Metabarcoding prey DNA from fecal samples of adult dragonflies shows no predicted sex differences, and substantial inter-individual variation, in diets

Abstract

Sexes often differ in foraging and diet, which is associated with sex differences in size, trophic morphology, use of habitats, and/or life history tactics. Herein, strikingly similar diets were found for adult sexes of a dragonfly (Leucorrhinia intacta), based on comparing 141 dietary taxa identified from the metabarcoding of mitochondrial DNA archived in feces. Arthropods in > 5% of samples included five species of dipterans, two hemipterans, two spider species and one parasitic mite. The mite was not traditional prey as its presence was likely due to DNA contamination of samples arising through parasitism or possibly via accidental consumption during grooming, and therefore the mite was excluded from diet characterizations. Common prey species were found with statistically indistinguishable frequencies in male and female diets, with one exception of an aphid more often found in male diets, although this pattern was not robust to corrections for multiple statistical tests. While rare prey species were often found in diets of only one sex, instances of this were more frequent in the more oft-sampled females, suggesting sampling artefact. Sexes did not differ in the mean prey species richness in their diets. Overall, sexes showed statistically indistinguishable diets both on a prey species-by-species basis and in terms of multivariate characterizations of diet composition, derived from presence-absence data of prey species analyzed via PERMANOVA and accumulation curves. Males and females may have similar diets by being both opportunistic and generalist predators of arthropods, using the same foraging habitats and having similar sizes and flight agilities. Notably, similarities in diet between sexes occur alongside large interindividual differences in diet, within sexes. Researchers intending on explaining adaptive sex differences in diet should consider characteristics of species whose sexes show similar diets.

Metabarcoding of trap nests reveals differential impact of urbanization on cavity‐nesting bee and wasp communities

“…The Leray data set consisted of 1,735,981 reads and ITS data set of 7,970,869 reads. For trimming and further analysis the reads were uploaded to CSC servers (IT Centre for Science, http://www.csc.fi) and analysed through the bioinformatics pipeline as described in Morrill et al (2021) as follows. First, primers were removed separately for R1 and R2 reads by using the Python program cutadapt (Martin, 2011) with 20% mismatch rate for primers and minimum length after trimming 100 bp.…”

“…For trimming and further analysis the reads were uploaded to CSC servers (IT Centre for Science, www.csc.fi) and analysed through the bioinformatics pipeline as described in Morrill et al (2021) as follows.…”

Brute force prey metabarcoding to explore the diets of small invertebrates

“…Since then, blocking primers have been used to study the prey of many different animals and with sample material ranging from whole-body extracts of copepods (Cleary et al, , 2017Durbin & Casas, 2014;Novotny et al, 2021;Ray et al, 2016;Zamora-Terol et al, 2020), to dragonflies and apex canine predators (Morrill et al, 2021;Shi et al, 2021).…”

“…Other variants of blocking primers have also been put to the test, such as oligonucleotides modified with inhibitory C3 spacers (Deagle et al., 2009 ; Vestheim & Jarman, 2008 ). Since then, blocking primers have been used to study the prey of many different animals and with sample material ranging from whole‐body extracts of copepods (Cleary et al., 2016 , 2017 ; Durbin & Casas, 2014 ; Novotny et al., 2021 ; Ray et al., 2016 ; Zamora‐Terol et al., 2020 ), to dragonflies and apex canine predators (Morrill et al., 2021 ; Shi et al., 2021 ).…”

eDNA metabarcoding vs metagenomics: an assessment of dietary competition in two estuarine pipefishes

“…The COI gene used for metabarcoding is a genetic marker commonly used in the sequencing of animal DNA (Hebert et al, 2003), and this marker has also been proven to be suitable for zooplankton DNA barcoding (Clarke et al, 2017). The primer combination used here has amplified more prey species from fecal DNA than any other primer combination (Leray et al, 2013), and has subsequently been used in numerous similar studies (Morrill et al, 2021;Tran et al, 2022). The PCR products were purified using the AMPure XP system (Beckman Coulter), and a NEBNext Ultra DNA Library Prep Kit (New England BioLabs, United States) was used for the preparation of genomic libraries.…”