Togetherness: How co-operation built the world

**Benjamin Thompson** (0:03)
Hi, Benjamin here, welcome to Episode 15 of Nature Hits the Books. In this episode, I'm joined by science journalist Rowan Hooper, who is podcast editor at the magazine New Scientist. Rowan's new book Togetherness, Symbiosis and the Hidden Story of Life's Greatest Collaborations, takes a deep dive into the world of cooperation between organisms, arguing that, although in many cases perhaps under-researched and under-appreciated, working together in symbiosis has been as important a driver for making the world the way it is as the classic evolutionary idea of competition. The book looks at the array of intimate symbioses that exist between organisms across the tree of life, their importance to ecosystems, how human activity is affecting them, and how researchers could adapt them to tackle global problems. Just a few other things we talked about in this podcast.
Rowan Hooper, thank you so much for being on Nature Hits the Books.

**Rowan Hooper** (1:15)
Hey, great to be here. Thanks for inviting me, Ben.

**Benjamin Thompson** (1:17)
Let's talk about your book, then. Symbiosis is the topic all the way through, but I think it'd be good off the bat to lay out what it is and what it isn't.

**Rowan Hooper** (1:26)
Yeah, because it's used in a sort of non-scientific way so much, the word symbiosis. But scientifically, it means living together. But then that can be for a long time, for a short time. How intimate does it have to be?
So I've defined it as two different species that live together for an extended period of time in an intimate way. So this isn't like a bee coming and pollinating a flower and then flying off. And it turns out to be incredibly widespread. It's all over the place, all over the world, and it happens at every stage of life. So it's an incredibly important process and phenomenon.

**Benjamin Thompson** (2:03)
And your book is peppered with examples of this. I have a fig tree in a pot on my patio. And I think the fig tree and the fig wasp is perhaps the classic example of a symbiosis. And one that you start your book with, it has to be said. I think a lot of folk will have heard of this. But I think the example of this symbiosis shows the incredible intricacy of these things. And this relationship has taken an unfathomable amount of time to come into existence. Maybe you could just lay out for folk who haven't heard of it what this symbiosis is.

**Rowan Hooper** (2:33)
So, I can't remember how many hundred species of fig there are. But everyone has its own species of wasp that it relies on to pollinate it. And the fig wasp only is attracted to that particular species of fig tree. It goes into the fruit. So, inside the fruit are the flowers that point inwards. The fig wasp has to crawl inside the fruit, pollinate them, and then it dies. And then the larvae grow inside the fig. So, the fig that you have in your garden, though, will be one of the few species that's wind pollinated. But all other figs, and they're really important species in forests all over the world, are pollinated by this very specific, very tight, and as you say, very, you know, anciently evolved form of symbiosis between the fig wasp and the, and the species of fig.

**Benjamin Thompson** (3:18)
And there are layers to it as well, right?

**Rowan Hooper** (3:20)
Yeah, it is quite a gruesome, well, it's incredibly strenuous. What the fig wasp has to do to get into it, once the wasp is inside, it's maybe had to break off some wings and it's an antennae to fit in and the tunnel entrance into the fig is blocked. The wasp can then move about and pollinate and then it dies. And then what happens, the larvae develop inside the fig and then the males hatch first and they go around and they copulate with their sisters while they're still in their larval form. And then they cut open a hole in the fig and then the sisters come out, like emerge out, already fertilised and crawl out and fly off to start the cycle all over again.

**Benjamin Thompson** (4:00)
And this is but one of a number then. Which one of these symbiosis stood out to you the most? Which one blew your mind, would you say?

**Rowan Hooper** (4:07)
I mean, it changes all the time. At the moment, I've been really delighting in seeing a whole load of orchids near my house in West London here. And orchids, one of the most successful groups of flowering plants, 28,000 species, every single one of them relies on symbiosis to grow.