Wolbachiastrains, and lack of genetic diversity and parthenogenesis in Brazilian populations ofTuta absoluta(Lepidoptera: Gelechiidae)

Abstract

The pheromone‐based control of the invasive tomato pinworm Tuta absoluta (Lepidoptera: Gelechiidae) has been unsatisfactory in some cases, and parthenogenesis was reported in this species. As the parthenogenesis phenomena is a shortcoming that compromises the pheromone‐based control of T. absoluta and that is potentially explained by the occurrence of the endosymbiont Wolbachia in this pest species, the objectives of this study were (i) to survey the Wolbachia strains in Brazilian pinworm populations, (ii) to assess the genetic diversity in the tomato pinworm, and (iii) to determine whether parthenogenesis does occur associated with the most representative combination of insect haplotype and Wolbachia strain. The 10 insect populations were infected with two Wolbachia strains (ST41 and ST354), with infection rates ranging from 70% to 100%. The insect genetic diversity was low with a single haplotype group present for both mitochondrial and nuclear DNA markers. The most representative combination of pinworm‐Wolbachia produced 6.88 ± 1.70 eggs per unmated female, all of which were inviable. Thus, Wolbachia infection does not lead to either parthenogenesis or pheromone‐based control failure among Brazilian populations of the tomato pinworm, but likely favours cytoplasmic incompatibility, which is also potentially useful as a pest management tool.

Similar Bacterial Communities among Different Populations of a Newly Emerging Invasive Species, Tuta absoluta (Meyrick)

“…Most Wolbachia infecting lepidopteran insects belong to supergroup A or B, and most of them belong to supergroup B [ 65 , 66 ]. In the current study, the Wolbachia detected in the three different geographical populations of T. absoluta appeared to belong to supergroup B, which was consistent with previous results in a Brazilian population and Iranian and Turkish populations [ 67 , 68 ].…”

Analysis of genetic variation in an important pest, Tutaabsoluta, and its microbiota with a new bacterial endosymbiont

“…Other comprehensive studies about Wolbachia infection in Lepidopteran families showed 58.3% in 120 species of Siberian populations (Ilinsky and Kosterin, 2017); 45% of 49 Japanese species (Tagami and Miura, 2004); 52% of 29 Indian species (Salunke et al, 2012), and 79% of 24 Acraea species from Uganda (Jiggins et al, 2001). In our study, all tomato leaf miner populations displayed 100% of Wolbachia infection, which is consistent with the populations from Brazil, Croatia, and Montenegro (Škaljac et al, 2012;Carvalho et al, 2018). Although Wolbachia is mostly known bacteria, Spiroplasma were present at low levels while Rickettsia was also not commonly found with only one species across Lepidopterans.…”

“…In this study, the findings of high genetic homogeneity among T. absoluta populations with high prevalence of Wolbachia and Pantoea infections seems to imply that both bacterial infections have less impact on the mtDNA variations. Our results are in accordance with the findings about the populations reported in Brazil (Carvalho et al, 2018). Even though these results differ from previous studies that report that Wolbachia spread affects the mtDNA diversity of its host through indirect selection, which means if a population gains any reproductive advantage or fitness from Wolbachia, the initial mtDNA type will hitchhike through the population and change the uninfected haplotypes (Hurst and Jiggins, 2005;Schuler et al, 2016).…”

“…In this study, we have detected T. absoluta using wsp gene sequencing, which has been used in phylogenetic studies and for microtaxonomic subdivision (Van Meer et al, 1999). Our result is congruent with other pinworm populations in which 2 Wolbachia strains were detected, including ST41 and ST354, and classified in the supergroup B (Carvalho et al,2018). Wolbachia sequences of T. absoluta analyzed in this study are grouped with the other Lepidopterans belonging to supergroup B, which is suitable with Croatian populations, as well (Škaljac et al, 2012).…”

“…CI has been observed at high frequency in various Lepidopteran families (Sasaki et al, 2002;Hornett et al, 2008). Wolbachia strains detected in Brazilian pinworms found to be associated with CI (Carvalho et al, 2018). Apart from Wolbachia, tomato leaf miner populations showed deuterotokous parthenogenesis in mating experiments under laboratory conditions (Caparros Megido and Haubruge, 2018).…”