2.1 Experimental insects A laboratory colony of T. castaneum maintained at the USDA Center for Grain and Animal Health Research for over 30 years free of exposure to insecticide was used for these studies. The colony was kept in 0.95-L glass jars with filter paper lids for air flow with a rearing diet consisting of 95% unbleached, organic flour with 5% brewer's yeast added. Jars were held in an environmental chamber set at a temperature of 30 °C, relative humidity (RH) of 65%, and a 16:8 h light/dark photoperiod. 2.2 Manipulating diet nutritional quality Unbleached, organic wheat flour was mixed with microcrystalline cellulose (Thermo Fisher Scientific, Waltham, MA, USA), a nonnutritive and nontoxic filler that has a similar particle size to wheat flour to produce three diet treatments that differed in nutritional quality: 0% flour (0 flour:100 cellulose), 25% flour (25:75), and 100% flour (100:0). A treatment with no flour or cellulose was also included, as a no-food control. 2.3 Long-lasting insecticide-incorporated polyethylene netting Two types of Long-lasting insecticide-incorporated nettings (LLINs), both commercially labeled in the USA, were used: CarifendTM (BASF, Ludwigshafen, Germany) and D-TerrenceTM (Vestergaard, Lausanne, Switzerland),. Carifend netting incorporated 0.34% (w/w) α-cypermethrin while D-Terrence netting incorporated 0.4% (w/w) deltamethrin. Control netting was physically identical to the Carifend netting or D-Terrence netting but lacked any insecticide. 2.4 Effects of diet on recovery of T. castaneum adults after exposure to LLIN The netting was cut into squares and secured to the bottoms of square Petri dishes (100 × 100 × 15 mm, L × W × H, VWRTM, Radnor, PA, USA) with double-sided tape and label tape. 20 mixed-sex adults (2- to 3-week-old) were exposed to one of the three netting types (Carifend, D-Terrence, and control) for 2, 24, 48, 72, 96, 120, 144, and 168 h, respectively, with a total of 24 combinations of netting and exposure time treatment. Immediately following exposure, 20 adults were examined for health condition (unaffected, affected and dead) and transferred from the netting arena to recovery arenas. Recovery arenas were Petri dishes (35 × 10 mm, D × H, FalconTM, Franklin Lakes, NJ, USA) with 0.5 g of one of the three flour:cellulose diets (0:100, 25:75, and 100:0)). In addition, arenas without any food were also included as controls. There were 4 replicates for each combination of netting × exposure time × diet. The condition of T. castaneum were assessed as number of unaffected, affected and dead at 0, 1, 2, 3, 4, 5, 6, and 7 d post-exposure to netting. Adults were recorded as unaffected if they were active and behaving normally with coordinated walking and species-specific movements; affected if they had uncoordinated walking and sluggish movements or were on their backs with legs twitching, and/or could not right themselves after being prodded (i.e., knocked down); finally, dead if they were completely motionless even after prodding. During exposure and recovery, insects were kept in an environmental chamber under the same conditions as described above. Because no T. castaneum adults were observed to be affected and the number of dead was very low after exposure to control netting (Fig. 1), recovery experiments on control netting were not included in rest of the study. 2.5 Effects of diet and netting exposure on mobility of T. castaneum adults Eighteen newly emerged (≤ 2-day-old), mixed-sex adults that had been reared on standard lab diet were transferred to 0.5 g of one of the assigned diets (0:100, 25:75, and 100:0 flour:cellulose) in Petri dishes (35 × 10 mm, D × H, FalconTM, Franklin Lakes, NJ, USA) for one week. As above, there was also a no food treatment as a control. After the one-week time period, 18 adults from each of the diet treatments were exposed to netting (Carifend, D-Terrence, or control) for 10, 30, 60, or 90 min. Only adults rated as unaffected or affected (e.g., not dead) were further evaluated for impacts on mobility. Immediately following the exposure, adults were recorded for a 30-min period using a video-tracking apparatus combined with Ethovision Software (v.16.0, Noldus, Inc., Leesburg, VA, USA). The equipment was set up to track 6 arenas simultaneously, within each arena a single adult was measured. A piece of white filter paper (85 mm, Ahlstrom-Munksjö, Mt. Holly Springs, PA, USA) was taped to the bottom of Petri dishes (100 × 15 mm, D × H, VWRTM, Radnor, PA, USA). The Petri dishes were affixed with white foamboard 80 cm below a network camera (GigE, Basler AG, Ahrenburg, Germany) and backlit with a LED light box (42 × 30 cm, W × L, LPB3, Litup, Shenzhen, China). The program calculated the total distance moved (cm), and the mean instantaneous velocity (cm/s) over the 30 min period for each adult. In total, there were 18 replicates for each of the treatment combinations (netting × exposure time × diet).