After The Storm – A Beetle Story
By Scott Hamilton
Columbia Ecological Services Field Office
When I last wrote, things were not looking good for the American burying beetle. Obviously, this is an endangered species, so most reports on this animal are at least tempered with a bleak history of decline, or a remark on its past abundance, now mysteriously reduced to the edges of its former range. But this story offers a little hope.
I last reported that the St. Louis Zoo, along with many volunteers, had paired up 600 beetles and introduced them to Missouri soil for the first time in their little beetle lives. Our otherwise successful day was spoiled by the next when an unexpected cloudburst filled the area with rain and washed the beetles from their burrows. The “brood check” 10 days after reintroduction, when we dug up one-third of our constructed burrows to measure breeding success, found only five grubs (last year we found 300).
Following our monitoring plan, zoo staff laid out baited pitfall traps near our reintroduction sites a couple months after we put the beetles in the ground. Honestly, we weren't expecting much.
Much to our surprise, on the second day of trapping, seven American burying beetles flew into the pitfalls overnight. The next day, we found three more. At the end of the monitoring cycle, a total of 15 beetles were found, a considerably better showing than the two beetles found the previous year.
None of the beetles captured had the elytra notches we put on the zoo-bred adults, so we were actually finding the offspring of the beetles we put in the ground.
Could it be possible that the beetles escaping the deluge found mates, raised their young, and completed their lifecycle largely without our help?
I can’t say for sure, because the grubs found during our brood count (after extrapolation) could be the exact same ones that matured and later fell into our pitfall traps. But I have a little hope.