Chapter Review: Orthoptera and Other Insects

General Overview of Orthoptera

  • Definition of Orthoptera: Order of insects including grasshoppers, crickets, and katydids.

  • General characteristics:

    • Long straight wings observed in many species.

    • Mouthparts: Manipulative mouthparts, non-specialized, enabling them to consume a varied diet.

    • Feeding habits:

    • Herbivores: Primarily feed on plant material.

    • Scavengers: Consume decaying organic matter.

    • Predaceous species: Less common, but some do exhibit predation.

Unique Features of Orthoptera

  • Synapomorphy:

    • Jumping legs: The hind legs, termed saltatorial, are adapted for jumping and are prominent in the group.

    • Most species possess the capability to fly, combining jumping and fluttering during escape.

    • Reference to plague locusts which can fly long distances.

Suborders of Orthoptera

  • Caliphora: Shorthorn grasshoppers.

  • Inciphora: Crickets.

  • Notable traits of each suborder are for mental categorization, not for testing.

Communication and Sensory Perception

  • Orthoptera are known for their vocalizations;

    • Use noise for communication, primarily during mating.

    • Presence of tympanums (eardrums) located in unique body areas (e.g., legs, sides) serves the purpose of sound reception.

Family Characteristics of Orthoptera

  • Families likely encountered:

    • Acrididae: Short-horned grasshoppers.

    • Gryllidae: Crickets, characterized by long filamentous antennae and flat wings like pancakes.

    • Tettigoniidae: Katydids.

    • Gryllotalpidae: Mole crickets.

    • Occasional sightings of other groups like cave crickets (Rhaphidophoridae).

Notable Orthoptera Species

  • Giant Weta:

    • Large, flightless grasshopper species from New Zealand.

    • Adaptive losses of flight due to island evolution.

    • Vulnerability to introduction of vertebrate predators (rats, cats, etc.) leading to their previous presumed extinction.

    • Rediscovered on predator-free islands like Lord Howe Island.

Noise Production in Orthoptera

  • Different sound production mechanisms:

    • Crickets: Create sound by rubbing wings together; typically males have sexually dimorphic wings suited for sound production.

    • Katydids: Use different structures for sound.

    • General communication patterns display sexual selection traits.

Life Cycle of Grasshoppers

  • Life stages:

    • Nymph stage: Grasshoppers hatch from eggs resembling miniature versions of adults; undergo approximately five instars before maturing.

    • Feeding: Modified mandibles are adaptations for consuming grasses, which are tough and contain silica.

    • Reproduction: Generally external fertilization without parental care; females lay eggs primarily underground or in plant stems.

Ecological and Economic Impact

  • Herbivores: Their roles as generalist herbivores are important; they serve as prey for various wildlife.

  • Economic pests: High populations can affect agricultural areas, particularly grasslands, leading to significant damage to crops. Examples given include:

    • Plague locusts are notorious for their migratory behavior causing agricultural devastation historically referenced in biblical texts.

Locust Behavior and Morphology

  • Gregarious phase: Under adverse environmental conditions, locusts can shift from a