Easy Bug Jars

By Sheldon Greaves

Note: an earlier version of this post originally appeared on the Citizen Scientists League blog in 2013.

This is a very simple project to get ready for the insect-rich days of summer. 

Finished bug jars made from repurposed peanut
butter jars

My spouse Denise likes insects and spiders; the creepier and crawlier, the better. Bugs that make it into our house and are fortunate enough to escape the notice of our cats usually get dropped outside or popped into an empty bottle or plastic box. The really lucky ones are immortalized in her album of nature photographs. She’s hatched several lepidopterae from chrysales, spiders from egg sacks, or just spent time examining some particularly interesting multi-legged beast.

Insects, particularly dragonflies, are one of her favorite photo subjects when she’s out shooting in her usual haunts.

This has led to some interesting situations. At one point we had several black widows in bottles on the kitchen counter. Normal for us, but it gave a pet sitter pause when we were away for a few days. On the other hand, one or two bottles of black widows helped Denise seriously impress some local kids who thought it was massively cool that this lady kept poisonous spiders in the house, albeit under careful containment.

A couple of days ago I purchased a set of hole saws at a local hardware store and decided to help Denise get ready for summer. Instead of improvising with whatever more or less empty transparent container happened to be around, I would make her some simple bug jars. We had cleaned out four plastic bottles that used to hold peanut butter. I had some plastic screening that I scavenged from a dumpster with the permission of a friend who was doing some remodeling. 

Inside the lid, showing the screening and applied
hot glue.

The task is simplicity itself. I used a 2 1/4″ hole saw and a cordless drill to cut a deep circular groove in concentric with the jar lid. When the saw finally cuts through it can become a little chaotic with a hand-held drill, so I just cut it almost all the way, the removed the circle with a sharp utility knife.  I smoothed off the rough edges with the knife and some sandpaper.

For the screened top, it turns out that a tuna fish can is only slightly smaller in diameter than the inside of the jar lid, so I set the can on the screening and cut around it with the utility knife to get four circles of plastic mesh screening. I used a hot glue gun (from a local dollar store) to attach screening to the inside of each lid, making sure that the glue went all the way around the circle to ensure full containment. The job was done in less than an hour. 

The jars are functional, they look good. Because they are plastic, if you happen to drop one, it bounces quite beautifully.

Particularly if you shop at bulk food stores like Costco, as we do, you’ll probably find many different sizes and shapes of plastic containers that lend themselves well to this kind of adaptation.


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