It often surprises many people that Butterflies often have elaborate courtship behaviour. This is partly to ensure that species do not interbreed ... although there are secondary physical features that help to ensure this does not happen ... such as claspers, twists, spines on the reproductive organs that differ from species to species. Some species will readily hybridise if they are closely related ...the Black Swallowtail (Papilio polyxenes) and The Old World Swallowtail (Papilio machaon) can be hand paired to produce a very lovely looking sterile hybrid that tends to display the best characteristics of both parents. Pairings between these two species does not often happen in the wild as this would place both at a distinct disadvantage in natural selection and survival of the fittest!
2. To hand pair or not?
Hand pairing is useful with some species ... but most species will happily pair naturally if the right conditions are provided. I tend to hand-pair Swallowtails and Monarchs because it is generally a very easy process. The benefit of hand-paring is that you know the females are gravid, you can accurately predict production levels, you can select strong healthy adults as breeding stock ... and/or introduce genes from wild stock to prevent in-breeding. Do give it a try ... but don't worry too much if you don't succeed ... use natural pairings.
3. Natural Pairing.
The best method to obtain a natural pairing is in a large outdoor flight cage ... however this is not always possible and most species will pair in a much smaller cage. The best cages are round netted cylinders, (No corners to get stuck in!) but do remember that many species ... especially Swallowtails like to flutter as they feed and lay their eggs. It is very important to make sure that the foodplant reaches close to the top of the cage ... the butterflies spend a lot of time at the top! The main problem is desiccation, spray the cage regularly ... especially in hot sunny weather and do try to ensure there is some dappled shade to allow the butterflies to escape the sun's heat if they need to. Many species that never sip water in the wild will eagerly drink the water from the netting ... this is a sure sign that there is not enough nectar available. Supplement the nectar with some cotton balls soaked in a 5% to 10% sugar water (Fructose is best!) placed on top of the netting ... give these a good spray with water too!
Males need to be a few days old before they pair.
Females can pair on the day of emergence.
Females may not start to lay eggs until a couple of days after pairing
4. Inside your house.
Remember that butterflies need sunshine to do well ... you will need to use lighting, a gentle airflow from a fan will increase activity, raise humidity if things aren't happening. Spray often ... you will be surprised to see how low humidity drops to inside your house ... it becomes a desert!