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Entomophagous Insects

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Entomophagous Insects The Insect-Consuming Insects Predators and Parasitoids What is Natural Control ? Ground Beetle Attacking Caterpillar Yellow Jacket ... – PowerPoint PPT presentation

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Title: Entomophagous Insects


1
Entomophagous Insects The Insect-Consuming
Insects
  • Predators and Parasitoids

2
What is Natural Control ?
Natural Control is the everyday occurrence of
predation of one insect upon another. In so
doing, populations of predators effect
populations of prey and vice versa.
This is analogous to the classic relationship
between the arctic hare and fox populations.
3
In the Natural World Predators Are Abundant and
Are Always Searching For a Meal
A Ground Beetle Attacking a Land Snail
4
Ground Beetle Attacking Caterpillar
Forest Tent Caterpillar
As you can see, ground beetles are not very
choosy. They will eat about anything that they
can overpower.
5
Yellow Jacket Wasp Collects Many Insects for its
Nest
6
Wasp Feeding on Birch Leafminer Larva
Wasp
Birch Leaf Miner
7
Sometimes Humans Are Active Predators of Insects,
Too!
8
What is Biological Control?
  • Biological Control is natural control that
    involves manipulation of predator populations to
    control pest populations in agro-ecosytems.
  • Biocontrol has been an active area of applied
    population ecology for about 50 years.
  • Today it is highly commercialized and is a viable
    addition to the arsenal used to combat pests.
  • It is part of a larger approach called
    Integrated Pest Management or I.P.M.

9
Beneficials
  • May be predators, parasitoids or pathogens
  • May serve singly or in combination as natural
    enemies but populations often have to be
    manipulated.
  • Reduce pest populations to economically
    tolerable levels rather than eliminating the
    pest.
  • Environmentally compatible.
  • Costs are comparable to pesticides.

10
Predators
  • Commonly used predators include lady-bird
    beetles, green lacewings, mantids and predatory
    mites.
  • Commercially available from insectaries.

11
Qualities of Good Predators
  • Considerably larger in size than the prey. Why?
  • Feed in juvenile stage as well as in the adult.
  • Focused feeding habits - specific predators are
    better than general ones usually.
  • Ability to switch to an alternative food source
    when prey populations are reduced.
  • Must be able to adapt to local environmental
    conditions.

12
Examples of Predators Follow
13
Twelve-spotted Lady Bird Beetle Attacks An Aphid
14
Close-up of Predator and Prey
15
Female Ovipositing on Leaf After Consuming Many
Aphids
16
First Instar Larvae Hatch From Eggs
17
Older Instar Larva Preying on an Aphid
18
Multicolored Asian Lady Beetle
19
The Mealybug Destroyer An Australian Import
A member of the ladybird beetle family.
20
Green Lacewing Adult
21
Green Lacewing Eggs
Eggs Are Laid on Stalks to Lessen Cannibalism
22
Lacewing Larva Scouting For Dinner (in this case
a bollworm)
23
Predator Uses Sickle-Like Mandibles That are
Hollow to Suck Out Contents of Bollworm
24
A Short Time Later Predator is Engorged and
Prey is Drained!
25
Flower Fly Larva and Adult
26
Other Well-Known Predators Most Available
Commercially
  • Preying Mantids
  • Some stink bugs (Hemiptera)
  • Minute pirate bug ( )
  • Some nabid bugs
  • Some mites are predatory

27
Why Arent All Insect Predators Effective As Good
Biological Control Agents?
  • ?

28
History of Control of the Cottony Cushion Scale
in California
29
Parasitoids
  • Generally a non-social wasp (braconids and
    ichneumonids are commonly used) or a tachinid fly
  • Egg(s) are laid on/into host by female using a
    modified stinger (ovipositor)
  • Larvae hatch and consume tissues of prey.
  • Move to surface of prey, pupate and emerge as
    adults

30
Trichogramma wasp Pupae Covering Tomato Hornworm
31
Typical Posture of Ichneumonid Wasp Female
Preparing to Oviposit
After ovipositing, the wasps deposits a pheromone
on surface that deters oviposition by a 2nd.
female. Why is this behavior very adaptive?
32
Wasp Inserting Egg Into Caterpillar Prey
33
Wasp Eggs In Prey
34
Wasp Larva Emerging From Caterpillar Pupa
35
Trichogramma Wasp Ovipositing Into Abdomen of
Aphid (Note egg at lower left)
36
Aphid Mummies
37
Tachinid Fly Adult
Note numerous bristles on abdomen
38
Tachinid Eggs on Caterpillar
Female Fly Attaches Eggs to Exterior of Body.
They Hatch and Bore In.
39
Tachinid Larva Emerging
Pupation Outside of Host
40
Host Caterpillar Containing Half Dozen Tachinid
Pupae
In this example, pupation is occurring inside the
host.
41
Sometimes Parasitoids Work Very Hard to Find
Their Hosts!
42
Parasitoids Attack All Developmental Stages of
Insects
  • Egg
  • Larva
  • Pupa
  • Adult

43
Egg Parasitoids
44
Annual White Grub Parasitoid
45
Nasonia Wasp Emerges From Dying Flesh Fly Pupa
46
The following 5 slides illustrate a sequence from
one generation to the next.
47
Adult Wasp Hatches From Cocoon
48
Annual White Grub Parasitoid
49
Last Larval Instar of the Next Generation Exits
from Host Caterpillar
50
Larva Spins Cocoon Dead Host at Right
51
Pupal Cocoon Completed
52
In nature, it turns out that different species of
wasps occupy different trophic levels ... some
wasps attack caterpillar hosts while other wasps
attack the wasps that attack the caterpillars.
53
How are Parasitoids Different From
Hyperparasitoids?
  • A parasitoid attacks a host organism.
  • What is the impact of a parasitoid population on
    a host population?
  • A hyperparasitoid attacks a parasitoid.
  • What is the impact of a hyperparasitoid
    population on a host population?

54
Parasitoids and Hyperparasitoids Associated With
Cecropia
55
END
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