I’ve cycled through many hobbies already, during this time in isolation – throwing darts, writing letters, building a chicken coop, an ill-fated attempt to get in the sourdough game … My current project is to set up a pitfall trap array on our property, mostly using construction scraps from a recent renovation.
I haven’t really done much pitfall trapping in my career, as the insects I usually study are better collected in pan traps and Malaise traps or reared from galls. I do have a growing interest in spiders, though. I also want to grow our collection of mygalomorphs. Maybe I can get some wandering males? Our lone Sphodros rufipes male is from a pitfall trap near Harrisburg.
This review of pitfall trapping strategies by Brown & Matthews (2016) was a great starting point, especially when thinking about what to use as a preservative. For the traps themselves I constrained myself to whatever we had on hand—plastic drink cups, pieces of PVC pipe, wood scraps from our old deck, leftover tiles, and glass jars. I read a bit more about propylene glycol in Thomas (2008) and trap spacing in Ward et al. (2001). Brown & Matthews (2016) found that many publications did not report sufficient details on trap design, so I made a point of documenting all aspects of my design and will draft an SOP (#25, soon to be available on our policies and procedures page).
Here’s what I came up with. The parts:
Here’s how the trap looks in situ:
I set up more than a dozen of these pitfalls on a hillside, in the forest. I’m using RV/Marine antifreeze (Splash brand -100F; Mfr. Model # 919626-G35; Elliott Auto Supply Co., Inc.) as my preservative, diluted a bit with water (1.2 L water: 0.7 L antifreeze: 2.5 mL biodegradable dish soap). The traps are arranged more or less haphazardly—basically wherever my rocky soil would let me dig. I can’t wait to see how well they work and to share what I found! If any of you pitfall experts have ideas for how this design can be improved please add them in the comments below.
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