Tuesday, August 2, 2016
Despite the geographically inappropriate name, this species is common throughout Ohio, including urban haunts such as where I dwell. I made the image above back in 2012, in the shadow of downtown Columbus's skyscrapers. They also appear from time to time at my nightlights.
After returning from some late night errand on the evening of July 27, I noticed a female Salt Marsh Moth had fluttered into the sphere of my porch light. When I left for work early the next morning, it was still present, firmly ensconced in a sheltered spot near the front door.
Making acceptable images of this Lilliputian scene was no easy feat, in large part because the moth had placed the eggs in a tough to access spot. I couldn't use a tripod to stabilize my rig for ultra-crisp exposures. For the last image, I used Canon's remarkable MP-E 65mm mega-macro lens. It can produce stunning images of the tiniest subjects, but demands dead still stabilization which was hard to achieve in this situation. Nonetheless, watching the cats emerging through the microscope-like view offered by this lens was cool. I could see them moving inside the opaque eggs, then suddenly a tiny hole would appear. The caterpillar would rapidly chew its way out at that point, taking only a few minutes or so to free itself once it first opened a hole.
The little caterpillars will face many perils, and most won't survive the predatory gauntlet. They've got to reach suitable food plants - many acceptable host plants are nearby - and eat and grow while avoid being eaten themselves. In spite of their best efforts, there will be near complete mortality. David Wagner, caterpillar expert and author of Caterpillars of Eastern North America, estimates that for many moth species larval mortality is about 99%. This is why many moths produce so many eggs. It's necessary in order to ensure that a few of them make it all the way to adulthood. Those that don't make it serve a vital purpose, too - they are part of Nature's complex food chain, and fuel a great many other animal species.