Genetic structure of sibling butterfly species affected byWolbachiainfection sweep: evolutionary and biogeographical implications

Abstract

It was recently recognized that in Japan, the common yellow butterfly, Eurema hecabe, consists of two sibling species, which have been unnamed yet and tentatively called yellow (Y) type and brown (B) type. We investigated the diversity of nuclear and mitochondrial genes in Japanese populations of Y type and B type of E. hecabe. The phylogeny based on nuclear genes agreed with the distinction between Y type and B type, which had been also supported by a wide array of biological data. However, the phylogeny based on mitochondrial genes did not reflect the distinction. PCR survey of Wolbachia revealed that B-type populations were all infected while Y-type populations contained both infected and uninfected individuals. A single genotype of Wolbachia, which was inferred to be a CI-inducing strain from their wsp gene sequence, was prevalent in these populations. Notably, the mitochondrial phylogeny was in perfect agreement with the pattern of Wolbachia infection, suggesting that the Wolbachia infection had affected the mitochondrial genetic structure of the host insects. Probably, the Wolbachia strain and the associated mitochondrial genomes have been occasionally introduced from B-type populations to Y-type populations through migration and subsequent interspecific hybridization, and CI-driven population sweep has been spreading the Wolbachia strain and the particular mitochondrial haplotypes, which originated from B-type populations, into Y-type populations. On the basis of these results together with the geological and biogeographical knowledge of the Japanese Archipelago, we proposed an evolutionary hypothesis on the invasion and spread of Wolbachia infection in B-type and Y-type of E. hecabe.

Multiple endosymbiont infections and reproductive manipulations in a linyphiid spider population

“…However, theoretical models suggest that competing endosymbionts may disrupt one another's spread (Engelstädter et al, 2004;Charlat et al, 2006). Indeed, the few previous empirical studies documenting multiple manipulations within a host population have primarily confirmed the dominance of one or the other manipulation (Hiroki et al, 2004;Charlat et al, 2006;Narita et al, 2006). In contrast, the presence of both manipulations at both time points for M. fradeorum (initial laboratory line collection and field survey 2 years later) suggests that both manipulations may persist in this system.…”

Linkage map of the peppered moth, Biston betularia (Lepidoptera, Geometridae): a model of industrial melanism

“…The gene composition of the Z chromosome is conserved in Lepidoptera, although not as strongly as some of the autosomes (Beldade et al, 2009;Baxter et al, 2011;Kroemer et al, 2011). A number of genes, such as kettin, tpi, 6-PGD, period, apterous and Ldh, have been assigned to the Z chromosomes of various Lepidoptera (Johnson and Turner, 1979;Gotter et al, 1999;Suzuki et al, 1999;Dopman et al, 2004;Narita et al, 2006;Pringle et al, 2007;Putnam et al, 2007;Van't Hof et al, 2008;Kroemer et al, 2011;Yoshido et al, 2011) and are now established lepidopteran Z-genes. The silkworm (Bombyx mori) whole-genome sequence assembly (The International Silkworm Genome Consortium, 2008) includes a large number of additional Z-linked genes, many of which have since also been found on the Z chromosome in other Lepidoptera (Beldade et al, 2009;Baxter et al, 2011;Kroemer et al, 2011).…”

Unexpected Mechanism of Symbiont-Induced Reversal of Insect Sex: Feminizing Wolbachia Continuously Acts on the Butterfly Eurema hecabe during Larval Development

“…This phenotype causes all-female broods of the host arthropods (17,39 (17,18,35). In lepidopteran insects including E. hecabe, the sex determination system is generally female heterogametic (i.e., ZZ males and ZW females) and cell autonomous (i.e., occurrence of sexual mosaics) (12,48).…”