Curator Interview: John Early
John Early is the museum’s Curator of Entomology, in charge of a collection of bugs, beetles, butterflies and other invertebrates.
John has been at the museum for 16 years and is an expert in understanding New Zealand’s native parasitic wasps, which attack the eggs, larvae and pupae of a wide variety of other native insects. Greg Meylan discusses Invertebrates in the Cretaceous with John Early:
Weta insect case, Origins Gallery, Auckland Museum
Do we know what kind of insects and other invertebrates lived here in the Cretaceous?
There is absolutely no direct evidence, we have not got any fossil insects from the Cretaceous at all. In fact, I think there are less than ten insect fossils from New Zealand in total over our entire geological history. I think we just do not have the right kind of rocks that were formed in the right kind of way to preserve them although we are finding a lot of Cretaceous leaf and plant fossils and there may well turn up on close scrutiny to be insects associated with them. It is possible you might find scale insects or holes chewed in leaves that may indicate that they were chewed by insects. Of course figuring out what kind of insect it was would be impossible.
But there definitely were insects in the Cretaceous?
Of course, because most of the insect groups we know today were evolved by that period, there are some groups that perhaps came a little bit later but things like dragonflies were here. We would have recognised large dragonflies like the big bush dragonfly that is quite common today, they were around as well as cockroaches, wetas of all kind, including the long legged cave wetas, the ancestors of present ones, and our giant wetas. I am sure they would have been here. I think the ancestors of our big kauri snails would have been around too, though whether they would have been that big is another question. If you looked in streams you would have found the usual aquatic insects, stoneflies, mayflies, those kinds of things. And if you were ripping apart a rotten log you’d find lovely little peripatus, or the velvet worm - though they’re not worms of course, in the scheme of things they fit somewhere between segmented worms and the arthropod animals like insects.
The velvet worms, are they unique to New Zealand?
No, they’re not, but the bulk of the diversity of them is in the southern hemisphere in the land masses that were once united in Gondwana and we do have a rich fauna of them.
There would have been earthworms here too, the ancestors of our native earthworms which you find in our forests, though they are hard to find.
Are these the great big earthworms?
They are not all big but there is a spectacular one, the giant earthworm which lives out on Little Barrier island which would probably passed through the bush in this part of the world and still lives down in the Hunuas.
How big is the giant earthworm?
Oh, 1.2 metres or so but that is in a fairly contracted state. I talked to a farmer once from the Hunuas who found one when he was younger and they hung it over the door of their old villa, so you know how high a door is, and it relaxed its muscles and touched the floor on both sides of the door when it was in that relaxed elongated state. But there are a lot of other native earthworms too that are related and the particular family they are in has it relatives in South America and the remains of Gondwana and I am sure they would have been here in the soil as we split off and moved out into the ocean.
Do we know if there were dinosaurs that fed on insects?
There must have been a wide diversity of feeding habits in dinosaurs as there are in other groups of animals. The other thing is you’ve got to imagine the land as a whole ecosystem with plants and animals and insects, and all those things going on. Insects are sort of the major gardeners in this world, if you like, commuting dead stuff and recycling nutrients and the land then would have been full of dead trees, dead leaves, dead dinosaurs and loads of dinosaur dung, all that kind of stuff to be recycled and I am sure it would have been humming with insects and other invertebrate creatures doing all the usual things they do today.
And that would have included pollination?
Pollination is an interesting one, because the evolution and radiation of the bees came with the flowering plants, the two probably spurred each other on. Now the question is were there any bees before the flowering plants appeared? It seems there were and they probably fed on pollen of gymnosperms plants, relatives of the pines and kauri and that kind of thing. Some of the first flowering plants I think were probably wind pollinated, the flowers were very open with the stamens and anthers exposed. But in terms of the fossil record, yes there were bees around at the end of the Cretaceous so it is quite possible that we did have bees and one of the groups of our native bees is in a group that is considered a bit primitive for its family and its closest relative I think is in South America, another part of old Gondwana.
And our native bees don’t live in hives, is that right?
All our bees are solitary bees, we don’t have the highly evolved social bees and of course the ones we have now that live like that are introduced.
What about ants?
We have very few native ant species, which is surprising. It is a bit hard, but when you look at the fossil record of ants on a global scale there were a few fossil ants from old Cretaceous amber from places like North America so the first primitive ants would have been around by then and presumably we may have had some, but we just don’t know. There are more ants trapped in amber from later periods.
What about uniquely New Zealand species, like the weta?
We like to claim wetas as ours but there are wetas in Australia. If you look at our giant wetas, relatives of them are found in Australia and in South Africa, again two places that are remnants of old Gondwana. If you look at our cave wetas, the ones with the long slender back legs and huge long antennae, the kind that we have here are related to other Gondwanan countries like Chile.
Are there other species that have survived from Cretaceous?
Spiders such as the tunnelweb spider can still be found quite easily, even living in the bush in Auckland Domain, hunting insect prey just as their ancestors did during the Cretaceous.
People often think of survivors from our Cretaceous past as wonderful things that are likely to be extinct like the moa, or threatened things like the tuatara, but in the insect and invertebrate world you can find these things quite easily. If you go out into the Domain here we can go down and find things like the tunnel web spiders, huge numbers of them, right now busy incubating their eggs. We would have had spiders just like them and they have survived here. Things like the cave wetas, easy to find with good populations of them in the Waitakeres. We would also have had giant wetas living on the mainland around here where Auckland is now but they are extremely susceptible to rats. In fact, Maori people noticed this way back in the late- 1800s and Sir Walter Buller, writing in the Transactions of the New Zealand Institute about giant wetas said Maori attribute their disappearance to the introduction of ship rats. So the effects of introduced mammals was known a long time ago, we did not just learn this recently. You see, wherever a giant weta can hide a rat can fit in too but with the tree weta they survived because they are smaller, because they live in holes in trees, old beetle holes or puriri moth holes, and of course they can escape where not even a mouse can get in.
Curator John Early
Gianormous earth worms longer than your outstretched arms have been squelching through the soil of New Zealand for more than 65 million years.
The ancestors of giant wetas lived in the Cretaceous landscape of prehistoric New Zealand and would have lived around Auckland, much the same right up until the arrival of ship rates with European settlers.