Symbioses shape feeding niches and diversification across insects

Area of Science:

• Evolutionary Biology
• Microbiology
• Ecology

Background:

• Insects have utilized symbiotic microbes for nutrition and defense for over 300 million years.
• The ecological drivers and diversification impacts of insect-microbe symbioses remain largely unexplored.

Purpose of the Study:

• To investigate ecological conditions favoring the evolution of insect symbioses.
• To determine how these symbioses have influenced insect diversification across various diets.

Main Methods:

• Analysis of 1,850 microbe-insect symbioses data from 402 insect families.
• Examination of nutrient limitations and dietary specializations associated with obligate symbiosis.

Main Results:

• Symbionts enable insects to exploit nutrient-imbalanced diets like phloem, blood, and wood.
• B vitamins were the sole consistent limiting nutrient linked to obligate symbiosis evolution.
• Dietary shifts facilitated by symbionts had varied effects on insect diversification, promoting it in herbivory but constraining it in blood-feeding niches.

Conclusions:

• Microbial symbioses are crucial for overcoming nutrient deficiencies in insects.
• The diversification consequences of insect symbioses are contingent upon the specific feeding niche invaded.