Flying in the winter

I caught this insect out of the corner of my eye the other day while I was on a hike.

This is a Winter Crane Fly (Diptera: Trichoceridae). It was sitting on the snow when I took the picture, but it had been flying moments before even though the air temperature was about 35℉  (1.5℃).

Winter crane flies are active in the fall and early spring, when temperatures are too cool for most other insects to fly. They are able to fly on cold winter days because they have a special enzyme system that allows their wing muscles to function at low temperatures. 
Insects have a number of different adaptations that allow them to survive at very cold temperatures. This is especially important in parts of the world where the temperature drops below freezing for several months of the year. Most insects are able to keep their blood from freezing with the help of special compounds called cryoprotectants. Cryoprotectants work like the antifreeze in a car by lowering the freezing point of the blood. Thanks to the cryoprotectants in its blood, the winter crane fly in this picture survived temperatures as low as 18℉ (-8℃) the night before. 
Insects can also allow their bodies to freeze completely by controlling where and when ice crystals form with the help of ice nucleating proteins. Ice nucleating proteins cause ice crystals to form outside of the insects' cells rather than inside of them. Ice crystals forming inside of the cells would destroy them and kill the insect. 
As amazing as these adaptations are, they do not happen instantly. The insects need  time to adjust their bodies and prepare for the cold weather, so if you catch an insect in the summertime and put it in your freezer overnight it will probably die.
If you're interested in reading more about this topic, check out the Wikipedia article on insect winter ecology or this book chapter on freeze tolerant animals.

Flying scorpion? No.

I'm sure this has happened to you. You're walking along in the woods and you see something black and wispy go by out of the corner of your eye. You naturally think, "Oh, there goes a damselfly, a mayfly, or a crane fly," but when it lands on a nearby plant you realize that its something much more sinister. That happened to me in late September this year and all I could get was this fuzzy photo before it flew away.

Fortunately, I was gardening a few weeks later, in October, and my friend found another one. This time it was not flying because it was probably too cold outside, so I was able to get in close for a really nice picture.

These are pelecinid wasps (Hymenoptera: Pelecinidae) in the genus Pelecinus and they are actually not that sinister...unless you are a june beetle (Coleoptera: Scarabaeidae Phyllophaga). That long "tail" is really just their abdomen, which all insects have. Their abdomen is longer and skinnier than most because they use it to dig into the soil in search of june beetle larvae (AKA white grubs). Once they find a white grub, they lay an egg on it. Eventually the egg hatches and the wasp larva attacks and kills the grub, feeding off of its corpse until it matures.  Then the wasp larva will pupate right there in the soil and emerge next summer as an adult wasp. 

Because of their long curved abdomen, pelecinids do sort of resemble scorpions which has led some people to call them scorpionflies. However, that name belongs to another group of insects in the order Mecoptera, the true scorpionflies. Of course, neither are flies (order Diptera) or scorpions, and scorpions are not even insects. Scorpions are arachnids (like spiders, harvestmen, and mites). Whew, glad we cleared that up. 

Regardless of how scientists classify them, pelecinid wasps attack and kill white grubs, which can be a nuisance to gardeners and homeowners, so we here at Crunchy Segments classify them as beneficial insects. Keep up the good work pelecinids!