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Rachel McLeod interviews
Seirian Sumner, Research Fellow, ZSL.
Seirian
and me by the sign for ZSL I met
Seirian at the Zoological Society of London, which is a conservation
organisation on zoology. I
found out about Seirian because I’m particularly interested in social insects.
Learning about sociability and learning about evolution go together as we
need to know about how sociality evolved. Paper
wasps have evolved the drifting pattern (workers helping at different nests) and
they are at the very beginning of being social, so we can understand more about
sociability by studying them. Wasps and
other social insects are so important because there are so many of them –
their biomass (the mass of living biological organism)
is absolutely huge. One chart
compares the number of social species with solitary species and the other shows
what the biomass of social and solitary insects.
There are very few social species compared to their biomass which means
that they are doing very well.
Species
compared to biomass Source
for data: Edward O Wilson Journey to the Ants Seirian
works on social paper wasps, and at the moment she is radio tagging them.
These tags are pet microchips but without the glass capsule.
They are super-glued to the wasps’ thorax.
This means that she can tell where each wasp has gone, and because of
this she has discovered nest drifting, where the workers help out at many nests.
Over 800 wasps were tagged. She
found this out in Panama, which is in between North and South America.
A
photograph of a tagged wasp (photo © Aidan Weatherill) Look
at my website, www.rachelmcleod.com/interviews to see the full transcript of
this interview. You can also listen
to it. If
you had to keep only one insect, which would it be and why? It would
have to be the paper wasp I’m very fond of the paper wasp. Once you understand
its behaviour, then it’s not at all aggressive, and you can get on very nicely
with it indeed. But I personally find them very interesting because they are a
primitive eusocial insect, which means that they are at the very beginning of
the eusocial spectrum, changing from a solitary to a social animal, which is
very exciting for somebody like me. What
is your favourite place to do field collecting and why? Well, most
of my field work’s been done in Panama recently, so I guess it would have to
be my favourite place. There are lots and lots of paper wasps there, and the
paper wasps in Panama, in the tropics, are much bigger than the wasps you get in
Europe, and they build much bigger aggregations of nests, which are fantastic
for entomologists like me who want to study lots and lots of nests all at once
with very little effort.
A
paper wasp nest What
was your favourite trip? I’ve just
returned from the field about a month ago, and I must say it was a very
successful trip, so I think it must be my favourite one. We had actually too
many wasps, we had too many wasps to tag, we were radio tagging them, they were
everywhere and they were very friendly and none of us got stung, so it was a
particularly nice trip. What
is the most exciting thing you’ve done? I think it
has to be my radio tagging. So I’ve been putting these little radio
transmitters onto wasps to monitor their movement between different nests.
A
tag Using those
we can follow the movements of wasps between different nests, and by doing that
we’ve discovered that they visit lots of different nests, which we didn’t
think they did before, and we’ve revealed a whole new behaviour called
drifting behaviour, and we think that they drift between different nests in
order to help raise the brood on lots of different nests that they’re related
to. So,
how social are different types of insect? In all the
ants you have a queen, and you have the workers, or you have several queens and
you have the workers. And the workers cannot become a queen. They can’t lay
eggs; they can’t lay fertilised female eggs. And so we call those advanced
social insects, they’re highly derived, highly evolved. And the honey bee
comes under that category as well. But these wasps, these Polistes
wasps, are primitively eusocial, which means that they’re only at the
beginning of life as a social animal, so they’re very interesting to study if
you’re interested in evolution and sociality and how things went from being
solitary to social, because they’re kind of bridging the gap between the two.
So the reason we know they’re primitively social is because any female that
emerges from the nest can become a queen. So when a female emerges from one of
these cells, a pupal cell, she can start life off as a worker, or she can later
on become a queen, or she could remain as a worker all her life, or she could go
off and found a new colony as a queen, or a worker on that nest. So, it’s a
very flexible life strategy. And this is how sociality first started, with these
flexible, plastic, we call them plastic castes, they’re behavioural castes,
they’re only determined by their behaviour rather than anything physiological
or morphological. What
do you think is the best way to get people involved in entomology? To get
interested in collecting whatever insect they come across. If they happen to
come across a bee on their windowsill, have a good look at it, and then maybe
work out what it is, look it up on the internet, and learn about the wonderful
life of insects and how interesting they are. What
does my generation need to do in terms of entomology? There’s
lots of new molecular techniques that are now becoming accessible for all kinds
of entomologists. So we’re able to study behaviour now at the level of the
genes, and until very recently that could only be done in what we call ‘model
organisms’, like the fruit fly drosophila
you might have heard of, and other lab organisms, but now we’re able to look
at the genes’ underlying behaviours in all sorts of different insects. They
don’t have to be in the lab, they can be in the field. What
parts of entomology do you not like? A: I don’t
like getting stung. My wasps have a
very big sting, and I react quite badly now. I swell up like a balloon if I get
stung. But I take precautions not to get stung now. I wear bee hats and big
gloves and stuff. I don’t think there’s any other aspect of entomology that
I don’t like. I think entomology’s a great thing to study because you can
have so many study organisms in one tiny little place, making it possible to do
all sorts of experiments very easily, whereas if you try to do the same thing on
mammals, for instance, it would be much more difficult to have the sample sizes
that you need. What’s
the most expensive piece of equipment you have bought for a trip, and why? Well,
equipment for molecular work is always very, very expensive, and my lab has
purchased very expensive pieces of equipment that we needed to analyse the
genes. I guess an example might be a real-time PCR machine, which costs around
£25,000. A real-time PCR machine enables us to amplify different parts of DNA
and to look at the expression of those genes in individual wasps, or individual
wasp brains is what I do, or you can look at them in different parts of the
body. Are
you scared of any arthropods? The only
thing I’m marginally near-scared of are the yellow-jacket wasps that you get
in this country. I really don’t like them. And people always laugh because
they think that I’m the wasp woman, I work on wasps, that’s my life, but I
really, really hate the yellow-jacket wasps you get here, because they chase you
while you’re having your ice creams or your dinner in the summer and they’re
just really nasty and unpredictable. What’s
the most embarrassing thing that’s happened to you? I got stung
on my eye once, and it ballooned up and I looked like Elephant Man, and that
evening I had to go and meet an important scientist and it was very embarrassing
because I looked horrendous with this huge blown-up face. I guess that’s
probably the most embarrassing thing that’s happened to me. What
do you spend most of your time doing? I spend most
of my time doing administration, at the moment. Filling in forms for students,
for people to come and work with me. Doing ethics forms, because believe it or
not we have to do ethics forms for tagging insects. Even cockroaches need an
ethics form. I guess the rest of my time I’m writing grants to get money in to
do more research, and any time that’s left over I’m writing papers or
supervising projects. What’s
your favourite thing to do in your job? Oh, I love
the field work. That’s when you really get to know your organism, and
there’s nothing better than being in your organism’s natural environment and
seeing, observing its behaviour, actually sitting and watching what it does. And
that’s when all the ideas come to you, because you realise things that you
can’t realise when you’re just reading a book or you’re just analysing
numbers on a screen. So definitely the field work. How
do you become an entomologist in your sort of job? You have to
do a degree first, and then you have to do a PhD, and then you just take it from
there. You start doing a Postdoc after that, where you work on somebody else’s
project. So the PhD is normally your own project that you work on,
And then after that, well what I did after that is I got fellowships,
which allowed me to set up my own independent research projects, and then it
just kind of builds from there. What
do you think would happen to insect populations if we suddenly disappeared off
Earth? I think the
insects would mostly do very well, except for the invasive ones. So there are
many species that we’ve helped by carrying them around the world, introducing
them to new countries where they haven’t got any natural predators, and then
there’s nothing to check their populations, to keep the populations down, and
they just explode into these huge, huge populations, and they cause immense
ecological damage. So I think that would be a good thing, actually, if that was
stopped. What
have you contributed yourself to entomology? Well, I’ve
contributed in my studies on social evolution. I’ve shown that the genes
underlying queen and worker behaviours in paper wasps are different, so if
you’re a queen you express different genes to those when you’re a worker.
I’ve also revealed this exciting behaviour of nest drifting, where the wasps
seem to help on multiple different nests. Previously I used to work on
leaf-cutting ants, and I did a little body of work on a social parasite of the
leaf-cutters, which was very under-studied, and that social parasite is at the
very beginnings of becoming a good parasite, an obligate parasite.
Some
Polistes wasps on their nest What
is your opinion on entomology being viewed as rather masculine? When you
first became interested in insects and you heard about entomology, did you think
an entomologist would be in a museum, with musty cabinets full of dead insects,
and a big beard? That’s how I imagine an entomologist. So I guess it can be
viewed as masculine. But maybe it’s more that the sciences in general are
viewed as a more masculine topic. But I think that’s changing, very much so,
definitely, with my generation and generations coming after me, there are a lot
more females in science and entomology, and I think that’s a very good thing. What’s
the most important question I could have asked you? I think you
could have asked me ‘why are social insects so interesting’, as opposed to
any other insects. Well, I think
social insects are so much more interesting than solitary insects because
they’re a whole new level of complexity. Solitary insects that live on their
own, they have possibly a very interesting life cycle and biology, but it’s
just that individual on its own, and it doesn’t have any complications around
it, except for its ecosystem, obviously. But in social insects, you’ve got
that extra level of complexity, so you’ve got the interactions of that one
individual with maybe ten, fifty, a hundred, thousand, even a million other
individuals, so I think that’s fascinating, and it’s much more of a
challenge to understand why and how those animals evolved. Also social insects
are incredibly successful. I can’t remember the actual facts, but I think that
ants represent a quarter of the insect biomass in the world, or something like
that, so they really are a key species for any ecosystem, and they form enormous
colonies, and I’m just fascinated by the way that one colony can function with
so many different individuals. So I think social animals in general add a whole
new layer of complexity that is really exciting to study as an entomologist. |
