Morph-linked variation in female pheromone signalling and male response in a polymorphic moth

Area of Science:

• Evolutionary Biology
• Behavioral Ecology
• Genetics

Background:

• Genetic variation in reproductive strategies is crucial for species survival.
• The wood tiger moth (Arctia plantaginis) exhibits color polymorphism (white and yellow hindwings) linked to mating success.
• Understanding the interplay between genotype, behavior, and environment is key to explaining polymorphism maintenance.

Purpose of the Study:

• To investigate the association between three color genotypes (WW, Wy, yy) and variations in female pheromone signaling and male antennal morphology in Arctia plantaginis.
• To determine if female attractiveness and reproductive success correlate with color genotype.
• To examine how male color genotype and antennal morphology influence their ability to locate females.

Main Methods:

• Field and enclosure experiments were conducted using females of three color genotypes to test attractiveness.
• Male Arctia plantaginis' ability to reach females was assessed in relation to their own color genotype and antennal morphology (length, area, lamellae count).
• Statistical analyses were performed to correlate morph-related reproductive success, attractiveness, and male sensory traits with population density.

Main Results:

• Contrary to predictions, morph-related reproductive success and attractiveness were not correlated.
• Heavier Wy females attracted fewer males; increased weight decreased Wy female attractiveness but increased yy female attractiveness.
• Yellow (yy) females were generally more attractive, potentially due to earlier pheromone release. Male antennae lamellae count and color morph influenced female location success, with context-specific strategies observed between field and enclosure settings.

Conclusions:

• Female attractiveness is influenced by a combination of pheromone release, female weight, and population density, with yy females showing higher attractiveness.
• Male search success is modulated by morph-specific behaviors and local population density.
• The maintenance of genetic variation in Arctia plantaginis is likely driven by genotype-related female signaling strategies interacting with environment-dependent male behaviors.