Biological effects of the symbiosis between insects and intracellular bacteria Wolbachia pipientis

Only a few decades ago, symbiosis between insects and bacteria was considered a relatively rare phenomenon. The concept of symbiosis has changed in the past two decades due to the development of molecular-genetic methods. At the same time, a peculiar variant of symbiotic relationships, reproductive parasitism (i.e., modification of the host reproductive strategy by symbiotic bacteria) has been actively discussed by researchers. The intracytoplasmic bacterium Wolbachia pipientis is the most common reproductive symbiont of insects. The age of the symbiosis between the Wolbachia and insects is estimated to be 150 million years. The biological effects of the bacterium on different insect species vary from sporadic asymptomatic carriage to obligate symbiosis with many intermediate forms. Each of the millions of insect species infected with Wolbachia develops its own unique genetic mechanisms of the interaction with the bacterium. New events of infection of insect species with Wolbachia and its losses occur quite often, and not only in evolutionary time periods. The present review summarizes the current data on the genetic control of modification of the insect reproductive behavior caused by the Wolbachia and data on the effect of Wolbachia on the adaptation of infected insects. The paper also presents the data on the relatively poorly studied process of genetic recombination in representatives of the bacterial genus.