January is a tough time to be an entomologist in North Carolina. Cold weather and lack of available food prevent arthropods (insects, spiders, slugs, etc) from making a living during the winter months. But with few notable exceptions—looking at you, monarchs—bugs are too small to migrate. That means most species need to find a protected place to hunker down and wait for warmer temperatures. They don’t truly hibernate; that’s a warm-blooded animal thing. But many do a similar thing called seasonal diapause, where they slow their metabolism and activity to almost nothing. Common overwintering locations include underground, in rotting wood, and at the bottom of streams and ponds.

Many bugs have annual life cycles, timing their life history stages with the seasons. Therefore, in addition to location, bugs vary in their overwintering life history stage. Some spend the winter as eggs (e.g. praying mantises) some as larvae (dragonflies), some as pupae (the majority of butterflies and moths) and some as adults (centipedes, lady bugs, and bumble bees). Overwintering strategies can vary dramatically even among closely related species. Because of challenges in finding them in the first place and then identifying them when you do (for example, identifying a larval or pupal stage insect requires first rearing it to an adult in a lab), we actually just don’t know where or how many species overwinter!

This week I went out to a local nature preserve to look for some bugs! I knew I could find some by flipping over logs and rocks, but I wanted to try a different strategy. Ecologically conscious gardeners know that leaving dead flower stalks standing though the winter is a great way to increase the abundance of beneficial insects such as bees. That’s because the hollow stalks are a great place to settle in for the winter. Supposedly. I’d never looked before! So armed with a pair of clippers and my fleece-lined pants (the high was 28 degrees), I set out to peer inside some plants.

The rules: stalks had to be 1) at least two feet off the ground 2) from about pencil to quarter thickness and 3) broken off or with holes or other potential entry points. Conditions of victory: find bugs in all four life history stages (egg, larva, pupa, adult).

Stunning success struck on second stem I split open! I found this adorable jumping spider in the genus Phidippus tucked into her silken hammock.

Jumping spiders don’t make webs to catch prey, but they do make little bivouacs when they settle in for the night or for a long winter’s rest. A couple centimeters further up the stem was a second web filled with little light-orange orbs.

This was her egg case, and the reason I know the spider is female—spiders generally do maternal care. After two stems, I already had found two of the four life history stages!

I continued down the trail, stopping to cut open a stem every 50 feet or so. Amazingly, the majority of stems I checked either had a bug currently, or showed evidence of former occupancy (insect poop (aka frass), boring holes, hollowed out cavities, etc.). I was expecting to find a lot of pupae, but instead, larvae were the most common life history stage. A few examples: 1) a beetle larva, showing some frass by its head. Beetle larvae have three pairs of legs near the head, but don’t have prolegs (additional sets of leg-like protrusions) like caterpillars do.

2) A bee larva, next to its chamber that was created by mom. Bee larvae don’t have any legs, just a fat, segmented body and a small, but distinct head.

3) A fly larva that  had formed a really strange gall. I have no idea what species this is, but check out the crazy tubes the larva created in the wood! Terrestrial fly larvae are skinnier than bee larvae, and don’t have a distinct head—think maggot.

After about 25 stems, I was beginning to worry that despite the amazing bug diversity I was finding, I would end my hike pupa-less. Finally, in a rotting stick sticking out of some mud, I found a dusty gray moth cocoon. It’s not pretty, but it assured me victory!

My favorite find of the day was this entire colony of ants in the genus Temnothorax hanging out in a dead, hollow branch. Their common name is the acorn ant, presumably because in addition to using stalks, they can set up shop in hollow acorns. I had no idea these tiny stripey guys existed!

It’s always a great day when I meet a new species. All in all, I’d call the expedition a huge success and it gave me a newfound appreciation for the importance of dead stalks!