Climbing ability of teneral and sclerotized adult bed bugs and assessment of adhesive properties of the exoskeletal fluid using atomic force microscopy.

We observed that teneral adults (<1 h post-molt) of Cimex lectularius L. appeared more adept at climbing a smooth surface compared to sclerotized adults. Differences in climbing ability on a smooth surface based on sclerotization status were quantified by measuring the height to which bed bugs climbed when confined within a glass vial. The average maximum height climbed by teneral (T) bed bugs (n = 30, height climbed = 4.69 cm) differed significantly (P< 0.01) from recently sclerotized (RS) bed bugs (n = 30, height climbed = 1.73 cm at ~48 h post molt), sclerotized group 1 (S1) bed bugs (n = 30, S1 = 2.42 cm at >72 h), and sclerotized group 2 (S2) bed bugs (n = 30, height climbed = 2.64 cm at >72 h post molt). When heights from all climbing events were summed, teneral bed bugs (650.8 cm climbed) differed significantly (P< 0.01) from recently sclerotized (82 cm climbed) and sclerotized (group 1 = 104.6 cm climbed, group 2 = 107.8 cm climbed) bed bugs. These findings suggested that the external surface of teneral bed bug exoskeletons possess an adhesive property. Using atomic force microscopy (AFM), we found that adhesion force of an exoskeletal (presumably molting) fluid decreased almost five-fold from 88 to 17 nN within an hour of molting. Our findings may have implications for laboratory safety and the effectiveness of bed bug traps, barriers, and biomimetic-based adhesives.

Using the DAS-ELISA Test to Establish an Effective Distance Between Bait Stations for Control of Linepithema humile (Hymenoptera: Formicidae) in Natural Areas.

Linepithema humile (Mayr), the Argentine ant, is an invasive pest that has spread throughout the United States and is a problem in natural and managed habitats in South Carolina. Foraging patterns and the effectiveness of liquid baits for control of this pest have been studied in urban areas. However, similar studies have not been conducted in natural areas such as parks, picnic grounds, or campsites. L. humile populations can be large and widespread, making them a major nuisance pest for visitors to these natural areas. The primary objective of this study was to determine an effective distance between bait stations for control of L. humile in a natural area. A double antibody-sandwich enzyme-linked immunosorbent assay (DAS-ELISA) procedure was used to detect individual ants that consumed rabbit immunoglobin (IgG) protein for marking and tracking. In both lab and field conditions, there was a significant difference in the detection of IgG in ants fed protein marker mixed with sugar water compared with ants only fed sugar water. Additional field studies revealed that an individual ant could retain detectable levels of protein marker for 3 d and that an ant feeding on IgG containing bait could be detected over 15 m from the original bait source. Overall, we found that using liquid ant baits, with a placement of 20 m between stations, was effective in reducing L. humile numbers between April to October, 2012 in a natural park area of Lake Greenwood State Park, SC.

Residual efficacy of insecticides applied to exterior building material surfaces for control of nuisance infestations of Megacopta cribraria (Hemiptera: Plataspidae).

The plataspid Megacopta cribraria (F.), which was recently introduced to the United States, forms nuisance aggregations on the exteriors of homes when it seeks overwintering sites in the fall. Little to no published information is available on the efficacy of insecticides labeled for professional use and exterior applications on homes and other structures against this insect. In a series of three experiments, we evaluated the residual efficacy of nine insecticides incorporating pyrethroid, neonicotinoid, and oxadiazine active ingredients on surfaces composed of five exterior building materials (vinyl soffit, brick, painted and unfinished plywood, and metal) at rates labeled for use in structural perimeter applications. Pyrethroids and pyrethroid-neonicotinoid mixes were broadly effective, resulting in 100% mortality or knockdown within 24 h in most cases. The neonicotinoid dinotefuran performed similarly on metal and vinyl surfaces, but its residual efficacy was reduced on more porous brick and wood surfaces. The oxadiazine indoxacarb acted more slowly than the other materials, but its performance was maintained on porous surfaces. Overwintering adults of M. cribraria were generally susceptible to the broad-spectrum insecticides most commonly used for exterior applications to homes and other structures.

Emergence of the introduced ant Pachycondyla chinensis (Formicidae: Ponerinae) as a public health threat in the southeastern United States.

Pachycondyla chinensis (Emery) (Formicidae: Ponerinae), a species introduced into North America > 70 yr ago, is found throughout Southeast Asia. Stinging of zookeepers by P. chinensis at the Greenville Zoo (Greenville, SC) initiated an investigation of this exotic species and a survey of sting victims. Eighty percent of sting victims experienced local reactions, including swelling < 5 cm in diameter around the sting site, recurring pain, skin redness, and mild-to-severe urticaria. These symptoms lasted 2 h to 5 d. Twelve percent of the sting victims reported minor reactions, including no swelling, localized redness, minor pain sensation at the time of sting, mild urticaria, and symptoms lasting < 1 h. Eight percent of the sting victims reported significant local reactions, including swelling > 5 cm in diameter around the sting site, recurring pain, skin redness, severe urticaria, and symptoms lasting 3-14 d. P. chinensis represents an emerging public health threat throughout its present range in the southeastern United States (i.e., Georgia, North Carolina, South Carolina, and Virginia). Because of reported adverse reactions to stings of P. chinensis, further studies on its ecology and medical and veterinary importance need to be undertaken.

Effects of contaminants on bait acceptance by Solenopsis invicta (Hymenoptera: Formicidae).

Three commonly used fire ant baits, Amdro (0.73% hydramethylnon [AI]), Ascend (0.011% abamectins [AI]), and Maxforce (1.0% hydramethylnon [AI]), were exposed to potential, volatile contaminants. The contaminants included the insecticides Orthene Fire Ant Killer (75.0% acephate [AI] ), Cyren (44.6% chlorpyrifos [AI]), and Tempo 2 (24.3% cyfluthrin [AI]); cigarette smoke; gasoline (unleaded, 89 octane); and fertilizer (10-10-10). Fire ant baits previously exposed for 48 h to these contaminants were analyzed using gas chromatography analysis. Orthene Fire Ant Killer, Cyren, Tempo 2, cigarette smoke, and gasoline had volatile components transferred to the baits. Baits exposed to these products were used in a field evaluation of bait acceptance by Solenopisis invicta Buren, the red imported fire ant. Uncontaminated Amdro was significantly preferred by S. invicta over Amdro contaminated by smoke, Cyren, Tempo 2, and gasoline. Uncontaminated Maxforce was significantly preferred over Maxforce contaminated by Tempo 2, Cyren, and gasoline, and uncontaminated Ascend was preferred over Tempo 2- and Cyren-contaminated Ascend. Orthene-exposed Amdro, Maxforce, and Ascend baits, and smoke-exposed Maxforce and Ascend baits were not significantly different from the control. These results indicate that volatile insecticides and products can contaminate fire ant baits. Some insecticides and products, such as gasoline, can significantly affect bait palatability and may adversely impact control.