昆蟲學

中山大學生物資優班

昆蟲學

蘇詠超

節肢動物 生物多樣性簡介

Phylum

Arthropoda

(節肢動物門)

Insects are arthropods

界 Kingdom 門 Phylum 綱 Class 目 Order 科 Family 屬 Genus 種 Species

Chelicerates (螫肢類) Hexapods (六足類) Crustaceans (甲殻類) Myriapods (多足類) Trilobites (三葉蟲) Pycnogonida (海蜘蛛) ancestor Extinct

HEXAPODA

(都是六隻腳的動物，但並不是都是昆蟲)

Entognaths(內口類) and Ectognaths(外口類)

(稱「類」而不稱「綱」-演化觀念之適用)

• Entognaths (

內口類

): Mouthparts

“pulled up” into head capsule

THE ENTOGNATHS

Orders Protura, Collembola, Diplura

• 小型生物、住在落葉及表土層中

Protura _Diplura

Entognaths(內口類) and Ectognaths(外口類)

六足類的早期分化

• Ectognathous

hexapods:

Mouthparts not

covered by

head capsule(口

器外露)

六足類的演化樹

Diplura

Collembola

Protura

Insecta

Entognaths

Ectognaths

外口類=昆蟲綱

Ectognaths: CLASS INSECTA

Order Achaeognatha (古口目) and Order Thysanura (衣 魚目) sometimes referred to as the apterygotes (有翅亞 “類”) — primitively wingless.

Pterygota are the winged insects

古口目(石蛃目) 衣魚目

• Order Archeognatha (古口目“ancient jaws”)

• Only 1 mandibular condyle (大顎接點一個)

Tree of Hexapod Groups

Diplura

Collembola

Protura

All other orders

Entognaths

Ectognaths

Archeognatha

Dicondylic

jaws

Order Thysanura (衣魚目、銀魚目)

Silverfish and firebrats

• New invention:

Diplu

ra

Coll

embola

Pro

tur

a

Entognaths

_Ectognaths

Ar

ch

eog

nath

a

Dicondylic

jaws

Th

ysan

ur

a

Wings!!

Pterygotes—winged insects

Ephemeroptera (蜉蝣目) and Odonata (蜻蛉目) sometimes called the Paleoptera (古生翅群 Old wings)

Orders Ephemeroptera (蜉蝣目) and

Odonata (蜻蛉目)

Neopteran Insects (新翅群)

• Most of the insect orders

• Special wing-folding mechanism

• Can fold wings flat over back (可以將翅

折與腹部平行)

Dictyoperan orders

• Blattodea(蜚蠊目)

• Blatteria-Roaches

• Isoptera-Termites

• Mantodea-Mantises

Order Orthoptera:Two big groups:

• Ensifera: “long horned”

• Crickets, katydids and

weta

• Caelifera: “Short-horned”

• grasshoppers, locusts

Hemipteroid Orders

Lacewing-Neuroptera Flea-Siphonaptera Beetle-Coleoptera Mosquito-Diptera Butterfly-Lepidoptera Bee-Hymenoptera

Phylum Arthropoda:

the jointed-foot animals

• Many basic features shared with other

animal phyla

• SEGMENTED BODY (身體分節)

• DORSAL HEART (心位於背部)

• PAIRED VENTRAL NERVE CORDS (成

對的神經索位於腹部)

Phylum Arthropoda



COMPOUND

EYES (複眼)

• many small units,

OMMATIDIA (複眼

單元)

• OMMATIDIUM

has lens, visual

pigments

Phylum Arthropoda

unique characters

• Coelom greatly reduced (體腔退化)

• Instead, open circulatory system (半開

放體循環)

Phylum Arthropoda

unique characters

• Hard, jointed exoskeleton (硬的外骨骼)

– Cuticle= protein and CHITIN, a

polysaccharide

– Sclerotization of cuticle:

tanning of protein to form hard plates

• Jointed, segmented appendages on

Segmented body plan,

Jointed exoskeleton

Anterior to mouth:

non-segmental acron

or prostomium

Just posterior to anus:

non-segmental tail,

or telson or periproct

Paired, jointed limbs

on

DORSAL VIEW

(腹面)

Tergites(背片): hard dorsal plates

hard ventral plates:

sternites(腹片)

Tagmosis (分節特化):

Modification of limbs

Head or head region

limbs  mouthparts, antennae.

Other limbs 

walking, swimming, (運動)

sperm transfer,

holding eggs, (生殖)

Insects: 3 body regions or tagmata

Segmentation (分節)–

how do we know(如何知道分幾節)?

• Count appendages (計算附肢)

– Each pair of appendages (or things derived from the appendages) indicates a segment

• Count pairs of nerve ganglia (計算神經節)

• Examine limb buds in embryos (由胚胎)

• (分子生物學的方法) Use labeled antibodies or

other method to determine where gene for

“front edge of a segment” is turned on in

developing embryo

Old view

New

view

Basic insect head

• Head capsule

• 1 pair compound

eyes(複眼)

• 3 simple eyes-ocelli (單

眼 )

• 1 pair antennae (觸角 )

• 3 pair mouthparts (口器)

Parts of the head

Gena

Maxillary palp

Parts of the head

Internal bracing in insect head

Eyes

• Compound eyes

• Up to 3 simple

eyes or ocelli

Antennae

• Sensory

– Chemoreception(化學接受器)

– Touch(觸覺接受器)

• Parts

– Scape (基)

– Pedicel (軸)

– Flagellum (with many small

flagellomeres)(羽)

Antennae

• Honey bee

Mouthparts

• Labrum

– “upper lip”

– May or may not be derived from limbs

• Mandible (2)

• Maxilla (2)

• Labium

– formed of fused left and right limbs

Labrum

Mandible

Maxilla Labium Clypeus (人中區)

Insect thorax

• Formed from three body segments

– 1

referred to with prefix “pro (前)”

– 2

“meso (中)”

– 3

“meta (後)”

• Three pairs of walking legs

• In winged (pterygote) insects, 2 pairs of

wings

Apterygotes:

Archeognatha &

Thysanura

Three segments clearly visible

Prothorax

Metathorax

Thoracic segments

often fused or

Basic thoracic sclerites

Larva of a trichopteran

Basic thoracic sclerites

Basic thoracic sclerites

Larva of a

trichopteran _{Lateral sclerites} are called “pleura” propleuron

mesopleuron

Basic thoracic sclerites

Larva of a

trichopteran Pleural sutures divide pleurons into episterna and epimera

proepisternum

mesepisternum

Basic thoracic sclerites

A more realistic mesothoracic segment

Leg attaches here Wing articulates

What about wings?

• Two pair

• On 1

_{and 2}

_{thoracic segments}

• Diptera (flies) have only anterior pair

• Second pair replaced by halteres

External

morphology-Abdomen

Abdominal segmentation

• Usually easy to observe

• 11 segments

• 9-10 easy to observe

• Specialized for digestion, fat storage,

reproduction

Dasyleptus- extinct apterygote

from Carboniferous period

“Modern” apterygote

Order Archeognatha, Family Machilidae

Note most abdominal appendages reduced to “peg-legs” called styli

Modern Nomadacris (Orthoptera)

Where did all the

abdominal appendages go?

• Most lost without a trace

• Genitalia (生殖器)

– 8

_{& 9}

_{segments of females}

– 9

_{of males}

• Cerci (one cercus) (觸毛)

Generalized

female genitalia

Genital opening on 8th _segment

Generalized

female genitalia

may form a tube for egg-laying

3rd valvulae may form protective sheath

Generalized

female genitalia

Generalized

female genitalia

Female of Romalea microptera (Orthoptera)

Generalized

male genitalia

Generalized

male genitalia

(or paramere) = modified leg Aedeagus = fused lobes from coxae of 9th appendages

Male of Romalea microptera (Orthoptera)