Here the complete version of the interview with Belinda Van Heerwaarden, published as short version in the issue 29 of PLaNCK!

You can read the interview also in italian language at the link: Intervista a Belinda Van Heerwaarden – PLaNCK!29




Flies, a rainforest in Australia and climate change. What do these things have in common? Let us ask Belinda Van Heerwaarden, evolutionary biologist from Melbourne University!

Belinda, tell us something about yourself and your research!

I am a scientist and I work in evolutionary biology at Melbourne University, in Australia. Evolutionary biology is a science studying the origins of plants and animals, trying to understand how they have changed through time and how they spread around our planet. My journey in science was a typical one: I went to university and, since I have always been passionate about animals, I specialized in conservation, biology and ecology. During my PhD, the professor I was working with was doing some research on a very strange animal: some flies that live in the Daintree rainforest, in Queensland, the north-eastern region of Australia. He was trying to give an answer to a very specific question: can these animals, used to living in the rainforest, adapt to different environments learning to withstand different climatic conditions? Surprisingly… it looks like they cannot! These flies, just like many other species living in the rainforest, are not able to evolve to resist in environments that are less humid than the one they are used to. Studying these topics, I started to ask myself some questions too: what will happen to this species when their environment will become different because of climate change?

What is unusual about the environment in a rainforest?

Rainforests, which are also called tropical forests, are warm and humid and the climate there changes very little during the year. Temperatures never rise or drop too much: during the summer rains a lot, temperatures are around 27 degrees, and it usually only gets up to 32 degrees, while in winter it rarely is below 15 degrees. These forests are very green and they have many resources (nutrients and food): for this reason there is great biodiversity and there we can find many butterflies and other insects but also mammals, reptiles and colourful birds.

And what is happening because of climate change?

We know that, in general, because of climate change our planet is turning into a hotter place. It is happening in tropical forests too: in November, a few years ago, during the Australian spring, in the forest in Queensland it was over 40 degrees for three days, a really high temperature! But it is not just that: the climate is also becoming more variable and it will become more and more common to experience colder periods followed by hotter ones.

And this is a problem for the species living in the tropical forest…

Exactly! All the species will have to adapt to the new climate, which means they will have to learn how to survive in environments that are sometimes hotter, sometimes more humid, sometimes drier and these adaptations will have to become part of their genetics, which means they will have to be passed down from parents to their offspring. Some species can adapt faster, but for those living in the tropical forest it is much harder: since their environment already has such specific characteristics and it is already quite warm, those animals are not able to withstand big changes in temperature. When it is too hot, the only thing they can do not to suffer is moving where it is a bit cooler, for example near a river or under a leaf. In the rainforest the can usually do that because there are many plants and, in Queensland, there are some mountains too where animals can hide. But if temperatures will continue rising these shelters will not be enough…

If the temperature in forests will become too high, one solution might be moving, going to a completely different environment. Could these species do that?

One of the strategies that animal and plant species have to respond to climate change is moving: since temperatures are rising everywhere on the planet, those who live in hot environments can move and find new places where to live, environments that used to be colder but that are now becoming similar to those where they used to live. However, this unfortunately cannot work for the species that live in the tropical forest, because of two reasons: in the environment they live in it rains very often, which does not happen as much in other places. Moreover, if we consider species that live in the Australian rainforest, by moving they would find areas with a strong human presence, where there is a lot of agriculture and tourism. Basically, they would find environments that are not suitable for their survival.

But then, if for these species it is difficult adapting and they cannot move to other environments… how will they survive climate change?

This is a huge problem: our studies show that the species used to living in rainforests do not have strategies to survive the changes that their habitat is going through and, because of this, their numbers are becoming smaller and smaller.

Why do you study flies of all things in your work?

When I started studying biology, I wanted to study cuter animals, cuddly and more charismatic: Australian marsupials! I worked with them for a while, but then I became passionate about the tropical forest environment and I started my research about how different species adapt and survive. And I found out insects are extremely important for the environment and the ecosystem: they pollinate plants, they recycle nutrients, they are food for other animals… and flies, in particular, are perfect for my studies. I can rear them in great numbers in the lab, sometimes even changing the conditions they live in, so that I can understand which characteristics they have in common and which are random. Besides, there are tons of types of flies, that live in different environments and that we can compare to give an answer to more general questions. And with time I have found out that flies are cute too: some of them look like little tigers, others have tiny dots, like leopards.

What interesting things have you found out about these flies?

In the last years we found out that some of the flies that live in widespread environments live in symbiosis with a particular bacteria called “Spiroplasma”, which may help them tolerate heat and lack of water. Flies living in rainforests, on the other hand, do not have this sort of bacteria: in the lab we were are injecting it into their bodies, to try and understand whether we can, with this method, help them develop new abilities to adapt. Thanks to these experiments we can understand how to help different species to develop new mechanisms to adapt to climate change.

Another very interesting thing we found out is that some genetic characteristics of flies living outside the tropics of Australia can be also found in flies living in similar environments in North America, Africa and Europe. And the flies that live in the Australian tropics are more similar to the flies that live in the tropics overseas than to flies in Melbourne!

How weird! Why is that?

 Many of these characteristics depend on the fact that these animals adapted to living in similar environments. Because of this, some of my colleagues started collecting information about the ability to adapt of species living in different places around the world and they are trying to understand whether there are common traits. For example, they found out that usually animals have a higher cold tolerance: just think about the species living at the Poles! On the other hand, it looks like it is harder to develop the ability to tolerate heat and only some ants and a few species living in the desert seem to be able to do it. If we will be able to understand why that happens, we might be able to help the other species to better adapt to global warming.

You talked a lot about climate change: what do you think we can do to help the planet and its species?

We need to reduce as much as possible our carbon footprint, which is how much we pollute: little things such as turning the lights off, using public transportation instead of the car, these are little things but we can try doing that. Even choosing to buy an electric car or installing solar panels can help. The most important thing to me, however, is informing people, creating awareness about this issue and making sure everybody cares about protecting and helping the planet. This way, we can also push governments in different countries to do more about it, for example investing in renewable energy and training and funding scientists to come up with new ideas and technology to help stop climate change.. We also need to learn how to take care about different species and not destroy their habitats. Keeping forests healthy and other ecosystems too, allowing species to spread and live in large populations: this is extremely important because it allows them to have a greater genetic variety, which means it is easier for individuals with different characteristics to be born and to have a greater chance of surviving in different environments.

Before we say our goodbyes, would you give a piece of advice to our readers who are passionate about science? How can you become a scientist?

Work hard in school, read a lot about the topics you are interested in, follow your passions and your interests. As you grow older, always be open to new opportunities: try to volunteer with associations working in science, or look for scientists who feel like teaching you new things. Usually, people working in science love it and they are happy to share their passion, through outreach activities or talking about it to children!