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

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 Aren’t 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. Note numerous bristles on abdomen
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. In this example, pupation is occurring inside the host.
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