Download Chapter 37 - Mrs. Latham

Chapter 37
Section 1 The Insect World
Objectives
• Relate the major characteristics of insects to
insects’ biological success.
• List both harmful and beneficial effects of
insects on human society.
• Describe the external structure and organ
systems of a grasshopper.
• Compare incomplete and complete
metamorphosis in insects.
• Describe defensive adaptations in insects.#
The body is divided into three
tagmata:
• 1. Head- mandibles and one pair of
unbranched antennae
• 2. Thorax- 3 pairs of jointed legs, or two pairs
of wings
• 3. abdomen- 9-11 segments no wings or legs
in adults.
• #
• Entomologist – the study of insects and other
terrestrial arthropods.
• There are 25 orders bases on characteristics:
– Structure of mouthparts
– Number of wings
– Type of development
–#
Factors responsible for their success
include:
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Ability to fly
Exoskeleton
Jointed appendages
Small size
Short life span
#
Insects negatively affect humans by:
• Competing for food
• Transmitting diseases
• Destroying building and other manufactured
products
• #
Insects benefit humans by:
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Serving as food for other animals
Pollinating flowers
Making valuable products such as honey
Recycling nutrients in ecosystems
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External Structure
• Three tagmata:
• 1. head
– Mouthparts
– Unbranched antennae
– Simple and compound eyes
–#
• 2. thorax
– Prothorax
– Mesothorax
– Metathorax
#
• 3. abdomen
– Upper and lower plates
The exoskeleton and waxy cuticle covering are
adaptations for a terrestrial life.
#
Feeding and Digestion
• Grasshoppers feed on plants, and their
mouthparts are modified for cutting and
chewing leaves and blades of grass.
• The Labrum and labium – upper and lower lips
• #
Circulation, Respiration, and Excretion
• Open circulatory system
• Gas exchange- air-filled tracheae
• Malpighian tubules – remove cellular wastes,
and conserve water
• #
Neural Control
• Contains a brain and ventral nerve cord with
ganglia located in each body segment.
• Sensory structures include:
– Simple and compound eyes
– Sensory hairs on antennae and other body parts
– In some species, a sound-sensing tympanum
–#
Reproduction
• All insects have separate sexes
• Male deposits sperm into the female’s seminal
receptacle, eggs are fertilized internally
• The female’s last segment of the abdomen
forms the ovipositor, she uses to lay fertilized
eggs.
• #
Insect Development
• Most go through metamorphosis
• Incomplete metamorphosis- nymph hatches
from an egg and looks like the adult.
– Undeveloped reproductive organs
– No wings
– Must molt several times to become and adult
–#
• Complete metamorphosis –wormlike larva
called a caterpillar hatches from and egg
• Molts several times, becomes a pupa
• Molts to produce the adult
• The adult does not resemble the larva or the
pupa.
• #
Importance of Metamorphosis
• Allows larvae and adults of the same species
to avoid competing for space and food
• Allows insects to survive periods of harsh
weather or scant resources
• #
Insect Defense
• Defend themselves by:
– Stinging
– Using camouflage
– Releasing noxious chemicals
–#
• Dangerous insects or the ones that taste bad,
they have warning coloration that predators
recognize
• Some harmless species may be mimicked the
warning coloration to elude predators.
• #
Section 2 Insect Behavior
• Identify three ways that insects communicate
• Describe the social organization of honeybees
• Explain how honeybees communicate
information about the location of food
• #
Communication
• Releasing pheromones
• Producing sounds
• Producing flashes of light
• #
Behavior in Honey Bees
• Social insects- live in groups or colonies
• Division of labor- creates interdependence
and a need to communicate
• Colonies- mostly of female worker bees
– Perform all of the duties, do not reproduce their
own offspring.
–#
• Reproduction- function of one queen bee and
a few hundred male drones.
• Worker bees live about six weeks
• At one stage, worker bees are called nurse
bees.
– Secrete royal jelly-feed to the queen and youngest
larvae
–#
• Queen bee will develop when fed royal jelly
• When a new queen matures, she secretes
queen factor, this prevents other female
larvae from developing into queens.
• #
The Dances of the Bees
• Honeybees use two types of dances:
• The round dance- indicates a food source is
nearby
• The waggle dance- the direction of food and
the distance from the hive.
• #
Altruistic Behavior
• In defending the colony, worker bees who
altruistic behavior toward their close relatives
in the colony. The unselfish concern for the
welfare of others.
• By working for the colony, the worker bees
increase the propagation of their own genes.
• #