Monarchs in diapause.  2500 miles of migration = naptime

by chelsea schuyler

Where do insects go at night? Which inevitably begs the question, do insects sleep?

Disclaimer: there are 900,000 known species of insects and thousands more are classified every year. So when you hear somethin different than what I tell you shove off, they do different things.

“Sleep” is the wrong word really. They call it “torpor” in insects, because it makes you have to say “state of ” and that sounds more Star Trekian, which is where all insect behavior is derived. Sleep in mammals is complicated. Brain functions, hormones, and nueron inhibitors have to work together to achieve it, including one that effectively paralyzes all voluntary muscle movement (unless you’re Bizkit the dog). Reading about it includes words like “cholinergic agonists,” “mesencephalic,” and “pedunculopontine tegmental nucleus,” all of which cause Strabismus, the condition of being cross-eyed.

Insects keep it more simple, they just sit. They become slow to respond to stimuli, but never go into REM or any of that weirdness. They still have a basic awareness of their surroundings (so you just have to tap on the glass harder and more often to get them to fly around again). Basically, at night, they just stop somewhere for hours. But some are weirder than others.

Like the Apidae family of bees. They sleep with their legs curled up underneath them,  biting a stem or leaf.  The most awesome sleeping position, ever.

the Blue Banded Bee (beautiful picture by Liewwk)

So what about the ultimate night: winter? One option is death. But secretly laying eggs at the last minute which stay dormant until spring. Very unpopular in mammals, movie portrayals in particular because you’re supposed to feel all better when the main character dies cuz they popped out some chillin’s beforehand, so they’re not “really” gone. Except they totally are and now there’s another mouth to feed. (see Premonition, or rather, don’t because it’s so dissatisfying I don’t even mind ruining it for you).

Ants head below the frost line to a store of food (Ant Pant-ry). Some insects migrate to warmer climes, like Monarch Butterflies. Many species enter a state of diapause, the insect version of hibernation. Again, eyes open, but not quite there. The human equivalent is called “com-puter games.”

Some insects just have to deal with being friggin cold. But if their body fluids freeze, they can suffer irreparable tissue damage due to the expanding nature of ice (ice being cold as ice and willing to sacrifice our love). What to do? Well, there are freeze-avoidant insects that defy it, and freeze-tolerant insects that become it.

Freeze avoidant (or Freeze intolerant) insects create their own anti-freeze, producing glycerol (the natural version of the same stuff we use in our cars) which blocks hydrogen bonding in water molecules, preventing the formation of crystal structures (ice) until the temperature gets much lower. Other insects are weirder. The thing is, ice crystals need to grasp on to something in order to form, like dust particles, bacteria, or anything teenie and solid, called “seeds” or “nucleators.” Without the presence of nucleators, water will remain a liquid until -42°C (-43°F)! So some insects stop eating to prevent the intake of nucleators, and some insects actually shed their gut during the molting phase. I know, what?!

Giant weta. not actually the kind that freezes itself (alpine), but apparently no one thinks that's worthy of photographing.

Freeze tolerant insects have a freaky protein that can induce ice crystals at high temperatures in order to control where they form, so as not to damage key cells and organs. The New Zealand megacricket, the Weta does this. You can find an ice cube of Weta one evening, and a functioning, live Weta the next.

ladybugs overwintering in diapause. whoa.