Host specialization involving attraction, avoidance and performance, in two phytophagous moth species

Area of Science:

• Ecology
• Evolutionary Biology
• Entomology

Background:

• Host specialization is a key driver of insect diversification.
• Mechanisms of specialization are known, but their impact on species divergence is unclear.
• Host preference and performance are hypothesized to be major sources of divergence.

Purpose of the Study:

• To assess host preference and larval performance in two moth species: European corn borer (ECB) and Adzuki bean borer (ABB).
• To investigate the role of these specialization components in insect species divergence.

Main Methods:

• Tested oviposition behavior of ECB and ABB in choice and no-choice setups.
• Performed reciprocal larval transplant experiments on usual and alternative host plants.
• Evaluated larval performance based on weight and survival.

Main Results:

• Both ECB and ABB exhibited strong host plant preference for oviposition.
• Relative larval performance on usual versus alternative hosts varied by experiment and trait (weight/survival).
• ECB's preference for maize involved avoidance of mugwort, a novel finding.

Conclusions:

• Host preference and performance are critical factors in phytophagous insect divergence.
• Differential performance and host avoidance/attraction contribute to specialization.
• These findings offer insights into the mechanisms underlying insect divergence.