Yes, been studied and shown it is overcrowding that causes this and you can by rubing the back legs of a grasshopper for about 30 mins(iirc maybe shooter time) and it will start to develop wings and change.
The rubbing of back legs in nature happens when you have high dense populations - overcrowding due to rushing for limited food in an area. Which evolving wings and flying elsewhere would be nature at play.
Real trick would be to curtail grasshopper numbers before they swarm and perhaps a more balanced approach to grasshoppers natural enemies and encouraging habits for those will do well. Chemicals for me are a desperate solution to a problem that got overlooked. Much the same way that ant do wonders with many pests for plants, yet production methods end up curtailing environments that see them thrive in area's that would benefit. So we end up with chemicals for things like aphids when ants will eat them all up for you.
I'm not pro-chemical, but it's hard to imagine other solutions that are actionable in the timeframe of a weather prediction (this timeframe is critical because these swarms were spawned due to weather anomalies). Indeed, according to TFA it sounds like the UN isn't even trying to curtail the locusts at all but are just preparing for disaster recovery.
Crop insurance seems like a more tractable solution.
I think the problem is rather that they destroy crops than insurance; farmers probably can't grow crops in time before another swarm destroy them.
As for stopping them, I would try covering a wide enough area with a giant electric net (just like those insects killers) also placing additional screening nets on the upper and lower side so that the screens would keep birds away, and the actual electric net would have its holes large enough so that smaller insects would remain mostly untouched. The idea is that if they're stupid enough, they will eat all crops in vicinity then eventually die attempting to attack the only remaining field.
Why it shouldn't? The purpose is to attract and exterminate locusts when it becomes the only field in vicinity with intact crops. Build a strip of nets large enough to cover some area where the locusts will travel during migration, and they'll attempt to feed from the fields underneath. Sure it will be costly, but we're talking about decades old technology and cheap materials.
That page says at the top that locusts are grasshoppers.
"Locusts are a collection of certain species of short-horned grasshoppers in the family Acrididae that have a swarming phase."
They are grasshoppers that have decided to change behaviour and physical characteristics for some reason. They used to be considered different species.
> So we end up with chemicals for things like aphids when ants will eat them all up for you.
The ants species I know of "milk" aphids for their sugary excretion, and as a counter service, protect aphids from their predators (such as ladybugs). It's... complicated. I agree with you that chemicals shouldn't be the first thing to reach for. It's interesting to try to find out how we got into this situation in the first place. The book Seeing like a State (https://en.wikipedia.org/wiki/Seeing_Like_a_State) has some interesting (but opiniated, in my opinion) notes on disastrous (on many axes - socially, economically, ecologically, ...) modernist agricultural reform programs that took place in Tanzania, Kenya and Ethiopia in the second half of the 20th century — a region much affected by these locust clouds.
A production rate of 32 locusts per person per 16-hour workday isn't enough to matter unless you have a small army of people rubbing grasshopper legs together all day, I'd think. Though it is a pretty funny image.
The grasshoppers self-activate as locusts under crowded conditions. Once they enter the swarming phase, the behaviour is self-perpetuating, generally until foid supplies are exhausted. With high mobility, this can take time and strip tremendous areas of land.
By stocking a sufficient population early on, in sufficient confinement,, it might be possible to create a perpetuating, expanding, swarm.
Looks like grasshoppers generally live 50ish days as an adult. That's gonna put some serious limits on your max per-grasshopper-leg-rubber total accumulated grasshoppers.
The rubbing only increased serotonin levels and 4-3 hours later after that boost, they transform. So if you was to increase their serotonin levels via other means, you would still only turn grasshoppers into locusts. Yes locusts metabolism in faster, so they are more veracious.
As a form of terrorism, well you would still need to bread and or/find a huge swarm of grasshoppers and if you found such a size large enough, they would already naturally be swarming. Though the prospect of some terrorist group breaking grasshoppers has an edge of Chris Morris about it that bemuses me.
Fascinating that it is related to serotonin! I wonder if an antagonist would prevent the behaviour? Might be challenging to dose large numbers of locusts.
Maybe target them with commercials for pro-depressants? Feeling restless, gregarious, like you just might take ravenous flight? Ask your locust doctor if pro-depressants are right for you.
Then we just need some sexually attractive locusts to lobby the locust doctors and problem solved!
The rubbing of back legs in nature happens when you have high dense populations - overcrowding due to rushing for limited food in an area. Which evolving wings and flying elsewhere would be nature at play.
Real trick would be to curtail grasshopper numbers before they swarm and perhaps a more balanced approach to grasshoppers natural enemies and encouraging habits for those will do well. Chemicals for me are a desperate solution to a problem that got overlooked. Much the same way that ant do wonders with many pests for plants, yet production methods end up curtailing environments that see them thrive in area's that would benefit. So we end up with chemicals for things like aphids when ants will eat them all up for you.