Additional Acentria ephemerella Information:

Acentria ephemerella (Denis & Schiffermüller) is a moth in the family Pyralidae (Passoa 1988). It was formerly called Acentropus niveus or Acentria nivea. It is native to Europe and Asia but was inadvertently introduced to North America in the 1920's (Buckingham and Ross 1981). Adult moths fly, out of the water, however, most females are flightless and stay on the water surface where they breed with flying males. Little is known about host choice. The larvae (caterpillars) feed on an array of aquatic macrophytes, however, they do have a high preference for and consumption rate of Eurasian watermilfoil (Buckingham and Ross 1981). Larvae eat the plant meristem, stem and leaves. One generation is produced each year and the larvae overwinter underwater (Batra 1977). The larvae will build retreats or cases of milfoil leaves. High densities were reported to cause declines of Eurasian watermilfoil in Ontario (Painter and McCabe 1988), but declines in New England lakes that have Acentria were more likely due to the weevil E. lecontei (Creed and Sheldon 1995). Densities have rarely exceeded 5/m2 in Minnesota, however, very high densities and apparent control of Eurasian watermilfoil has been documented in New York (Johnson 1995, Johnson et al. 1998, Johnson et al. in press). Researchers have developed a site on this caterpillar's life history which includes some excellent photographs.