Download Generalized insect head: Anterior aspect Suture lines: lines of

Generalized insect head:
Anterior aspect
VERTEX
coronal suture
ocular suture
compound eye
dorsal ocellus
antennal suture
subocular suture
antenna
frontal suture
GENA
FRONS
clypeus
anterior tentorial pit
mandible
labrum
subgenal suture
epistomal suture
Suture lines: lines of weakness associated with molting
flexible region as in
wing hinge of
Schistocerca (locust)
flexible region
as in wing base
of Lepidoptera
epicuticle
exocuticle
endocuticle
epidermis
flexible region
lacking exocuticle
(membrane)
fibrous protein
resilin plus chitin lamellae
pure resilin
wedge of partially
sclerotized “mesocuticle”
ecdysial cleavage
line or suture (lacks
exocuticle)
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Generalized insect head:
Posterior aspect
VERTEX
coronal suture
occipital suture
compound eye
GENA
OCCIPUT
(occipital area)
postoccipital suture
ocular suture
remnants of head somites?
cervix (neck)
foramen magnum
mouthpart region
(mouthparts removed)
Generalized insect head: cockroach (Dictyoptera: s.o. Blattodea)
Blattodea
2
Head articulations and muscles
extrinsic
muscles
condyles
condyles
Mandible –
Antenna –
monocondylar
(monocondylic)
extrinsic
muscle
condyle
condyle
(antennifer)
dicondylar
(dicondylic)
tentorium
adductor (flexor) muscle
abductor (extensor) muscle
Md
point of articulation
(condyle)
(sagittal plane)
Head shape I: the effect of Muscles
[Note sexual & caste dimorphism]
(a proctotrupoid
parasite of woodboring beetle larvae)
vertex
Mandible
muscles
tentorium
sclerotized,
flattened “tendon”
exodont mandibles
brain
Vanhornia larva –
Soldier ant –
huge abductors
huge adductors
Atta
clypeus
cibarium
clypeus
labrum
Cicadidae
“soldier”
sucking
mouthparts
Pharyngeal/cibarial
pump muscles
clypeus
Thysanoptera (thrips)
3
Head shape II: Compound eyes
Stemmata and Dorsal Ocelli
Lateral ocelli
(stemmata)
Dorsal ocellus
Dorsal ocelli
larva of Lepidoptera
(Holometabola/
Endopterygota)
adult (or nymph) of Cicadidae
(Hemimetabola/Exopterygota:
Hemiptera)
Head shape:
Extreme effect of eyes
antenna
Odonata
(s.o. Anisoptera)
antenna
Diptera (a)
antennae
Neuroptera
(Ascalaphidae)
Aeschnidae
(Odonata)
(also sexually dimorphic)
antenna
Diptera (b)
Diopsidae
(Diptera – a)
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Other modifications of the compound eye
Odonata
male Strepsiptera
Thysanoptera
Gyrinidae
(Coleoptera)
male
male
Ephemeroptera
Ephemerida
water
surface
Ascalaphidae (Neuroptera)
Sexual
dimorphism:
Ascalaphidae
(Neuroptera)
Male
and female
Drosophila
(Diptera)
Simple eyes:
Stemmata and Dorsal Ocelli
Stemmata and Dorsal Ocelli
Lateral ocelli
(stemmata)
larva of Lepidoptera
(Holometabola/
Endopterygota)
•
•
Dorsal ocellus
Dorsal ocelli
adult (or nymph) of Cicadidae
(Hemimetabola/Exopterygota:
Hemiptera)
Dorsal ocelli are commonly lost (even whole orders).
Compound eyes usually retained, but lost in cavernicolous species.
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Structure of the Antenna
nerve fibers
Johnston’s Organ
antennal suture
socket
PEDICEL
antennifer
SCAPE
FLAGELLUM
(with annuli
separating the
antennomeres)
intrinsic muscle
nerve bundle
extrinsic muscle
OR:
antennifer
Lost in some endoparasites
(Strepsiptera females)
and ectoparasites (plant
lice: Sternorrhyncha)
Culicidae
(Diptera)
scale insect (Coccidae)
Modifications of the antennae:
filiform
moniliform
setaceous
clavate
capitate
serrate
lamellate
pectinate
flabellate
pedicel
geniculate
plumose
pedicel
aristate
pedicel
•
•
stylate
•
•
(pedicel with
Johnston’s
Organ)
tactation (touch)
mechanoreception (vibration
& sound, e.g. mosquitoes)
chemoreception (e.g. moths)
prehension (sexual selection)
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pectinate (Lepidoptera)
aristate
(muscoid Diptera)
geniculate (Formicidae)
Modifications
of the antennae
flabellate (Coleoptera)
clavate
(Lepidoptera)
1 2 34
5
6
I
7
II
III
‘Trignathous’
insect mouthparts
procephalon
plus somite 1
2 3 4
6
5
7
--- THORAX --I
III
II
procephalon
plus somites 1, 2, 3
4
postoccipital
suture
labrum
mandible (2)
5
6
7
I
II
III
labium (4)
maxilla (3)
7
Trignathous mouthparts:
Back view
Lateral view
pharynx
salivary duct
labium
maxilla
mouth
cibarium
clypeus
preoral
cavity
labrum
mandible
labrum
salivarium
labium
hypopharynx
clypeus
LABRUM
abductor and
adductor muscles
MANDIBLE
molar area
point of
articulation
MAXILLA
incisor area
cardo
LABIUM
stipes
palpifer
submentum
lacinia
galea
maxillary palp
postmentum
Note ‘serial
homology’ of
maxilla and labium
mentum
prementum
labial palp
glossa
paraglossa
HYPOPHARYNX
suspensory sclerite
lingual sclerite
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