Arthropods Week 2

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Autapomorphy Insects

Body consisting out of head, thorax and abdomen

Four principal mouthpart types

Biting-chewing

Piering-sucking

Siphoning (like straw, Lepidoptera)

Sponging (Diptera that do not sting; flies)

6 major wing veins

Costa
Subcosta
Radius
Media
Cubitus
Analis

Protura apomorphies

No antennae, using front legs for probing substrate
Blind

Collembola apomorphies

Only 6 abdominal segments

Retinaculum and furca for jumping

Ventral tube for multiple purposes (e.g. used for cleaning and taking up H2O from air)

4 groups of Collembola

Entomobryomorpha: Prothorax very small, well developed furca

Poduromorpha: Short legs, elongated body, Many without furca; Uniform colouration

Symphypleona: Body globular; Thorax and Abdomen segments seemingly fused together

Neelipleona: Tinyyyyy

Diplura apomorphies

long homonomous flagellate antennae & cerci

blind

(generally mostly based on molecular data tho??)

2 groups of Diplura

Japygoidea: Predatory, forceps

Campodeoidea: eat fungi hyphen, detritus and carrion

Entognathy

Mouthparts hidden within head capsule: Gena fused to labium (and labrum?) → creates a mouth cone, within mouth cone are mandibles and maxillae

Collembola mouthparts

piercing-sucking;
stylet-like mouthparts
rotation of mandibes to grind particles

Archaeognatha apomorphies

7-segmented palpus maxillaris

Zygentoma apomorphies

Presence of 4 labial muscles

Collembola + Protura synapomorphies

Not morphologically well-reasoned, mostly molecular data

Diplura + Archaeognatha + Zygentoma + Pterygota synapomorphies

long terminal filaments,

long antennae

SUCKS as argument bc there are a lot of reductions

Archaeognatha + Zygentoma + Pterygota synapomorphies

Ectognathy
(also: presence of ovipositor)

Zygentoma + Pterygota synapomorphies

Dicondyly (2 joints on mandibles)

Palaeoptera apomorphies

Form of maxillae: lacinia with well-developed teeth = Dentisetae

Very short antennae

Reduction of a muscle within the labium

Neoptera apomorphies

can fold wings flat over the abdomen, with two folding lines

Ephemeroptera apomorphies

Subimaginal stage
Imago without mouthparts
Tracheal gills on several abdominal segments

Odonata apomorphies

Flight muscles directly attached to wings
Head arrester system
Males with secondary copulatory apparatus
Nymphs with labial mask

WHY evolved head arrester system??

Head microstructures and neck microstructures connected in velcro-like manner

more stable connection of head and thorax

During flight activated to counter G-forces, otherwise head would be dislocated during rapid flight and turning maneuvers

Polyneoptera apomorphies? Which groups?

Hard to argue for monophyly from morphological point of view :/ based on molecular studies

Plecoptera (Stone flies)

Grasshoppers,

Cockroaches and alliesss

Order Blattodea (cockroaches and termites)

Order Mantodea (praying mantises)

Order Orthoptera (grasshoppers, crickets, katydids)

Order Dermaptera (earwigs)

Order Embioptera (web-spinners)

Order Plecoptera (stoneflies)

Order Grylloblattodea (ice-crawlers)

Order Mantophasmatodea (gladiators)

Order Phasmatodea (stick and leaf insects)

Order Zoraptera (angel insects)

Zoraptera apomorphies

Angel insects <3

9-segmented antennae

Dermaptera apomorphies

Forewings modified into tegmina/hemielytra
Hindwings with complicated folding structure
Cerci

Plecoptera apomorphies

Stone flies

two long multisegmented cerci (plesiomorphic lol)

Reduction of certain head muscles and abdominal muscles

Monophyly mainly based in reduction characters

Poorly reasoned based on morphology

2 lineages of Plecoptera

Antarctoperlaria
Arctoperlaria

Orthoptera

+the suborders pleasee

Jumping hindlegs with enlarged femur

Ensifera: long antennae, sword-like ovipositor

Caelifera: short antennae, no ovipositor, use whole abdomen to lay eggs into substrate

Orthoptera mouthparts

biting-chewing

orthognathous

Mantophasmatodea mouthparts

Heel walkers

orthognathous

Grylloblattodea

Ice crawlers

cold adapted (1-4°C)

Hemolymph with anti-freezing substance

no wings:/

Mouthparts Grylloblattodea

prognathous

Embioptera

footspinners
spinning apparatur: silk glands on enlarged tarsal segment on foreleg

in colonies

females wingless

Embioptera mouthparts

prognathous

Phasmatodea mouthparts

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Orthognathous

Mantodea apomorphies

Raptorial forelegs for catching prey

Blattodea mouthparts

Biting-chewing

"hypognathous"

Isoptera mouthparts

Chewing-biting

"hypognathous"

show same bite characteristics as some holometabolan lineages

-> might be related to wood-feeding lifestyle since ancestral holometabolan probably also wood-feeding

Mouthparts of Hemiptera

Piercing-sucking:

Maxillae fused (lock and key), enframed by mandibles

inside labial tunnel

Mouthparts Hymenoptera

Mandibles biting-chewing,

but labio-maxillary complex used for licking up food

Mouthparts Brachycera

sponging mouthparts

Mandibles reduced; Maxillae and Labium -> Labellum

Mouthparts Nematocera

piercing-sucking

Mandibles, Labrum, Hypopharynx and laciniae modified into proboscis. Labium as guiding structure;

Food goes through labrum, saliva through hypopharynx

Name the orders of Paraneoptera

• Psocodea - lice

  • Psocoptera – book lice

    • Phthiraptera – biting (“true”) lice

• Thysanoptera – thrips

• Hemiptera – true bugs

Psocoptera apomorphies

(book lice)

Elongated freely movable laciniae

Phthiraptera: Adaptations for parasitism

Biting lice

Tarsi with single claw to cling to hair

Dorsoventrally flat

No wings/reduced wings

Thysanoptera apomorphies

thrips <3

only have one single (LEFT) mandible

wings reduced to thin bands with many hairs (“Fransen”)

Hemiptera apomorphies

Proboscis with characteristic configuration:

maxillae fused (form 2 inner lumen: for saliva and food), enframed by mandibles, surrounded by labium

2nd maxillae (=LABIUM) modified into sheath

Hemiptera suborders

Sternorrhyncha (plant bugs)

Auchenorrhyncha (cicadas)

Heteroptera (true bugs)

How can you differentiate plant bugs, cicadas and true bugs?

Point of insertion of proboscis and length of antennae:

Sternorrhyncha: Proboscis originates from “below” the head capsule, long antennae

Auchenorrhyncha: Proboscis originates from “below” the head capsule, short antennae

Heteroptera: Proboscis originates at anterior part on head capsule

What are the reasons for the strong diversification of hemipterans?

Camouflage (→ sometimes draastic morphological changes)

special life cycles, e.g. parthenogenesis, parasitism

What is a synapomorphy Hexapoda share with (other lol) crustaceans?

2 corneagenous cells in ommatidia

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What are dicondyle mandibles?

mandibles with two ball and socket joints

Posterior: condyle

Anterior: socket

Mouthparts Lepidoptera

Basal ones (Micropterigidae) biting chewing

higher taxa: siphoning mouthparts!

coiled up proboscis (= right and reft galea fused)

Zygentoma families

• Nicoletidae: often associated to ants, live in ant nests, have same smell, are not attacked therefore; FAST, short terminal filaments and relatively short antennae, shorter legs  

• Lepismatidae: well-developed terminal filament, very long antennae  

• Lepidotrichidae: basal-most branching family 

flight apparatus Odonata

“indirect-direct”

Some muscles attach directly at wing base, some muscles insert indirectly, on thorax 

no longitudinal muscles?

flight apparatus Neoptera + Ephemeroptera

“indirect”

Muscles attach to roof of thorax, and have longitudinal muscles going through thorax  

Archaeognatha families

Machilidae, Meinertellidae

Suborders of Odonata

Zygoptera, Epiprocta (Anisoptera, Epiophlebiidae)

Collembola sperm transfer

external sperm transfer

male desposits spermatophore,

female: uptake via mouth opening/digestive tract

Archaeognatha feeding

rolling movements of mandibles → grind molar areas of mandibles against each other
(little bit like cows <3)

feed on algae, lichen, fungi

In what group did we talk about directed gliding?

Meinertellidae (→ Archaeognatha)

Paraneoptera apomorphies

1st maxillae stylet-like

→ adaptation for liquid food uptake

Thysanoptera + Hemiptera synapomorphies

Mandibles stylet-shaped

Blattodea apomorphies

Monophyly poorly argued from morphological point of view,

mainly based on molecular data