Genetic colour variation visible for predators and conspecifics is concealed from humans in a polymorphic moth

Area of Science:

• Evolutionary Biology
• Genetics
• Animal Behaviour

Background:

• Colour polymorphism is defined by discrete genetic variants and phenotypes.
• Human perception is subjective and may miss subtle colour differences.
• Cryptic morphs, or phenotypes not easily distinguished by humans, may exist in polymorphic species.

Purpose of the Study:

• To investigate cryptic colour polymorphism in the wood tiger moth (Arctia plantaginis).
• To determine the inheritance patterns of hindwing colouration.
• To compare the ability of machine learning, humans, and vision models to discriminate between colour morphs.

Main Methods:

• Analysis of pedigree data from nearly 20,000 individuals to infer inheritance.
• Application of machine learning algorithms (Linear Discriminant Analysis) for genotype prediction.
• Utilisation of vision modelling to assess discriminability for humans, moths, and birds.

Main Results:

• Hindwing colouration in male moths is controlled by a single Mendelian locus with two alleles.
• Machine learning accurately predicted male genotypes (97%), while humans could only identify the yellow morph.
• Vision models incorporating ultraviolet sensitivity showed that birds and moths could distinguish between white morphs, unlike humans.

Conclusions:

• Human-based categorization of colour polymorphism can be unreliable due to perceptual limitations.
• Cryptic morphs, undetectable by humans, may be subject to selection pressures from other receivers.
• Objective methodologies are essential for accurate study of colour polymorphism and its evolutionary implications.