Surveying house-infesting ants after 87 years: species identity and economic impact in central Illinois

Walker, Andrea

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https://hdl.handle.net/2142/46686 Copy

Description

Title

Surveying house-infesting ants after 87 years: species identity and economic impact in central Illinois

Author(s)

Walker, Andrea

Issue Date

2014-01-16T17:59:03Z

Director of Research (if dissertation) or Advisor (if thesis)

Suarez, Andrew V.

Department of Study

Entomology

Discipline

Entomology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Ants
• Biodiversity
• Urbanization
• Homogenization
• Pesticide Use
• Citizen Science

Abstract

Quantifying the long-term impacts of urbanization on taxa requires historic records and long-term surveys. In the mid-1920’s, Dr. Marion R. Smith conducted a 3-year survey of house-infesting ants in Urbana, Illinois. He reported species diversity, relative abundance, and the economic impact of control measures. I replicated this study in 2012-2013 to examine how the house-infesting ant fauna and measures used for their control have changed over this 87-year time frame. I complemented this survey with pitfall traps, visual surveys and leaf litter samples to characterize the urban ant fauna from which the house-infesting ants were being drawn. In addition to this urban sampling, I used similar methods to sample three remnant forest fragments in Champaign County. The forest fragments and urban site were all once part of a contiguous forest (known as The Big Grove), allowing me to compare the richness and structure of ant communities among sites that varied in their disturbance history since isolation by agricultural and urban development. The urban survey revealed long-term trends in the incidence and abundance of ants that persist in urban environments and the relative economic impact of these ants on households. In the 1920s, 12 species were collected in houses and the four most common were Tapinoma sessile (Say), Lasius alienus (Förster), Camponotus pennsylvanicus (DeGeer) and Solenopsis molesta (Say). In contrast, I found 9 species infesting houses in 2012-13 and the 4 most common were Tapinoma sessile(Say), Tetramorium caespitum (Linnaeus), Camponotus pennsylvanicus (DeGeer) and Camponotus nearcticus Emery. I also documented significant turnover in the ant fauna, including 21 species that were present in the mid-1920s but not detected in 2012-13 and 15 species that were not present at the time of the initial survey but were detected in 2012-2013. The cost and identity of control measures have also changed dramatically in the last 87 years, with almost a doubling in the cost spent on control per household in 2012-2013. Current pesticides have targeted effects on the insect rather than being general repellents or blanket toxins that were generally harmful in the 1920s. Comparing the residential urban site to three nearby forest fragments, I found significant variation in the number and relative abundance of ant species at each site, with the greatest species richness estimated to occur in the disturbed deciduous upland forest. Notably, the Urbana site had similar estimated ant richness to one of the undisturbed sites. These results suggest that the diversity of some arthropod groups can remain high in disturbed forests and residential neighborhoods. Moreover, each site maintained a unique community of species, reinforcing the value of both small forest fragments and urban sites for preserving diversity.

Graduation Semester

2013-12

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Copyright 2013 Andrea Walker

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