Abstract
Simple SummaryInsect hosts have close relationships with microbial symbionts. The limited metabolic networks of most insects are enhanced by these symbiotic relationships. Using symbiotic microorganisms for biological control of insects and insect-borne diseases has become an important research topic and shows potential for the development of applicable control approaches. Blattella germanica (L.) is public health pest worldwide; it is difficult to control because of its strong reproductive ability, adaptability, and resistance to insecticides. In this paper, the diverse biological functions (nutrition metabolism, reproductive regulation, insecticide resistance, defense, and behavior management) of symbionts, their interaction mechanism with hosts, and the research progress in the control of B. germanica are reviewed and discussed.Insects have close symbiotic relationships with several microbes, which extends the limited metabolic networks of most insects. Using symbiotic microorganisms for the biological control of pests and insect-borne diseases has become a promising direction. Blattella germanica (L.) (Blattaria: Blattidae) is a public health pest worldwide, which is difficult to control because of its strong reproductive ability, adaptability, and resistance to insecticides. In this paper, the diverse biological functions (nutrition, reproductive regulation, insecticide resistance, defense, and behavior) of symbionts were reviewed, and new biological control strategies on the basis of insect–symbiont interaction were proposed. We highlight new directions in B. germanica control, such as suppressing cockroach population using Wolbachia or paratransgenes, and combining fungal insecticides with synergistic agents to enhance insecticidal efficacy.
Highlights
Cockroaches are an ancient group representing one of the most successful life forms
Insects including cockroaches harbor a large number of symbiotic microorganisms; these symbionts have coevolved with the host insect, thereby forming a complex and dynamically balanced microecosystem
Our results showed that the gut microbiota of B. germanica was closely involved in defending against pathogenic fungal infection
Summary
Cockroaches are an ancient group representing one of the most successful life forms. They have high adaptability to a wide range of habitats and environmental conditions from Arctic cold to tropical heat [1]. Insects including cockroaches harbor a large number of symbiotic microorganisms; these symbionts have coevolved with the host insect, thereby forming a complex and dynamically balanced microecosystem. They play an irreplaceable role in insect evolution and adaptation and are the health guardians of host insects. We highlight new directions in controlling B. germanica, such as utilizing Wolbachia to manipulate host reproduction to suppress the pest population or promoting applications of entomopathogenic fungi by disturbing the microecological balance of cockroach gut microbiota with a gel bait synergy agent. Bacteria can synthesize pheromones (e.g., volatile carboxylic acids) or interstitial hormones [42]
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