The hemolymph microbiome of insects.

Area of Science:

• Insect microbiology
• Insect immunology
• Symbiotic relationships

Background:

• Hemolymph traditionally viewed as sterile and hostile to microbes in healthy insects.
• Recent findings reveal stable or transient microbial inhabitants in diverse insect hemolymph.
• Key examples include Spiroplasma in Drosophila and Hamiltonella defensa in aphids.

Purpose of the Study:

• To challenge the conventional view of sterile insect hemolymph.
• To highlight the prevalence and impact of non-pathogenic microorganisms in insect hemolymph.
• To identify research priorities for understanding insect-hemolymph microbiota.

Main Methods:

• Review of current research on insect hemolymph microbiota.
• Analysis of known microbial inhabitants and their interactions with insect hosts.
• Identification of knowledge gaps and future research directions.

Main Results:

• Overwhelming evidence supports the presence of diverse microorganisms in insect hemolymph.
• These microbes can be nutritionally costly but offer benefits like protection from natural enemies.
• Microbial persistence involves evasion and tolerance of host immune responses.

Conclusions:

• Insect hemolymph is not universally sterile and harbors a complex microbiota.
• Understanding these symbiotic relationships is crucial for insect physiology, nutrition, and immunity.
• Future research should focus on microbial diversity, host-microbe interactions, and their physiological impacts.