Does Mutualism Drive the Invasion of Two Alien Species? The Case of Solenopsis invicta and Phenacoccus solenopsis

Abstract

Although mutualism between ants and honeydew-producing hemipterans has been extensively recognized in ecosystem biology, however few attempts to test the hypothesis that mutualism between two alien species leads to the facilitation of the invasion process. To address this problem, we focus on the conditional mutualism between S. invicta and P. solenopsis by field investigations and indoor experiments. In the laboratory, ant colony growth increased significantly when ants had access to P. solenopsis and animal-based food. Honeydew produced by P. solenopsis also improved the survival of ant workers. In the field, colony density of P. solenopsis was significantly greater on plots with ants than on plots without ants. The number of mealybug mummies on plants without fire ants was almost three times that of plants with fire ants, indicating a strong effect of fire ants on mealybug survival. In addition, the presence of S. invicta successfully contributed to the spread of P. solenopsis . The quantity of honeydew consumption by S. invicta was significantly greater than that of a presumptive native ant, Tapinoma melanocephalum . When compared with the case without ant tending, mealybugs tended by ants matured earlier and their lifespan and reproduction increased. T. melanocephalum workers arrived at honeydew more quickly than S. invicta workers, while the number of foraging S. invicta workers on plants steadily increased, eventually exceeding that number of T. melanocephalum foragers. Overall, these results suggest that the conditional mutualism between S. invicta and P. solenopsis facilitates population growth and fitness of both species. S. invicta tends to acquire much more honeydew and drive away native ants, promoting their predominance. These results suggest that the higher foraging tempo of S. invicta may provide more effective protection of P. solenopsis than native ants. Thus mutualism between these two alien species may facilitate the invasion success of both species.

Ants (Hymenoptera: Formicidae) Associated withDiaphorina citri(Hemiptera: Liviidae) and their Role in its Biological Control

“…The species involved in this system have been found tending other hemipterans, i.e., B. osbcurior tending Dalbulus quinquenotatus Delong & Nault (Cicadellidae) (Larsen et al. 1991), B. patagonicus tending Aphis gossypii Glover (Aphididae) (Barnum 2008), P. megacephala tending Coccus viridis (Coccidae) (Reimer et al 1993), and S. invicta tending Phenacoccus solenopsis Tinsley (Pseudococcidae) (Zhou et al 2012).…”

Effects Of Tending BySolenopsis Invicta(Hymenoptera: Formicidae) On The Sugar Composition And Concentration In The Honeydew Of An Invasive Mealybug,Phenacoccus Solenopsis(Hemiptera: Pseudococcidae)

“…Our previous9studies have demonstrated that ant workers foraging foliar is significantly enhanced on the P. solenopsis infested cotton plant (Zhou et al. ). Ant colony growth and ant worker survival were significantly improved when ants had access to P. solenopsis (Zhou et al.…”

“…Aphids exhibit enhanced feeding and excretion rates when they are attended by ants (Banks & Nixon 1958;Mittler 1958;Takeda et al 1982). Ant tending can even increase the reproductive period and shorten the developmental period of hemipterans (Stadler & Dixon 1999;Zhou et al 2012a). Several studies have indicated that the quality and quantity of the honeydew produced by hemipterans play an important role in the stability and outcomes of hemipteran-ant interactions (Addicott 1978;Sakata 1995;V€ olkl et al 1999).…”

Do organic silicon and imidacloprid synergistically induce toxicity to the new invasive mealybug Phenacoccus solenopsis Tinsley on Portulaca grandiflora plants?

“…In a bad infestation, their honeydew induces the development of sooty mold fungus (Saeed et al, 2007). This species has been recognized as an aggressively invasive species of agricultural and ornamental plants in China. P. solenopsis in the fields is difficult to manage (Ram and Saini, 2010;Vennila et al, 2010;Huang J et al, 2012;Zhou et al, 2012) for the following reasons: 1) this species possesses a waxy coating that protects it from insecticides and natural mortality factors, 2) P. solenopsis can also hide in soil cracks and crevices, 3) P. solenopsis exhibits a high reproductive rate and produces serious overlapping generations, and 4) the higher foraging tempo of ants provides additional effective protection for P. solenopsis. P. solenopsis cannot be controlled effectively; the losses in cotton yield in 2008 or 2009 were 1.4 × 10 6 t in China, 1.12 × 10 6 t in India, and 0.48 × 10 6 t in Pakistan (Wang et al, 2010).…”