My memories of rice weevils

My mother’s daily meal preparations in Korea would always start with her grabbing a bucketful of white rice from our glazed brown pottery in the kitchen. Sometimes, I would volunteer to help. While digging into a potful of smooth and tiny rice grains with my bare hands had its therapeutic values, what I enjoyed more from the experience was looking for “rice bugs.”

My mom would always tell me to watch out for them and that I should look carefully through the bucket to see if there are any crawling around. As a result, I poured the rice into my mother’s cooker only when I was absolutely confident that my bucket was completely bug-free. On rare occasions I actually saw one, I remember picking it out with my fingers. I was fearlessly determined to make sure that these critters don’t end up in our meals.

Dark-colored rice weevils are distinctly visible against the white color of rice. (Source: quora.com)
Dark-colored rice weevils are distinctly visible against the white color of rice. (Source: quora.com)

Google tells me that these insects I’ve only referred to as “rice bugs” until now are actually “rice weevils,” or Sitophilus oryzae. They are apparently common stored product pests, and they have orange spots on their elytra that are too small to observe unless magnified. I also learned an interesting fact about their reproductive system: females deposits their egg inside a grain kernel by chewing a hole into it. What a pleasant revelation.

Using their mandibles, the female rice weevils chew into a grain of rice and deposits their egg into the hole. The egg forms into a larva and undergoes development inside the rice. (Source: Department of Primary Industries)
Using their mandibles, the female rice weevils chew into a grain of rice and deposit their single egg into the formed hole. The egg forms into a larva and undergoes development inside the rice grain. (Source: Department of Primary Industries)

It is fascinating to learn that within the same genus exists two other notable species, each with slight evolutionary variations that allow them to feed on different stored harvests. There are the wheat weevils (S. granarius) and the maize weevils (S. zeamais), and their common names serve as obvious clues to their niche. This type of specialization came to me as simply amazing, but I figured that this is only a tip of the massive iceberg that is the Coleoptera order.

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