The document describes the goldenrod gall fly larva parasite-predator guild associated with Canada goldenrod. It details how the gall fly larva initiates formation of ball galls on the stems by secreting a plant growth hormone. This provides food and shelter for the larva. However, the gall fly larva faces predation from the larvae of two wasp species which are endo- or ectoparasites, and a tumbling flower beetle larva which eats gall fly larvae and other insects in the gall. Other gall-forming insects on goldenrod include a gall moth and midge.

1. Goldenrod Gall Fly Larva Parasite – Predator Guild

2. Canada Goldenrod Solidago canadensis

3. Ball Gall

4. Ball gall formation is initiated by a goldenrod gall fly larva.

5. Ball gall formation is initiated by a goldenrod gall fly larva. The larva produces the plant growth hormone Indole Acetic Acid (IAA) and “spits” it into the stem.

6. Ball gall formation is initiated by a goldenrod gall fly larva. The larva produces the plant growth hormone Indole Acetic Acid (IAA) and “spits” it into the stem. IAA initiates lateral growth (girth) in plant stems.

7. Ball gall formation is initiated by a goldenrod gall fly larva. The larva produces the plant growth hormone Indole Acetic Acid (IAA) and “spits” it into the stem. IAA initiates lateral growth (girth) in plant stems. The dose of IAA into the stem causes the stem tissue around the larva to swell causing the gall to grow.

8. Ball gall formation is initiated by a goldenrod gall fly larva. The larva produces the plant growth hormone Indole Acetic Acid (IAA) and “spits” it into the stem. IAA initiates lateral growth (girth) in plant stems. The dose of IAA into the stem causes the stem tissue around the larva to swell causing the gall to grow. The gall provides a supply of food and shelter for the growing larvae.

9. Ball gall formation is initiated by a goldenrod gall fly larva. The larva produces the plant growth hormone Indole Acetic Acid (IAA) and “spits” it into the stem. IAA initiates lateral growth (girth) in plant stems. The dose of IAA into the stem causes the stem tissue around the larva to swell causing the gall to grow. The gall provides a supply of food and shelter for the growing larvae. The larva will spend one year in the gall.

10. The goldenrod gall fly larva is barrel-shaped and cream-colored.

11. The goldenrod gall fly larva is barrel-shaped and cream-colored. Compared to the other insect larvae that can be found in a ball gall it is the largest.

12. The goldenrod gall fly larva is barrel-shaped and cream-colored. Compared to the other insect larvae that can be found in a ball gall it is the largest. The gall fly larva is a herbivorous parasite.

13. Because they will overwinter inside the gall, gall fly larvae must have a survival strategy for enduring the subfreezing temperatures they will face in temperate zones.

14. Because they will overwinter inside the gall, gall fly larvae must have a survival strategy for enduring the subfreezing temperatures they will face in temperate zones. They produce antifreeze agents that prevent the formation of ice crystals inside their cells.

15. Because they will overwinter inside the gall, gall fly larvae must have a survival strategy for enduring the subfreezing temperatures they will face in temperate zones. They produce antifreeze agents that prevent the formation of ice crystals inside their cells. Although the strategy is the same as that of some frogs, the chemicals they produce are different. The strategy is called freeze tolerance.

16. The larvae of two wasp species are parasites of the goldenrod gall fly larva.

17. The larvae of two wasp species are parasites of the goldenrod gall fly larva. The female wasps lay their eggs directly into the gall tissue.

18. Some gall fly larvae are invaded by the larva of the obtuse wasp.

19. Some gall fly larvae are invaded by the larva of the obtuse wasp. It is an endoparasite.

20. Some gall fly larvae are invaded by the larva of the obtuse wasp. It is an endoparasite. However, unlike typical parasites, this wasp larva eventually kills the fly larva. Such a parasite is called a parasitoid .

21. Some gall fly larvae are invaded by the larva of the obtuse wasp. It is an endoparasite. However, unlike typical parasites, this wasp larva eventually kills the fly larva. Such a parasite is called a parasitoid . The obtuse wasp larva causes the fly to pupate in September. Any fly larvae that go unparasitized don’t pupate until March after overwintering in the gall.

22. Some gall fly larvae are invaded by the larva of the obtuse wasp. It is an endoparasite. However, unlike typical parasites, this wasp larva eventually kills the fly larva. Such a parasite is called a parasitoid . The obtuse wasp larva causes the fly to pupate in September. Any fly larvae that go unparasitized don’t pupate until March after overwintering in the gall. This puparium was made by the fly larva before it was consumed by the obtuse wasp larva. The wasp larva is inside and will remain there until spring.

23. The giant goldenrod wasp larva is pear-shaped, and cream-colored.

24. The giant goldenrod wasp larva is pear-shaped, and cream-colored. It parasitizes the fly larva and eventually completely consumes it (it too is a parasitoid).

25. The giant goldenrod wasp larva is pear-shaped, and cream-colored. It parasitizes the fly larva and eventually completely consumes it (it too is a parasitoid). It is an ectoparasite.

26. The giant goldenrod wasp larva is pear-shaped, and cream-colored. It parasitizes the fly larva and eventually completely consumes it (it too is a parasitoid). It is an ectoparasite. After finishing the fly larva, the giant goldenrod wasp larva begins consuming the gall tissue.

27. The giant goldenrod wasp larva is pear-shaped, and cream-colored. It parasitizes the fly larva and eventually completely consumes it (it too is a parasitoid). It is an ectoparasite. After finishing the fly larva, the giant goldenrod wasp larva begins consuming the gall tissue. It is always found with frass (brown powdery feces) inside the gall. There is so much frass because plant tissue’s cellulose does not digest completely.

28. Another insect larva, that of the tumbling flower beetle, also can be found in the ball gall.

29. Another insect larva, that of the tumbling flower beetle, also can be found in the ball gall.

30. Another insect larva, that of the tumbling flower beetle, also can be found in the ball gall. The adult female beetle lays her eggs on the ground at the base of a goldenrod stem. After hatching the larva crawls up the stem and invades its tissues. If it happens to invade a gall it will eat the gall tissue.

31. Another insect larva, that of the tumbling flower beetle, also can be found in the ball gall. The adult female beetle lays her eggs on the ground at the base of a goldenrod stem. After hatching the larva crawls up the stem and invades its tissues. If it happens to invade a gall it will eat the gall tissue. If it enters the gall fly larva’s chamber it will eat the gall fly larva.

32. Another insect larva, that of the tumbling flower beetle, also can be found in the ball gall. The adult female beetle lays her eggs on the ground at the base of a goldenrod stem. After hatching the larva crawls up the stem and invades its tissues. If it happens to invade a gall it will eat the gall tissue. If it enters the gall fly larva’s chamber it will eat the gall fly larva. If the gall fly larva has been eaten by a giant goldenrod wasp larva and the wasp larva is inside the gall, the beetle larva will eat it.

33. Another insect larva, that of the tumbling flower beetle, also can be found in the ball gall. The adult female beetle lays her eggs on the ground at the base of a goldenrod stem. After hatching the larva crawls up the stem and invades its tissues. If it happens to invade a gall it will eat the gall tissue. If it enters the gall fly larva’s chamber it will eat the gall fly larva. If the gall fly larva has been eaten by a giant goldenrod wasp larva and the wasp larva is inside the gall, the beetle larva will eat it. The tumbling flower beetle larva does not chew through the puparium which contains an obtuse wasp larva.

34. The goldenrod gall fly larva is not the only insect that causes galls to form on goldenrod stems.

35. The goldenrod gall fly larva is not the only insect that causes galls to form on goldenrod stems. The goldenrod gall moth is responsible for the development of the spindle gall (an oblong gall).

36. The goldenrod gall fly larva is not the only insect that causes galls to form on goldenrod stems. The goldenrod gall moth is responsible for the development of the spindle gall (an oblong gall). The moth larva is parasitic on the goldenrod but it does not attack any insects.

37. The goldenrod gall fly larva is not the only insect that causes galls to form on goldenrod stems. The goldenrod gall moth is responsible for the development of the spindle gall (an oblong gall). The moth larva is parasitic on the goldenrod but it does not attack any insects. The moth’s chrysalis can be seen inside the spindle gall.

38. The bunch gall occurs at the very top of the goldenrod stem.

39. The bunch gall occurs at the very top of the goldenrod stem.

40. The bunch gall occurs at the very top of the goldenrod stem.

41. The bunch gall occurs at the very top of the goldenrod stem. It consists of a bunch of tightly clumped leaves that form a mass that is similar to a head of lettuce or cabbage.

42. The bunch gall occurs at the very top of the goldenrod stem. It consists of a bunch of tightly clumped leaves that form a mass that is similar to a head of lettuce or cabbage. The bunch gall is caused by the larva of a goldenrod gall midge, a tiny gnat-sized fly.

43. The bunch gall occurs at the very top of the goldenrod stem. It consists of a bunch of tightly clumped leaves that form a mass that is similar to a head of lettuce or cabbage. The bunch gall is caused by the larva of a goldenrod gall midge, a tiny gnat-sized fly. The midge larva eats only the plant tissue.

44. A group of orgnanisms that are so tightly linked to each other, and cannot survive outside their sybiotic relationships form a guild.

45. A group of orgnanisms that are so tightly linked to each other, and cannot survive outside their sybiotic relationships form a guild. This one is referred to as the Goldenrod – Parasite – Predator Guild.