The cliff swallow bug Oeciacus vicarius (Cimicidae : Hemiptera) :

The cliff swallow bug is a nest-dwelling, polyphagous ectoparasite of the cliff swallow Hirundo pyrrhonota. The bugs anticipate the spring arrival of the migratory swallows by aggregating in the necks of the nests in colonies that were inhabited by birds the previous year. Swallow use of cliff colonies is unpredictable and bugs disperse between colonies by clinging to the swallows. Adaptations to an ephemeral host-food resource include iteroparity, few young, a lengthy maturation time, multivoltine life cycle and a long life. Newly emerged bugs mate before overwintering at a time when the sex ratio is male biased. Spring collections are biased towards females which may lay eggs as soon as they feed, without remating.Bug populations increase when the swallows are present (April to July in Oklahoma). Swallows depart synchronously from cliffs, which are abandoned for one or more years before being reused. Bug populations survive overwinter in protected crevices and nests on the cliffs. In contrast, bridges were reused each year with departure spread over 3 weeks. The density of bugs in bridge nests was significantly lower than on cliffs that were used that year, but not significantly different than cliff colonies abandoned for 1 year. Bugs were fewer in newly built colonies and on the edges of older colonies, but nesting weight was significantly lower as well. Alternate hosts give an opportunity for bugs to feed and develop after swallows migrate