Download Lecture 5 - life.illinois.edu

IB1090905 Herbivores
January 30, 2009, pages 99-107
1. Provide an example that proves the following statement false:
In the phylum Arthropoda, herbivores are found only in the class Insecta.
Phytophogous mites and phytophagous jumping spiders
2. Roughly what percentage of all insects are herbivorous?
a. 10-20%
b. 25-35%
c. 80-90%
3. What order of insects is exclusively phytophagous? Phasmida (walking sticks)
4. Provide an example that proves the following statement false:
Insect families are either entirely phytophagous or entirely predaceous.
Coccinellidae (lady beetles) or Pentatomidae (stink bugs)
5. List two characteristics that make plants good food for insects:
a. abundant
b. doesn’t run away/ stationary
and two characteristics that make plants less than ideal food for insects:
a.low in protein, sodium (salt) and water
b. lots of indigestible material (cellulose)
c. full of poisons (allelochemicals)
6. List two problems with plant proteins
a. low in content
b. not the same as animal protein. Lacks essential amino acids
7. What does Liebig’s law have to do with protein nutrition?
Growth is limited by the amount of the essential amino acid that are present in food
8. Puddling by butterflies is a solution to what nutritional deficiency in plants?
Sodium (Salt)
9. The term for "feeding on many species" is polyphagous whereas the term for "feeding on only
a few species" is oligophagous. Most herbivorous insects are which? oligophagous
10. The function of allelochemicals (secondary metabolites) in plants is:
a. to harvest light for photosynthesis
b. to mediate ecological interactions with other organisms
c. to burn fuel to provide energy to the cells
d. all of the above
11. In a caterpillar alimentary system, indicate where (choices are foregut, midgut, hindgut)
a. food mingles with saliva foregut
b. water is absorbed hindgut
c. digestive and detoxification enzymes are secreted midgut
12. Define 'frass." Insect excrement
13. Insects that suck plant sap can be found primarily in the order Hemiptera .
14. Water and nutrients are carried in the xylem , which is consumed by cicadas: carbohydrates
are transported in the phloem, which is consumed by aphids.
15. What is honeydew? Excess phloem sap that aphids excrete that is full of sugar.
16. Name 2 orders in which leafminers are found
a. Lepidoptera
b. Diptera c. Coleoptera
and two orders in which gall-formers are found:
a. Hemiptera b. Lepidoptera c. Diptera d. Hymenoptera c. Acari d. Coleoptera
and two orders in which fruit-feeders are found:
a.
Dipterea b. Lepidoptera c. Coleoptera
17.How old are the oldest fossils of insect damage to plants?
a. no more than 100 million years old
b. over 300 million years old
c. over 600 million years old
18. True or false: Relative to large mammals, insect herbivores have little impact on nutrient
cycling and energy flow in ecosystems.
19. Name a plant disease vectored by aphids: barley yellow dwarf and a plant disease vectored
by spotted cucumber beetles cucumber wilt.
20. About when were crop plants first domesticated? 8000-10000 years ago
Where? All over the world. Specific sites: SE Asia, China, Mesoamerica, Mediterranean region,
Andes/Brazil/Paraguay, India, Turkey-Iran, and Ethiopia
21. How do irrigation and fertilization affect the susceptibility of plants to herbivorous insects?
Irrigation increases water content and fertilization increases the nitrogen (protein) content and
makes them more suitable and susceptible to herbivorous insects.
22. List three ways artificial selection has altered the biology of crop plants:
a. Decrease toxins
b. Increase production
c. Eliminate dispersal mechanisms
d. increase synchrony