Ephemeroptera - mayflies Intro (from Merritt and Cummins) http://www.entomology.umn.edu/midge/VSMIVP%20Key/English/VSMIVP.htm

Lotic and lentic Highest diversity in rocky-bottom, 2nd and 3rd order headwater streams Information primarily from larvae - why?

Repro? Eggs laid at surface In some (Baetis), females crawl under water and lay eggs on stems

Eggs hatch in 3 - 9 months Larval life ~ 3-6 months Hexagenia in Lake Winnipeg = 1-2 years Many molts (12 - 30)

Collectors or scrapers usually Detritus, algae, macrophytes, etc. Few carnivores Usually shift diet with size Subimago (winged, sexually immature form)

Mating Males usually emerge after dusk, females shortly before dawn Mating swarms

Morphology of larvae Large eyes, outer position Antennae anterior or ventral to eyes Mouthparts:

Thorax Wingpads: on meso- and metathorax Pair of legs on each thoracic segment

Abdomen 10-segmented Gills usually on abdomen 3 caudal filaments usually

Adult mayfly Males have large eyes

You will need to be comfortable with key to family 13 families: Baetiscidae, Potamanthidae, Ephemeridae, Polymitarcyidae, Tricorythidae, Caenidae, Ephemerellidae, Heptageniidae, etc. http://www.entomology.umn.edu/midge/VSMIVP%20Key/English/VSMIVP.htm

Ephemeroptera key Baetiscidae = large thoracic notum Armored mayflies

Mandibular tusks? Yes? Abdominal gills held laterally = Potamanthidae = hacklegill mayflies

Mandibular tusks? Yes, pointed upward, abdominal gills held dorsally = Ephemeridae Common burrowing mayflies

Mandibular tusks? Yes, project downward, abdominal gills held dorsally = Polymitarcyidae Pale burrowing mayflies

No mandibular tusks? Abdominal gills on segment 2 plate-like, operculate, triangular = Tricorythidae Little stout crawler mayflies

No mandibular tusks? Abdominal gills on segment 2 plate-like, operculate, square = Caenidae Small square-gill mayflies

No mandibular tusks? Abdominal gills on segment 2 similar to other gills if present, or gills operculate and no gills on segment 2 = Ephemerellidae = spiny crawler mayflies

No mandibular tusks? Abdominal gills on segment 2 similar to other gills if present, or gills operculate gills present on segments 1-7 or 2-7 Flattened head and body = Heptageniidae = flathead mayflies

No mandibular tusks? Abdominal gills on segment 2 similar to other gills if present, or gills operculate gills present on segments 1-7 or 2-7 Head and body not flat Abdominal gills forked = Leptophlebiidae Prong-gilled mayflies

Same characters as last slide: Head and body not flat Gills oval or heart-shape Foreleg claws forked = Metretopodidae Cleft-footed minnow mayflies

Same characters as last slide: Head and body not flat Gills oval or heart-shape Foreleg claws simple Long setae on inner fore legs = Isonychiidae = brush-legged mayflies

Same characters as last slide: Head and body not flat Gills oval or heart-shape Foreleg claws simple No long setae on inner fore legs Labrum w/deep notch = Baetidae Small minnow mayflies

Same characters: Head and body not flat Gills oval or heart-shape Foreleg claws simple No long setae on inner fore legs, spine Labrum entire = Siphlonuridae Primitive minnow mayflies

Get comfortable with all mayfly families = run them through key Today: Get comfortable with all mayfly families = run them through key