Water balance in the Argentine ant (Linepithema humile) compared to five common native ant species from southern California

SCHILMAN, P.E., LIGHTON, J.R.B. & HOLWAY, D.A.

PHYSIOLOGICAL ENTOMOLOGY (PRINT)

Blackwell Publishing

Lugar: Oxford, England; Año: 2007 vol. 32 p. 1 - 7

0307-6962

Little attention has been given to the effect of physiological limitations on the ability of introduced species to invade ecological communities. In this study, the water balance of the invasive Argentine ant (Linepithema humile) is compared with five common ant species native to southern California. Total and critical water contents were measured as well as rates of water loss and survival times. Results show that the body size of ant species has a strong effect on water balance, explaining between 99% of total and 90% of critical water content (i.e., the amount of water remaining when the ant becomes moribund). The measured survival times at 40 ºC and c. 0% RH were shorter for L. humile than for the other five native ant species. The area-independent water loss rate was higher for L. humile than for the other native ant species studied. This finding was corroborated by independent data using two different methods (i.e., gravimetric measurement and open-flow respirometry). Somewhat surprisingly, significant differences in the water loss rates of different sizes of Solenopsis xyloni workers were found, even after adjusting for surface area. The area-independent water loss rate was significantly lower for larger than for smaller workers. Consistent with circumstantial evidence from the field, the results suggest that the physiological constraints of invasive species, such as water loss rates and critical water content, can limit their distribution and abundance not only at regional scales but also at fine scales.