Cricotopus
myriophylli Oliver (Oliver
1984) is a member of the midge or Chironomidae family (Diptera).
The adults fly but do not feed; oviposition behavior is not known,
but somehow larvae land on milfoil meristems. The larvae eat the
watermilfoil meristem and spin a tufted case (MacRae
and Ring 1993). One generation is produced per year and larvae
overwinter in the water under the ice. Host choice work indicates
that the larvae are highly specific to watermilfoils: larvae can
develop on the exotic Eurasian and the native northern watermilfoil,
but will not successfully develop on other genera of aquatic plants
(MacRae et al. 1990).
The midge is endemic to North America (including
the midwest) and its native host was likely northern watermilfoil,
however, it readily adopted Eurasian watermilfoil as a new host
(Kangasniemi
et al. 1993, Newman
and Maher 1995). The midge was associated with milfoil declines
in British Columbia (Kangasniemi
et al. 1993), unfortunately, research was curtailed. Although
the midge appears not to be as promising as the weevil, it deserves
more research and consideration. Furthermore, for the scientifically
curious, the midge is rather unique and worthy of study. It is
a very rare example of a submersed aquatic macrophyte specialist
herbivore from a predominantly aquatic family (Chironomidae).
Most specialist herbivores are from predominantly terrestrial
families, such as beetles and moths (Newman
1991). Little is known about oviposition behavior of the adults
or how larvae end up on the appropriate host plant. Nothing is
known about how this species evolved from the other members of
the broadly occurring Cricotopus genus or the C. sylvestris
group, which appears to be composed of generalists, albeit often
associated with macrophytes.