Penetrance interactions of colour pattern loci in the African Monarch and their implications for the evolution of dominance.

Scoring the penetrance of heterozygotes in complex phenotypes, like colour pattern, is difficult and complicates the analysis of systems in which dominance is incomplete or evolving. The African Monarch () represents an example where colour pattern heterozygotes, formed in the contact zone between the different subspecies, show such intermediate dominance. Colour pattern in this aposematic butterfly is controlled by three loci , and .

Eyespot variation and field temperature in the Meadow Brown butterfly.

Since the classic work of E.B. Ford, explanations for eyespot variation in the Meadow Brown butterfly have focused on the role of genetic polymorphism.

African Queens find mates when males are rare.

In butterflies and moths, male-killing endosymbionts are transmitted from infected females via their eggs, and the male progeny then perish. This means that successful transmission of the parasite relies on the successful mating of the host. Paradoxically, at the population level, parasite transmission also reduces the number of adult males present in the final population for infected females to mate with.

Global biogeography of warning coloration in the butterfly .

Warning coloration provides a textbook example of natural selection, but the frequent observation of polymorphism in aposematic species presents an evolutionary puzzle. We investigated biogeography and polymorphism of warning patterns in the widespread butterfly using records from citizen science ( = 5467), museums ( = 8864) and fieldwork ( = 2586). We find that polymorphism in three traits controlled by known mendelian loci is extensive.

Whole-chromosome hitchhiking driven by a male-killing endosymbiont.

Neo-sex chromosomes are found in many taxa, but the forces driving their emergence and spread are poorly understood. The female-specific neo-W chromosome of the African monarch (or queen) butterfly Danaus chrysippus presents an intriguing case study because it is restricted to a single 'contact zone' population, involves a putative colour patterning supergene, and co-occurs with infection by the male-killing endosymbiont Spiroplasma. We investigated the origin and evolution of this system using whole genome sequencing.

Neo Sex Chromosomes, Colour Polymorphism and Male-Killing in the African Queen Butterfly, (L.).

(L.), one of the world's commonest butterflies, has an extensive range throughout the Old-World tropics. In Africa it is divided into four geographical subspecies which overlap and hybridise freely in the East African Rift: Here alone a male-killing (MK) endosymbiont, , has invaded, causing female-biased populations to predominate.

Karyotypes versus Genomes: The Nymphalid Butterflies Melitaea cinxia, Danaus plexippus, and D. chrysippus.

The number of sequenced lepidopteran genomes is increasing rapidly. However, the corresponding assemblies rarely represent whole chromosomes and generally also lack the highly repetitive W sex chromosome. Knowledge of the karyotypes can facilitate genome assembly and further our understanding of sex chromosome evolution in Lepidoptera.

A neo-W chromosome in a tropical butterfly links colour pattern, male-killing, and speciation.

Sexually antagonistic selection can drive both the evolution of sex chromosomes and speciation itself. The tropical butterfly the African Queen, Danaus chrysippus, shows two such sexually antagonistic phenotypes, the first being sex-linked colour pattern, the second, susceptibility to a male-killing, maternally inherited mollicute, Spiroplasma ixodeti, which causes approximately 100% mortality in male eggs and first instar larvae. Importantly, this mortality is not affected by the infection status of the male parent and the horizontal transmission of Spiroplasma is unknown.