The 2020 Big Butterfly Count has come to an end on the 9th August. What a better moment to find out the ecological role played by this beautiful insect, if not now? Let’s find out, as always, together.
The life cycle
I have always been impressed and fascinated by the life cycle of butterflies. Their growth happens throughout four stages, during which the soon-to-be butterfly will undergo some sort of transformation, scientifically called metamorphosis.
Everything starts with an adult butterfly laying down eggs. Once the egg breaks, what comes out is a caterpillar, an insect very similar to worms. Caterpillars spend most of their time foraging leaves and storing energy needed to undergo the next stage.
Once they’re ready and well-fed, caterpillars look for the perfect spot (a leave or a twig) to hang themselves upside down and cover themselves with a silky layer, entering the phase of the cocoon. It is at this stage that the magic happens. To transform into a butterfly or a moth, caterpillars don’t simply grow wings and antennas: they decompose all their body tissues, resulting in something that resembles a broth in the middle stage. Subsequently, the cells are re-assembled to form the many parts of the adult butterfly (wings, antennas, body, genitals etc). Once this process is over, the butterfly breaks out from the cocoon and fly out as beautiful as they can be. Some studies suggest that butterfly have memories of their caterpillar stage but nothing has been confirmed yet. It is also very hard to observe the broth-stage of caterpillar because if you were to break a cocoon too early, you will literally see a liquid insect pour down from it.
However, even though it is not easy to observe the cocoon stage, we know what happens inside. The caterpillar digests himself, releasing enzymes that decompose his body tissues. Some management cells, known as imaginal discs, survive this process and are in charge of reassembling the body cells into a butterfly. Some studies show that after the digestion phase, only 50 imaginal discs are left alive and functioning: once they complete their task, a fully developed butterfly has more than 50 000 cells!
After looking at the unbelievable life cycle of butterflies, it is now time to understand what they do and what their presence can tell us.
For some reasons, butterflies play a similar role to bees for ecosystems. They are very efficient pollinators. Considering the dropping numbers in the bee population and that nearly 90% of plants need a pollinator to reproduce, it is clear that the role of these insects is still vital to the ecosystem. Also, butterflies are a very efficient pollinator, contributing to the genetic variation of plants. This happens because rather than staying close to the nest as bees do, butterflies cover a wide area and so they help to spread pollen in plants far from the one they fed on. This process, as well as increasing biodiversity and continuity of the species, also increase the resilience of wildflowers, considering that genetic variation is a good weapon against pest disease. Nonetheless, butterflies act also as pest removal in some area, keeping plant populations healthy.
Moving on, as well as pollination, butterflies have a very important role for being food for other animals. Many species of birds and mice feed on butterflies. If they were to disappear, the effect on the ecosystem could affect even at trophic levels. This is because it has been demonstrated that nearly ⅔ of invertebrates are connected to butterflies in the food chain. The presence of butterflies is an indicator of a healthy and balanced ecosystem, while their disappearance could trigger the so-called “butterfly effect”, mining on other species.
Protecting this insect is a vital target that each one of us should aim to reach: as it is always the case, insects are affected by pesticides and climate change. In our daily life, we should simply make ethical choices. I will never stop stressing on the point of the importance of our grocery: buy organic, do not waste. A very simple binomial that could save species and the environment.
Did you take part in the Big Butterfly Count? Let us know in the comment and don’t forget to Stay Green!