There are many examples of the influence of sperm competition in other invertebrates as well as vertebrate mating systems. One of the basic experimental strategies in assessing sperm competition is known as multiple mating experiments. In these experiments a single female is allowed to sequentially mate with two or more males. Among insects, the general finding is that the first male does not always fare quite so well. Here are two examples of strategies to increase chances of the mating success of the last male.
Fruit flies displace sperm from previous mating.
These actions serve to reduce the competition for egg fertilization posed by the sperm populations already in a female's possession. There are many adaptations, behavioral and physiological, that appear to give a competitive edge to one's own sperm, relative to another population of sperm. Some of these adaptations seem to work in concert. The cricket mating system includes a biochemical mechanism to release egg-laying behavior. For another component of the same system, males perform their calling, courtship and mating in a pre-constructed arena.