You may have noticed bedbugs have made the news as of late with terms like “infestation” “outbreak” or “out-of-control” regularly in the headlines, only adding to a growing atmosphere of fear and the spread of misinformation about these insects❌. But how much do you really know about bedbugs🧐?
First of all, bedbugs are not new arrivals, and have long been in Hong Kong and according to a study were already found in a majority of homes in 2019. The species that tend to be a nuisance to humans are the common bedbug, 𝘊𝘪𝘮𝘦𝘹 𝘭𝘦𝘤𝘵𝘶𝘭𝘢𝘳𝘪𝘶𝘴 Linnaeus, 1758 (pictured above), and the tropical bedbug, 𝘊𝘪𝘮𝘦𝘹 𝘩𝘦𝘮𝘪𝘱𝘵𝘦𝘳𝘶𝘴 (Fabricius, 1803), both of which are found here and belong to the Cimicidae family under the order Hemiptera (the “true bugs”). The bedbug 𝘊. 𝘭𝘦𝘤𝘵𝘶𝘭𝘢𝘳𝘪𝘶𝘴 is oval-shaped, reddish-brown, and adults are wingless. At around 5-7 mm, they are about the size of an apple seed and can neither fly nor jump, opting instead to crawl. Bedbugs are nocturnal insects, meaning that they will be active at night. Their small size and flattened bodies allow them to fit into narrow gaps like the edge seams of a mattress or cracks in a wooden headboard so they may rest during the day before coming out at night to feed🌙.
Speaking of feeding, have you ever hear of the children’s rhyme “Good night, sleep tight, don’t let the bedbugs bite💤”? Despite popular belief, bedbugs do not in fact bite, nor can they. Instead, they have long, straw-like mouthpart called a proboscis that can pierce skin, much like that of a mosquito🦟. Their saliva, which contains an anticoagulant, allows 𝘊. 𝘭𝘦𝘤𝘵𝘶𝘭𝘢𝘳𝘪𝘶𝘴 to drink 1.3-2 times their own body weight every 5-10 days. A full meal of blood can thus be obtained in 5-20 minutes, the result of such behaviour can leave raised itchy bumps in a line, zigzag pattern, or randomly dispersed on the skin that typically resolve in about 1-2 weeks, and in rare cases bites may eventually trigger an allergic reaction.
Additionally, bedbugs can live without feeding for 20 to 400 days. Adult bed bugs may even live up to one year or more without eating and breed up to 4 generations😱! Further, 𝘊. 𝘭𝘦𝘤𝘵𝘶𝘭𝘢𝘳𝘪𝘶𝘴 partake in “traumatic insemination”, meaning that as they mate the male bedbug pierces directly into the female’s body cavity (as opposed to into the female’s genital tract) using its dagger-shaped penis, called an aedeagus. From there the sperm is diffused through the female’s hemolymphs (a fluid tissue found in most invertebrates that is analogous to blood), thereby reaching the ovaries and resulting in fertilisation. This process is so traumatic that this causes severe damage to the female’s health, reducing their lifespan by up to 50%. It’s a pretty hardcore way to mate and is suspected to have evolved as a response to the female’s ability to select mates.
The human-bedbug relationship is one that spans thousands of years, with the oldest specimen of 𝘊. 𝘭𝘦𝘤𝘵𝘶𝘭𝘢𝘳𝘪𝘶𝘴 found in a 3,550-year-old Egyptian tomb! However, we have reason to believe this relationship goes back even further. Based on molecular data, the ancestors of the modern bedbugs were thought to live in caves, feeding on bat blood🦇. As our own ancestors started to share similar habitats, living in proximity to bat colonies, some of these insects found access to a new, additional source of blood, and nowadays 𝘊. 𝘭𝘦𝘤𝘵𝘶𝘭𝘢𝘳𝘪𝘶𝘴 remains associated with bat colonies or gregarious birds such as swifts or swallows. Bedbugs have a fondness for animals, including us, living in tight groups composed of several individuals. Over time, as humans made the eventual transition from caves to beds, they brought along some of these insects, essentially partaking in the evolution from “cave bugs” to “bedbugs”, and the rest is itchy history.
At this point, you may be wondering about modern human-bedbug relations. As humans found new, and further ways to travel the globe🌏, bedbugs have followed and spread all around the world – another example of biological invasions. In the early 1940s, however, the use of synthetic organic insecticides like DDT (now banned in many countries due to multiple toxic effects) contributed to a near eradication of the insects in developed countries by the 60s. Unfortunately, this came at a cost, as populations resurged in the late 90s, now with high resistance to pesticides; a phenomenon commonly observed in insects due their biology but also to the poor application of these products.
So what do we do? Because of this modern insecticide resistance, you should put away the bug spray. While bedbug infestations should be reported and managed by trained professionals, we can also take simple preventative steps. Examples include checking your mattress for bedbugs while travelling, especially along the seams. Temperatures of 60°C have been shown to effectively kill all stages of bedbugs, so wash clothes and linens in high heat after travelling or purchasing second-hand items. You can also spread a very thin layer of diatomaceous earth on sensitive areas such as around the bed feets or other potential cracks in your floor or walls. Additionally, while travelling avoid putting suitcases and other travel items on your bed✈️.
For better or for worse, bedbugs and humans are intrinsically connected. And while these insects are so often demonised, perhaps the most important thing to note is that while bedbugs feed on our blood, contrary to some blood-feeding mosquito species, there is no scientific evidence to suggest that bedbugs transmit blood-borne diseases. So except for some unwelcome suction and itchiness, there is nothing else to fear👍🏻.
Text: Lydia Chang, Deidra Wirakusumah
Photo credit: Benoit Guénard
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