Arthropoda (節肢動物門)

中山大學生物資優班 昆蟲學

蘇詠超

高雄醫學大學生物醫學暨環境生物學系

節肢動物 生物多樣性簡介

OVERVIEW OF Arthropod DIVERSITY

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

Major groups within the Arthropoda

節肢動物可能的演化關係

HEXAPODA

(都是六隻腳的動物，但並不是都是昆蟲)

ENTOGNATHS (內口類)

ECTOGNATHS (外口類)

彈尾目 原尾目

雙尾目 昆蟲綱

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

Collembola

https://www.youtube.com/watch?v=MXeS nWY6DNc

Springtails take jumps

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 (無翅亞

“類”) — primitively wingless.

Pterygota (有翅亞綱)are the winged insects 古口目(石蛃目) 衣魚目

有翅亞綱

• 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

(大顎接點兩個)jaws

Order Thysanura (衣魚目、銀魚目) Silverfish and firebrats

• New invention:

dicondylic jaws (大顎接點兩個、見模型)

Diplura CollembolaProtura

Entognaths Ectognaths

Archeognatha

Dicondylic jaws

Thysanura

Wings!!

https://www.facebook.com/DeepLookPBS/videos/8080094 12716973/

Brizard mouth part of dragonfly nymph

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

and their relatives

Hemipteroid Orders

Hemiptera/

Homoptera

Crab louse-Phthiraptera

A thrips

Thysanoptera

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)

https://www.facebook.com/ScientificAmerican/videos /10159107115145246/

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

each body segment (外骨骼及附肢分節)

Segmented body plan, Jointed exoskeleton

Anterior to mouth:

non-segmental

Just posterior to anus:

non-segmental tail,

or

Paired, jointed limbs

on

each body segment

DORSAL VIEW (腹面)

Tergites(背片): hard dorsal plates

hard ventral plates: sternites(腹片)

Soft, thin pleural membrane

Tagmosis (分節特化):

Fusion, specialization of body segments

Modification of limbs

Head or head region

limbs  mouthparts, antennae.

Other limbs 

walking, swimming, (運動) sperm transfer,

holding eggs, (生殖) Limbs may be lost

Insects: 3 body regions or tagmata

• Abdomen(腹), thorax(胸), head (頭)

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)

– (one pair per segment)

• 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

“Traditional” view

Old view New view

Based on gene expression studies

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)

– Mandibles(大顎) – Maxillae(小顎 ) – Labium (唇 )

Parts of the head

Gena

Maxillary palp

Labial palp

Parts of the head

Labrum Maxilla

Foramen Magnum Vertex

Internal bracing in insect head

Tentorium

Eyes

• Compound eyes

• Up to 3 simple eyes or ocelli

• More on eyes later

Eyes of praying mantis

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

• (Apis mellifera)

Many modifications

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)

Modified Mouthparts

https://www.facebook.com/DeepLookPBS/vi deos/912356292282284/

The “needle” of mosquitos

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

Legs similar

Thoracic segments clearly visible

Three segments clearly visible

Prothorax

Metathorax

Mesothorax

Thoracic segments often fused or

modified

Basic thoracic sclerites

Larva of a trichopteran

Basic thoracic sclerites

Larva of a trichopteran

Tergites are called “nota”

Pronotum (前背板)

Metanotum (後背板) mesonotum (中背板)

Basic thoracic sclerites

Larva of a

trichopteran Lateral sclerites

are called “pleura”

propleuron

mesopleuron

metapleuron

Basic thoracic sclerites

Larva of a

trichopteran Pleural sutures

divide pleurons into episterna and epimera

proepisternum

mesepisternum

metepisternum

Basic thoracic sclerites

Larva of a trichopteran

proepimeron

mesepimeron

Metepimeron

A more realistic mesothoracic segment

Leg attaches here Wing articulates

here

Honey bee thorax

Thorax highly modified in a bee

Thorax highly modified in a bee

https://www.facebook.com/SeekerMedia/

videos/10155233269088387/

Inside of bee

Insects take fly

https://www.youtube.com/watch?v=Cnn9CfsYJqc

What about wings?

• Two pair

• On 2nd and 3rd thoracic segments

• Diptera (flies) have only anterior pair

• Second pair replaced by halteres

https://www.facebook.com/Natur eNews/videos/14325730901465 29/

Embioptera (紡足目)

2000 species

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

Note appendages on abdominal segments!

“Modern” apterygote

Order Archeognatha, Family Machilidae

Note most abdominal appendages reduced to

“peg-legs” called styli

Modern Nomadacris (Orthoptera)

T11 T1

T9 T10 T2

T6 T8 T4

T5 T7 T3

T = tergite, S = sternite S1

Spiracle (氣孔) S8 Ear

Ear = Tympanum

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)

– 11

segment

Generalized female genitalia

Ovipositor (產卵器) Genital opening on 8^th segment

Generalized female genitalia

3^rd valvula 2^nd valvula 1^st valvula

8 9

1^st and 2^nd valvulae may form a tube for egg-laying

3^rd valvulae may form protective sheath

Generalized female genitalia

3^rd valvula

2^nd valvula 1^st valvula

8 9

8 9

cercus

1^st valvifer

2^nd valvifer

1^st valvula 2^nd valvula

3^rd valvula

Generalized female genitalia

Valvifers = coxae of Modified appendages

Valvulae =

lobes on coxae

Female of Romalea microptera (Orthoptera)

1^st valvula 2^nd valvula

3^rd valvula cercus

T9 T10

Genitalia of most insects highly modified from basic plan

Generalized male genitalia

S9 Aedeagus (= penis)

gonocoxite

gonostylus anus

Paramere =

Gonostylus+gonocoxite

Generalized male genitalia

S9 Aedeagus (= penis)

gonocoxite

gonostylus anus

Gonostylus+gonocoxite

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

Male of Romalea microptera (Orthoptera)

Not much to see from the outside

Abdomen highly modified in a bee

Mosquitos kill one million people/ year

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd

=&cad=rja&uact=8&ved=2ahUKEwjqvvWw5PLvAhW-

wosBHQT3D_4QFjACegQICBAD&url=https%3A%2F%2Fwww.mos quito.org%2Fpage%2Fdiseases&usg=AOvVaw0_T1Rqk_Co25TwJ3 mSJ6Rm

A bacterium (Yersinia pestis) spread by fleas killed 25 million

people, more than a quarter of the European population, in 14 th century Europe. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjxg-

vA5PLvAhWjHqYKHXcYDTEQFjAAegQIAhAD&url=http%3A%2F%2Fwww.idph.state.il.us%2Fenvhealth%2Fpcfleas.htm&usg=AOvVaw1Grfi84B_kHGM5s91IU xJf

Bees and flies are important pollinators