Happy Halloween to you all! We’re wrapping up this month’s gruesome topics with a primer on the vampires of the insect world. Mosquitos have certainly earned their place as the number one bloodsucking arthropod, killing around 725,000 people a year through mosquito-borne illnesses, but there are plenty of other examples that would have even Bela Lugosi shaking in his vampire boots.
Ticks are a relatively young order of arachnids, showing up in the fossil record about 146 – 66 mya during the Cretaceous period. There are only 3 described families (as opposed to 120 spider families) and one family contains a single species. The other two families are divided into hard-bodied ticks and soft-bodied ticks.
Depending on the species, the life cycles of ticks can become very complicated very quickly, with most species requiring two or more hosts. Hard bodied ticks attach to a host and feed until they are grotesquely bloated, which can take days to weeks, depending on the age of the tick and what life stage they are at. After feeding, they will drop, molt, and search for a new host.
Soft-bodied ticks, on the other hand, feed quickly (within hours), usually going unnoticed by their hosts. They feed at night, and are attracted to their host by the carbon dioxide expelled from their breath.
Tick fun fact! The pathogen that causes Lyme disease is a spirochete bacterium called Borrelia burgdorferi; and while this disease is spread by hard-bodied ticks on the east coast, the bacterium was discovered right here in Montana by Willy Burgdorfer, a world renowned medical entomologist based out of Rocky Mountain Labs (RML) in Hamilton, MT.
Also appropriately known as vampire bugs, these members of the Reduviidae family have a certain… affection for vertebrate blood. They tend to congregate in sheltered places, and will feed from the soft tissue around their victim’s face and eyes. They will inject their saliva into the bite site, which has anesthetic properties and allows the insect to feed unperturbed. Not surprisingly, kissing bugs are also important disease vectors, with every species in the kissing bug subfamily being a potential vector of Trypanosoma cruzi, the parasite that causes Chagas disease.
Tsetse flies strike me as something out of an H. G. Wells fever dream. These vampiric, bloodsucking flies are considered one of the major barriers to overcoming poverty in rural sub-Saharan Africa. The fly is a vector for trypanosomes, protozoan parasites that cause trypanosomiasis or sleeping sickness. Trypanosomiasis can affect humans and animals, most notably cattle, which prevents many of these populations from utilizing cattle for agriculture.
Sleeping sickness in humans is characterized by several symptoms, most notably by a disturbance in the sleep-wake cycle. Those infected may experience sleep inversion, where they suffer insomnia at night and periods of extreme sleepiness during the day. I don’t know about you, but the idea of such a disturbed sleep cycle scares me more than any bloodsucking phantom.
It’s impossible to think, study, or write about bedbugs without habitually scratching. I’ve never dealt with a bedbug infestation but the thought alone is enough to keep me up at night. Unlike the other bloodsuckers presented on this list, bedbugs are not known to transmit any diseases to humans, but their presence is enough to cause insomnia and anxiety. However the method of feeding is similar: they feed at night, attracted by the carbon dioxide expelled in breath. They will use their saw-like mouthparts to break open the skin and inject saliva, which contains anticoagulants and anesthetic properties, and feast on our tasty mammalian blood.
Sleep well tonight, fellow mammals.