If the taste of tobacco is addictive to some, then you may learn that it can be as well for some insect species๐ฌ. The species ๐๐ข๐ด๐ช๐ฐ๐ฅ๐ฆ๐ณ๐ฎ๐ข ๐ด๐ฆ๐ณ๐ณ๐ช๐ค๐ฐ๐ณ๐ฏ๐ฆ (Fabricius, 1792), also known as the Tobacco Beetle, is a Coleoptera commonly found in commodities, especially in cigarettes and cigars๐. This species belongs to the Anobiidae family which also includes several other economically important species with strange names such as the deathwatch beetle (๐๐ฆ๐ด๐ต๐ฐ๐ฃ๐ช๐ถ๐ฎ ๐ณ๐ถ๐ง๐ฐ๐ท๐ช๐ญ๐ญ๐ฐ๐ด๐ถ๐ฎ), the drugstore beetle (๐๐ต๐ฆ๐จ๐ฐ๐ฃ๐ช๐ถ๐ฎ ๐ฑ๐ข๐ฏ๐ช๐ค๐ฆ๐ถ๐ฎ) or the furniture beetle (๐๐ฏ๐ฐ๐ฃ๐ช๐ถ๐ฎ ๐ฑ๐ถ๐ฏ๐ค๐ต๐ข๐ต๐ถ๐ฎ).
The exact origin of the Tobacco Beetle remains a mystery as the species has been spread over the world for centuries as illustrated by its first mention in Paris in 1848 on cured tobacco. But traces of this beetle in human history goes back for many more centuries! Indeed, the species was recorded in a sealed amphora within the tomb of the most famous pharaoh, Tutankhamun, suggesting its presence in Egypt at least 3,500 years ago! And yet, the species was described in 1792 by the Danish zoologist Fabricius, from specimens associated with dry plants collected in the Americas. Thus if the origin of this species is uncertain, we know, however, that it likely originates from some subtropical or tropical regions and is now widespread all over the world thanks to human trade. A small comfortโฆ or discomfort to some.
Letโs face it, the 2 to 3 mm length and brown colouration of the adults of the Tobacco Beetle has probably helped in its spreading, remaining unnoticed by merchants and other customs officers, while its larvae were feeding within the goods๐. You may already find it hard to notice these tiny beetles as adults. However, consider that a female can lay up to 100 eggs in her lifetime, each of those being of course much smaller than the adults, measuring at best only 0.5 mm! Whenever you see a few brown bean-like beetles, there are probably a bunch of larvae already feeding around. Contrary to what the vernacular name may suggest, the beetle does not limit itself to feeding on tobacco, but instead feeds on a wide range of products of plant or animal origin. This gives them a strong adaptability for different environments without relying on a single source. Most damages, however, are not made by adults, which as often in the insect world are more busy with reproduction than eating, but by the rather voracious larvae.
We all know that tobacco is harmful for human health๐ต, but what about beetles? Tobacco plants absorb cadmium, a toxic element, into their tissues so as to repel the damage from insects. How can tobacco beetles live through this deadly trap? Tobacco beetles have developed special strategies to keep them from poisoning. Within the beetle's body, live some symbiotic yeasts able to degrade the toxin, producing nutrients and vitamins thus supporting the living of the beetles. Nicotine is another molecule produced by tobacco plants, acting as a natural insecticide. The tobacco beetle, however, is able to secrete out the molecules of nicotine, preventing their accumulation within the body, without which it could reach a lethal level. Together with its symbiotic yeasts, they can adapt to a variety of environments and enjoy different kinds of food, helping them to spread through the world.
The defensive abilities of those beetles also include some tricks against their predators. When the beetles detect a potential predator, they will feign death๐. This strategy, referred as thanatosis, is very common in many animals facing an inescapable threat. At first, the beetle will stop its motion, coil up its legs into a spiracle shape and pretend to be dead. This can deceive the predators by reducing the predatorsโ vigilance. The beetle will then wait and all of a sudden, it will quickly fly away. Sometimes, it may deceive us too! If you would like to learn more about thanatosis in other animals, donโt hesitate to look up at our previous post๐ > https://bit.ly/3NsUWAH.
Come and observe some of this beetle, and many other species at the Hong Kong Biodiversity Museum. No worries, there is no chance for these to follow you home and enjoy your belongings.
Text: CH Law
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