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10/8/2015
1
I. A surface, with supportII. Some sort of articulation mechanismIII. Muscles to power the surface (more later)IV. Mechanisms to generate lift
• Passive mechanisms• Tilt• Twist• Camber
• Active mechanisms
III
III
III & IV
co-opted from leg base
Tricks for generating lift:
Fast-flying birds(from side & top):
Slow-flyingbirds (side
& top):
Path of wing tip
Complex wing motion(active & passive mechanisms)
Drosophila (Diptera)
Muscidae (Diptera): red = top surface, blue = bottom surface
Odonata: Anisoptera
10/8/2015
2
Tracing the path of wing motion in Hymenoptera
hovering flight
backwardsflight
forward flight
Changes in orientation ofbody axis changes in flight
Compare with hovering flightin a bird:
Ephemeroptera
PlecopteraSialidae
Mecoptera Trichoptera
FulgoroideaMuscidae
Coleoptera
Hemerobiidae
Plecoptera
Sisyridae
Symphyta
= path offore wing
= path ofhind wing
body axis
10/8/2015
3
Clap & fling (also clap & peel, etc.)
Closing dorsally(upstroke)
Opening dorsally(downstroke)
1 2 3 4
1 2 3 4
anterior
leading edgeof wing
leading edgeof wing
posterior
axial view
anterior
posterior
axial view
(peel)
(clap)
Major wing regions:Remigium, Vannus/Anal area/Clavus, and Jugum
a = axis of rotation (torsion)b = axis of massc = axis of aerodynamic pressure
pterostigmaarea of
articulation
Jugum RemigiumVannus
anal suture
“Ground Plan” of insect wing:• relatively large size
• isopterous in structure & venation
• half as broad as long
• smooth membrane: semi-transparent, little pigmentation, and a few small hairs on veins
• complete complement of veins
10/8/2015
4
Changes in the proportions of remigium vs. vannus
area ofarticulation
Orthoptera: Acrididae
jugal area(jugum)
analarea
remigium
anal suture
(also called vannus or clavus)
remigium remig.
anal area(fan)
lines of axial folding
folds of “fan”anal area
(fan)
anal area
Generalized condition: archaic Insecta
Coleoptera: Staphilinidae
Coleoptera
Blattodea
Orthoptera
coriaceous texture
elytron
Hemiptera: Heteroptera
hemelytron
anal fan(vannus)
Front wing/back wing
differences: size & texture
anal fan
coriaceousmembrane
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Other color & textural changes: hairs (setae) and scales
Trichoptera
Lepidoptera
Hairs & scales:
• protection
• smoothing of air flow
• sensing air movements
Colors:
• aposematic
• thermoregulation
• crypsis & mimicry
• courtship & mating
elytron
Dermaptera
Diptera
Front wing/back wing
differences:
extreme specialization
haltere
resilin
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6
More front wing/ back wing
differences:
Tails
Neuroptera: Nemopteridae
Lepidoptera: Papilionidae
Likely function: protection by predator distraction
Front/back, left/right, & sex differences: strigils
male (left = right) female female
male
leftright
≠
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7
Jugal specializations and wing coupling mechanisms
by a jugum: Hepialidae by a frenulum: Psychidae
by hamuli: Hymenoptera retinaculum
humeral lobe
frenulum
jugum
hamulus
radialvein
(ventral views)
Wing coupling mechanisms, magnified
Frenulum in aganaid moth
Hamuli in wasps
retinaculum
(classified as “frenate moths”)
frenulum
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8
Pterostigmata
Odonata: Anisoptera
Neuroptera: Ascalaphidae
Hemiptera: Aphidae
Functions:• flexible tip for aerodynamics
• flexible tip for clap & peel
• fluid-filled counterweight to prevent “stalling”
• other unknown advantages
Independently evolved many times
pterostigma
Insect wing venation: ancestral archedictyon
(an “ancient net”)
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9
Importance of wing venationfor classification & phylogenetic analysis:
1. Single origin of wings: interpretations can be based on the assumption of monophyly & real homology
2. Conservative evolution: venation changes slowly so phylogenetic signal remains intact over long time periods
3. Provides a set of characters shared by nearly all insects
4. Nicely preserved in the fossil record -- often, only wings are present (like leaves of extinct plants)
C+ Sc-R+
Rs-
MA+
MP-
CuA+CuP-
1A+2A+3A+
R+M-
Cu+
Sc1 Sc2
R1
Rs1
Rs2
Rs3
Rs4
MA1
MA2
MP1
MP2
MP3MP4CuA1CuA2
Interpreting wing venationin modern insects
Major wing veins:Costa (C) (+)
Subcosta (Sc) (–)
Radius (R) (+)
Radial Sector (Rs) (–)
Anterior Media (MA) (+)
Posterior Media (MP) (–)
Anterior Cubitus (CuA) (+)
Posterior Cubitus (CuP) (–)
Anal (A) (+)
Interpreters:- Redtenbacher
- Hagen (mid-1800s)
- Comstock &
Needham (1918 book)
CONVEXITY (+)
CONCAVITY (–)
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Major wing veins:Costa (C)Subcosta (Sc)Radius (R)Radial Sector (Rs)Anterior Media (MA)Posterior Media (MP)Anterior Cubitus (CuA)Posterior Cubitus (CuP)Anal (A)
A more detailed view of wing venationpterostigma
axill
ary
scle
rite
s
Homologizing wing veins: the pretracheation theory
AB
cross-over
R
ScCWING
RADIUS
Rs
1ARs+CuA
(Cu1)
CSc
RRs r
s
M1
M2Cu1Cu21A2A
3A
B
RADIUS (+)
Rs (-)MA (+)
Comstock & Needham;“Cornell (U.S.) school”
of venation.
John Henry Comstock
10/8/2015
11
Alternatives to the pretracheation theory(“European school” of wing venation – Tillyard, esp.)
Tracheae grow into pre-existing “lacunae”(Holdsworth 1937)
Homologizing wing veins:Convexities and concavities (Martynov & Lameer, 1930s)
tracheal branch nerve“lacuna”
cuticular surfaces
convex veins
concave veinscuticular layers
C(+) R(+) MA(+) CuA(+) 1A(+)
Sc(–) Rs(–) MP(–)CuP(–)
(separation using KOH-- Holdsworth’s method)Exceptions (too specialized, or flattened):
• tegmina & elytra• mid-section of holometabolous wing
Robin John Tillyard
Neuroptera: Chrysopidae
Hymenoptera: Chalcidoidea
Thysanoptera
Odonata: Anisoptera
ColeopteraHemiptera: Heteroptera
cross-vein
marginal twigging
one vein
one vein
setae
pterostigma
nodusarculus
elytron
hemelytron
Proliferation:
Reduction:
Special functions: