Labelled taste receptors (green) expressing in cell membranes
Study to leave bad taste in the mouths of insects
New research into how insect taste receptors work could help us to understand why insect pests eat what they do.
Glen Paul: G’day, and welcome to CSIROpod, I’m Glen Paul. Insects that attack crops have been the bane of humans since the dawn of civilisation, and while many advances in their control have been made, they remain a concern for food security due to the negative impact on crop yields and food storage. It’s estimated that between four to six percent of grain worldwide is lost to insects each year.
To combat this problem a team of CSIRO scientists working on understanding how insects use their sense of taste to determine which plants to eat, have for the first time identified a specific taste receptor used by the silk moth to identify an essential nutrient it needs to survive.
Joining me on the phone to discuss it is CSIRO’s Doctor Alisha Anderson, and visiting scientist Doctor Hui-jie Zhang from Southwest University in Chongqing, China. Firstly, Alisha, aside from dealing with their boring diet, how do the silkworm’s taste receptors differ from our own tongues and tastebuds?
Dr Anderson: They’re actually quite similar. Just like we have tastebuds, insects have little structures on their mouths that hold the receptors. When they come in contact with say something sweet, a message from the receptor goes to the brain to say, “Ooh this is sweet, and I want to eat that.”
Glen Paul: Well that does sound similar to us. So, Hui-jie why the study on the silk moth, it not being a pest, rather than an actual study on a pest insect?
Dr Zhang: The insect can eat only one type of food; it’s a very important thing to understand why it’s like that. This work is first important to understand how the other insect can taste the different type of foods.
Glen Paul: Many insects that we consider pests, such as the cotton bollworm, generally eat lots of different kinds of plants, so are they just gluttons, or is there some specific ingredient in these plants that attracts them?
Dr Anderson: Well that’s part of the research that we’re conducting at the Food Futures Flagship, so silkworm is a good, what we call a model insect, so it’s not a pest, but it’s one that we not have a lot of information about how it works. Cotton bollworm as you said, that pest eats lots of different plants, and we want to understand whether it is just a glutton and it eats anything, or if there are particular things in each plant that it likes to eat, or even things in plants that it doesn’t like to eat.
Glen Paul: But if it’s so voracious, how will the study on the silkworm help to address that problem?
Dr Anderson: Well once we have an understanding of how the insects taste, so we know with insects, like with humans and dogs, humans and dogs have quite similar senses of taste, so it’s the same with the cotton bollworm and the silkworm, that the way they taste is quite similar. So if we have an understanding of how the silkworm eats, we can try to develop alternatives to insecticides, so you could think about I guess a little bit like something like an Aerogard for crop plants. So we know that if we spray Aerogard on ourselves, insects no longer bite us, so we want to develop something similar for crop plants.
Glen Paul: One of the problems with insecticides is that they have the potential to alter ecosystems, could there be a knock-on effect in the food chain by repelling insects via their receptors?
Dr Anderson: Well what we want to do is not actually kill the insect, so insecticides kill the insects and can obviously change the ecosystem, so just by repelling them we hope that they would then go and eat more natural plants that they would normally eat, rather than our crop plants.
Glen Paul: So when do you foresee this research moving from the lab to the paddock?
Dr Anderson: Well I guess science does take a long time – good science takes a while – so at the moment we’re still looking at how their taste system works, and once we have a good understanding of that we can start to develop alternatives to insecticides, and I think that that type of research would probably start within the next five years, so maybe we’ll be looking at five to ten years before we see something in the field.
Glen Paul: OK. Well the sooner the better with food security looming as a major problem, every little bit of extra food’s going to help. Thank you both very much for your time today.
Dr Anderson: Thanks, Glen.
Dr Zhang: Thank you.
Glen Paul: Doctors Alisha Anderson and Hui-jie Zhang. For more information find us online at www.csiro.au. You can like us on Facebook, or follow us on Twitter at CSIROnews.