Male And Female Bed bugs
Bed bugs provide an interesting and compelling example of a conflict of interest between mates. Generally, scientists have assumed that both male and female parents have similar interests in reproduction. However, bed bugs mate in a peculiar manner that is advantageous for males but downright dangerous for females. The genitalia of the female bed bug do not function in copulation. Instead, the male injects sperm through the abdominal wall into a paragenital organ, a phenomenon known as traumatic insemination. Traumatic insemination wounds the females and may also result in infection.
In an experiment designed to evaluate the effects of remating on female bed bugs, Stutt and Siva-Jothy (2001) assigned female bed bugs to two treatment groups. In the low mating frequency treatment, they placed virgin female bed bugs with virgin male bed bugs initially. After one week, they replaced the male bed bug with another male whose intromittent organ was glued to his abdomen and therefore nonfunctional. In the control group, each virgin female bed bug was placed with a virgin male for four weeks. Females in the low mating frequency treatment produced eggs at the same rate as the control bugs, indicating that additional copulation does not increase female fitness. However, females in the control group died at a higher rate, resulting in reduced lifetime reproductive success.
Male Cimex lectularius produce an abdominal wound in females during mating, a phenomenon that is likely to be costly to females. To investigate the fertilizing capacity of a single copulation, 20 virgin females each received a single copulation from a virgin male. The number and proportion of fertile eggs produced were counted over eight clutches (one clutch per week). Virgin females where allocated at random to one of two experimental treatments. In the first treatment group, females were allowed to copulate once with a virgin male (allocated at random), whereas in the second treatment group, females were allowed to copulate once with each of five virgin males (allocated at random). Females then were isolated and fed at weekly intervals, and the eggs were collected for five clutches.