Category Archives: Ant stories

What can we learn from insects on a treadmill with virtual reality?

When you think of a treadmill, what comes to your mind?

Perhaps the images of a person burning calories, or maybe the treadmill fail videos online. But almost certainly not a miniature treadmill for insects, and particularly not as a tool for understanding fundamental biology and its applications to technology.

Researchers have been studying insects walking on a treadmill.

But why!?

Traditional methods for investigating an insect’s biology include observing them in their natural habitat or in lab, and manipulating the animal or its surroundings. While this is sufficient for some research questions, it has its limitations for others. It is challenging to study certain behaviours like flight and navigation as it is difficult to manipulate insects in motion.  Scientists have been using the simple concept of a treadmill to address this. (1, 2). When insects fly or navigate, they typically use visual cues from their surroundings. So a screen with images/videos projected on can be used to study how the insects behave with such cues. Alternatively, a virtuality reality set-up added to the treadmill can help in manipulating the cues in real-time.

How do you make a treadmill for insects?

A miniature insect treadmill is a light-weight hollow Styrofoam ball suspended on an airflow. An ant, bee or a fly is tethered using a dental floss or a metal wire and place on the top of the ball. Motion of the ball as the insect walks on it is recorded by two optical sensors similar to the one you find in a desktop mouse. This set-up can be used as is outdoors or with stationary images projected on a screen, or with a virtual reality screen instead. For virtual reality, as the ant walks on the ball, the sensors record the movement of unique patterns on the ball to extract the fictive movement of the insect in two dimensional space. This information is then transmitted to a computer which creates corresponding movement in the images/video on virtual reality screen. For ants, this is almost as if they are walking and experiencing the change in the surroundings in real-time.

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What can you learn from this about the insects?

Scientists have been able to learn about how visual cues influence flight and navigation in bees and ants by projecting them on a screen while tethered insects walk on a treadmill. Neural responses in different parts of their brain can also be recorded while the tethered insects are performing different behaviour. Such experiments can inform us about how they learn and remember different visual cues.

Do they show naturalistic behaviour on the treadmill?

At least in some ants like Cataglyphis fortis, the behaviours on the treadmill are similar to natural behaviour. However, the treadmill setup is still not free of shortcomings.

For example, restricting the movement of a flying insect like bees or flies tethered over the treadmill can affect their sensorymotor experience. Insect brains are evolved such that certain sensory feedback is required to elicit motor actions (behaviour). Flying on the treadmill might not feel the same for the insects. But recent technology has made it possible to use the virtual reality in real time for freely moving insects (and also mice and fish). High speed cameras can now record the 3-D position of a freely flying insect, and transmit that to a computer which updates the visuals on the screen accordingly. The whole set-up looks as if the insects are in a computer game.

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(The experimenters control the fly’s position (red circles) and its flight direction by providing strong visual motion stimuli. Left: live camera footage, Right: plot of flight positions. Credit: https://strawlab.org/freemovr  )

On the other hand, this set up cannot be used to study depth perception or 3D vision (stereopsis) in insects like praying mantises as the projections on the screen are two dimensional. Luckily, researchers at the Newcastle University (link) have found another ingenious way—3D movie glasses! They cut out mantis-eye-sized glasses out of an ordinary human 3D glasses and attach them to the mantis eyes using beeswax. The visuals on the screen can now be similar to any 3D movie. This technique can potentially help in build simpler 3D vision systems for robots.

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http://www.itv.com/news/tyne-tees/story/2014-04-28/newcastle-scientists-put-3d-glasses-on-praying-mantis/

Another challenge to the treadmill set-up include not being able to re-create different kinds of sensory information that they experience in nature. This may also be achieved in future.

What are the applications of this fundamental research?

The treadmill with virtual reality set-up is an example of how technology can advance science, and how fundamental biological research in turn can inspire technology.  Since insects have simpler nervous and sensory system than humans, they are easier to mimic. While the latest technology has helped uncover biological secrets of insects, that in turn can be an inspiration for bio-robots.

Take for example, the Moth robots. Moths use chemicals (pheromones) to communicate. So moths on a treadmill can navigate towards the smell. The motion of the treadmill as the tethered moth walks towards the smell can drive a small robot. Using the insect pilot in the cockpit of a robot, one can locate necessary odour signals in areas where humans cannot reach.

https://www.youtube.com/watch?v=d8t27M66ESA

Ants navigating on the treadmill can also inspire visually navigating robots and driverless cars (link). This can have applications ranging from disaster management to extra-terrestrial navigation. Perhaps in future, ants-sized robots can visually navigate and search for the victims stuck under rubble after a devastating earthquake.

So a simple concept of a treadmill and the latest virtual reality can help biological research and inspire technology in different ways. What might be next, an insect gym?

 

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Is summer the best time for ant outreach? A Google-trends analysis

How popular is the word ‘ant’ in google searches from different countries? How does it change over time?

I used Google trends to check that. World wide, there seems to be a seasonal pattern in the search popularity.

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Note: Here 100 means the most popular (given the range of time, country, topic (Biological sciences etc). 0 means less than 1% popular relative to the most popular score (of 100).

Although it could be biased by the population who knows how to use internet and have access to it, North American countries like Canada and US follow a seasonal search pattern with summer periods getting more searches.

 

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The United Kingdom has a similar pattern too.

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Perhaps it could be to get rid of ants in their houses. (This is definitely a correlation and a speculation, but not causation). But not all ants are bad. Maybe summer time is the best to teach people about ants, organise ant outreach programs and school visits etc. Although any time is good time to teach anything (almost), making more online content during the summer months can be helpful for people and raising awareness about ants, diversity, conservation, pest control, and all the cool ant science!

I expected a similar pattern for most norther hemisphere countries, but it was not true for countries like Russia and Germany (although there seems like a weak pattern towards recent years in Germany). It could be due to various reasons like culture,and internet literacy/usage/availability.

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Souther hemisphere countries like Australia have a peak in its summer time (Dec-Feb). But this was not true for South Africa.

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So more ants for the summer. More ant searches. More ant content for the summer. That is what we need.

 

Ant walk 2016

Here is our recent science outreach ‘antwalk’ in Canberra. Although it is like science outreach every day I work outside collecting data on the ANU campus. There are always curious people asking about my work, learning  and getting interested in knowing more about  how f-ant-astic ants are! There are curious magpies and possums too (maybe they just want to eat the ants or the cookies that I give them).

Delectable weavers!

For Asian weaver ants (Oecophylla smaragdina), a tree is like a city. They run on their invisible pheromone highways on branches of the tree,  from one ‘room’ of their house to another. You just can’t help noticing their houses–leafy and silky–no less than any architectural beauty. Their nest making involves a team of ants pulling leaves together, while an ant squeezes a larva (an ant baby) to produce threads of silk which she uses to weave the leaves together (and thus the name, weaver ants).

 (not my video)

These master weavers are pretty aggressive and are good at biological pest control: they protect the host plant from many insects (studied here and a detailed review here). However, this also means that it decreases the flower-visiting rate of various pollinators.

“But the ants themselves can act as pollinators”, you might ask.

It turns out that it is rare. A possible reason can be the pollen inhibition function of antibiotics that the ants produce. These antibiotics are produced by them to fight pathogenic microbes. Unfortunately, this also reduces different functions of the pollen, leading to reduced percentage germination, short pollen tube formation etc. Furthermore, they are not aggressive towards all insects. In fact, they are ‘friends’ with a few. They interact with honeydew-producing scale insects, larvae of butterfly etc. In this interaction, ants get honeydew from them, and in return they protect them from predators. Ironically, sometimes they cannot protect themselves from hungry people!

Some people enjoy these ants and their larvae as a delectable dish. In fact, farming them is suggested to be highly profitable.

Have you ever tasted them? You might want to take a closer look at them, the next time you are in your garden.