Cimex lectularius and Cimex hemipterus (bed bugs)

Bed bugs are obligate blood-feeding hemimetabolous insect ectoparasites with a life cycle that includes five instars, each requiring a blood meal to molt. Adults live for several months, hiding in crevices where females repeatedly layclutches of eggs. Bed bugs mate traumatically: the male inserts its genitalia into the female secondary sex organ(spermaledge), then sperm travels to spermatheca through the hemolymph. Humans are parasitized by two bedbug species that are hard to distinguish-Cimex lectularius and Cimex hemipterus. Their historical distribution over-lapped only partially, with C. lectularius and C. hemipterusbeing more common in temperate regions and (sub)tropics, respectively. In the 1950s, both species nearly vanished from households due to the widespread use of insecticides. However, they made a remarkable comeback in the past two decades, fueled by insecticide resistance and increased human mobility. As a side effect, these two species have become more sympatric on a global scale.