Mutualism Between Fire Ants and Mealybugs Reduces Lady Beetle Predation

Area of Science:

• Ecology
• Invasive Species Biology
• Entomology

Background:

• Solenopsis invicta (red imported fire ant) is a significant invasive pest impacting biodiversity.
• The ecological effects of interactions between invasive ants and honeydew-producing hemipteran insects are not well understood.
• Phenacoccus solenopsis (cotton mealybug) is an invasive hemipteran pest.

Purpose of the Study:

• To investigate how the interaction between invasive Solenopsis invicta and Phenacoccus solenopsis affects predation by the lady beetle Propylaea japonica.
• To determine if Solenopsis invicta tending influences the predation rates of Phenacoccus solenopsis by Propylaea japonica.

Main Methods:

• Field investigations were conducted to compare lady beetle populations in areas with and without Solenopsis invicta.
• Indoor experiments assessed the impact of Solenopsis invicta tending on lady beetle predation of Phenacoccus solenopsis.
• Olfaction bioassays were used to evaluate lady beetle olfactory preferences between tended and untended mealybugs.

Main Results:

• Solenopsis invicta tending significantly reduced predation of Phenacoccus solenopsis by Propylaea japonica lady beetles, with larvae more affected than adults.
• Field surveys revealed lower lady beetle species richness and abundance in plots infested with Solenopsis invicta.
• Lady beetles showed a preference for moving towards untended mealybugs in olfaction bioassays.

Conclusions:

• The mutualistic interaction between Solenopsis invicta and Phenacoccus solenopsis negatively impacts predation by lady beetles.
• This interaction may facilitate the population growth of the invasive Phenacoccus solenopsis.
• Understanding these invasive species interactions is crucial for managing their ecological impact.