Northward Expansion of the Invasive Linepithema humile (Hymenoptera: Formicidae) in the Eastern United States is Constrained by Winter Soil Temperatures

被引:18
作者
Brightwell, R. J. [1 ]
Labadie, P. E. [1 ]
Silverman, J. [1 ]
机构
[1] N Carolina State Univ, Dept Entomol, Raleigh, NC 27695 USA
关键词
abiotic interactions; environmental limitation; invasive species; range limitation; low temperature; ARGENTINE ANT HYMENOPTERA; ABIOTIC FACTORS; BIOLOGICAL INVASIONS; SOLENOPSIS-INVICTA; FIRE ANT; SUCCESS; CLIMATE; SPREAD; ESTABLISHMENT; DETERMINANTS;
D O I
10.1603/EN09345
中图分类号
Q96 [昆虫学];
学科分类号
摘要
The invasive Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae) has been evident in the North Carolina Piedmont, United States for 90 yr but has failed to spread further north. We investigated the mechanisms preventing this expansion. The Argentine ant ceases foraging at temperatures below 5 degrees C and we hypothesized that winter soil temperatures at higher latitudes restricted foraging long enough to cause colony starvation. We tested if the Argentine ant could successfully feed at temperatures below 5 degrees C and found that colonies would starve. We subjected Argentine ant nests to a range of sub- and above-freezing temperatures and measured worker mortality at various time intervals. We found that Argentine ant colonies will collapse after 8.5 d at 5 degrees C. Argentine ants can escape ambient cold temperatures by moving nests into the soil column. We tested how deeply into the soil Argentine ant queens and workers need to move to survive winter in North Carolina. Soil temperatures in the North Carolina Piedmont do not fall below 5 degrees C for longer than nine consecutive days; therefore, Argentine ant colonies need only to retreat a few centimeters into the soil column to escape unsuitable temperatures. Winter soil temperature data from four climate stations situated from latitudes 35, the current Eastern United States latitudinal limit for Argentine ant population expansion, to 39 were searched for periods where soil temperatures would have led to colony extirpation. North of their current distributions, extended periods of soil temperatures below 5 degrees C regularly occur, preventing Argentine ant colonies from persisting.
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页码:1659 / 1665
页数:7
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