Exposing the structure of an Arctic food web
H. K. Wirta, E. J. Vesterinen, P. A. Hambäck, E. Weingartner, C. Rasmussen, J. Reneerkens,
N. M. Schmidt, O. Gilg, and T. Roslin
Appendix S2. Further components of the Zackenberg interaction web
To provide further support for the notion that complexity is a general feature of the Zackenberg
interaction web – rather than a characteristic of a given guild, a given trophic level or some given
type of interaction – we here describe two local interaction networks beyond the predator-prey food
webs discussed in the main paper: As an example of a mutualistic interaction web, we show the
local pollinator-plant web reconstructed from the data of (Rasmussen et al. 2013). As an example of
an antagonistic food web, we show a local herbivore-plant web based on data from (Roslin et al.
2013). Both of these interaction webs were reconstructed, and their potential compartmentalization
assessed, by the package bipartite (Dormann et al. 2009) as implemented in R (R Core Team 2012).
For the specific methods used to collect the data for the respective trophic interactions, we refer the
reader to the original source papers (pollinators and plants, Fig. S4 A; (Rasmussen et al. 2013),
herbivores and plants, Fig. S4 B (Roslin et al. 2013)) and to the Materials and methods section in
the main paper and Text S1 of the current study.
In the current context, it is important to notice that each of the networks presented in
this Appendix was reconstructed by different techniques. Given this variation, we have refrained
from presenting any links between them – as this set of links would be conditional on the set of
methods used to reconstruct them. Instead, we present the different communities separately, seeking
for general patterns in their structure, and for traits either conforming to or departing from the
patterns described in the main paper.
As main findings, both the mutualistic and the antagonistic interaction webs among
plants and arthropods (Fig. S4 A and B) show a densely-linked structure. Moreover, they both
consist of a single compartment, implying that each species in the web is connected to all other
species through shared pollinators, herbivores and/or host plants. In all of these features, they match
the predator-prey webs described in the main text. Overall, we believe that these representations all
show joint support for the notion that our target web is characterized by dense links – across biotic
interactions of many kinds.
What our study does not adequately resolve are the links between interactions of
different types. It is well evident that the trophic food web of predator-prey interactions (cf. main
paper) is intricately linked with the other types of interaction webs presented in this Appendix. Of
the prey taxa targeted in the main paper, Diptera form the main pollinators in this community
(Elberling & Olesen 1999; Rasmussen et al. 2013), and Lepidoptera are pollinators as adults but
herbivores as larvae (Roslin et al. 2013). Linking the separate modules into a regional interaction
‘metaweb’ (cf. Pocock, Evans & Memmott 2012) is thus our ultimate objective, and the subject of
ongoing work.
Figure S4. Local interaction webs for supplementary interaction types at Zackenberg: A) pollinators
and the plants that they visit (Rasmussen et al. 2013) and B) lepidopteran herbivores and the plants
that they consume (Roslin et al. 2013). The species are numbered as in the table S3 below.
Table S2. Plant, pollinator and herbivore species forming the mutualistic interaction web of
pollinators and plants in Fig S4 A (Rasmussen et al. 2013) and the antagonistic food web of
lepidopteran herbivores and plants in Fig S4 B (Roslin et al. 2013).
#
Plant
species
#
Pollinator/ herbivore
order
family
species
Diptera
SI-1
SI-2
SI-3
SI-4
SI-5
SI-6
SI-7
SI-8
SI-9
SI-10
SI-11
SI-12
SI-13
SI-14
SI-15
SI-16
SI-17
SI-18
SI-19
SI-20
SI-21
SI-22
SI-23
Arenaria pseudofrigida
Armeria scabra
Arnica angustifolia
Betula nana
Cardamine pratensis
Cassiope tetragona
Cerastium arcticum
Chamaenerion latifolium
Cochlearia groenlandica
Draba arctica
Draba lactea
Draba spp.
Dryas octopetala
Erigeron compositus
Eriophorium triste
Lesquerella arctica
Melandrium triflorum
Papaver radicatum
Pedicularis flammea
Pedicularis hirsuta
Polygonum viviparum
Potentilla hyparctica
Potentilla rubricaulis
SI-44
SI-45
SI-46
SI-47
SI-48
SI-49
SI-50
SI-51
SI-52
SI-53
SI-54
SI-55
SI-56
SI-57
SI-58
SI-59
SI-60
SI-61
SI-62
SI-63
SI-64
SI-65
SI-66
SI-24
SI-25
SI-26
SI-27
Pyrola grandiflora
Ranunculus hyperboreus
Ranunculus pygmaeus
Ranunculus sulphureus
Rhododendron
lapponicum
Salix arctica
Saxifraga caespitosa
Saxifraga cernua
Saxifraga hirculus
Saxifraga hyperborea
Saxifraga nivalis
Saxifraga oppositifolia
Saxifraga rivularis
Silene acaulis
Stellaria humifusa
Stellaria longipes
Taraxacum arcticum
Taraxacum
phymatocarpum
Vaccinium uliginosum
grass
SI-67
SI-68
SI-69
SI-70
Phytomyza fuscula
Delia echinata
Fucellia pictipennis
Paradelia arctica
Pegomya icterica
Zaphne divisa
Zaphne frontata
Zaphne occidentalis
Zaphne tundrica
Cynomya mortuorum
Brachypogon spp.
Culicoides sp.
Chironomus hyperboreus
Cricotopus magus
Cricotopus spp.
Limnophyes asquamatus
Limnophyes brachytomus
Limnophyes cf. natalensis
Limnophyes cf. ninae
Limnophyes ninae
Limnophyes spp.
Metriocnemus spp.
Orthocladius spp.
Paraphaenocladius
impensus
Procladius paragretis
Psectrocladius limbatellus
Pseudosmittia cf. nanseni
SI-71
SI-72
SI-73
SI-74
SI-75
SI-76
SI-77
SI-78
SI-79
SI-80
SI-81
SI-82
SI-83
Pseudosmittia nanseni
Pseudosmittia spp.
Rheocricotopus chapmani
Smittia sp. 17
Smittia sp. 2
Smittia sp. aff. edwardsi
Smittia sp. x
Smittia sp. y
Smittia spp.
Tanytarsus sp. 1
Aedes impiger
Aedes nigripes
Rhamphomyia filicauda
SI-28
SI-29
SI-30
SI-31
SI-32
SI-33
SI-34
SI-35
SI-36
SI-37
SI-38
SI-39
SI-40
SI-41
SI-42
SI-43
SI-84
SI-85
SI-86
SI-87
Agromyzidae
Anthomyiidae
Calliphoridae
Ceratopogonidae
Chironomidae
Culicidae
Empididae
Muscidae
Rhamphomyia nigrita
Drymeia groenlandica
Drymeia segnis
Limnophora groenlandica
SI-88
SI-89
SI-90
SI-91
SI-92
SI-93
SI-94
SI-95
SI-96
SI-97
SI-98
SI-99
SI-100
SI-101
SI-102
SI-103
SI-104
SI-105
SI-106
SI-107
SI-108
SI-109
SI-110
SI-111
SI-112
SI-113
SI-114
SI-115
SI-116
SI-117
SI-118
SI-119 Hemiptera
SI-120 Hymenoptera
SI-121
SI-122
SI-123
SI-124
SI-125
SI-126
SI-127
SI-128
SI-129
SI-130
SI-131
SI-132
SI-133
Phoridae
Piophilidae
Scathophagidae
Sciaridae
Syrphidae
Tachinidae
Lygaeidae
Ichneumonidae
Braconidae
Lophosceles minimus
Phaonia bidentata
Spilogona almqvistii
Spilogona arcticola
Spilogona deflorata
Spilogona denudata
Spilogona dorsata
Spilogona malaisei
Spilogona megastoma
Spilogona micans
Spilogona obsoleta
Spilogona sanctipauli
Spilogona tendipes
Spilogona tornensis
Spilogona zaitzevi
Megaselia arcticae
Lasiopiophila pilosa
Gonarcticus arcticus
Scathophaga furcata
Scathophaga nigripalpis
Bradysia spp.
Lycoriella sp. 1
Eupeodes punctifer
Eupeodes rufipunctatus
Helophilus groenlandicus
Helophilus lapponicus
Parasyrphus tarsatus
Platycheirus carinatus
Platycheirus lundbecki
Syrphus torvus
Peleteria aenea
Nysius groenlandicus
Atractodes alpestris
Atractodes aterrimus
Atractodes sp. 1
Buathra laborator
Gelis maesticolor
Gelis sp. 1
Neurateles sp. 1
Picrostigeus sp. 1
Plectiscus sp. 1
Plectiscus sp. 2
Stenomacrus sp. 2
Stenomacrus micropennis
Stenomacrus sp. 1
Cotesia hallii
SI-134
SI-135
SI-136
SI-137
SI-138
SI-139
SI-140
SI-141
SI-142 Lepidoptera
SI-143
SI-144
SI-145
SI-146
SI-147
SI-148
SI-149
SI-150
SI-151
SI-152
SI-153
SI-154
SI-155
Apidae
Encyrtidae
Eulophidae
Pteromalidae
Geometridae
Erebidae
Lycaenidae
Noctuidae
Nymphalidae
Pieridae
Pyralidae
Tortricidae
Dacnusa groenlandica
Praon brevistigma
Protapanteles fulvipes
Bombus hyperboreus
Bombus polaris
Pseudencyrtus sp. 1
Aprostocetus meltoftei
Pachyneuron
groenlandicum
Entephria punctipes
Entephria sp.
Gynaephora groenlandica
Plebeius glandon
Apamea zeta
Euxoa adumbrata
drewseni
Polia richardsoni
Sympistis zetterstedtii
Syngrapha parilis
Boloria chariclea
Boloria spp.
Colias hecla
Pyla fusca
Olethreutes mengelana
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