Genetic Diversity of <I>Bactrocera dorsalis</I> (Diptera: Tephritidae) on the Hawaiian Islands: Implications for an Introduction Pathway Into California

Abstract

Population genetic diversity of the oriental fruit fly, Bactrocera dorsalis (Hendel), on the Hawaiian islands of Oahu, Maui, Kauai, and Hawaii (the Big Island) was estimated using DNA sequences of the mitochondrial cytochrome c oxidase subunit I gene. In total, 932 flies representing 36 sampled sites across the four islands were sequenced for a 1,500-bp fragment of the gene named the C1500 marker. Genetic variation was low on the Hawaiian Islands with >96% of flies having just two haplotypes: C1500-Haplotype 1 (63.2%) or C1500-Haplotype 2 (33.3%). The other 33 flies (3.5%) had haplotypes similar to the two dominant haplotypes. No population structure was detected among the islands or within islands. The two haplotypes were present at similar frequencies at each sample site, suggesting that flies on the various islands can be considered one population. Comparison of the Hawaiian data set to DNA sequences of 165 flies from outbreaks in California between 2006 and 2012 indicates that a single-source introduction pathway of Hawaiian origin cannot explain many of the flies in California. Hawaii, however, could not be excluded as a maternal source for 69 flies. There was no clear geographic association for Hawaiian or non-Hawaiian haplotypes in the Bay Area or Los Angeles Basin over time. This suggests that California experienced multiple, independent introductions from different sources.

Population structure of a global agricultural invasive pest, Bactrocera dorsalis (Diptera: Tephritidae)

“…Endemic to the Indo-Asian region, the fly first established outside this native range in Hawaii in 1945, where it remains a major pest (Vargas, Piñero, & Leblanc, 2015). The fly has subsequently invaded the continental United States on numerous occasions and, while the formal regulatory position is that it is currently absent from the continental United States, debate exists in the scientific literature as to whether it is permanently established in California (Papadopoulos, Plant, & Carey, 2013), or is a repeat invader (Barr et al, 2014). Regardless of the position in the United States, B. dorsalis is invasive and permanently established in several South Pacific countries (Vargas et al, 2015), has invaded and been eradicated twice in Australia (Cantrell, Chadwick, & Cahill, 2002), is currently actively invading Central China (Chen, Zhang, Ji, Yang, & Zheng, 2014), and is an "A1" quarantine pest for the European Union (EPPO, 2015).…”

Eradication of tephritid fruit fly pest populations: outcomes and prospects

“…To date three teams with 45 authors including some of us have opposed the interpretation by Papadopoulos et al (Barr et al (), Gutierrez et al () and a 30+ author presentation with an abstract from the Ninth International Symposium on Fruit Flies of Economic Importance (McInnis et al )). Gutierrez et al () said of the Papadopoulos, Plant and Carey analysis: "In summary, inference of establishment of fruit flies based on recurrence data is neither explanatory nor provides confirmation of establishment in California…".…”

“…Molecular approaches that enable phylogenetic analyses have contributed further evidence to inform this debate. Barr et al () compared Hawaiian fly DNA sequences to those of 165 flies from outbreaks in California between 2006 and 2012 concluding that a single‐source introduction of Hawaiian origin was unlikely to be responsible for many of the flies in California, suggesting multiple, independent introductions from different sources.…”

Population genetic structure of Zeugodacus tau species complex in Thailand

“…The complete sequence of the mitochondrial COI of Z. tau complex has a total length of 1534 bp (Yong et al ., ). Partial sequences of this gene are commonly used when studying population genetic structures and phylogenetic relationships in tephritid fruit flies, such as Bactrocera latifrons (Meeyen et al ., ), Bactrocera dorsalis (Shi et al ., ; Barr et al ., ; Choudhary et al ., ), Bactrocera correcta (Kunprom et al ., ), Zeugodacus ( Bactrocera ) cucurbitae (Prabhakar et al ., ; Kunprom & Pramual, ) and including Z . ( Bactrocera ) tau (Prabhakar et al ., ; Shi et al ., ), although they have not been reported for Thai populations.…”