Location: Biological Control of Pests ResearchTitle: A comparative study between Solenopsis invicta and Solenopsis richteri on tolerance to heat and desiccation stresses) Author
Submitted to: PLoS One
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/13/2014
Publication Date: 6/10/2014
Publication URL: http://handle.nal.usda.gov/10113/61832
Citation: Chen, J., Rashid, T., Feng, G. 2014. A comparative study between Solenopsis invicta and Solenopsis richteri on tolerance to heat and desiccation stresses. PLoS One. 9(6):e96842. doi: 10.1371/journal.pone.0096842. Interpretive Summary: The red imported fire ant is one of the most successful invasive ants in the world, which is included in the 100 of the World's Worst Invasive Alien Species. The black imported fire ant is a closely related invasive species to the red imported fire ant but with much less success. Although the black imported fire ant was introduced and established more than one decade earlier than the red imported fire ant in the United States, the latter has gradually displaced the black imported fire ants throught most of their distribution area. Comparative study on these two species may help us identify species attributes that contribute to the invasion success of red imported fire ants and predict its pattern of future spread. In this study, we found that red imported fire ants have significantly higher tolerance to heat and desiccation stress than black imported fire ants, which may contribute to the success of the red imported fire ants.
Technical Abstract: Solenopsis invicta and Solenopsis richteri are two very closely related invasive ant species. Although S. richteri was introduced and established in the United States earlier than S. invicta, the latter has displaced S. richteri throughout most of its distribution area. Why is S. invicta more successful than S. richteri despite being so similar in many aspects of biology and behavior? The answer must lie in differences in some less noticeable traits among these two species. Comparative studies may help us identify attributes which are important to the invasion success of S. invicta. Physiological tolerance to abiotic stress has been hypothesized to be important to the success of an invasive species. Unfortunately, the only comparative study between S. invicta and S. richteri on response to abiotic stresses was on cold tolerance. In this study, the difference in response to heat and desiccation stress between these two ant species was investigated. S. invicta was found to be significantly less vulnuerable 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. Cuticular hydrocarbons from S. invicta were significantly more effective in preventing water loss than those from S. richteri, most likely because the carbon chains of hydrocarbons from S. invicta were longer. The higher tolerance to heat and desiccation stress may contirbute to the success of S. invicta.