DOI: 10.5061/dryad.50554tg
title: Data from: Seasonally varying marine influences on the coastal ecosystem detected through molecular gut analysis

description: Terrestrial predators on marine shores benefit from the inflow of
 organisms and matter from the marine ecosystem, often causing very high
 predator densities and indirectly affecting the abundance of other prey
 species on shores. This indirect effect may be particularly strong if
 predators shift diets between seasons. We therefore quantified the
 seasonal variation in diet of two wolf spider species that dominate the
 shoreline predator community, using molecular gut content analyses with
 general primers to detect the full prey range. Across the season, spider
 diets changed, with predominantly terrestrial prey from May until July and
 predominantly marine prey (mainly chironomids) from August until October.
 This pattern coincided with a change in the spider age and size structure,
 and prey abundance data and resource selection analyses suggest that the
 higher consumption of chironomids during autumn is due to an ontogenetic
 diet shift rather than to variation in prey abundance. The analyses
 suggested that small dipterans with a weak flight capacity, such as
 Chironomidae, Sphaeroceridae, Scatopsidae and Ephydridae, were
 overrepresented in the gut of small juvenile spiders during autumn,
 whereas larger, more robust prey, such as Lepidoptera, Anthomyidae and
 Dolichopodidae, were overrepresented in the diet of adult spiders during
 spring. The effect of this inflow may be that the survival and growth of
 juvenile spiders is higher in areas with high chironomid abundances,
 leading to higher densities of adult spiders and higher predation rates on
 the terrestrial prey next spring.
description: Fasta file - with
 sequencesThis Fasta file contains
 all unique sequences accompanied by a unique identification number from 1
 to 9193, which corresponds to a number in the file ’Frequency
 table.xls’Frequency
 tableThis file tabulates
 sequences for all spider individuals. Each row in this file represents a
 unique sequence with the identification number (in column 1) corresponding
 to the sequence number in the file ’Fasta file – with sequences.txt’. The
 following columns have the following descriptions: Sequence count = the
 total number of sequence across all spider individuals Order = Arthropod
 order corresponding to the sequence Sequence identity = The identity based
 on best match in Barcode of Life Data bas Match = best match where 1.00
 corresponds to perfect match (100%) Spindel_1 .. Spindel_504 = unique
 identity for each spider individual, which corresponds to a number in the
 file ’GutTesta.txt’. The numbers in this column indicates the number of
 sequences for each unique sequence and spider
 individualTabulated gut
 contentsThis file summarises
 presence-absences for a given prey group in the gut of a spider
 individual. The columns have the following descriptions: Spider no =
 unique identity for each spider individual, with a number corresponding to
 columns in the file ’Frequency table.xls’ Site = Collection site, see
 Figure 1 in the paper Date = Collection date Month = Collection month
 Identity = Identification of spider individual: ’Pardosa prativaga’,
 ’Pardosa agricola’, ’Pardosa sp’ Sex, f = female, m = male, x =
 unidentified Age, ad = adult, subad = subadult, juv = spiderling Predation
 events = total number of predation events Pepred = Predation events –
 occurrence of predator in gut Weight = Weight in mg Two group columns,
 Aqua = Aquatic larvae, Terr = Terrestrial larvae Nine group columns, Chir
 = Chironomids, Aqu = other aquatic diptera, Det = detritivores, Pred =
 predators, Herb = herbivores, Leps = Lepidoptera, Cole = Coleoptera, Hete
 = Heteroptera, Coll = Collembola 22 columns for taxonomic
 categories.GutTesta.txtNetwork dataThis ’consumer’ file was used for the null model analysis in econullnetr, and is based on occurrence in spider gut contents. The columns have the following descriptions: Period, 1 = May-July, 2 = August-October Sample, Site_Period Identity = Identification of spider individual: ’Pardosa prativaga’, ’Pardosa agricola’, ’Pardosa sp’ Group 15 columns for taxonomic categoriesPrey abundancesThis ’resource’ file was used for the null model analysis in econullnetr, and is based on the data from malaise traps. The columns have the following descriptions: Period, 1 = May-July, 2 = August-October Sample, Site_Period 15 columns for taxonomic categoriesBytesabund.txtSample tagsThis file contains individual tags used during parallell sequencing for each spider, where the spider identity corresponds to the identity shown in the file 'Tabulated gut contents' (GutTesta.txt)