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Unformatted text preview: Unit 10 - Insect and Plant Interaction
1. Describe how plant and insect relationships evolved together.
2. Using examples, explain how insects can protect, and help propagate plants.
3. Describe the ways plants protect themselves from insects.
4. Describe an insect gall.
5. Describe how plant/insect interactions are similar to the Cold War.
In the beginning
What insects are thought to be the first pollinators?
beetles What is the difference between nectar and pollen and on which do insects
feed? Many plants provide sweet nectar as food to bees, wasps, moth, ﬂies, butterﬂies, etc.
In return, these insects can carry pollen caught on their bodies to other plants. Which orders are the most common pollinators?
Why do some plants put nectar deep within the flower?
Why is it beneficial for a plant to attract specific pollinators? Mutualism
What part of the seed does the ant eat? How does this help the seed?
ants pick up seeds off the forest ﬂoor to carry back to their nest. Once inside the nest, the ants chew the ends of the seeds for food.
This action promotes germination in the seeds at a later date. This is how we get many of our wildﬂowers. Protection:
What does the cecropia plant give to the ants?
the cecropia plant provides shelter and food for the ant, and the ant protects the plant from herbivory. How is the plant benefited by having ants live inside it?
Where is the pollen glued on to the butterfly?
in order for most plants to make seeds, pollen from one plant must be transferred to another plant. Butterﬂies, bees and other
insects often suck sweet nectar from ﬂowers for food and pick up pollen as they do so. Which position must a butterfly assume in order to suck nectar out of the flower? Why is the hover fly the only insect that can get nectar from the small iris in South Africa? the only tongue that can reach that nectar.Itʼs not so much a tongue as a ﬁne tube, but in proportion to body length, it is one of the longest feeding implements in the animal kingdom.
The clear markings are particularly important, because the tongue is so long that even in the lightest wind, the end blows about. What is the purpose of the flower's white arrows?
The tiny entrance to it is indicated with exemplary clarity and absolute accuracy by these white arrows on the petals. Describe the relationship between fig trees and the fig wasp you read about.
The male and female Yucca moth emerge from their cocoons under the soil in the early spring and congregate on ﬂowering plants where they mate. The female Yucca moth uses her yucca palps to place a small bundle of pollen into the
Describe the relationship between the maxillary plant and moth you read about. bowl shaped stigma of the plantʼs ﬂower.
This pollination is important because the moth only lays eggs during this time so the larva can feed on the newly formed seeds.
The males do not have these prehensile appendages, therefore only the female Yucca moth can pollinate the delicate ﬂower.
This relationship is absolute for the survival of both the moth and the plant. The Iowa Agriculture Research Service were not always able to use bees to pollinate their
plants. They have only used bees since 1970. Before this time, how did they get their
What is an insect gall? These growths may be a result of fungi, bacteria, nematodes or mites, but insects are the prime cause.
These growths are called galls because they contain large amounts of tannin, which has a very bitter taste Are galls harmful to plants? Why or why not?
Gall susceptibility varies greatly between species in the same location, probably due to the general condition of the particular plant and its natural resistance.
Galls seem to cause a lot of concern to the general public. They usually don't cause serious harm to the plant. What is the best way to control an insect gall?
After formation, it is impossible to eliminate the galls or the pests, for that matter, with insecticides because the pests are enclosed and well protected inside of the gall.
Those that occur on the leaves will drop off with the leaves, but those occurring on the trunk, roots and stems may persist for several years. Plant defenses
Name the two general categories of plant defenses.
physical or chemical List three ways plant use chemicals to fight off insect predators.
secondary plant compounds: behavioral (repel insects or inhibit feeding) or physiological (poisoning)
allelochemicals Give an example of an insect that has overcome a plant’s chemical defenses.
Monarch butterﬂy List three physical defenses plants employ to ward off insects.
spines or pubescence on stems and leaves
silica or sclerenchyma in leaf tissue
leaf shapes that aid camouﬂage Notes: ...
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- Summer '08