Evidence of niche shift and global invasion potential of the tawny crazy ant, Nylanderia fulva

Authors: KUMAR, SUNIL - Natural Resource Ecology Laboratory; LEBRUN, EDWARD - University Of Texas; STOHLGREN, THOMAS - Us Geological Survey (USGS); STABACH, JARED - Colorad0 State University; MCDONALD, DANNY - Sam Houston State University; Oi, David; LAPOLLA, JOHN - Towson University

Submitted to: Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2015
Publication Date: 10/26/2015
Citation: Kumar, S., Lebrun, E., Stohlgren, T., Stabach, J., Mcdonald, D., Oi, D.H., Lapolla, J.S. 2015. Evidence of niche shift and global invasion potential of the tawny crazy ant, Nylanderia fulva. Ecology and Evolution. 5:4628-4641.

Interpretive Summary: The tawny crazy ant, Nylanderia fulva, is a rapidly emerging and economically important invasive species in the southern United States. Originally from east-central South America, this invasive ant develops extremely large populations that dominate invaded habitats. In a collaborative study among researchers from Colorado State Univ., the Univ. of Texas at Austin, the U.S. Geological Survey Ft. Collins CO, Sam Houston State Univ., Towson Univ., and ARS Gainesville FL, a global map of the potential distribution of the tawny crazy ant was generated based on the ant’s native and invaded geographic occurrences, and climatic variables. This helped to identify important climatic factors associated with its current distribution, and indicated that the tawny crazy ant’s climatic range has changed across its invasive range. This suggested that this ant has the ability to survive in areas with diverse temperature ranges. The risk maps produced in this study can be useful in preventing the tawny crazy ant’s future spread, and in managing and monitoring currently infested areas.

Technical Abstract: Analysis of an invasive species’ niche shift between native and introduced ranges, along with potential distribution maps, can provide valuable information about its invasive potential. The tawny crazy ant, Nylanderia fulva, is a rapidly emerging and economically important invasive species in the southern United States (US). It is originally from east-central South America and has also invaded Colombia and the Caribbean Islands. Our objectives were to generate a global potential distribution map for N. fulva, identify important climatic drivers associated with its current distribution, and test whether N. fulva’s realized climatic niche has shifted across its invasive range. MaxEnt niche model was used to map the potential distribution of N. fulva using its native and invaded range occurrences and climatic variables. We used principal component analysis methods for investigating potential shifts in the realized climatic niche of N. fulva during invasion. There was strong evidence for a shift in the realized climatic niche of N. fulva across its invasive range. Our models predicted potentially suitable habitat for N. fulva in the US and other parts of the world. Our analyses suggest that the majority of observed occurrences of N. fulva in the US represent stabilizing populations. Mean diurnal range in temperature, degree days at =10°C, and precipitation of driest quarter were the most important variables associated with N. fulva distribution. The climatic niche expansion demonstrated in our study may suggest significant plasticity in the ability of N. fulva to survive in areas with diverse temperature ranges shown by its tolerance for environmental conditions in the southern US, Caribbean Islands, and Colombia. The risk maps produced in this study can be useful in preventing N. fulva’s future spread, and in managing and monitoring currently infested areas.