Thursday, September 21, 2006

The cicada's avenger


Bill Trankle, a regular correspondent on these pages, writes from Indianapolis:

Your late post of the activities of the cicada-killer wasp females reminded me of something as well; I think I may have discovered a rather unusual predator of the C-K wasp, specifically their buried future-offspring: The common mole.

As I told you earlier this summer, I've had a banner year for Cicada-Killer wasps, and the last two active tunnels must have been huge affairs, judging by the enormous mounds of dirt thrown out by the females. I actually got to watch a female enter one of the tunnels on two different occasions with cicadas in tow.

However, both of those tunnel complexes are no more, as far as I can tell. Perhaps it is coincidence, but they were both dead-center in two separate dirt eruptions that are the results of moles coming to the surface. I know moles will eat just about everything, and perhaps they enjoy the un-dead cicada that the wasps leave for their unhatched larvae (if the moles eat the cicada, I'm sure they snack on the larvae as well!). My neighbor across the street had a C-K wasp burrow that met a similar fate. Mother Nature does like to keep things interesting.

Note from MW: At the Central Park BioBlitz that took place on June 24, 2006, a new species was added to the mammal list: mole, as the disappointingly non-scientific results of the Bioblitz's survey simply named it . It was probably an Eastern Mole, Scalopus aquaticus, the most widespread mole in the northeast US. That is, if it was there at all. I understand that the mole was not actually seen on the day of the Bioblitz, but was only ID'd by its droppings. I'd like to know more about how these were analyzed. Basing my judgement on the slapdash way the mammal team posted its final report [check it out on the Explorers Club website] I have quite a few doubts about that mole...

But in any event, according to the Kaufman Focus Guide: Mammals of North America, Eastern Moles don't exactly "eat just about everything," as Bill suggests. In the Order Insectivora, Eastern Moles eat insects and grubs but they "especially like earthworms " according to the book's authors. The moles on Bill Trankle's lawn may not have had their favorite dinner there, but they might have been quite satisfied with Mom Cicada-Killer Wasp and her offspring, as well as whatever left-over Cicada they found in the wasp nest.