Data from: Delayed recovery and sublethal effects on the semiochemical-mediated taxis by khapra beetle after exposure to long-lasting insecticide-incorporated netting

Source Insects

For all assays, older (=larger) T. granarium larvae were used (according to the specifications in Morrison et al. 2020 and Arthur et al. 2018). Trogoderma granarium larvae were derived from the quarantine facility in Buzzards Bay, MA, which originally came from Pakistan. They were continuously reared on pulverized dog food (300 g SmartBlend, Purina One), with rolled oats, and a crumpled, moistened paper towel on the surface in a 800 ml mason jar. They were held in an environmental chamber at 32°C, 60% RH, and 14:10 L:D. All individuals were starved up to 48 h prior to use in experiments.

Direct Lethality Assay

Cohorts of 20 T. granarium larvae were exposed to control netting (without insecticide), Carifend 0.34% alpha-cypermethrin LLIN (BASF Corps, Ludwigshafen, Germany), or D-terrence 0.4% deltamethrin LLIN (Vestergaard Inc., Lausanne, Switzerland) for periods of 5 or 60 min in Petri dishes (90 × 15 mm). The percentage of individuals alive, affected, or dead were then tracked 0, 4, 24, 48, 72, or 168 h after exposure. Alive individuals were observed moving normally without impediment, while affected individuals exhibited twitching, drunken or slowed movements, and/or an inability to right themselves after prodding. If individuals exhibited no movement at all, they were classified as dead (according to the definitions in Ranabhat et al. 2022 and Morrison et al. 2018). Cohorts were held in an environmental chamber set at 32°C, 65% RH, and 16:8 L:D. There was a total of n = 5 replicate cohorts per combination of netting, exposure time, and postexposure holding duration.

Sublethal Effects: Movement Assay Using Video-Tracking

Cohorts of 20 T. granarium were exposed for 5 min to netting without insecticide, Carifend 0.34% alpha-cypermethrin LLIN (BASF Corps, Ludwigshafen, Germany), or D-terrence 0.4% deltamethrin LLIN (Vestergaard Inc., Lausanne, Switzerland). The movement of six larvae that were alive or affected were tracked individually in separate Petri dishes (90 × 15 mm) using a network camera suspended 80 cm above the arenas and hooked up to an adjacent laptop equipped with Ethovision Software v.16.0 (Noldus Inc., Wageningen, the Netherlands). The whole setup was located in an environmental chamber set to 32°C, 65% RH, and 16:8 L:D. Larvae were tracked immediately after exposure to netting for 30 min. The distance moved, instantaneous velocity, angular velocity (deg/s), cumulative duration of low acceleration (s), and cumulative duration of not moving by T. granarium larvae were automatically recorded. There were a total of n = 30 replicate individuals per treatment.

Sublethal Effects: Semiochemical-Mediated Foraging

Pitfall traps (Storgard traps, Trece, Inc., Adair, OK, USA) were placed individually on the far side of a medium-sized Sterilite container (44.5 × 36.2 × 17.8 cm L:W:H) that had been scuffed up with sandpaper. The trap was baited with a bullet lure (IL-203, Insects Limited, Westfield, IN, USA) containing the T. granarium and T. variabile sex pheromone, (E)-14-methyl-8-hexadecenal, 3 g of wheat germ, or was left unbaited (e.g., control). Cohorts of 10 T. granarium were exposed to control netting (without insecticide) or D-Terrence with 0.4% deltamethrin (Vestergaard Inc., Lausanne, Switzerland) in a Petri dish. Subsequently, the cohort of 10 larvae were removed, and were released on the opposite side of the container with the trap, and given an opportunity of 24 h to forage to the trap. At the end of the dispersal period, the total number of larvae inside the trap, on the stimulus half of the container, and on the non-stimulus half of the container were recorded.