North American Invasion of the Tawny Crazy Ant (Nylanderia fulva) Is Enabled by Pheromonal Synergism from Two Separate Glands.

A new invader, the "tawny crazy ant", Nylanderia fulva (Hymenoptera: Formicidae; Formicinae), is displacing the red imported fire ant, Solenopsis invicta (Formicidae: Myrmicinae), in the southern U.S., likely through its superior chemical arsenal and communication. Alone, formic acid is unattractive, but this venom (= poison) acid powerfully synergizes attraction of tawny crazy ants to volatiles from the Dufour's gland secretion of N. fulva workers, including the two major components, undecane and 2-tridecanone. The unexpected pheromonal synergism between the Dufour's gland and the venom gland appears to be another key factor, in addition to previously known defensive and detoxification semiochemical features, for the successful invasion and domination of N. fulva in the southern U.S. This synergism is an efficient mechanism enabling N. fulva workers to outcompete Solenopsis and other ant species for food and territory. From a practical standpoint, judicious point-source release formulation of tawny crazy ant volatiles may be pivotal for enhanced attract-and-kill management of this pest.

Evidence of niche shift and global invasion potential of the Tawny Crazy ant, Nylanderia fulva.

Analysis of an invasive species' niche shift between native and introduced ranges, along with potential distribution maps, can provide valuable information about its invasive potential. The tawny crazy ant, Nylanderia fulva, is a rapidly emerging and economically important invasive species in the southern United States. It is originally from east-central South America and has also invaded Colombia and the Caribbean Islands. Our objectives were to generate a global potential distribution map for N. fulva, identify important climatic drivers associated with its current distribution, and test whether N. fulva's realized climatic niche has shifted across its invasive range. We used MaxEnt niche model to map the potential distribution of N. fulva using its native and invaded range occurrences and climatic variables. We used principal component analysis methods for investigating potential shifts in the realized climatic niche of N. fulva during invasion. We found strong evidence for a shift in the realized climatic niche of N. fulva across its invasive range. Our models predicted potentially suitable habitat for N. fulva in the United States and other parts of the world. Our analyses suggest that the majority of observed occurrences of N. fulva in the United States represent stabilizing populations. Mean diurnal range in temperature, degree days at ≥10°C, and precipitation of driest quarter were the most important variables associated with N. fulva distribution. The climatic niche expansion demonstrated in our study may suggest significant plasticity in the ability of N. fulva to survive in areas with diverse temperature ranges shown by its tolerance for environmental conditions in the southern United States, Caribbean Islands, and Colombia. The risk maps produced in this study can be useful in preventing N. fulva's future spread, and in managing and monitoring currently infested areas.

Comparison of multiple steam treatment durations for control of bed bugs (Cimex lectularius L.).

BACKGROUND: The factors contributing to the current resurgence of bed bug Cimex lectularius L. populations across the United States and elsewhere include, among others, the development of resistance to chemical insecticides and population management practices. This has led to the development and attempted refinement of many non-chemical control methods that contribute to an IPM approach to solving the current bed bug population density increase in urban dwellings. One such approach is the use of heat in the form of steam to provide an effective mechanism for controlling localized infestations of bed bugs. RESULTS: The work reported herein was designed to refine our understanding of the duration of bed bug/steam contact necessary to affect mortality of bed bugs in laboratory trials. Beg bug eggs, nymphs and adults were exposed to three steam treatment exposure periods in these trials. Mean percentage mortality of bed bug eggs was 100% (regardless of duration of exposure), and that of nymphs and adults ranged from 88.0 to 94.0%. Survivorship of nymphs and adults in the trials was the result of experimental protocol restrictions that would not usually be associated with actual pest management efforts. CONCLUSIONS: The treatment equipment used in these trials is portable and relatively inexpensive and represents a non-chemical means of killing all life stages of bed bugs. While this method would likely be seen as an inefficient means of remediating a mature bed bug infestation within a structure, it does represent a practical component of integrated management of this pest insect.