When areas are flooded by heavy rains or other means, considerable flotsam results in the form of stems, twigs, trash , and other debris, and clinging to it for dear life are thousands upon thousands of terrestrial arthropods.

Recently, after heavy non-stop rains, I noticed a runoff catchment basin was brim full and decided to investigate the concentration of flotsam the stiff wind had pushed to one end of the expanded body of water. I was already dressed for the rain with rubber boots and rainsuit and I had my sweep net with me. I scooped up a net full of flotsam and dumped it out on a flat surface, pawing through it looking for beetles. The material was loaded with all sorts of very active spiders but I also began finding wet, bedraggled beetles.

I stayed for a couple hours, discovering that the favorite type of flotsam was plastic foam objects from packing material to coffee cups. Often these pieces of trash were refuge to scores of beetles, mostly tiny roves and phalacrids. I also saw springtails, bugs, flies, mites, centipedes, millipedes, and spiders-a-plenty as well as one camel cricket or something similar that I lost. At home I later found three tiny pseudoscorpions.

The next day after work I went home, got a medium-sized plastic trash barrel, two five-gallon buckets, and a telescoping extension pole for my sweep net. Returning to the now somewhat-receded catchment basin I began fishing out floating pieces of plastic foam, getting plenty of organic debris in the process.

I am less than halfway through sorting my haul of flotsam and have collected more specimens than I can possibly do a decent job of photographing. I have discovered that under the conditions I experienced flotsam can be an arthropod gold mine.

This image was captured two days after the rain stopped and water has receded substantially. I didn't attempt to collect any more arthropods on this visit.