1. Ephemeroptera - mayflies
Intro
(from Merritt and Cummins)

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

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

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

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

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

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

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

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

10. Adult mayfly
Males have large eyes

11. You will need to be comfortable with key to family
13 families:
Baetiscidae, Potamanthidae, Ephemeridae, Polymitarcyidae, Tricorythidae, Caenidae, Ephemerellidae, Heptageniidae, etc.

12. Ephemeroptera key
Baetiscidae = large thoracic notum
Armored mayflies

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

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

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

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

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

18. 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

19. 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

20. 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

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

22. 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

23. 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

24. 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

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