G B
Personally, I think that Wallace’s role as an environmentalist has been a bit exaggerated. He didn’t really write that much about it. And yet, what he did write was very powerful and it was probably far ahead of its time. For people like Darwin, on the other hand, it was wonderful that all the natural habitats were going to be replaced by monocultures; he thought that was progress. Wallace sometimes thought like that, but he realized that there would be a major loss of scholarship if all these species were destroyed by development. He was also passionate about the giant redwoods and their destruction in America. He met the pioneer of American conservationism, John Muir, and Wallace was ahead of his time in that respect, but he didn’t really focus his work on environmentalism or conservationism. I suppose that back then it was far less of a problem; it wasn’t nearly as serious as it is today.

A S
We are eager to know whether the species Wallace collected could still be found today, or, if one could currently come up with the theory of natural selection based on available specimens, given the habitat loss one encounters in certain parts of Indonesia?

G B
Actually, very few of the species of insects and birds that Wallace collected in Southeast Asia are known to be extinct. I can’t think of any, in fact. Many of them are probably much more rare than they were, but if you had all the official permissions you could still make collections like Wallace’s today. But it would be impossible now to travel from island to island shooting every bird you wanted. Anyway, collecting birds is not done very often these days. So, the birds are still there, and you could go to Halmahera and kill a whole lot of Wallace standardwings if you had permission. But that wouldn’t be a very responsible thing to do given how rare they are. With insects, it’s a different picture because, in general, you can’t collect enough of one particular species to damage the population. At least it’s pretty difficult to do so. But entomologists are still very active in Indonesia, observing habitats and collecting different kinds of species, just like Wallace did.

E T
So, even though larger mammals are extinct or rare, there’s still a wide array of living evidence for natural selection?

G B
Sure, it’s just that the political situation has changed. It would actually be impossible today to just travel wherever you like and collect what you wanted. So, say for example that the Wallace Line hadn’t yet been discovered. There are two ways you could discover it today: either by doing all the collecting yourself, or by reading enough about the patterns that others have discovered. You might be able to work it out just by reading about the distributions of various groups.

E T
Are such categories changing as a result of new forms of DNA analysis?

G B
Not as much as you might think. It tends to be that DNA studies confirm what expert taxonomists have always thought, or at least that’s the overriding trend. A good example is some work that I did on cockroaches and termites; I initiated a big DNA study of these critters, and we finally proved that termites are actually, truly cockroaches that have evolved to be highly social. This was actually first proposed in the 1930s using obscure morphological characteristics like the structure of the gizzard and different protozoa in the guts of termites and cockroaches—very technical, anatomical things. This is the cockroach tree. [Fig. 06] Rather than being an outlying relative, termites arise from within the tree. Since then, other DNA and RNA studies have confirmed our findings. Anyway, all of this is to say that we reinforced what expert morphologists realized a hundred years ago.

E T
What about mimicry? This idea has been very important for discussions of natural selection; have these discussions been changed by more recent DNA or RNA studies?

G B
Well no, not much anyway. Color patterns and mimicry were the first great tests of the natural selection theory. If you look at the early papers on the topic, they used mimicry as an example because it was clear—one species has evolved to look like another because it’s tasty and the other’s nasty. All of the arguments were centered around these visual examples, and mimicry was of great interest. Wallace proposed a lot of the ideas that are still valid today about animal colors, and he discovered sex-limited polymorphic mimicry in butterflies, where one species has females that look like members of several other different species living in the same habitat. In one species of swallowtail butterfly, for example, males all look the same and aren’t mimetic, but the females have various morphs that each mimic a different species of poisonous butterfly. Wallace was the first person to explain this.