WEEK 4

pls end my pain

Ametabolous

• E.g. Zygentoma, Archaeognatha  

• Ancestral strategy 

• Direct development  

Hemimetabolous

• Have juvenile phase: pronymph (hatches from egg), then nymph 

• Immature stages (nymphs) very similar to adults, feed and live in same habitat 

Holometabolous

• Several larva stages – pupa (mostly nonmobile) whole body rearranged; true metamorphosis  

Neometabolous

• Thysanoptera (thrips), some Hemiptera,  

• Propupa before adult stage 

In what two main groups are Diptera classically divided? How do they differ from each other?

“Nematocera”:

• Adults with long, multisegmented antennae; similar flagellomeres. 

• Larvae with cephalic capsule well-developed and mouth with mandibles  

Brachycera:

• Antennae of adults with a few segments and with stylus/arista; heterogeneous flagellomeres 

• Larvae with modifications in mandibles and without complete cephalic capsule

Key innovations of Coleoptera

Elytra

(Antennae with 11 antennomeres (reduced in length))

Primary functional units of beetle body:

Head - Prothorax - Pterothorax (=meso+metathorax) + abdomen

Name the suborders of Coleoptera

Archostemata

Myxophaga

Adephaga

Polyphaga

Families that evolved stridulation

Curculionidae, Scolytidae, Cerambycidae, Buprestidae, Hydrophilidae, Cicindelinae, Scarabaeidae, Glaresidae, larval Lucanidae, Passalidae, Geotrupidae 

Cantharidae

soldier beetles (Weichkäfer)

soft-bodied

tarsal formula 5-5-5

Coccinellidae

clubbed antennae

Tarsal formula 4-4-4 (may appear 3-3-3 because the third segment of each tarsus is reduced)

Chrysomelidae

Leaf beetles

Tarsal formula 5-5-5

Tenebrionidae

Darkling beetles

often adaptations to dry conditions

Carabidae

Adephaga!

have defense glands

Geotrupidae

Dung beetles

e.g. Anoplotrupes stercorosus

Stridulation

Cerambycidae

Longhorn beetles

antennae as long as or longer than body (in most species…)

3rd tarsomere heart-shaped

elongated body

e.g. Aromia moschata

Curculionidae

WEEVILS!!!

downwards-curved snout (rostrum) possessed by many species, though the rostrum is sometimes short

elbowed antennae

e.g. Curculio elephas

Buprestidae

Jewel beetles

Shape is generally cylindrical or elongate to ovoid

Mordellidae

tumbling flower beetles (Stachelkäfer)

have abdominal tip which aids them in performing tumbling movements

Elateridae

Click beetles

Click-mechanism: A spine on the prosternum can be snapped into a corresponding notch on the mesosternum, producing a violent "click" that can bounce the beetle into the air

Oedemeridae

false blister beetles (Scheinbockkäfer)

slender, soft-bodied beetles of medium size found mostly on flowers and foliage

Dasytidae

Wollhaarkäfer

body covered in shaggy hairs

Horizontal gene transfer

Phytophagous lineages acquired genes from bacteria for better digesting plant material  

Staphylinidae

Rove beetles (Kurzflügler)

Shortened elytra

Archostemata

• Smallest suborder, less than 50 species known worldwide 

• Number of primitive characteristics, similar in morphology to first beetles, which appear in fossil record 250 ma  

Myxophaga

• Contains about 100 described species in four families, mostly very small  

• Most belong to Hydroscaphidae and the genus Sphaerius  

Adephaga

• 10 families, mostly largely predatory beetles  

• 35,000 species 

• Carabidae, Dytiscidae (diving beetles) and Gyrinidae (whirligig beetles)

• Coxae of the hind legs are positioned in a way that divides the first abdominal segment

• Often useful as bioindicators  

Polyphaga

• Largest of the suborders, 300,000 described species in 170 families 

• Including rove beetles, scarab beetles, blister beetles, stag beetles, ...  

Dytiscidae

Adephaga

oval habitus

smooth, flat and solid :) streamlined

Families with parental care

Geotrupidae (dunng beetles): brood ball; rollers vs. tunnellers

some Chrysomelidae (leaf beetles)

Silphidae (carrion beetles)

Examples for active collection approaches

hand nets, aspirators,

barking, beating sheets

The two types of passive collection approaches

interception traps

baiting traps

What information should labels contain?

Locality label:

Country: Province/state,
City/area, point, coordinates,
altitude, date, trap, host
Leg.: Collector’s name

Identification label

TYPE material?
Genus’ name
Specific epithet Author, Year
Det.: Identificatior’s name, Year

Barcode

How could you catch ground-living beetles?

Pitfall traps

e.g. Carabidae

How would you catch Scarabaeidae?

Light traps, since they are often nocturnal

or bait traps, pheromone traps

How would you catch flower visiting beetles/insects?

Yellow plate trap (plus other colours)

e.g. Mordellidae

How would you catch flying insects?

Malaise traps,

emergence traps,

flight interception traps (also measure activity patterns)  

How would you catch water beetles/water insects?

with a small net (e.g, kitch sieve), needs to be robust, e.g. Dytiscidae

panning

How would you catch soil and litter layer arthropods?

Swifting

Berlese/Winkler apparatus

How would you catch foliage living beetles?

beating, with beating sheets, e.g. Curculionidae

fogging mayhaps (using a pyrethroid-based insecticide, collecting panels with a collection tube)

Variation of a trait

2 character states can

be fully separated (like in molecular data)

or

overlap (often in morphological data, e.g. color, size,…)

Why do we even still need morphological data/morphology?

• Says a lot about lifestyle/habitat of a species

• Easily accessible even in distance

• Available in fossils/images etc.

• (easier link to taxonomix category; just comes naturally to us/easier to understand…)

Quantitative tools to study morphology:

• Distance measurements

  • Measure size

• Landmarks

  • Putting specific landmarks on well-homologized spots of different specimens

  • Can be analyzed in coordinate system

• Shape outline

  • E.g. measuring from central point

PCA

:) Principal component analysis:

is mathematically defined as an orthogonal linear transformation that transforms the data to a new coordinate system such that the greatest variance by any projection of the data comes to lie on the first coordinate (called the first principal component), the second greatest variance on the second coordinate, and so on.

Cluster analysis

assigning a set of objects into groups (called clusters) so that the objects in the same cluster are more similar (in some sense or another) to each other than to those in other clusters.

Methods to infer apomorphies:

1) Defining character polarity a priori (Hennig: outgroup comparison)
(“old fashioned” method as it fails with more complex data)

2) To perform a phylogenetic analysis (computer-based)
and using an outgroup to define character polarity (i.e. apomorphic vs. plesiomorphic state by rooting the tree)

Silphidae

Carrion beetles (Aaskäfer)

parental care <3

Phytophaga

Contains superfamilies Chrysomeloidea and Curculionoidea

e.g. Cerambycidae, Chrysomelidae, Curculionidae

Tarsi pseudotetramerous or cryptopentamerous, where the fourth tarsal segment is typically greatly reduced or hidden by the third tarsal segment.

Phytophaga: horizontal gene transfer

acquisition of genes from bacteria and fungi that encode enzymes capable of breaking down plant cell wall components (cellulose)

Name examples for aquatic beetle families and their adaptations for their aquatic lifestyle!

Dytiscidae (Diving Beetles):

• Strong swimmers and predators

• with streamlined bodies

• long, fringed legs for propulsion

Gyrinidae (Whirligig Beetles):

• habit of swimming in circles on the water surface

• divided eyes to see both above and below the surface. 

name types of active/passive traps/collection methods and the corrosponding insects that are caught with them

active

aspirator : usually small flying insects

beating sheet : nonflying insects on trees, foilage

barking : beetles and their larva that eat/live in wood

passive

sticky traps (with and without pheromones) : flying insects

moericke traps : hymenoptera and some diptera

pitfall traps : ground walking insects

malaise traps : flying insects especially diptera and hymenoptera

emergence traps : insects that emerge from the soil

Holometabola

• Hymenoptera, Neuropteroids, Coleoptera, Trichoptera and Lepidoptera, Mecoptera, Siphonaptera, Diptera