Monarch Butterflies (Danaus plexippus) have been having a hard time of it in many areas of the world. Habitat destruction, pesticides and lack of their foodplants have all taken a heavy toll, and even pollen from genetically modified crops that has landed on Milkweed growing close by has been shown to poison the caterpillars.

Here on Tenerife in the Canary Islands, the main problem these beautiful insects face is lack of Milkweed. Unless gardeners and local councils decide to grow the plant the caterpillars have nothing to eat and the female butterflies have nothing to lay their eggs on.

Although I have no garden but only a balcony, I have had a lot of success rearing Monarchs to their adult stage by growing their food plants in pots and making sure the fully-grown caterpillars have a safe place to transform into chrysalises.

When they are in their last stage of growth, if they have eaten all the leaves on the plant they are on, then they will wander about looking for more food. To stop them getting lost and dying of potential starvation I came up with an idea that would keep the caterpillars safe and allow me to make sure they had food until they were ready to change into the next stage of their lifecycle.

I am very concerned about the amount of plastic that goes to waste and pollutes the oceans and environment and have been pleased to find another use for empty plastic water bottles. The large 5 litre bottles make an ideal home for Monarch Butterfly chrysalises until they emerge as adults.

If you remove the label on the bottle so you can see inside a lot better and cut most of the way around the bottle you can easily get your hand inside to add leaves and caterpillars, clean the container out and so you can release the adult butterflies. Several strips of Sellotape will seal where you have cut the plastic and can be peeled back for easy access.

I have found that the fully grown caterpillars are happy to spin a pad of silk and then hang down and transform into chrysalises at the top part of these plastic water containers. I have had as many as 35 in just one of these bottles and all emerged as adult Monarchs.

It is easy to see when the chrysalises are about to emerge because the wingcases colour up with red and black. When you see them like this you can get ready for the butterflies to hatch out and after letting them dry their wings they can be released.

Last year, my friend Stefania Carvello from Cueva del Viento’s Finca Alternativa and I held a successful workshop and display at a centre called the Ecocentro in Chayofita. As well as providing a lot of fun for the children who attended, we also taught them a lot about butterflies and what they need to survive.

With the help of living caterpillars and chrysalises of the Monarch butterfly as well as an information board with photos and text in English and Spanish, Stefania explained all about the insects to both the fascinated children and their parents too in many cases.

Pot-grown plants of Scarlet Milkweed (Asclepias currassavica), which the caterpillars feed on, were also on display and we gave out free packets of the seeds.

Having had a lot of success using these empty plastic containers to help the conservation of Monarch Butterflies, I am sure they could also be used for the same purpose with other species of insects.

Alternatively, if you have a garden you can get Milkweed seeds and grow plenty of food for the caterpillars of this beautiful butterfly.