Hydroptila metoeca Blickle and W.J. Morse, 1954
Basis for Listing
Hydroptila metoeca (a purse casemaker caddisfly) is known in Minnesota from a single male specimen collected in Crow Wing County (Mille Lacs Uplands) in 1965. This species has not been relocated in the state despite searches in and around this site (Ludeman 1991; Houghton et al. 2001). Further survey work is needed to find other populations of this species and delineate its range in the state. Hydroptila metoeca was listed as a special concern species in Minnesota in 1996.
Caddisfly species can only be identified by examining their abdominal processes under a microscope. Houghton (2012) has developed an identification manual and key to Minnesota caddisflies. Macroscopically, adults of H. metoeca are about 3 mm (0.12 in.) long with light brown wings. Larvae of Hydroptila are 3-5 mm (0.12-0.2 in.) long with cases compressed and composed of two silken valves covered with a layer of sand grains (Wiggins 1996). Larvae and females, specifically, of H. metoeca are unknown.
Hydroptila metoeca has not been positively correlated with its natal habitat. Larvae of Hydroptila are found in both lakes and streams (Wiggins 1996). The collection site in Minnesota is near several small lakes and streams as well as Mille Lacs Lake.
Biology / Life History
Adults of H. metoeca have been found in July and August; the Minnesota specimen was collected in August. Larvae are unknown but likely reach peak maturity in early summer. No further specific life history data are known for this species, but larvae likely feed by piercing the cells of filamentous algae and consuming the contents (Wiggins 1996).
Conservation / Management
No specific conservation measures or management strategies can be developed for this species until larval habitat is confirmed. Few data are available on general Hydroptila tolerance to anthropogenic disturbances.
Conservation Efforts in Minnesota
Field surveys in conjunction with a University of Minnesota study on the Caddisflies of Minnesota (Houghton et al. 2001) have been conducted to search for additional populations of this species, and an identification manual and key to Minnesota caddisflies has been developed (Houghton 2012).