A Comparative Study between Solenopsis invicta and Solenopsis richteri on Tolerance to Heat and Desiccation Stresses

Abstract

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.

Comparative Cutaneous Water Loss and Desiccation Tolerance of Four Solenopsis spp. (Hymenoptera: Formicidae) in the Southeastern United States

“…richteri ). The higher number of replicates in the study by Chen et al [ 45 ] could have contributed to the detection of significant differences in their study. The body water content values recorded for all four Solenopsis spp.…”

“…invicta and S . richteri have been reported to be significantly different [ 45 ]. However, our data show no body water content difference for combined sizes of workers of both the tropical/subtropical species ( S .…”

“…richteri workers despite the significantly greater body water content in S . richteri [ 45 ]. Size also plays a role in cuticular permeability in Solenopsis spp.…”

A Potential Role for Phenotypic Plasticity in Invasions and Declines of Social Insects

“…S. invicta first became invasive in the USA, where it is currently outcompeting the earlier invaders S. geminata and S. richteri, and subsequently invaded in many other parts of the world. In the USA, S. invicta displays better acclimatization than S. geminata to extremes in temperature, relative humidity and light levels (Wuellner and Saunders, 2003), and it also shows more tolerance than S. richteri to heat and desiccation (Chen et al, 2014). A series of studies also revealed that S. invicta better responds to habitat disturbance than S. geminata (Plowes et al, 2007;LeBrun et al, 2012;Axen et al, 2014) and displays higher potential of dispersal than S. geminata, being able to engage in mating flights earlier in the season (Tschinkel, 2006) and to produce larger colonies on average (Trible et al, 2018).…”

Volcanic ash decreases dehydration tolerance in the field cricket Gryllus bimaculatus (Orthoptera: Gryllidae)

“…The volcanic ash with the sharp ash particles will lead to reduced survival, growth, and dehydration tolerance due to increased water loss through the damaged cuticle (Edwards and Schwartz, 1981). Indeed, the cuticle beneath the lipid layer protects from desiccation in ants Solenopsis invicta and S. richteri (Chen et al, 2014).…”