In August, Genoa NFH biologists spent time checking this year’s cohort of Hine’s Emerald Dragonfly larvae. These larvae had hatched at GNFH in March and April of this year, and by summer they were large enough to be housed in mesh-screened, flow-through cages in a rearing trailer on site. During the first half of the growing season- June to August- cages have 500-micron screen, which is a large enough mesh to allow small zooplankton prey items to enter the cages, but fine enough to keep large predators out and the Hine’s Emerald larvae safe inside. By late summer, the larvae are large enough to be in mesh cages with 1000-micron screen. This larger screen allows larger prey items to enter the cages, while still excluding larger predators that would either compete with the Hine’s larvae for food or prey upon the larvae themselves. The Hine’s Emerald larvae will remain in these larger mesh cages until the end of the growing season, when they’ll be checked and counted again, and moved to over-wintering conditions with partner institutions- University of South Dakota or the Forest Preserve District of DuPage County, IL.
By: Beth Glidewell

Photo: A Hine’s Emerald larvae during the mid-season check. Photo credit: USFWS