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ARS Home » Research » Publications at this Location » Publication #122906
Title: EFFECTS OF RED IMPORTED FIRE ANTS ON ABUNDANCE OF PEANUT ARTHROPODS

Author
item Vogt, James
item MULDER, PHILIP - OKLAHOMA STATE UNIV.
item SMITH, WAYNE - OKLAHOMA COOP EXT SERVICE
item WRIGHT, RUSSELL - OKLAHOMA STATE UNIV.

Submitted to: Imported Fire Ants Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/30/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: The role of the red imported fire ant in peanut production is poorly understood. Some people in recently-invaded areas (e.g., Oklahoma) have attributed kernel damage in peanuts to fire ants. Others believe fire ants are important predators of pest insects. Our research indicates that fire ants do not damage mature peanut kernels, and do not reduce abundance of other predatory insects in peanut fields. They may, however, be linked to increased abundance of three-cornered alfalfa hoppers, a minor pest in peanuts. Our research impacts producers by demonstrating that fire ants do not reduce the presence of beneficial insects in their fields and do not damage mature kernels. Recent reports of peanut graders mistaking kernel damage (probably wireworm damage) to fire ants demonstrate the need to better understand the ants' effects on peanuts. Our research is the first to experimentally manipulate fire ant populations and examine their effects on other peanut insects. The positive relationship between fire ants and three-cornered alfalfa hoppers merits further investigation.

Technical Abstract: Red imported fire ant (Solenopsis invicta Buren) population densities were manipulated with baits [Amdro (hydramethylnon) outside and Extinguish (methoprene) within] in a southern Oklahoma peanut field to investigate their effects on other peanut arthropods. The experiment was set up as a randomized block design replicated 5 times (30.5 m**2 plots) and blocked by location in the field. Arthropod populations were monitored using biweekly pitfall and sweep samples. Data were log10-transformed for analysis. After collembolans (14,864 collected), S. invicta workers were the most abundant insects in pitfall traps (13,070 collected). Significantly more S. invicta were present in untreated than treated plots throughout the season (repeated measures analysis of variance, P<0.01). Pitfall traps in plots with high S. invicta abundance yielded more collembolans, adult Diptera (various species), and coccinellid larvae than those in treated plots (repeated measures analysis of variance, P<0.05). This is probably due to these species being carried into the pitfalls by foraging ants. Spiders (various species), ground beetles (Carabidae), and Cicadellidae occurred in similar numbers in treated and untreated plots. Three-cornered alfalfa hoppers [Spissistilus festinus (Say)] were more abundant in plots with high S. invicta abundance than in treated plots (repeated measures analysis of variance, P<0.05). Examination of plants within and not within S. invicta mounds revealed a greater percentage of damaged kernels in plants not within mounds.