Significance: Mitigating thermal stress through evolutionary adaptation or physiological plasticity is critical for species’ persistence in changing climates. Sparse knowledge of genetic and physiological architectures of thermal plasticity hampers our ability to predict organismal resilience to climate change. Understanding the independence of short- and long-term plasticity and constraints of basal thermotolerance on plasticity is important for understanding responses to climate change. We show heritable genetic variation for basal cold tolerance and plasticity in a midlatitude Drosophila melanogaster population. High long-term plasticity predicted high short-term plasticity, and basal cold tolerance constrained both plasticity measures. There was no overlap in SNPs associated with either plasticity type. Overlapping molecular function of SNPs suggests shared physiology between long- and short-term plasticity, despite distinct genetic architectures.

Climate change is a danger to the agricultural system and will impact the availability of food to feed the world. While much attention has focused on the effects of climate change on pest management prior to harvest, much less attention and time has been devoted to determining the effects of climate change on pest management in the postharvest supply chain from farm to fork. Climate change may percolate to pest management at a macro level through compositional changes in which species attack commodities through distributional changes or what commodities are grown in a region (and thus processed in that area). However, climate change may also result in altered microclimates at food facilities, which can be tied to increased generation times, elevated damage and contamination potential, greater abundance of species, and greater need for external inputs. A variety of integrated pest management (IPM) strategies may help increase the resiliency and adaptation of management to climate change. Tactics susceptible to warming temperature changes in climate showing decreased efficacy include semiochemical-based, behaviorally-based tactics, a subset of insecticides (e.g., pyrethrins and pyrethroids), and those that rely on low temperature (e.g., grain aeration, grain chilling). Tactics at food facilities showing resilience to warming temperature changes in climate include packaging, other groups of insecticides, and likely sanitation. Data gaps include predicting changing distributions for stored product insects under climate change, translating macro climate changes into microclimate changes at food facilities, and rigorously investigating how IPM tactic efficacy varies under changing climate. Increased scrutiny of how climate change will affect pest management in the postharvest supply chain will deliver improved outcomes for the entire agricultural system.

The commercial availability of low-gluten or gluten-free flours has been increasing due to consumer demands, which raises new challenges for the management of stored product insects since little is known about the susceptibility of these flours to infestation. Here we measured oviposition and development of Tribolium castaneum, the red flour beetle, a major pest of wheat and rice mills, on 18 different commercially available flours (almond, amaranth, barley, buckwheat, cassava, coconut, corn, garbanzo, millet, oat, potato, quinoa, rice, rye, sorghum, spelt, teff, and wheat) to assess the level of risk. The average number of eggs laid was highest for teff flour, with wheat, rice, buckwheat, sorghum, barley, rye, and spelt flour also having high oviposition. The lowest oviposition was for potato, quinoa, amaranth and cassava. Holding the eggs laid in these flours and evaluating the ability to develop to the adult stage demonstrated that the average number of adult progeny was highest for teff and wheat, followed by buckwheat, rye, oat, spelt, and millet. In an experiment where single eggs were placed directly in flour, the highest percentage development was in barley, buckwheat, sorghum, spelt, teff, and wheat. Time for 50% of single eggs to develop to adults was quickest for sorghum, spelt, teff, and wheat, while sorghum, buckwheat, corn, spelt, and barley had the quickest development of 90% of eggs to reach adults. There was substantial variation among the different flours which indicates variation in risk of insect infestation. As consumer interest in these flours continues to grow and these alternative flours become more prevalent in food facilities, understanding what diets insects successfully infest is critical to developing management tools.

Insect infestations can result in a damaged or destroyed product, costing producers and retailers millions of dollars annually. Postharvest insects move through space searching for mates, food, and shelter. Movement of product, sanitation activities, and insecticide applications also drive their spatial distribution patterns. Determining spatial distributions and population density of insects provides important information to develop targeted and cost-effective management programs. Monitoring data collected using traps to capture insect pests have provided information under a range of conditions: in bins of grain, grain elevator silos and their immediate environment, milling and processing facilities, commercial warehouses, and retail stores. In evaluating available data, we identified key influences that may be leveraged to increase the impacts of future monitoring schemes. Species-specific locations of infestation were common among stored product insect pests and seasonal variation was highly influential in population growth patterns. Competition among different species also drives spatial and temporal distributions and overlap among species is rare. Vertical distribution of insects was common in bins, elevators, and silos. More insects were often found in the receiving and storage areas of mills and processing facilities and insects often migrated into facilities from surrounding natural reservoirs. Previously stored grain and spillage can also harbor insect populations, which also reinforces the need for sanitation in and around stored grain products. Continued monitoring research will provide information to develop predictive tools which will use behavioral patterns to further our understanding of these insect pests within these unique facilities and circumstances.

The larger grain borer (Prostephanus truncatus [Horn] [Coleoptera: Bostrichidae]) is a wood-boring insect native to Central America and adapted to stored maize and cassava. It was accidentally introduced to Tanzania and became a pest across central Africa. Unlike many grain pests, P. truncatus populations can establish and move within forests. Consequently, novel infestations can occur without human influence. The objectives of our study were to (i) develop an updated current suitability projection for P. truncatus, (ii) assess its potential future distribution under different climate change scenarios, and (iii) identify climate variables that best inform the model. We used WALLACE and MaxEnt to predict potential global distribution by incorporating bioclimatic variables and occurrence records. Future models were projected for 2050 and 2070 with Representative Concentration Pathways (RCPs) 2.6 (low change) and 8.5 (high change). Distribution was most limited by high precipitation and cold temperatures. Globally, highly suitable areas (> 75%) primarily occurred along coastal and equatorial regions with novel areas in northern South America, India, southeastern Asia, Indonesia, and the Philippines, totaling 7% under current conditions. Highly suitable areas at RCPs 2.6 and 8.5 are estimated to increase to 12% and 15%, respectively, by 2050 and increase to 19% in 2070 under RCP 8.5. Centroids of highly suitable areas show distribution centers moving more inshore and away from the equator. Notably, the result is a range expansion, not a shift. Results can be used to decrease biosecurity risks through more spatially explicit and timely surveillance programs for targeting the exclusion of this pest.