Fig 1.
Gut content metabarcoding workflow used in this study.
Siphonophore colony illustrated by Freya Goetz. Silhouettes in the plankton net downloaded from phylopic.org. Solid arrows indicate physical material transfer and processing, dashed lines indicate information transfer and processing. Yellow islands indicate elements processed in the laboratory bench, green islands represent bioinformatic datasets processed in the high-performance computing cluster, and red islands represent curated data products.
Table 1.
Barcodes used in this study.
Fig 2.
Summary table of the siphonophore species sampled for this study indicating their vertical habitat, the number of specimens sampled, the number of specimens with recognizable prey sequences, and hypothesized feeding guild.
Guilds are based on published feeding records used in Damian-Serrano et al. [26], predicted feeding guild from the DAPC analysis in Damian-Serrano et al. [27] based on tentilla morphology, and prey found in this study. Photo credits: (A) Casey Dunn, (B, D,) Stephan Siebert, CC BY licensed and reprinted from Munro et al. [73], (C) reprinted from https://www.theredshrimp.com/ with permission from Reyn Yoshioka, original copyright (2018), (E) Steven Haddock, (F) reprinted from https://biolum.eemb.ucsb.edu/organism/pictures/bargmannia.html with permission from Steven Haddock, original copyright (1997), (G, I) Alejandro Damian-Serrano, (H) NOAA, CC BY licensed, reprinted from https://www.flickr.com/photos/noaaphotolib/19988388271 (J) reprinted from http://www.roboastra.com/Cnidaria2/brac836.htm with permission from Denis Riek, original copyright (2021).
Fig 3.
Relative log-abundances of prey reads colored by taxon.
(A) For each siphonophore species, and (B) for each siphonophore specimen and barcode.
Fig 4.
Species-wise grid with the frequency of the major prey types identified from the metabarcoding data and the average prey-type selectivity.
Gut content cells in white indicate absence, and cells in grey indicate presence in one specimen, or more than one specimen if labeled with a number. Selectivity colors mapped to Strauss’ L.I. values. The siphonophore cladogram (left) is a simplified version of the phylogenetic tree published in Damian-Serrano et al. [26].
Fig 5.
Feeding interactions between siphonophores and their prey from different data sources.
Including prey identified by our metabarcoding results (red), observations published submersible observations (blue), observations published visual gut content analyses (green), and prey types predicted by the morphology-based DAPC model in Damian-Serrano et al. [27]. Gelatinous prey refers to ctenophores, medusae, and salps. Larvaceans were excluded as their own category since they are not gelatinous when swimming freely outside their mucous ‘houses’, which would be the only times they would be able to trigger a prey-capture response in siphonophore tentacles.