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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
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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 mandibulartusks? • Abdominal gills on segment 2 plate-like, operculate, triangular = Tricorythidae • Little stout crawler mayflies
No mandibulartusks? • Abdominal gills on segment 2 plate-like, operculate, square = Caenidae • Small square-gill mayflies
No mandibulartusks? • 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 mandibulartusks? • 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 mandibulartusks? • 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
Today: Get comfortable with all mayfly families = run them through key