Controversial patterns of Wolbachia infestation in the social parasitic Maculinea butterflies (Lepidoptera: Lycaenidae)

Abstract

Wolbachia is a common group of intracellular bacteria found in arthropods and filarial nematodes. Since the past decade they have attracted considerable interest owing to their various effects on hosts, which range from reproductive manipulation to mutualism. Moreover, they can influence the mitochondrial DNA pattern which do not reflect the real evolutionary history of the target species and may be incongruent with nuclear data.Previously Wolbachia-manipulated mtDNA patterns, namely mito-nuclear discordance and deep mitochondrial splits associated with specific Wolbachia infections have been also discovered in the genus Maculinea. Here we present a comprehensive study on Wolbachia infestation and the genetic diversity of all Maculinea species in the Carpathian Basin. The prevalence and the pattern of the infestation highly differ among Maculinea species. M. alcon and M. arion are infected in 100%, each of these species with a single strain, but the infection level of M. nausithous and M. teleius is much lower, additionally, they are infected with multiple strains. The genetic diversity of Maculinea species proved to be generally low, only M. nausithous showed geographic pattern based on mitochondrial sequences and allozymes. In contrast with the previous studies, we could not detect mitonuclear discordance or find evidence for Wolbachia-induced selective sweep. Based on our results, we cannot hold only Wolbachia responsible for the restricted genetic diversity of Maculinea in the Carpathian Basin.Probably several factors shape together the level and pattern of genetic variability in Maculinea butterflies.

Assessment of the role of Wolbachia in mtDNA paraphyly and the evolution of unisexuality in Calligrapha (Coleoptera: Chrysomelidae)

“…Nevertheless, in the case of Calligrapha , the observed pattern is consistent with a dynamics of multiple infection, extinction, or turnover involving few strains of Wolbachia , where the strain of bacteria can change, but without evidence for loss or replacement of mtDNA diversity in the host, at least beyond the establishment of the main lineages. The results obtained for Calligrapha , where geography or even demography plays a major role in the structure and diversification of mtDNA despite of Wolbachia , parallel those obtained for spider mites across China (Chen, Zhang, Du, Jin, & Hong, ), or to some extent those for the oak gallwasp in Europe (Rokas, Atkinson, Brown, West, & Stone, ), increasing the body of Wolbachia literature reporting lack of evidence for selective sweeps, or at least showing that these are not a dominant feature for the mtDNA evolution of the host (Bereczki, Rácz, Varga, & Tóth, ; Keller et al, ).…”

Maculinea rebeli (Hirschke) – a phantom or reality? Novel contribution to a long‐standing debate over the taxonomic status of an enigmatic Lycaenidae butterfly

“…DNA was extracted from the heads of imagoes or the distal end of larvae or pupae following the protocol in Bereczki et al (2014). The mitochondrial cytochrome oxidase subunit I gene (COI) together with the nuclear genes histone H3 (H3), malate dehydrogenase (MDH), 28S ribosomal DNA (28S rDNA) and wingless (wg) were amplified by specific primers modified at their 5 ′ -end to include the universal sequencing primer T7promoter (Wahlberg & Wheat, 2008) following the amplification protocol described in Bereczki et al (2015). PCR products originating from 21 individuals were sequenced by commercial service provider Macrogen Inc. (Seoul, South Korea).…”

Incipient sympatric speciation via host race formation in Phengaris arion (Lepidoptera: Lycaenidae)

“…Although previous studies have found significant morphological differences between the two arion forms both in wing and genitalia, they could not show any genetic isolation between them based on either the investigated mitochondrial and nuclear gene regions or allozyme loci (Bereczki et al 2011(Bereczki et al , 2014(Bereczki et al , 2015. Nevertheless, the authors raised the possibility that the analysed markers were not suitable for the detection of the divergence between the forms because of their fairly low variability.…”

“…P. arion has two phenological forms whose coexistence has been recorded in certain parts of the species range, such as the Carpathian Basin (Bereczki et al 2011(Bereczki et al , 2014(Bereczki et al , 2015. The fast-flying, smaller-sized and dark violet-blue form (referred to as 'spring arion' hereafter) flies from mid-May to mid-June and prefers short-grass dry swards with cushions of early flowering Thymus species, which serve as initial food plants.…”