Hissing Caterpillars and Jumping Beans

Weird title, I know. It's the best thing I could come up though, after 5 seconds of intense brainstorming to briefly describe the two cool stuff I learned recently that I am about to share with you. So, let's begin:

1. Hissing Caterpillars

When it comes to sound production and communication, insects resort to mechanisms that are vastly different to the ones we humans and other vertebrates use. For us, it's easy. We just open our mouth and talk stuff. But insects rely on other methods, like rubbing or vibrating parts of their body.

Take for example the lesser water boatman (Micronecta scholtzi) for which I have talked in the past. These tiny, 2 mm long insects produce their courtship song by rubbing their penis across the abdomen! And a very loud song that is, up to 99 db strong! Yeah, I chose this example in purpose to have an excuse to link to my awesome "9 Incredibly Weird Animal Penises" post from some months back XD

But there is one insect that has come up with a mechanism that is pretty similar to the one we use. Meet the Nessus sphinx hawkmoth or Amphion floridensis as it is scientifically described, one of the most commonly encountered day-flying moths in eastern United States and Canada, so there is a good chance you have seen one if you are from any of those places. Here's a photo to give you an idea of how they look like:

A Nessus sphinx moth, notice the distinguishing  bright bands across the abdomen (CC BY 2.0, credit)

What's really interesting about these critters is when they are in the caterpillar stage. As explained in a paper published last month, this caterpillar has the ability to produce a hiss-like sound from its mouth! Which is a bit weird considering how, unlike other creatures, caterpillars don't have vocal cords.

So how they do it if they have no vocal cords? Well, the sound is produced "by forcing air into and out of its gut", so I guess it's more of a burb rather than a real hiss. 

 When disturbed, larvae of the Nessus sphinx hawkmoth (Sphingidae: Amphion floridensis) produce sound trains comprising a stereotyped pattern of long (370 ms) followed by multiple short-duration (23 ms) units. Sounds are emitted from the oral cavity, as confirmed by close-up videos and comparing sound amplitudes at different body regions. [credit]

And speaking of videos, here's one showing the hissing in action:

As previous research has shown,  these sounds probably function as "acoustic aposematic signals" primarily directed towards auditory predators, rather than visual ones.

According to the researchers, some other species that probably produce sounds in a similar fashion are Sphecodina abbottii, Amphion floridensis, Pachygonidia drucei and Nyceryx magna. However, this is the first and only species that has been verified to do this with microphones, cameras and everything. 

And now let's move from hissing caterpillars to..

2. Jumping Beans

Ok, let start this one with a video:

Any ideas of what's going on? Why and how do these beans move around and even occasionally jump? No? Here's the deal.

The "beans" you just saw are seed pods, commonly known as Mexican Jumping Beans and grow on shrubs of the Sebastiania family. But why the heck do they jump around? The culprit is again a larva of another moth that lurks inside them, Cydia deshaisiana, which not surprisingly is commonly known as the jumping bean moth. And yeah, these "beans" are found in Mexico, hence the name "Mexican jumping beans".

The life-cycle of the insect begins with the moth laying its eggs on the host plant. Then the larvae enter the beans and start to eat the inside until the beans become hollow. There they can live for months and if all goes well they eventually enter the pupal stage and at some point they become moths and exit the beans through a "trap door".

Mexican magic bean with trap door, the moth has already left the hall (public domain)  

However, the larvae are really sensitive to warmth. So, if the seeds start to get warm for reasons, they start to twitch and spam, in an effort to move the beans to a cooler location. If they fail, they die. And if it dies, it dies:

This phenomenon is so easy to trigger that even holding the beans in your hand for a few minutes will do the trick:

The beans are actually a bit of a novelty item and there are many places where you can get some, e.g. 5 of them for 10 bucks on Amazon. A real steal if you ask me! Just make sure to take good care of them and who knows, with a bit of luck you might soon have 5 new friends that will look something like this:

C. deshaisiana moth (public domain)

If you do manage to "hatch" them try not to get really attached to your new friends as they only live for a couple of days :( 

Interestingly, the beans need to be hydrated every now and then, by soaking them with water once or twice a month. This essentially mimics the monsoon weather of Mexico where they come from. In case you wonder, the beans are non-toxic but are not generally eaten... Although I bet they are rich in protein :D 

And that's pretty much all the basics you need to know about Mexican magic beans. Here's a video if you would like to learn more:

 

The End

It's been a long time since I posted a weird caterpillar but today you got two for the price of one so don't complain. Here are some more weird ones I have posted in the past in case you missed them:

•  The Jewel Caterpillar (This one is freaking awesome!)  
• Beauty Stings: The Stinging Rose Moth Caterpillar
• Beauty Stings #2 - The Wattle Cup Caterpillar
• Lexias Pardalis: The Caterpillar That Wanted to Be a Peacock!

See you tomorrow!

References & Further Reading

 - All references are provided in the form of clickable links in the main body of the post :)