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Insect populations—locusts!
February 2, 2009, pages 108-118
1. Define “population.” members of the same species living in the same space at the same time
2. List four characteristics that populations possess that individuals lack.
a. . density
b. age structure
c. birth and death rates
d. immigration and emigration
e. genetic composition
3. Three factors that increase reproductive potential are:
a. age at first reproduction
b # of eggs per reproduction
c. # reproductions per lifetime
4. Correct this sentence: The longer the generation time, the lower the reproductive potential.
5. Carrying capacity is (choose a or b):
a. the number of viable eggs or embryos that a particular female can carry
b. the number of individuals that a particular habitat can sustain given its resources
6. Classify the following mortality factors as density-dependent or density-independent:
a. hurricane DI
b. predation DD
c. competition for food DD
d. microbial infection DD
7. The Latin word “gregaria” means “herd” or “flock.” Why is Schistocerca gregaria so named?
aggregate in large populations, flock together when migratory
8. Identify two characteristics that distinguish S. gregaria var. gregaria from S. gregaria var. solitaria:
a. soliaria- yellow, sexually mature as adults, low wing length
b. gregaria- pink, sexually immature, high wing length
9. What environmental cues are known to promote the appearance of gregarious locusts?
a. Crowding
b. Decrease in food availability or nutritional content
10. What physical cues are known to promote gregarization?
Touching upper hind leg (“thigh”)
11. What chemical cues are known to promote the appearance of gregarious locusts?
Frass pheromones, other pheromones
12. What is serotonin and what does it have to do with gregarization?
High levels of serotonin (a neurotransmitter) in the brain is associated with gregarization.
13. What is the function of the locust descending contralateral movement detectors (DCMDs)?
a. they detect the presence of the horizon
b. they detect impending collisions
c. they detect the presence of an overhead swarm
d. they detect approaching predators
14. True or false: Locusts can eat their own weight in food in a day.
15. The area constituting the usual habitat of S. gregaria is called the recession area.
16. Where is the Intertropical Convergence Zone and what does it have to do with locusts?
where trade winds converge and rising air cools adiabatically along the equator. Locusts migrate there
to eat food.
17. Is there a biological explanation for the apparent success of insect exorcisms? If so, what is it?
populations crashed (density dependent factors), natural mortality, or went dormant
18. Where was the Anti-Locust Research Center founded? London
19. True or false: Entomological control techniques have progressed to the point today that outbreaks of
locusts are a thing of the past.
20. What is Metarhizium anisopliae var acridum (Maa)?
fungus used in biocontrol of locust
21. What are GPS and GIS and how do they help with locust plague management?
GPS Global Positioning System
GIS Geospatial Information System
Used to track the spread of a swarm
22. EMPRES stands for Emergency Prevention System and is a multinational program created
by the Food and Agriculture Organization to promote early intervention in stopping outbreaks
of locusts.
23. T or F: Melanoplus spretus is native to North America and is subject today to periodic outbreaks.
What’s the common name of this species? Rocky Mountain Locust, extinct today
24. Who is St. Urho?
Patron Saint of Finnish vineyard workers who drove the grasshoppers out of Finland
25. Name a film with locust plague footage.
The Good Earth, Beginning of the End, Days of Heaven, Exorcist II: The Heretic