.
E A hut for tools.
(Diagram courtesy IFTA, Bulolo)
The Life Cycle
Normally, each butterfly species has a preferred food plant for its larvae. After the female has mated she searches for the correct plant and lays her eggs on or near it. In a few days the eggs hatch, and the young caterpillars usually eat their own eggshells and begin feeding on the softer leaves and shoots of the food plant.
As they grow, the caterpillars shed their skins. Each molt is called an instar, and five instars occur before a larva is big enough to pupate. Pupation is a resting stage during which the adult butterfly develops inside the hard, protective chrysalis. For pupation the larva selects the underside of a stem or leaf to protect it from rain and predators.
After 10 days to 3 weeks, depending on the type of butterfly, the pupal case splits open and the adult insect emerges. This usually occurs before 9 o'clock in the morning. The freshly emerged adult then takes from 3 to 4 hours to expand and dry its wings before flying off to feed on nectar and to search for a mate to begin the life cycle once again.
Once the farm is well established, pupae can be collected daily. Ideally, about 50 percent should be left or released. At least as many females as males should be released. Pupae that are too high to reach are usually left to emerge naturally and repopulate the farm. Others are left because they are not quite perfect.
The farmer can usually see that emergence will occur on the next day, since the pupa becomes darker in color as the adult wing and body colors develop. He then plucks off the stem or leaf to which the pupa is attached. (The soft, new pupae are not touched because this damages the adult.)
He pins the leaf to a board or puts it in a net or in a small cage. Often these are kept inside to protect the pupae against pests and large predators. However, some farmers construct small houses out of bush materials to hold pupae ready for hatching. Others keep their pupae in the open and count on being able to collect the adults before they have flown away.
Care is taken to protect the specimens from ants and rats. For example, the legs of the cage are placed in bowls of water to deter ants from climbing up. The pupae are sprayed with water 2-3 times a week to speed up the hatching process and to prevent them from drying out. (Only a light spray is used; otherwise the pupa develop mold.)
The pupae are best kept in a shady place so the butterflies will remain calm after hatching and will not flap and damage their wings.
When the newly emerged butterfly has completely dried its wings, it is carefully caught by the thorax and injected with a small amount of a killing agent such as ethyl acetate or boiling water.
Small butterflies are particularly easily damaged if handled, so they are placed for about 10 minutes in a killing jar containing cotton (cotton wool) soaked with a little ethyl acetate. A layer of cardboard is placed above the cotton so that the butterflies are not stained by the solvent.
The farmer places the dead butterflies in paper envelopes, being careful at all times not to touch or damage the wings. The envelopes are easily made from grease-proof paper, which the agency supplies on request.
To ensure that the butterflies will not mold, they are placed on a black plastic tray and dried in the sun, in their papers, for about 4 days. During this time they are protected from pests such as ants, and the drying trays have a screen on top to prevent the envelopes from blowing away or from being rained on.
Once properly dried, the insects, still in their envelopes, are stored in boxes, preferably airtight to prevent condensation and molding. When enough specimens have been collected, the villager packs them carefully in strong cardboard boxes (which the agency also supplies) with cotton or kapok. A few naphthalene crystals are added to keep away pests, and the box is wrapped and sent to Bulolo.