Cigarette Beetle

Lasioderma serricorne — the cigarette beetle, also called the tobacco beetle — is one of the most cosmopolitan stored-product pests in the world and a flagship example of insect-microbe symbiosis enabling otherwise impossible diets. The species is small (2-3 mm), oval, brown, and infests an extraordinary range of dried organic materials: tobacco products (cigars, cigarettes, pipe tobacco), spices (paprika, cumin, coriander, cinnamon), dried fruit (dates, figs, apricots), dried herbs (medicinal and culinary), dried fish, dried meat (jerky), dried plant material in herbarium collections, and dried insect specimens in museum entomology collections. The species' ability to digest tobacco is biologically remarkable: nicotine is a potent neurotoxin that kills almost any insect, and the cellulose-rich plant material is otherwise indigestible. Cigarette beetles solve both problems with a yeast endosymbiont — Symbiotaphrina kochii — that lives in special pouches connected to the gut. The yeast detoxifies the nicotine through enzymatic degradation and produces cellulases and other digestive enzymes that allow the beetle to extract nutrients from cellulose. The endosymbiont is transmitted from female to offspring via egg-coating, ensuring the next generation has the symbiotic capability. The species' stored-product role is global: cigarette beetles have been documented in essentially every type of dry-goods storage worldwide, including found inside intact ancient Egyptian tomb papyri (dating to 3,000+ years ago), inside sealed museum exhibit cases, and inside unopened cigarette packs (the species can chew through paper packaging from inside). Modern tobacco and spice industries spend significant budgets on integrated pest management for cigarette beetle, including pheromone trapping (the male-produced aggregation pheromone serricornin), modified atmosphere fumigation, and refrigerated storage.