The fire ant (Solenopsis geminata) is an effective colonizer and has become invasive in a number of ecosystems. Sometimes, efforts to eliminate this species have had an unexpected impact on community structure. It is argued that S. geminata can play a beneficial role in corn production. The graph shows how the presence of S. geminata can impact insect diversity in areas where crops of corn are grown.
State the impact of S. geminata on insect species diversity.
[1]Reduction in number of species/richness/diversity 1 mark
Discuss whether S. geminata might play a positive role in corn production.
[2]a. biological control of/reduction in corn pests 1 mark b. reduction in the use of pesticides 1 mark c. damage on beneficial species 1 mark d. reduction in insect diversity can have broad ecosystem negative impact OR example of negative effect 1 mark e. long-term effects unknown 1 mark
Researchers have argued that S. geminata is a keystone species in the corn agricultural system. Outline what is meant by a keystone species.
[2]definition a. keystone species is one in which presence has a disproportionate impact on the ecosystem 1 mark impact b. removal often leads to significant changes OR valid example 1 mark
