Chen Jian, Rashid Tahir, Feng Guolei
Biological Control of Pests Research unit, Mid South Area, Agriculture Research Service, United States Department of Agriculture, Stoneville, Mississippi, United States of America.
Alcorn State University, Extension/Research Demonstration Farm & Technology Transfer Center, Mound Bayou, Mississippi, United States of America.
PLoS One. 2014 Jun 10;9(6):e96842. doi: 10.1371/journal.pone.0096842. eCollection 2014.
Solenopsis invicta and Solenopsis richteri are two very closely related invasive ant species; however, S. invicta is a much more successful invader. Physiological tolerance to abiotic stress has been hypothesized to be important to the success of an invasive species. In this study, we tested the hypothesis that S. invicta is more tolerant to heat and desiccation stress than S. richteri. The data strongly support our hypothesis. S. invicta was found to be significantly less vulnerable than S. richteri to both heat and desiccation stress. Despite S. richteri having significantly higher body water content, S. invicta was less sensitive to desiccation stress due to its significantly lower water loss rate (higher desiccation resistance). After the cuticular lipid was removed, S. invicta still had a significantly lower water loss rate than S. richteri, indicating that cuticular lipids were not the only factors accounting for difference in the desiccation resistance between these two species. Since multiple biological and/or ecological traits can contribute to the invasion success of a particular species, whether the observed difference in tolerance to heat and desiccation stresses is indeed associated with the variation in invasion success between these two species can only be confirmed by further extensive comparative study.
红火蚁和黑火蚁是两种亲缘关系非常密切的入侵蚂蚁物种；然而，红火蚁是一种更成功的入侵者。对非生物胁迫的生理耐受性被认为对入侵物种的成功很重要。在本研究中，我们检验了红火蚁比黑火蚁对高温和干燥胁迫更具耐受性这一假设。数据有力地支持了我们的假设。研究发现，红火蚁在高温和干燥胁迫下比黑火蚁明显更不易受影响。尽管黑火蚁的身体含水量显著更高，但红火蚁由于其显著更低的失水率（更高的抗干燥能力），对干燥胁迫更不敏感。去除表皮脂质后，红火蚁的失水率仍显著低于黑火蚁，这表明表皮脂质不是导致这两个物种抗干燥能力差异的唯一因素。由于多种生物学和/或生态学特征可能有助于特定物种的入侵成功，观察到的对高温和干燥胁迫耐受性的差异是否确实与这两个物种入侵成功的差异相关，只能通过进一步广泛的比较研究来证实。
