Susceptibility of Alphitobius diaperinus in Texas to permethrin- and ß-cyfluthrin-treated surfaces.

BACKGROUND: Effective control of the lesser mealworm beetle, Alphitobius diaperinus, relies heavily on insecticides. The susceptibility level of beetles to these insecticides can be dependent on active ingredient, population treated, formulation, surface treated and timing of observation. The susceptibility of adult beetles from six populations to ß-cyfluthrin was determined up to 48 h after exposure. The susceptibility of adult beetles to the label rate of ß-cyfluthrin and permethrin formulations on concrete, wood-chip-type particle board and pressure-treated wood was determined up to 48 h post-exposure. RESULTS: Variation in LC50 values at 2 and 24 h was found within and between beetle populations from two regions of Texas. The permethrin formulation had lower mean mortality than the ß-cyfluthrin formulation on all surfaces tested. The permethrin formulation had high levels of recovery on all surfaces tested after 2 h. Surface affected the efficacy of the insecticides tested on killing adult beetles. CONCLUSION: Permethrin-based insecticide had lower knockdown and persistence on various surfaces over time than ß-cyfluthrin-based insecticide. Beetle recovery in less susceptible populations may necessitate longer observation periods for efficacy evaluations. Our study also shows that surfaces chosen can affect the efficacy of the compound on killing adult beetles. © 2016 Society of Chemical Industry.

Functional Segregation within the Muscles of Aquatic Propulsion in the Asiatic Water Monitor (Varanus salvator).

Water monitor lizards (Varanus salvator) swim using sinusoidal oscillations generated at the base of their long (50% of total body length) tail. In an effort to determine which level of the structural/organizational hierarchy of muscle is associated with functional segregation between the muscles of the tail base, an array of muscle features-myosin heavy chain profiles, enzymatic fiber types, twitch and tetanic force production, rates of fatigue, muscle compliance, and electrical activity patterns-were quantitated. The two examined axial muscles, longissimus, and iliocaudalis, were generally similar at the molecular, biochemical, and physiological levels, but differed at the biomechanics level and in their activation pattern. The appendicular muscle examined, caudofemoralis, differed from the axial muscles particularly at the molecular and physiological levels, and it exhibited a unique compliance profile and pattern of electrical activation. There were some apparent contradictions between the different structural/organizational levels examined. These contradictions, coupled with a unique myosin heavy chain profile, lead to the hypothesis that there are previously un-described molecular/biochemical specializations within varanid skeletal muscles.