Article selection from our Insect Science journals

Editor-in-Chief: David Denlinger

1. Glucose aversion: a behavioral resistance mechanism in the German cockroach opens in new tab/window DD: Under selection pressure the German cockroach has evolved a variety of resistance mechanisms to toxic baits. This paper describes the evolution of an aversion to glucose, a widely used component of such baits. A taste polymorphism changes the quality of glucose from sweet to bitter and results in an olfactory learning-based avoidance of baits, an aversion to other sugars, as well as shifts in mating choices. The paper thus presents a remarkable example of how anthropogenic selection can drive the evolution of an altered gustatory trait that reshapes foraging ecology and sexual communication.

2. Control of the insect metamorphic transition by ecdysteroid production and secretion opens in new tab/window DD: This highly cited paper presents the fine details regulating the production and secretion of ecdysteroids by the insect’s prothoracic gland. Although the major features have been known for some time, this paper nicely summarizes many new details and demonstrates the complexity of ecdysone biosynthesis and the trafficking pathways that are critical control steps for controlling molting and metamorphosis.

Editor-in-Chief: Jérôme Casas

3. The effect of climate change on invasive crop pests across biomes opens in new tab/window JC: On a global scale, crop pests are expected to increase due to climate change. This highly cited paper reviews the impact for different biomes and shows that temperate regions will be the most affected.

4. Processing insects for use in the food and feed industry opens in new tab/window JC: Insects as feed and food is currently one of the hottest topics in insect science. This highly cited paper reviews the commercial processing methods for food/feed formulation.

Editor-in-Chief: Brent Sinclair

1. Structure of an antennally-expressed carboxylesterase suggests lepidopteran odorant degrading enzymes are broadly tuned opens in new tab/window BS: Insects that rely on pheromone cues have detection systems that are exquisitely sensitive to certain complex molecules emitted by conspecifics. But how do they make sure they are responding to the correct molecule, and not just one that looks similar? One hypothesis is that the cells in the antenna express enzymes that break down irrelevant molecules – and moths, for example, certainly express a lot of different carboxylesterases in their antennae, which supports the hypothesis. Corcoran et al. tested this hypothesis by choosing one of the many carboxylesterases expressed by the light brown apple moth, solving its structure with x-ray crystallography, and then measuring the ability of the enzyme to break down a range of molecules similar to the moth’s pheromone. Surprisingly, rather than being quite specific, the enzyme will break down a wide range of linear acetate-ester molecules… including the moth’s pheromone! Even though I’m not a chemical ecologist, I enjoyed this paper because of its intellectual rigor (taking on a widely-held assumption) and the breadth of the techniques used in the study – going from mRNA expression to enzyme function is wonderfully integrative biology!

2. Field bands of marching locust juveniles show carbohydrate, not protein, limitation opens in new tab/window BS: Juvenile locusts sometimes do an odd thing: banding together and marching en masse (they can’t fly yet!) It’s been generally assumed that this is because they are seeking additional protein to support their growth (as is the case with some other marching Orthoptera). Using a nutritional geometry approach, Cease et al. show that, actually, these South American locusts aren’t limited by protein at all but are limited by carbohydrates. Usually, these experiments are conducted in the lab (and Cease et al. present robust data supporting their conclusions), but what sets this paper apart for me is that they also measured these preferences in swarming locusts in the field, which took them to multiple sites across Argentina, Bolivia, and Paraguay. Finally, they placed their data firmly in context by showing (as predicted) that the nutrient distribution of the food plants in areas where the locusts were swarming simply weren’t providing enough carbohydrate in the diet. From experience, I know that doing physiology in the field is challenging, especially if one is relying on an unpredictable, sporadic event like juvenile locust swarming; I was hugely impressed that this large, multinational, team was able to meet those challenges head-on and produce rigorous data in a strong theoretical context.

3. Stronger interspecific sexual differences may be favored when females search for mates in the presence of congeners opens in new tab/window BS: Tephritid flies are problematic as crop pests, but no one can deny that they have beautiful wings. In four members of the genus Strauzia, the males have very distinct wings (i.e. they’re sexually dimorphic). Why have only these species evolved sexual dimorphism? By placing these species on a phylogeny and putting them into their ecological context, Hippee et al. show that the sexually dimorphic species share host plants. Only one other genus of North American tephritids (Eutreta) includes sexually wing-dimorphic members in host-sharing species… and what Eutreta and Strauzia have in common is that the males hold territories while the females look for mates. This paper grabbed me because morphological diversity is at the heart of what makes insects special, and the authors use a combination of systematics and natural history to understand how some of that diversity evolved.

Editor-in-Chief: Kun Yan Zhu

1. Transcriptome analysis reveals the inhibitory mechanism of 3,4-Dimethoxyphenol from Streptomyces albidoflavus strain ML27 against Xanthomonas oryzae pv. oryzae opens in new tab/window KYZ: Bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major rice disease in many rice-growing regions. This research revealed antimicrobial activity of 3,4-dimethoxyphenol isolated from the metabolites of the soil bacterium Streptomyces albidoflavus strain ML27. The antimicrobial properties of 3,4-dimethoxyphenol against Xoo are attributed to its ability to induce damage to cell membranes, inhibit protein synthesis and secretion, and interfere with various metabolic and biosynthetic pathways in Xoo. These results demonstrate great potentials of using 3,4-dimethoxyphenol as a new biopesticide for managing rice bacterial leaf blight.

2. Bulk segregant mapping and transcriptome analyses reveal the molecular mechanisms of spinetoram resistance in Spodoptera frugiperda opens in new tab/window ​KYZ: Insecticide resistance has become a significant challenge to insect pest management. This research aimed to understand the molecular mechanisms underlying spinetoram resistance in the fall armyworm, Spodoptera frugiperda, a highly damaging pest of numerous crops. The authors employed bulk segregant analysis (BSA) in combination with DNA and RNA sequencing and found that spinetoram resistance in S. frugiperda appears to be mediated mainly by target site insensitivity in combination with minor roles of detoxification enzymes. Results from this study can help researchers develop new strategies for controlling this devasting insect pest.