Invasive Spiders and Their Microbiomes: Patterns of Microbial Variation in Native and Invasive Species in Hawai'i

Area of Science:

• Ecology
• Microbiology
• Evolutionary Biology

Background:

• Invasive species disrupt ecosystems, especially on islands with unique biota.
• Gut microbiota influence arthropod fitness, with endosymbionts and acquired microbes serving distinct roles.
• Understanding microbial roles is key to explaining invasion success in novel environments.

Purpose of the Study:

• To investigate how gut microbiomes facilitate spider adaptation to new environments.
• To test if microbial composition is driven by environment or invasion status.
• To assess endosymbiont diversity and specificity in native versus invasive spiders.

Main Methods:

• Examined native and invasive spider pairs across Hawaiian Islands and mainland sites.
• Utilized 16S rRNA amplicon sequencing to analyze gut microbial communities.
• Compared microbial composition, diversity, and endosymbiont abundance between host groups.

Main Results:

• Site explained more microbial variance (11.7%) than host species (6.5%), indicating environmental filtering.
• Invasive spiders showed lower relative abundance of gut endosymbionts.
• Endosymbionts were locally acquired, not from ancestral ranges, with some invasives lacking them.

Conclusions:

• Gut microbiota composition is context-dependent, shaped by local environmental filters.
• Reduced endosymbiont diversity in invasive spiders may facilitate adaptation.
• Host-symbiont interactions differ between native and invasive species, potentially aiding invasion.