Question

A promising biological method for insect control involves the release of insects that could interfere with the fertility of the normal resident insects. One approach is to introduce irradiated sterile males to compete with the resident fertile males for mating. A disadvantage of this strategy is that the sterile males are not robust and can have problems competing with the fertile males. An alternate approach that is cur- rently in testing is to release laboratory-reared insects that are homozygous for several translocations. Explain how this strategy will work. Be sure to mention which insects will be sterile

Answer 1

Answer: In this strategy, the laboratory-reared insects are bred in such a way that they are homozygous for several translocations, which means that they carry two copies of each altered chromosome. When these modified insects are released into the wild, they will mate with the resident wild-type insects. However, the translocations make it difficult for the offspring to produce viable gametes, which leads to a reduction in the number of fertile offspring produced.

Over time, the population of wild-type insects will decline, as their offspring are less likely to survive to reproductive age. The laboratory-reared insects that carry the translocations will also produce fewer viable offspring, but their reduced fertility is less of a concern because they were not meant to reproduce in the wild. Therefore, the sterile insects in this case are the offspring of the wild-type insects that have mated with the laboratory-reared insects carrying the translocations.

Compared to the use of irradiated sterile males, this method has the advantage of using insects that are not weakened by radiation and that can compete more effectively with the resident fertile males for mating opportunities. Additionally, the homozygous translocation approach can be applied to a wider range of insect species, whereas the use of irradiated sterile males is limited to certain types of insects.