The global economic impact of termites is estimated to be approximately USD 40 billion annually, and subterranean termites are responsible for about 80% of the total impact. Twenty-eight species of termites have been described as invasive, and these termites are spreading, partially due to global trade, making effective control methods essential. Termite control is complex, as is the biology and behavior of this social insect group. In the U.S., termite prevention and control (with claims of structural protection) is regulated by more than one industry (pest control and building construction), and at the federal and state levels. Termite prevention has historically relied on building construction practices that do not create conducive conditions for termite infestations, but as soil termiticides developed, heavy reliance on pesticides became the standard for termite control. The concern for human and environmental health has driven the development of termite control alternatives and regulation for products claiming structural protection. Product development has also provided unprecedented opportunities to study the biology and behavior of cryptobiotic termites. Technological advances have allowed for the re-examination of questions about termite behavior. Advances in communications via social media provide unrestricted access to information, creating a conundrum for consumers and science educators alike.
31 December 2007 in Insect Biochemistry and Molecular Biology
Nylanderia fulva (Mayr) is an invasive ant that is a serious pest in the southern United States. Pest control operators and homeowners are challenged to manage pest populations below acceptable thresholds. Contact and bait insecticides are key components of an Integrated Pest Management (IPM) strategy, however, little is known about their efficacy. In repellency and efficacy bioassays, N. fulva were not completely repelled by any insecticide tested, although fewer ants crossed a surface treated with Temprid®. Few insecticides provided rapid control. Termidor® and Temprid® were the best performing with mean mortality of 100% in 13.4 and 19.0 days, respectively. In no-choice bait acceptance studies, it was shown that N. fulva generally had greater acceptance of carbohydrate-based ant baits (Advion®, InTiceTM (gel), and InTiceTM (granular)). However, mortality was low for the InTiceTM baits in a 7-day bioassay. Maxforce® Ant Killer Bait Gel and Advance® 375A in the spring and Maxforce® Complete in the summer and fall required the fewest days to reach 100% mortality. Bait active ingredients that resulted in the highest mortality were hydramethylnon and fipronil. These data on the efficacy of commercially available contact and bait insecticides provide valuable information to manage this invasive pest.
Nylanderia fulva (Mayr), the tawny crazy ant,is an invasive pest established in Florida and several other Gulf Coast states. In their invasive ranges in the Southeastern USA, large N. fulva populations have reduced species abundance, even displacing another invasive ant, Solenopsis invicta(Buren).In North Florida, N. fulva populations survive winter temperatures that reach below freezing for extended periods. However, the shallow littoral debris used by N. fulva for nest construction offers little insulation to brood and reproductives when exposed to freezing temperatures. Field populations of N. fulva in North Florida were observed tunneling below ground, a previously undescribed behavior. Other invasive ants exhibit similar subterranean tunneling behavior as a means of thermoregulation. To test the hypothesis that N. fulva has the capacity to construct subterranean tunnels across a range of ecologically relevant temperatures, tunneling performance for N. fulva and S. invicta, another invasive ant that tunnels extensively, were compared at four temperatures (15.0, 18.0, 20.0, and 22.0 °C). Overall, N. fulva tunneled significantly less than S. invicta. Nylanderia fulva tunneled furthest at warmer temperatures whereas S. invicta tunneled furthest at cooler temperatures. However, N. fulva constructed subterranean tunnels at all temperatures evaluated. These data support the hypothesis that N. fulva is capable of tunneling in temperatures as low as 15.0 °C, confirming that this ant can also perform a behavior that is used by other ants for cold avoidance.