Diversity of fall armyworm, Spodoptera frugiperda and their gut bacterial community in Kenya

Abstract

9The invasive fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) is a polyphagous pest that causes 10 widespread damage particularly to maize and sorghum in Africa. The microbiome associated with S. 11frugiperda could play a role in their success and adaptability. However, these bacterial communities remain 12 poorly studied, especially for S. frugiperda in Africa. We investigated the composition, abundance and 13 diversity of microbiomes associated with larval and adult specimens of S. frugiperda collected from four 14 maize growing regions in Kenya through high throughput sequencing of bacterial 16S rRNA gene. We 15 identified Proteobacteria and Firmicutes as the most dominant phyla and lesser proportions of 16 Bacteroidetes and Actinobacteria. We also observed differences in bacterial microbiome diversity between 17 larvae and adults that are a likely indication that some prominent larval bacterial groups are lost during 18 metamorphosis. Several bacterial groups were found in both adults and larvae suggesting that they are 19 transmitted across developmental stages. Reads corresponding to several known entomopathogenic 20 bacterial clades as well as the non-bacterial entomopathogen, Metarhizium rileyi (Farl.) Kepler, Rehner & 21 Humber (2014), were observed. Mitochondrial DNA haplotyping of the S. frugiperda population in Kenya 22 indicated the presence of both 'Rice' and 'Corn' strains, with a higher prevalence of the 'Rice' strain. Insights 23 into the microbiota may ultimately provide alternative avenues for controlling of this pest.24

Microbiome of the larvae of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) from maize plants

“…These findings are in agreement with the recent report by Gichuhi et al. (2020) on the occurrence of the same bacteria groups in S. frugipeda in their study.…”

“…Four bacteria genera, Enterococcus , Pseudomonas , Delftia and Serratia , observed in this study have previously been isolated from S. frugiperda (Almeida, Moraes, Trigo, Omoto, & Cônsoli, 2017); Acevedo et al, 2017; Gichuhi et al., 2020). Additionally, Staphylococcus , Microbacterium and Arthrobacter recorded were previously isolated from S. frugiperda in Brazil (Almeida et al., 2017).…”

“…However, Gichuhi et al. (2020) did not report the presence of Klebsiella in S. frugiperda rather recorded high proportion of Enterococcus in two larval samples from Nigeria in Kenya. Other authors also documented high relative abundances of Enterococcus and unclassified Enterobacteriaceae in the United States (Jones, Mason, Felton, & Hoover, 2019).…”

“…This observation is in line with the earlier reports on the gut bacteria biota of other lepidopteran insects such as in European Corn Borer Ostrinia nubilalis (Belda et al., 2011), Diamondback Moth, Plutella xylostella (L.) (Ramya, Venkatesan, Srinivasa Murthy, Jalali, & Verghese, 2016; Xia et al., 2013,2017), the African maize stem borer Busseola fusca (F.) (Snyman, Gupta, Bezuidenhout, Claassens, & van den Berg, 2016), the Spruce Budworm ( Choristoneura fumiferana ) (Landry, Comeau, Derome, Cusson, & Levesque, 2015), Pine processionary moth, Thaumetopoea pytiocampa (Denis &Schiff.) (Strano, Malacrinò, Campolo, & Palmeri, 2018), Silkworm Bombyx mori (Chen et al., 2018) and S. frugiperda (Gichuhi et al., 2020).…”

Peer Review #1 of "Diversity of the gut microbiome in three grasshopper species using 16S rRNA and determination of cellulose digestibility (v0.1)"

“…Bacteria of those two phyla accounted for more than 98% of the total intestinal bacteria of the three grasshopper species, which was consistent with previous reports on the primary species of insect microbiomes. Previous studies have shown that Proteobacteria are the primary bacteria in the intestinal tract of many insects: Schistocerca gregaria in Orthoptera (Dillon et al, 2010), Acyrthosiphon pisum in Hemiptera, and Ectropis obliqua (Engel & Moran, 2013) and Spodoptera frugiperda (Gichuhi et al, 2020) in Lepidoptera. Among the Lepidoptera insects studied, the primary bacteria in the intestinal tract of Lymantria dispar, Helicoverpa armigera, Bombyx mori and Plutella xylostella larvae are Proteobacteria and Firmicutes (Zhou et al, 2015;Priya et al, 2012;Broderick et al, 2004).…”