Bull? IT! (with butterfly wings)

So butterflies, as you know, are ectothermic.

I think that's the correct word.

which means that they don't produce any warmth themselves.

They need to get warmth from external sources, the sun largely.

So they need their bodies to be warmed by the sun to be able to fly and to be able to move around.

And butterflies are also considered to be one of those species that's quite susceptible to small changes in the climate, not just the big climate, but also microclimates, right? They need particular warm patches to be able to move around and to fly.

Different species around the world have been shown to do that.

There was a study that was published last month that pulled together research about so many different butterfly species from all over the globe.

They were looking at, oh, I can't even remember how much it was, over 6,000 reports of butterflies, different types of butterflies, and they found that over 80% of butterflies are shifting their ranges.

And you might think this is just a temperature thing.

Temperatures are increasing and so butterflies are moving further south or they're moving further up alpine regions if they're kind of alpine butterfly species.

But it's more complicated than that because they're pollinators and they need specific plants and they need specific microclimates as well to be able to move from shrub to shrub and all these kinds of things.

So temperature is really important for butterfly behavior.

But this study that came out a month or so ago has also identified that temperatures are quite important for butterfly color too.

So most animals produce their color, there's a couple of different ways.

You can have pigment changes, right? So where you've got light coming in and different wavelengths are absorbed and different wavelengths are spat back out again to be interacted with our eyes.

So like the green of a leaf or most of the colors that we see, but there's also iridescent coloration.

You have lots of birds and butterflies that use that where the different structure of the membranes or the different sort of patterns that occur will cause light to bend in different directions.

So Mother of Pearl is an excellent example of that, the kind of shiny feathers of a duck, for example.

That's quite specific, but I did see a duck the other day and my daughter was like, oh, look, it's got blue on its under feathers, you know.

So that's kind of an example of iridescence.

Lots of studies have found that different bugs and butterflies that use colour pigmentation, the colour of the pigmentation is affected by the temperature that those insects experience during their developmental phase.

So, for example, there's been studies to show that different beetles are darker if they develop in a colder area, for example.

Presumably because that's better for them, it's safer, they can avoid predators.

But not many studies had looked at whether temperature affects iridescent coloration properties of butterflies.