mayflies order: ephemeroptera. life cycle hemimetabolous (egg, naiad, adult) –naiad: aquatic,...
TRANSCRIPT
Mayflies
Order: Ephemeroptera
Life Cycle• Hemimetabolous (egg, naiad, adult)
– Naiad: aquatic, gill-breathing nymph– Nymph: larva of an insect without a pupal stage
• 1-3 generations / year; 12-50 molts!• Subimago stage (“duns”)• Short-lived adult stage (“spinners”)
General Morphology
Naiads:Large eyesChewing mouthpartsGills on abdomenUsually 3 tails
Adults:Soft-bodiedFW large, triangular, veinedElongated forelegs, tails
Naiad Morphology
• Well developed eyes• Slender antennae
• Well-developed legs, with one claw
• Gills (abdomen sides)• Fore-wing pads may be
present
• Usually 3 caudal filaments (tails)
Adult Morphology
• Elongate, very soft• FW large, many veins• HW small or absent• Wings above body at
rest• Mouthparts vestigial• Fore-legs very long• 2-3 long tails
Systematics• 2 suborders: Schistonota
(“Splitbacks”) and Pannota (“Fusedbacks”), refers to wing pads
• 3 superfamilies in each suborder• 17 families• Characters used include gill structures,
mouthparts, hairs/spination: these change with age!
Suborder Schistonota“Splitback Mayflies”
• Larval fore wing pads free for at least half of the pad length
• Thorax usually slim and delicate• Gill series usually well developed
on sides of abdomen• Active and diverse mayflies
Suborder Schistonota
SuperfamiliesBaetoidea (6 families)
Leptophlebioidea (1 family)
Ephemeroidea (5 families)
Superfamily Baetoidea
Families:
Siphlonuridae (“Primitive Minnow”)
Metretopodidae (“Cleftfooted Minnow”)
Ametropodidae (“Sand Minnow”)*
Baetidae (“Small Minnow”)
Oligoneuridae (“Brushlegged”)
Heptageniidae (“Flatheaded”)* Western. 3 species, not covered here.
Siphloneuridae(“Primitive Minnow Mayflies”)
• Streamlined• Long axis of head vertical• Fore legs w/o hairs• Platelike gills oriented
dorsally• Sharp spines on posterior
abd. Segments
Ameletus sp.
Metretopodidae(“Cleftfooted Minnow Mayflies”)
• Strong swimmers• Medium/large rivers• 2 claws on foreleg
Siphloplecton basale
Baetidae(“Small Minnow Mayflies”)
• Small, 9-10 mm• Variety of habitats• Good swimmers• Some tolerate
polluted water• Some with 2 tails!
Callibaetis (left)Pseudocloeon
(right)
Baetidae
• Fall emergence in some species
• Note rounded 9th abdominal segment
Baetis longipalpus
(Antennae more than twice width of head)
Subimago Baetis tricaudatus
• Shorter front legs• Dull wings• Fringe of ciliated
hairs on wings• Dun, “little iron blue
quill”
Adult Baetis tricaudatus
• Longer front legs• Brighter colors• Spinner, “blue
winged olive (applies to Baetids in general)”
Oligoneuridae(“Brushlegged Mayflies”)
• Streamlined shape• Filter feed with hairs
on front legs• Swift currents
Isonychia sadleri
Isonychia Filter Feeding
Isonychia bicolor“Leadwing Coachman,”
“Mahogany Dun.”
Isonychia sadleri imago
Heptageniidae(Flatheaded Mayflies)
• Greatly flattened head, legs
• Clinging under rocks• Often very long tails
Stenonema rubrum
(Note unique 7th gill structure)
Heptageniidae(7th abdomimal gill)
S. rubrum
HeptageniidaeStenacron interpunctatum
• Subimago called “Light Cahill”
• 7-12 mm, excluding tails, legs
• May-September• Note relatively short
legs of subimago
Heptageniidae
S. Rubrum imago
Heptageniidae
• Cup-shaped to cling• Bright red gill color
Rhithrogena sanguinea
(Ventral view)
Superfamily Leptophlebioidea
Family
Leptophlebiidae (“Pronggills”)
Leptophlebiidae(“Pronggills”)
• Gills on segs. 1-6 or 1-7• Gills double or forked• Prefer crevices
Leptophlebia sp.
Leptophlebiidae
• Subimago called “dark blue quill”
• Small (6-8mm excluding tails, legs)
• August-October• Note long legs of
imagoParaleptophlebia debilis
imago
Superfamily Ephemeroidea
Families:
Behningidae (“Tuskless Burrowers”)*
Potatamanthidae (“Hacklegills”)
Polymitarcyidae (“Pale Burrowers”)
Ephemeridae (“Common Burrowers”)
Palingeniidae (“Spinyheaded Burrowers”)***Southeast U.S. only **South only
Potamanthidae(“Hacklegills”)
• Somewhat like Heptageniidae, but…
• Gills unique, laterally oriented
• Tusks, curve inward
Polymitarcyidae(“Pale Burrowers”)
• Larvae in silt, stream banks• Adult with nonworking legs• Sexually mature subimago• Subfamily id uses frontal
processes
Ephoron sp.
Polymitarcyinae
Campsurinae
Ephemeridae(“Common Burrowers”)
• Large, 12-32 mm• Tusks lack spines,
curve up & out• Burrow in silt-sand
in rivers or lakes
Ephemera sp.
Hexagenia sp.
Ephemera sp.
Hexagenia limbata(“Michigan Caddis”)
Ephemera guttulata subimago(“Green Drake”)
(18-21 mm + tails)
Suborder Pannota“Fusedback Mayflies”
• Naiad with wing pad fused to thorax for at least half of pad length
• Thorax robust
• Gills lay on abdomen
• Operculate (covering) gills
Suborder Pannota
Superfamilies
Ephemerelloidea (2 families)
Caenoidea (2 families)
Propistomatoidea (1 family)
Superfamily Ephemerelloidea
Families:
Ephemerellidae (“Spiny Crawlers”)
Tricorythidae (“Little Stout Crawlers”)
gills
Ephemerellidae(“Spiny Crawlers”)
• 5-15 mm + tails• dorsal spines on head,
thorax, abdomen• No gills on segment 2• Gills lie on abdomen
Serratella sp. (left)Timpanoga sp. (right)
Tricorythidae(“Stout Little Crawlers”)
• 3-10 mm + tails• Hind wing pad
absent or minute• Gills on seg. 2-6• Gills on 2 are
triangular and operculate
Superfamily Caenoidea
Families:
Neoephemeridae (“Large Squaregills”)
Caenidae (“Small Squaregills”)
Caenidae(“Small Squaregills”)
• Widespread and common in east
• Small, 3-4 mm + tails• No hind wing pads• Operculate gills
overlap slightly
Caenis simulans
Superfamily Propistomatoidea
Family
Baetiscidae (“Armored Mayflies”)
Baetiscidae(“Armored Mayflies”)
• Banks of medium streams
• Striking thoracic shield