No abstract

We compared the efficacies of two arthropod pitfall trapping techniques: live (dry) trapping and kill trapping with three killing agents (water, ethylene glycol, and the recently developed propylene glycol, whose efficacy has not been previously assessed). Kill pitfall traps caught more species than did live pitfalls. Forty‐one species were collected only from kill traps (3 being unique to water, 11 to ethylene glycol, and 8 to propylene glycol), 12 were collected only from live traps, and 32 were collected from both kill and live traps. The same average number of individuals per species was caught for most of those taxa that were collected in both trap types, indicating that better retention of captured arthropods by the killing agent was not responsible for the differences observed in the two pitfall trapping methods. There were no significant differences in captures between propylene and ethylene glycol traps or between water and live traps. Because of species‐specific differences in the efficiencies of live and kill pitfall trapping, cross‐study entomological comparisons made using kill pitfall trapping and live pitfalling may be confounded.

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Natural enemies of the imported fire ants, Solenopsis invicta Buren S. richteri Forel (Hymenoptera: Formicidae), and their hybrid, include a suite of more than 20 fire ant decapitating phorid flies from South America in the genus Pseudacteon. Over the past 12 years, many researchers and associates have cooperated in introducing several species as classical or self-sustaining biological control agents in the United States. As a result, two species of flies, Pseudacteon tricuspis Borgmeier and P. curvatus Borgmeier (Diptera: Phoridae), are well established across large areas of the southeastern United States. Whereas many researchers have published local and state information about the establishment and spread of these flies, here distribution data from both published and unpublished sources has been compiled for the entire United States with the goal of presenting confirmed and probable distributions as of the fall of 2008. Documented rates of expansion were also used to predict the distribution of these flies three years later in the fall of 2011. In the fall of 2008, eleven years after the first successful release, we estimate that P. tricuspis covered about 50% of the fire ant quarantined area and that it will occur in almost 65% of the quarantine area by 2011. Complete coverage of the fire ant quarantined area will be delayed or limited by this species' slow rate of spread and frequent failure to establish in more northerly portions of the fire ant range and also, perhaps, by its preference for red imported fire ants (S. invicta). Eight years after the first successful release of P. curvatus, two biotypes of this species (one biotype occurring predominantly in the black and hybrid imported fire ants and the other occurring in red imported fire ants) covered almost 60% of the fire ant quarantined area. We estimate these two biotypes will cover almost 90% of the quarantine area by 2011 and 100% by 2012 or 2013. Strategic selection of several distributional gaps for future releases will accelerate complete coverage of quarantine areas. However, some gaps may be best used for the release of additional species of decapitating flies because establishment rates may be higher in areas without competing species.

No abstract