Loco Locust and a Mantis!
Quite a while back I decided to explore my fascinations for these incredible insects. So off i went to photograph and interview an expert! ( See below) I am fascinated by their history, their population, their appearance and by their ability to survive. Yet what truly grabs me is their ability to captivate me so easily and drag me away from my world and into their world. It feels kind of abstract.
… did you know…. In Japan, there is a long tradition of listening to the sounds produced by crickets!
TALKS WITH DARRON.
'What makes a locust go from living peacefully alone in the desert, to become aggressive and dangerous and to cause loads of harm? ' I guess this is not the kind of question most of us ask ourselves that often. For Darron Cullen however, a research associate at the Department of Zoology in Cambridge, the investigation into the swarming behaviour of locusts is what keeps him occupied on a daily basis. At the roof of a tall building in the centre of Cambridge is a shed, a home to hundreds of crickets and locusts. They are bred there for research and are being monitored in every single stage of their development by Cullen and his work friends. I met Darron on a warm and sunny day and we went up to have a look.
-‘The Locust I’m most interested in is called ‘Schistocerca gregaria’ or ‘Desert locust’ he explains. It lives across Africa, the Middle East, and even as far as India.
Darron and I are inside the locust room on the roof and I’ve got my head and camera lens in the middle of the locust mating cage.
-These looks like a grasshoppers to me. What is the difference between locust and grasshoppers?
Locusts are just grasshoppers, but unlike most grasshoppers they have two approaches to life. Most regular grasshoppers, the green and camouflaged, do not really move very far. They generally like to keep their head down to avoid competition with other locusts, or attention from predators. However, Evolution has also furnished locusts with another strategy…
As I’m watching a female locusts trying lay her eggs in the sand extending her backside downwards and digging down through the sand. Darron continues;
When their part of the desert sees some local rainfall (and the resulting growth of some fresh vegetation), they follow their noses to the big payload of food. And so do all the other locusts. They can’t rely on being camouflaged and hidden any more, because predators like birds and lizards tend to notice the big mass of insects that have all converged in one place - they need another tactic. After a few hours together, locusts become more active and tend to stick with the crowd, creating some ‘safety in numbers’ to avoid predation. They eventually change colour as well, as they moult into their new cuticle, and this new black and yellow patterning probably makes it harder for predators to distinguish individual insects, as well as warning predators that they are now more poisonous (from the different variety of plants that they tend to eat in a crowd).
This is sounding worryingly dangerous. Are these the grasshopper swarms I’ve heard about in the news?
Yes, when numbers are dense enough and the food has disappeared the locusts begin to move together, in search of fresh vegetation. This is what we tend to call a swarm. A swarm can consist of billions upon billions of individual locusts that can affect up to 10% of the world’s human population as they sweep across the desert in search of food. Locusts do not pose a threat to humans themselves, only by eating all their food.
So at one stage its actually a kind and friendly locust and then, at a flip of a coin, it changes and turn into a mean machine- in only a few hours?
Yeah, well, the local weather obviously plays a crucial role in bringing these animals together in the first place, but at the level of the individual locust, the swarming process is clearly driven by two behavioural phenomena - their search for food that brings them together, and then their switch from the lonely ‘solitarious phase’ to the swarming ‘gregarious phase’ when they are in a crowd. Behaviour is controlled by the nervous system, so that’s where we focus our research. How does that switch to swarming behaviour occur? Which brain chemicals and genes are important in the behavioural change? These are the main questions I’m trying to answer.
Apparently There are about 11,000 species of grasshopper that have been described so far (there are certainly many more than this that remain undiscovered). Of those, about 20 have a swarming behaviour and those species are called ‘locusts’. Darron and I gather a few locust from the shed at the roof and put them in a plastic box to bring them down for further studying and photographing. However they need a 20 min stop, in fridge! This is to make them less active and to stop them jumping around if taken out of their box. Once they heat up again they will start hopping around. Darron tells me about a regular week of a scientist.
My week generally consists of genetic experiments in the lab, where I try to see which genes are playing a role in making locusts swarm. I also find myself reading a lot of the old scientific papers on locusts, to make sure we haven’t missed anything that people observed in the field nearly a century ago. Fortunately we have a great library in the Department of Zoology, and that’s where I do most of my reading.
You just came back from a big locust conference in China, what happened there??
I need to discuss my ideas with other locust scientists quite regularly, so I decided to go to a Locust conference in China. We all converged for a week to drink beer and discuss our recent findings. I guess I’m quite unusual in that I have visited most of the big locust labs in the world now, taking me to France, Belgium, China, Germany, Australia and the UK. In France they look at the genetic structure of locust populations, and in Australia my old lab focuses on both behaviour and nutrition so we all have different approaches.
Being a scientist is a lifestyle choice you have to assist and get founding to supporting your projects. It can be hard to get your stuff published and hard to earn enough for a living Darron explains. Oh and then i was the locusts in the fridge, we nearly forgot them! Whilst rushing through the corridors I ask Darron: Why locusts?
I first became interested in locusts during my degree at Oxford. I had tutorials with a Professor of Entomology called Steve Simpson. Locusts are great insects to study because they’re pretty big, which makes it easier to work on their physiology and nervous system. We think that understanding their behaviour could ultimately help us to develop new ways of controlling their swarming - unfortunately, many others don’t see it quite the same way, and in these austere times the funding bodies would prefer to give money to cancer research and climate change. Which is understandable of course; but it does mean that I’m probably out of a job at the end of this year. It would be a shame to leave science after more than ten years of studying biology in a university setting, but I guess a change might do me some good. As long as I can still travel, and keep a pet insect on my desk…
Looking through the microscope it can’t help but think Locusts really are incredible fascinating. Darron tells me these editable insects have been referred to in both the Bible and the Quran. I look again and realise how important the knowledge of these insects are and how much we humans got yet to learn of nature. So you can actually eat these? Yes, that is true! They are the only insects that are both Kosher and Halal. Which makes sense, because when they had eaten all the food back when the Torah and Koran were written, they would have been one of the only sources of protein left to eat! I’ve eaten them myself a few times - they don’t taste of very much, just the oil you fry them in.
Then it was insect feeding time and we went to through the building to collect a few cups of praying mantises. An amazing, alien looking creature, with a lot of character. The mantis eat the baby locust freshly bred on the roof and we decided to try to capture it on video.
I’ve recently started looking at praying mantises as well, just for fun - I bought a few as pets for the office, but after they bred I had seventy baby mantas to look after! My friend Alexis in the lab next door has done a great job of rearing them, and we have been doing some experiments on their jumping and striking behaviour. We also do experiments on the other changes that happen when locusts experience a crowd, Like a change in leg length, which might have something to do with their migration. That’s why we have a lot of locust legs in the fridge..!