Development of a single nucleotide polymorphism-based DNA marker for fall armyworm (Lepidoptera: Noctuidae) biotyping: a case study from the fall armyworm outbreak in Sri Lanka

Abstract

Crop damage caused by fall armyworm (FAW), Spodoptera frugipera J.E. Smith (1797) (Lepidoptera: Noctuidae), has generated concern among agriculturists globally. In 2019, FAW was first reported in Sri Lanka, where it caused significant losses to corn crops. However, given that the two FAW biotypes – “rice strain” (R-FAW) and “corn strain” (C-FAW) – are morphologically identical, the biotype(s) present in Sri Lanka were unknown. The current study used the mitochondrial cytochrome c oxidase subunit I gene (mt-CO1) of FAW to biotype nine FAW samples collected in Sri Lanka. The resulting molecular phylogeny revealed that both R-FAW and C-FAW biotypes were present among the samples. In addition, we used the temperature-switch polymerase chain reaction (PCR) technique to develop a gel-based molecular marker. Two fragments were successfully amplified by the newly developed marker ABUOP0002, with fragment sizes of 341 bp from R-FAW and 204 bp from C-FAW. This demonstrates that ABUOP0002 can serve as a diagnostic gel-based molecular marker to identify the R-FAW and C-FAW biotypes from samples already identified to species level as S. frugiperda through taxonomical keys and provides a possible alternative to more expensive sequencing-based assays.

Multiple species delimitation approaches with COI barcodes poorly fit each other and morphospecies – An integrative taxonomy case of Sri Lankan Sericini chafers (Coleoptera: Scarabaeidae)

“…So far, only a handful of larger barcoding studies have been conducted on the Indian subcontinent. These include the identification of disease vectors (Tabanid flies: Banerjee et al, 2015; sand flies: Gajapathy et al, 2016; biting midges Culicoides: Harrup et al, 2016; mosquitos: Weeraratne et al, 2018), and also of highly invasive agricultural pests (fruit fly: Khamis et al, 2012; tea mosquito bugs: Rebijith et al, 2012; Pentatomomorpha bugs: Tembe et al, 2014; Kaur & Sharma, 2016; thrips: Tyagi et al, 2017; and fall armyworm: Nanayakkara et al, 2020). Furthermore, barcoding approaches have been used to resolve taxonomic questions in butterflies (Goonesekera et al, 2019; Rajpoot et al, 2018), fishes (Dhaneesh et al, 2015; Ekanayake et al, 2021; Lakra et al, 2016; Raja & Perumal, 2017; Senevirathna & Munasinghe, 2013), frogs (Biju et al, 2014; Meegaskumbura et al, 2015), freshwater crabs (Beenaerts et al, 2010), spiders (Ileperuma Arachchi & Benjamin, 2019; Kanesharatnam & Benjamin, 2019), snakes (Pyron et al, 2013), and snails (Raheem et al, 2017).…”