Classifications of Insects Flashcards

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Questions and Answers

What are insects?

phylum arthropoda, superclass/subphylum Hexapoda, class insecta

What is subclass hexapoda?

Six-legs, body segments organised into three groups: head, thorax and abdomen

What is class insecta?

Simple eyes (ocelli) and compound eyes usually present, legs with at least 6 segments, exposed mouthparts (ectognathus) consisting of mandibles, maxillae and labium

What is the evolution of six-legged arthropods (Hexapoda)?

Oldest fossil hexapods are Collembola ('springtails') from 394-401 million years (Devonian period) ago from Scotland Signup and view all the answers

What are non-insect hexapods?

Protura, Collembola, Diplura Signup and view all the answers

Before which period were all the major groups of modern insects established?

The Triassic (245 Mya), except for Hymenoptera (bees, wasps, ants) and Lepidoptera (moths & butterflies) Signup and view all the answers

What do insects in amber provide?

A history of insects 45-15 million years old Signup and view all the answers

What are Pterygotes unusual for?

No limbs have been lost in the acquisition of wings Signup and view all the answers

What does the EXITE-ENDITE HYPOTHESIS suggest?

Wings arose from gills in ancestral aquatic forms Signup and view all the answers

What are the routes to flight from small winglets?

Floating, Paragliding, Running-Jumping, Surface sailing Signup and view all the answers

What characterizes Collembola, or springtails?

Sucker-like ventral tube and forked jumping organ (furcula), small, usually up to 2-3 mm Signup and view all the answers

What are Proturans?

Small, without antennae, entognathous (mouthparts within the folds of the head), legs five segmented Signup and view all the answers

What characterizes STREPSIPTERA?

Bulging eyes, branched antennae, males with stubby forewings and fan-shaped hind wings Signup and view all the answers

What are the classifications of mouthparts?

Entognathous or ectognathous Signup and view all the answers

What are mandibulate mouthparts?

Mandibles usually obvious and suited for seizing objects or chewing food Signup and view all the answers

What are suctorial mouthparts?

Most adult Lepidoptera and Diptera obtain their food solely by sucking up liquids Signup and view all the answers

What characterizes Coleopteran species?

May have either suctorial or mandibulate mouthparts Signup and view all the answers

What does Siphonaptera have?

Suctorial mouth parts Signup and view all the answers

What are wings in insects?

Only fully developed in the adult, with a 'ground-plan' of 3 zones and eight wing veins Signup and view all the answers

Study Notes

General Overview of Insects

Insects belong to the phylum Arthropoda, specifically the superclass/subphylum Hexapoda and class Insecta.
Characterized by three body segments: head, thorax, and abdomen; the presence of six legs.

Morphological Features

Class Insecta features simple eyes (ocelli) and compound eyes; legs contain a minimum of six segments.
Mouthparts are ectognathous, meaning they are externally visible, consisting of mandibles, maxillae, and labium.

Evolutionary Background

The earliest known hexapods, Collembola (springtails), date back to the Devonian period, approximately 394-401 million years ago.
Most modern insect groups emerged before the Triassic period (245 million years ago), with Hymenoptera and Lepidoptera being exceptions.

Fossils and Historical Insights

Insects preserved in amber date from 45 to 15 million years ago, offering valuable insights into their history.

Flight Adaptations

Pterygotes uniquely retain all limbs while developing wings, which might have evolved from gill structures in aquatic ancestors.
Multiple theories suggest that pathways to flight may have included floating, paragliding, running-jumping, and surface sailing.

Non-Insect Hexapods

Include groups such as Protura, Collembola, and Diplura, which present distinct anatomical features like a lack of antennae in Proturans.

Specific Insect Groups

Collembola (Springtail): possess a ventral tube for jumping, lack cerci, and are primarily detritivores.
Proturans: characterized by a lack of antennae, exist in soil and leaf litter environments, with mouthparts hidden in the head.
Strepsiptera: exhibit bulbous eyes and have both parasitic males and wingless females, primarily targeting Hemiptera and Hymenoptera.

Mouthpart Classifications

Mouthparts can be categorized as entognathous (hidden) or ectognathous (visible).
Mandibulate mouthparts are adapted for gripping or chewing, while suctorial mouthparts are specialized for liquid feeding, with variations found across different insect orders.

Insect Wing Structure

Wings develop only in adult life stages, sharing a basic structure characterized by three zones and eight wing veins across all winged insects.

Families and Orders

Further exploration of specific orders such as Blattodea (cockroaches), Coleoptera (beetles), Hymenoptera (bees, ants, wasps), Lepidoptera (butterflies, moths), Odonata (dragonflies, damselflies), and Orthoptera (grasshoppers, crickets) can provide additional insights into diversity and adaptations within the class Insecta.

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Description

Explore the fascinating world of insects with this quiz on their classifications. Learn about their biological definitions, subclasses, and physical characteristics. Perfect for biology students or anyone interested in entomology!