In Praise of the Not-So-Lowly Grasshopper

Can Grasshoppers sniff out explosives?

 The grasshopper is a common insect that is easily recognized by its ability to jump up or hop quickly due to their strong back legs. They are a typical insect with a head, thorax and abdomen and they hatch from eggs that have spent the winter underground. They shed or molt their tough skin 5 or 6 times as they are growing into an adult. When they are young and have not grown their little wings yet, they are called nymphs.

When there are too many grasshoppers in an area, a strange behavior overtakes them, they become a swarm. They eat plants and can chew their way through fields and fields of grain if they become a swarm. In a swarm, they change their color and behavior, and they gang up with hundreds or thousands of other grasshoppers becoming a giant cloud of insects, a swarm of locusts. They can cause a lot of serious damage to food crops when this happens.

These insects blend in well with their environment and hide from other animals that want to eat them for lunch by camouflage. They can also escape from predators by startling them when they suddenly jump or hop up and take a short flight for a quick getaway.

Grasshoppers have a set of large compound eyes on their heads and have better range of vision all around than humans. The two antennae on their heads detect smell and touch and they have jaws made especially for chewing up the plants they like to eat. They have ear like structures on their abdomens. On their bodies tiny hairs detect touch and sense the movement of wind. They also have 2 sets of wings, but can only fly for short distances, they are aided in getting into flight position by their powerful rear legs. Of their three pairs of legs, the rear legs are extremely strong for such a tiny insect, this helps them jump quickly and high. On the ends of their legs they have tiny claws. The female grasshopper is larger than the male. The male’s legs have structures on them that enable them to make sounds and little grasshopper songs. Scientists have studied grasshopper songs and they can identify different ones according to what the grasshopper is trying to communicate. There are 11,000 different species of grasshoppers that have been identified on the earth.

 Can grasshoppers really smell explosives?

Did anyone ever think that this tiny insect could be used to detect the scent of a bomb? Although we are still a long way from the practical use of such ideas, tuck it in your imagination and see where it goes. The creatures that surround us in our world have many wonders waiting to be discovered.

While doing a unit for home learning about nature in our neighborhoods, I came upon this nugget of information that took my respect for the lowly grasshopper up to a new level.

Explosive sniffing grasshoppers have been studied and tested by scientists! At Washington University in Missouri, scientists have conducted experiments to create biological bomb-sniffers using a common insect, the grasshopper! The smell or olfactory receptors in their antennae can detect chemical odors of explosives.

Electrodes were implanted into their insect brain and different groups of nerve endings were activated when exposed to explosive vapors. By studying the signals scientists were able to distinguish explosive and non-explosive chemical vapors. The grasshoppers were fitted with tiny little sensors that recorded the brain signals and transmitted them wirelessly to a computer. Accuracy was better for a group of grasshoppers, who were 80% correct when sniffing out the right vapors. Single grasshoppers by themselves were just 60% accurate with their vapor sniffing.

So, will the grasshopper one day replace a sniffing dog? They would probably be easier to feed and don’t need the same kind of training but don’t hold your breath for that amazing day, yet…and of course, you would need a lot of them and many tiny receptor backpacks for them to carry into the field. The thing that makes this research unique is that it combines a biological sense (smell) with technology to detect certain chemicals.

Actually, bears, have the best sense of smell around, but they are notoriously harder to keep and train than good old man’s best friend- the dog. Dogs have the intelligence and the ability to do the job quite nicely and have historically been used for this purpose. Can you picture a future where a swarm of locusts is released into a room at the airport to descend upon travelers’ luggage?

References:

www.telegraph.co.uk Bomb-sniffing grasshoppers tested by Scientists

www.newscientist.com/article/2233645-cyborg-grasshoppers-have-been-engineered-to-sniff-out-explosives by Donna Lu 17 Feb 2020

www.freethink.com Scientists Engineered Cyborg Grasshoppers to Sniff Out Bombs by Kristen Houser 24 Feb 2020

https://interestingengineering 18 Feb 2020

Picture: PBS

(McKelvey School of Engineering, Washington University, St. Louis, Missouri)