Nothing can hold out against civilization and the power of industry. The only animal species to survive will be those that industry multiplies.
— Jean-Baptiste Say
A female Aedes aegypti remains in suspended pregnancy until she ingests vertebrate blood. With hundreds of eggs in her ovaries, she begins a search for carbon dioxide and heat. Once detected, she lands on her host to penetrate the epidermis with her proboscis and deposit saliva, which as an anti-coagulant, ensures her meal of blood will flow smoothly to the next generation. Within sixty hours of this fluid exchange—spit for blood—oviposition is triggered in the expectant Aedes aegypti and her eggs are released along the surface line of still water where they complete their embryogenesis and wait. As rainwater delivers new microorganisms into this watery exometabolic womb (so often unwittingly prepared by humans), respiration reduces the available oxygen and causes the eggs to hatch. Without vows or affection, humans and mosquitoes become kin, bound by blood to the rhythm of microbial breath.
Mosquitoes sucked the blood of vertebrates for millions of years before Homo sapiens emerged from the evolutionary phylum, and until recently, humans weren’t particularly appealing hosts. But then they tilled, irrigated and settled, and as the Sahara dried, their settlements became the primary source for the blood and water that Aedes aegypti needed to survive. A sylvan arthropoid first domesticated the land, and was in turn domesticated as host; an evolutionary lesson in becoming-hospitable.
While settlement patterns drew almost all of Aedes aegypti’s host species near—dogs, cats, rodents, cows, pigs, and birds—they still came to favor blood from its human architects. Due to low levels of isoleucine, the blood of Homo sapiens extends the life of Aedes aegypti and ensures the production of offspring counts in the thousands. Not only that, but with higher levels of lipids than in other primates, human blood helps co-produce thirstier vectors. Because mosquitoes’ sanguine preference is based on their first successful blood-feed, as humans become ever more densely arranged into their urban settlements, the likelihood that Aedes aegypti’s first feed will be on human blood increases in turn, thereby establishing a lifelong affection; affine commitments are this way produced without the awkward requirement of affinity.
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