Skip to page content
USDA Forest Service

Research & Development Treesearch

Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help - We Participate  Government Made Easy

Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (604 KB bytes)

Title: Comparison of dietary overlap between allopatric and sympatric geckos

Author: Klawinski, Paul D.; Vaughan, R. Kathryn; Saenz, Daniel; Godwin, William;

Date: 1994

Source: Journal of Herpetology. 28(2): 225-230

Publication Series: Miscellaneous Publication

Description: Two gecko species, Hemidactylus turcicus and Cyrtopodion scabrum, have been introduced into the Port of Galveston, Texas. While H. turcicus has been established for a longer period of time, the relatively recent introduction of C. scabrum near the entrance of the Port has apparently led to the displacement of H. turcicus in that area. This has resulted in a distribution in which the two populations’ are largely allopatric except for a narrow band of sympatry at the periphery of each of their ranges. We examined stomach contents of both species in allopatry and sympatry in order to determine if dietary overlap in sympatry is less than that in allopatry. We calculated Pianka's (1973) symmetric overlap for geckos occupying sympatric areas (0.55) and allopatric areas (0.81). We found significant differences between the resource utilization distributions of the two species in sympatry but not in allopatry. In addition, we compared overlap between allopatric and sympatric populations within each species and found that the differences in resource utilization between the two species in sympatry was due to a dietary shift exhibited in H. turcicus but not C. scabrum. Observed differences in resource utilization may be a response to competition between these two species in sympatry which may have led to the exclusion of H. turcicus on areas of the docks occupied by this species prior to the introduction of C. scabrum.

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
  • You may send email to to request a hard copy of this publication. (Please specify exactly which publication you are requesting and your mailing address.)



Klawinski, Paul D.; Vaughan, R. Kathryn; Saenz, Daniel; Godwin, William. 1994. Comparison of dietary overlap between allopatric and sympatric geckos. Journal of Herpetology. 28(2): 225-230.


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.