摘要: Despite the fact that all vertically transmitted symbionts sequester resources from their hosts and are therefore costly to maintain, there is an extraordinary diversity of them in invertebrates. Some spread through host populations by providing with fitness benefits or manipulating sex ratio, but some do not: maintenance lineages remains enigma. In this review, I explore evolutionary ecology impact on resistance, provide overview evidence for three-way interactions between these symbionts, natural enemies invertebrate hosts. A number recent empirical theoretical studies suggest may protect pathogens. If ‘symbiont-mediated protection’ widespread, it likely contribute significantly variation measures resistance enemies.