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Trophic niche and capture efficacy of an ant-eating spider, Euryopis episinoides (Araneae:1
Theridiidae)2
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Eva Líznarová  Stano Pekár*4
Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 6115
37, Brno, Czech Republic6
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* Corresponding author: E-mail address: pekar@sci.muni.cz (S. Pekár)10
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Running head: LÍZNAROVÁ  PEKÁR: TROPHIC NICHE OF EURYOPIS EPISINOIDES22
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Abstract — Field and laboratory observations of the feeding ecology (natural diet, prey26
acceptance, and predatory behavior) of Euryopis episinoides spiders were combined in this study27
to reveal their trophic niche and capture efficacy and to test the hypothesis that this species is a28
myrmecophagous specialist. Natural prey was investigated from individuals collected in southern29
Portugal and was found to contain only ants of several species. Prey acceptance experiment30
revealed that spiders accepted several prey types occasionally, but only ants, termites, and fruit31
flies were accepted with a high frequency. Prey capture behavior was similar for four tested prey32
types. Wrapping time, number of bites, and waiting time differed among prey types with longest33
wrapping time, highest number of bites and longest waiting time during capture of Myrmicinae34
ants. From our findings we conclude that E. episinoides is a myrmecophagous specialist35
possessing specialized adaptations that enable them to capture ants. Yet, they maintain the ability36
to capture alternative prey.37
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Keywords: ants, diet breath, myrmecophagous, trophic specialization43
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Spiders are among the most abundant predators in terrestrial ecosystems and diversified45
enormously in foraging habits (Cardoso et al. 2011). The majority of spider species seem to be46
euryphagous or oligophagous with a slightly restricted diet (Nentwig 1987) and only a few47
species are stenophagous, feeding on restricted prey types. Most spider species hunt preferably48
prey which is innocuous (Pekár et al. 2012), so the prey capture is not risky for them, but some49
spiders catch also dangerous prey, such as other spiders (e.g. Whitehouse 1987), ants (e.g. Pekár50
2004; Jackson & Nelson 2012), or termites (e.g. Eberhard 1991). Spiders, which hunt dangerous51
prey frequently, evolved various adaptations to avoid being injured or even killed by such prey52
during prey capture (Pekár & Toft 2015).53
Specifically, ants as dangerous prey are avoided by most of the euryphagous spiders (e.g.54
Huseynov et al. 2008). However, some spider species specialized on ant capture; indeed55
myrmecophagy is the most frequent type of stenophagy in spiders (Pekár et al. 2011a).56
Predominantly myrmecophagous spiders are found in a number of families, particularly of the57
cursorial guild (Cushing 2012; Pekár & Toft 2015). For example, many species of the genus58
Zodarion feed only on ants and reject other prey types (Pekár 2004, Allan et al. 1996; Pekár et al.59
2005; Pekár et al. 2008).60
Myrmecophagous spiders use specialized capture strategies to subdue ants (Cushing 2012;61
Jackson & Nelson 2012), which differ from the hunting strategy used for other prey. For62
example, myrmecophagous web-building spiders from the family Theridiidae use sticky silk63
when preying on ants (Nørgaard 1956; Nentwig 1987). Passing ant is stuck at the end of the trip64
line, which is equipped with highly adhesive gumdrops (Hölldobler 1970; MacKay 1982;65
Nyffeler et al. 1988). Web-building spiders situate their webs close to places with high ant66
occurrence. They often build their webs over ant foraging trails (Nørgaard 1956; MacKay 1982;67
Cushing 2012) or even directly over ant nest entrances (Hölldobler 1970; MacKay 1982).68
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Cursorial myrmecophagous spiders may not use silk but venom for ant capture (Jackson &69
Nelson 2012). Ant-eating spiders from the family Zodariidae or Salticidae typically employ70
attack-and release strategy that minimize the time in the ant proximity (Pekár 2004; Li et al.71
1999; Jackson & Li 2001; Huseynov 2008). Cursorial spiders occur near to ants as well and they72
must be able to move among them safely. Zodarion spiders build igloo-like shelters from the73
detritus under the rock that are situated in the close proximity to ant nests and serves them as a74
safe place when they are not hunting (Jocqué 1991; Pekár & Král 2001). Both Zodarion spiders75
and myrmecophagous crab spider of the species Aphantochilus rogersi O. P.-Cambridge use76
paralyzed ant as a shield to protect themselves from attack by passing ants (Castanho & Oliveira77
1997; Pekár & Král 2002).78
In this study, we focused on the spider species Euryopis episinoides (Walckenaer) from the79
family Theridiidae that occurs in the Mediterranean area and Asia (World Spider Catalog 2017).80
Although most theridiid species are web-builders, spiders of the genus Euryopis do not build any81
permanent web for prey capture (Carico 1978). However, they use silk during prey capture as82
they throw silk over the prey from their spinnerets while running around it, in similar way as83
spiders of the genus Oecobius (Glatz 1967) and Hersilia (Bristowe 1930). After the prey is84
tangled in silk and cannot escape, they give one or more bites to paralyze it.85
There has been more than 70 species of Euryopis described in the world (World Spider86
Catalog 2017). Published data on their prey indicate that Euryopis spiders prey mostly on ants,87
suggesting they are myrmecophagous. For example, Levi (1954) listed observations on several88
Euryopis species preying on ants. Berland (1933) reported that Euryopis episinoides captured89
Crematogaster ants. Carico (1978) observed individuals of all instars and both sexes of Euryopis90
funebris (Hentz) wandering on the trunks, branches and leaves; adult females fed mainly on large91
red carpenter ant Camponotus castaneus (Latreille), whereas immature spiders fed on variety of92
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other ant species corresponding to their body size. Gertsch (1979) observed female of Euryopis93
texana Banks preying upon small ants. Porter & Eastmond (1982) frequently observed spiders of94
Euryopis coki Levi closely associated with Pogonomyrmex ants. However, adult females and late95
instars accepted also fruit flies in a laboratory (Porter & Eastmond 1982).96
Here, we studied specifically natural diet, prey acceptance, prey capture behavior and capture97
efficacy of E. episinoides spiders to reveal if this species is stenophagous and specialized on ants98
as suspected.99
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METHODS101
Study species.—We collected individuals of Euryopis episinoides spiders together with their102
silken retreats made under stones in Lagoa do Santo André, Alentejo, Portugal. After transfer to103
the laboratory in the Czech Republic, we kept living individuals singly in plastic tubes (diameter104
5 mm, height 50 mm) with a layer of plaster of Paris at the bottom. The tubes were plugged with105
rubber-foam and maintained under controlled conditions (26 °C, L: D = 16:8). The plaster of106
Paris was moistened with a few drops of water at 4-day intervals.107
108
Natural prey analysis.—Spiders’ silken retreats contained prey remnants (carcasses). These109
spiders usually place prey carcass after feeding on one spot, thus creating small bundles of prey110
remnants. We collected seven prey bundles and placed them separately in plastic tubes with111
ethanol. We took them to laboratory where we counted number of prey individuals in each prey112
bundle and identified each prey individual to the species level. We identified collected ant113
remnants to species level using Collingwood & Prince (1998).114
115
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Prey acceptance experiment.—In the prey acceptance experiment, we observed the spiders’116
capture success with different prey types. We used 11 prey species from ten invertebrate orders117
and only adult female spiders. We took fruit flies (Drosophila melanogaster, Diptera, mean body118
length 2.0 mm), termites (workers of Reticulitermes sp., Isoptera, 3.5 mm), springtails (Sinella119
curviseta Brook, Collembola, 4.0 mm), crickets (Gryllus assimilis (Fabricius), Orthoptera, 5.0120
mm), and cockroaches (Paratemnopteryx couloniana (Saussure), Blattodea, 5.0 mm) from121
laboratory reared cultures. We collected spiders (Thomisidae, Araneae, 3.5 mm), beetles122
(Curculionidae, Coleoptera, 3.0 mm), bugs (Miridae, Heteroptera, 3.5 mm), ants (workers of123
Messor sp., 7 mm, Myrmica sp., 5 mm, Lasius sp., 3 mm, Hymenoptera) and thrips124
(Thysanoptera, 1.0 mm) from the field.125
Before start of the experiment we placed spiders (n=45) individually in a Petri dish (diameter126
40 mm). We used only adult female spiders. We left spiders in the Petri dish for one hour before127
we released one living prey individual in each dish occupied by spider. We recorded whether the128
spider attacked and captured the prey. If the spider did not attack the prey within 15 minutes, we129
removed the prey from the dish and replaced with another prey type. We used a randomized130
incomplete block design so that each prey type was used with at least ten spider individuals in a131
random order.132
The breadth of the fundamental trophic niche was estimated by using the standardized133
Levin’s index (BA), which varies between 0, when the niche breadth is minimal, up to 1, when the134
species does not discriminate among prey types (Hurlbert 1978). Values of BA higher than 0.6135
indicate a wide trophic niche, and values below 0.4 indicate narrow niche (Novakowski et al.136
2008).137
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Prey capture behavior.—In the prey capture behavior experiment, we observed predatory139
sequence with different prey types. We used only adult female spiders. As prey we used ants140
from the two ant subfamilies, Formicinae (Lasius spp., n=11) and Myrmicinae (Messor sp.,141
Myrmica sp., n=14), termites (Reticulitermes sp., n=10), and fruit flies (Drosophila142
melanogaster, n=12) because these were frequently accepted in acceptance experiments. Before143
start of the experiment, we placed spiders individually in a Petri dish (diameter 40 mm). We left144
spiders in the Petri dish for one hour before we released one living prey individual in Petri dish145
occupied by spider. Following prey capture behavior was recorded on a videocamera (Canon146
Legria HF R56). These recording were then analysed and used to construct a kinematic diagram147
of prey capture behaviours.148
We distinguished the following behavioural events: encounter - when the spider first149
encountered prey; wrap - the spider circled around the prey and wrapped it in silk; bite – the150
spider bit the prey; wait – the spider retreated from the prey and waited for a while at a distance;151
attach – the spider attached immobilised prey to its spinnerets; carry – the spider dragged the152
immobilised prey away; feed – the spider started to consume the prey. The sequences and153
frequencies of hunting behaviour that followed encounter and ended with a successful subduing154
(feed) were recorded to construct the flow diagrams with transition frequencies for selected prey155
types. The transition frequencies for the first step were estimated from the total number of156
individuals used with particular prey. The transition frequencies for all next steps were estimated157
from the number of individuals, which went through the previous step thus the sum of the158
transition frequencies leaving each step was 1.159
From the predatory sequence for each prey species we estimated entropy index using the160
Shannon formula (Lehner 1998) to measure the stereotypy of hunting behaviour.161
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Capture efficacy.— During prey capture behavior experiment we also measured the time during163
which the spiders wrapped the prey into the silk; number of bites; and waiting time (time between164
bite and beginning of feeding).165
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Data analyses.—We performed all analyses with R (R Development Core Team 2010). The167
probability of prey acceptance was compared using GLM with Binomial distribution. Wrapping168
time and waiting time were compared among prey types using GLM with Gamma distribution169
(GLM-g). Number of bites was compared among prey types using GLM with Poisson170
distribution (GLM-p) (Pekár & Brabec 2016).171
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RESULTS173
Natural prey.—Analysis of seven prey bundles collected from the retreat of E. episinoides174
female spiders revealed in total 94 prey items. All individuals were ants, belonging to three175
species (Table 1): the majority of the prey (94.6%, n=94) were Tapinoma erraticum Latreille176
(Dolichoderinae, 3-4 mm), remaining individuals were Messor marocanus Santschi (6-8 mm,177
Myrmicinae), and Aphaenogaster senilis Mayr (6-7 mm, Myrmicinae).178
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Prey acceptance.—The probability of prey acceptance in laboratory differed significantly among180
11 used prey types (GLM-b, X2
309=256.37, P<0.0001, Table 2). Euryopis episinoides spiders181
accepted only termites, ants and fruit flies in more than 50% of the cases. Springtails, crickets and182
bugs were accepted much less frequently (< 10%), and beetles, cockroaches, spiders, and thrips183
were rejected. Levin’s index (BA) of fundamental trophic niche breadth was 0.38 indicating184
narrow niche.185
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Prey capture behavior.—When on hunt, Euryopis episinoides spiders used a specific hunting187
posture, with the first three pairs of legs placed on the ground and hind legs lifted up in the air188
alongside its elevated abdomen. At the same time, they drew a short thread of silk from189
spinnerets by repeated lifting of abdomen. Once prey walked close enough to the threads, the190
spider started throwing silk from its spinnerets on it while circling around with abdomen pointing191
at the prey (Fig. 1A). Usually the hunting sequence continued with the spider biting the prey (Fig.192
1B) and wrapping it in more silk, then the spider waited for some time, until the prey become193
motionless. Finally, the spider started to feed on the hunting spot or attached immobilized prey to194
its spinnerets and carried it away (Video 1).195
There were some differences in prey capture sequence among four prey types (Fig. 2). Ants,196
both Formicinae and Myrmicinae, were always bitten at least once during prey capture sequence,197
while termites and fruit flies were not often bitten and spiders started feeding immediately after198
wrapping the prey.199
The Shannon entropy index of behavioral sequences was 2.05 for Formicinae, 2.64 for200
Myrmicinae, 2.22 for termites and 0.83 for fruit flies.201
202
Capture efficacy.—Wrapping time differed among prey types (GLM-g, F3,99=34.2, P0.0001):203
wrapping of Myrmicinae ants was much longer than other prey types (Fig. 3A). Number of bites204
during prey capture also differed among used prey types (GLM-p, χ2
3=20.4, P0.0001):205
significantly more bites were used in capture of Myrmicinae ants than other prey types (Fig. 3B).206
The waiting time differed among prey types too (GLM-g, F3, 99=14.3, P0.0001): the longest207
waiting time was during capture of Myrmicinae ants and the shortest during capture of fruit flies208
(Fig. 3C).209
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DISCUSSION211
Analysis of natural prey revealed that realised trophic niche of E. episinoides is narrow as it212
includes only ants, which is well in agreement with observations on other Euryopis species213
(Berland 1933; Levi 1954; Allred 1969; Carico 1978; Porter & Jorgensen 1980; MacKay 1982).214
Thus would be tempting to consider E. episinoides specialized myrmecophagous spiders. Yet,215
narrow diet may be observed in unspecialized predators if the habitat is dominated by a single216
prey type (Pekár et al. 2011a; Monzó et al. 2013). Indeed, Euryopis spiders seem to prefer217
microhabitats with high ant abundances.218
Yet, acceptance experiments revealed that the fundamental trophic niche of E. epsinoides is219
wider than realized as it includes some other prey types than ants. Nevertheless, according to the220
Levin’s index the fundamental trophic niche is still narrow. We expected termites to be accepted,221
as this prey type is frequently accepted by other myrmecophagous spider species (Pekár 2004).222
Termites probably produce a signal similar to that of ants (e.g. movement pattern) and are223
therefore accepted. Fruit flies were captured as well by E. episinoides with quite high frequency;224
nevertheless, we believe that flies are seldom captured in nature because capture strategy of E.225
episinoides is designed for crawling insects (Carico 1978).226
Results of realized and fundamental trophic niche indicate that E. episinoides spiders are227
myrmecophagous thus able to feed on ants. Yet, are they specialized in the capture of ants? A228
strict specialist sensu Pekár & Toft (2015) involves presence of a variety of adaptations that229
enhance efficiency in preferred prey utilization. Moreover, prey-specific adaptations will be230
found primarily when predators take exceptionally dangerous prey (Brodie & Brodie 1999),231
which applies to ants as a prey for most of the spiders (Huseynov et al. 2008). Hereafter, we will232
deal with traits, which might be specialized in ant capture.233
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Due to the restricted diet range, specialists have adapted to recognize a narrow range of prey234
cues (Dukas & Kamil 2001). Predatory behavior of E. episinoides is driven by olfactory cues235
deposited on the substrate and was found that they have innate olfactory preference to ants (Pekár236
& Cardenas 2015). Such selective attention is beneficial as it may help the spider to prepare for237
the use of a specific foraging strategy, may increase prey capture efficiency, and decrease the risk238
when hunting dangerous ants. Chemical cues from their preferred prey are found to be important239
in prey capture in other myrmecophagous and araneophagous salticids as these chemical cues240
primed selective attention to visual cues of their prey (Clark et al. 2000; Jackson et al. 2002).241
The ability to recognize prey type before initiation of the hunting sequence may be important242
if predator uses versatile strategies tuned to the particular prey type (Jackson & Nelson 2012).243
The hunting sequence when hunting various prey types may be distinctively different. For244
example, in Portia fimbriata (Doleschall), an araneophagous spider, uses three different hunting245
tactics for catching other salticid depending on the prey species and context (Jackson 1992). Most246
myrmecophagous salticids capture ants using ant-specific prey capture tactics but use other247
tactics to take other prey (Jackson & Olphen 1991; Jackson & Li 2001). One myrmecophagous248
salticid Anasaitis canosa (Walckenaer) even distinguish ant of different size and accordingly use249
different hunting tactic (Edwards et al. 1974). Web–building spider Araneus diadematus Clerck250
attacked muscid flies twitching in the web by first wrapping them in silk and biting them after,251
whereas motionless flies were attacked first by biting and then by wrapping (Robinson &252
Robinson 1976).253
On the other hand, the hunting sequence used when hunting different prey may be overall254
similar. Hunting of bigger or more dangerous prey usually requires more silk, or venom, and time255
investment. Prey capture of E. episinoides when hunting four different prey types did not differ256
much in sequence of behavior events. Only in trials with fruit flies or termites, the prey was only257
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wrapped into silk and not bitten. Probably the wrapping was efficient enough to immobilize the258
prey and spider did not need to invest any venom. The lowest value of Shannon entropy index of259
fruit fly hunting sequence indicate that this prey was hunted in the most stereotyped way, while260
other prey types required more complex hunting behavior.261
However, greater difference among prey types appeared when we looked into investment of262
silk, venom and handling time. Wrapping and waiting time was longest and number of bites263
highest during capture of Myrmicinae ants, which were the biggest prey used and thus were more264
dangerous. On the contrary, capturing of smaller Formicinae (Lasius) ants required similar265
investment of venom, silk and time as capture of innocuous fruit flies. The size of Lasius ants266
was probably optimal for E. episinoides spiders as it was similar to body size of Tapinoma267
erraticum Latreille ants that were the most abundant prey of E. episinoides in nature. Termites268
were wrapped only for a short time bur their capture involved repeated bites and long waiting for269
the paralysis, probably due to less efficient venom (Líznarová, unpublished data).270
Even if the specialized predator is able to catch alternative prey, it may have negative effect on271
its fitness. Our previous study (Líznarová & Pekár 2016) with E. episinoides revealed that fruit272
flies do not provide suitable food source. Probably the presence of metabolic adaptations to ants273
constrains the utilization of alternative prey. Their ability to capture and feed on alternative prey274
is probably advantageous only for a short period of preferred prey scarcity.275
Our results revealed that E. episinoides is stenophagous, capturing only ants. Further, we276
found that E. episinoides was able to capture Formicinae ants with a similar efficiency as277
innocuous alternative prey indicating that it is adapted to ant capture with adaptations such as278
hunting strategy suitable for dangerous prey and efficient venom. Their capture strategy even279
allows them to catch ants bigger then themselves, which is another indication of specialization.280
However, presence of specialized adaptations may constrain the ability to feed efficiently on281
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alternative prey (Pekár 2005; Cárdenas et al. 2015). This is supported by finding that fitness of E.282
episinoides reared on alternative prey was markedly decreased (Líznarová & Pekár 2016). All283
these findings together indicate that E. episinoides spiders have specialized adaptations in ant284
capture and thus we can consider them as myrmecohagous specialist.285
286
Acknowledgment287
We would like to thank Magdalena Neradilová for help with the experiments, which were part of288
her bachelor thesis.289
290
LITERATURE CITED291
Allan, R.A., M.A. Elgar & R.J. Capon. 1996. Exploitation of an ant chemical alarm signal by the292
zodariid spider Habronestes bradleyi Walckenaer. Proceedings of the Royal Society of293
London B: Biological Sciences 263(1366):69–73.294
Allred, D.M. 1969. Spiders of the national reactor testing station. Great Basin Naturalist 29(2): 5.295
Berland, L. 1933. Contribution a 1'etude de la biologie des arachnides . Archives de zoologie296
experimentale et generale 76(1):1–23.297
Brodie, E.D. III & E.D. Brodie, Jr. 1999. Predator–prey arms races. Asymmetrical selection on298
predators and prey may be reduced when prey are dangerous. BioScience 49:557–568.299
Cárdenas, M., P. Jiroš & S. Pekár. 2012. Selective olfactory attention of a specialised predator to300
intraspecific chemical signals of its prey. Naturwissenschaften 99(8):597–605.301
Cardoso, P., S. Pekár, R. Jocqué & J.A. Coddington. 2011. Global patterns of guild composition302
and functional diversity of spiders. PLoS One 6(6): e21710.303
14
Carico, J.E. 1978. Predatory behavior in Euryopis funebris (Hentz)(Araneae: Theridiidae) and the304
evolutionary significance of web reduction. In Symposia of the Zoological Society of305
London 42:51–58.306
Castanho, L.M. & P.S. Oliveira. 1997. Biology and behaviour of the neotropical ant‐mimicking307
spider Aphantochilus rogersi (Araneae: Aphantochilidae): nesting, maternal care and308
ontogeny of ant‐hunting techniques. Journal of Zoology 242(4):643–650.309
Clark, R.J., R.R. Jackson & B. Cutler. 2000. Chemical cues from ants influence predatory310
behavior in Habrocestum pulex, an ant-eating jumping spider (Araneae, Salticidae). Journal311
of Arachnology 28(3):309–318.312
Collingwood, C.A. & A. Prince. 1998. A guide to ants of continental Portugal (Hymenoptera:313
Formicidae). Boletim da Sociedade Portuguesa de Entomologia Suplemento 5:1–49.314
Cushing, P.E. 2012. Spider-ant associations: an updated review of myrmecomorphy,315
myrmecophily, and myrmecophagy in spiders. Psyche: A Journal of Entomology 2012:1–316
23.317
Dukas, R. & A.C. Kamil. 2001. Limited attention: the constraint underlying search image.318
Behavioral Ecology 12(2):192–199.319
Eberhard, W.G. 1991. Chrosiotes tonala (Araneidae:Theridiidae): a web-building spider320
specializing on termites. Psyche: A Journal of Entomology 98:7–20.321
Edwards, G.B., J.F. Carroll & W.H. Whitcomb. 1974. Stoidis aurata (Araneae: Salticidae), a322
spider predator of ants. Florida entomologist 57(4):337–346.323
García, L.F., M. Lacava & C. Viera. 2014. Diet composition and prey selectivity by the spider324
Oecobius concinnus (Araneae: Oecobiidae) from Colombia. Journal of Arachnology325
42(2):199–201.326
15
Hölldobler, B. 1970. Steatoda fulva (Theridiidae), a spider that feeds on harvester ants. Psyche: A327
Journal of Entomology 77(2):202–208.328
Hölldobler, B. & E.O. Wilson. 1990. The Ants. Harvard Belknap, Cambridge.329
Hurlbert, S.H. 1978. The Measurement of Niche Overlap and Some Relatives. Ecology: 67–77.330
Huseynov, E.F., R.R. Jackson & F.R. Cross. 2008. The meaning of predatory specialization as331
illustrated by Aelurillus m-nigrum, an ant-eating jumping spider (Araneae: Salticidae) from332
Azerbaijan. Behavioural Processes 77:389–399.333
Jackson, R.R. 1992. Conditional strategies and interpopulation variation in the behaviour of334
jumping spiders. New Zealand journal of zoology 19(3-4): 99–111.335
Jackson, R.R., R.J. Clark & D.P. Harland. 2002. Behavioural and cognitive influences of336
kairomones on an araneophagic jumping spider. Behaviour 139(6):749–775.337
Jackson, R.R., & D. Li. 2001. Prey‐capture techniques and prey preferences of Zenodorus338
durvillei, Z. metallescens and Z. orbiculatus, tropical ant‐eating jumping spiders (Araneae:339
Saiticidae) from Australia. New Zealand Journal of Zoology 28(3):299–341.340
Jackson, R.R., & X.J. Nelson. 2012. Specialized exploitation of ants (Hymenoptera: Formicidae)341
by spiders (Araneae). Myrmecological News 17:33–49.342
Jackson, R.R. & A.V. Olphen. 1991. Prey‐capture techniques and prey preferences of Corythalia343
canosa and Pystira orbiculata, ant‐eating jumping spiders (Araneae, Salticidae). Journal of344
Zoology 223(4):577–591.345
Jocqué, R. 1991. A generic revision of the spider family Zodariidae (Araneae). Bulletin of the346
American Museum of Natural History 201:1–160.347
Lehner, P.N. 1998. Handbook of ethological methods. Cambridge University Press. Cambridge.348
16
Levi, H.W. 1954. Spiders of the genus Euryopis from North and Central America (Araneae,349
Theridiidae). American Museum novitates no. 1666.350
Li, D. & R.R. Jackson. 1997. Influence of diet on survivorship and growth in Portia fimbriata, an351
araneophagic jumping spider (Araneae: Salticidae). Canadian Journal of Zoology352
75(10):1652–1658.353
Li, D., R.R. Jackson & D.P. Harland. 1999. Prey-capture techniques and prey preferences of354
Aelurillus aeruginosus, A. cognatus, and A. kochi, ant-eating jumping spiders (Araneae:355
Salticidae) from Israel. Israel Journal of Zoology 45(3):341–359.356
Líznarová, E., L. Sentenská, García, S. Pekár & C. Viera. 2013. Local trophic specialisation in a357
cosmopolitan spider (Araneae). Zoology 116(1):20–26.358
Líznarová, E. & S. Pekár. 2015. Trophic niche of Oecobius maculatus (Araneae: Oecobiidae):359
evidence based on natural diet, prey capture success, and prey handling. Journal of360
arachnology 43(2):188–193.361
Líznarová, E. & S. Pekár. 2016. Metabolic specialisation on preferred prey and constraints in the362
utilisation of alternative prey in an ant-eating spider. Zoology 119(5):464–470.363
MacKay, W.P. 1982. The effect of predation of western widow spiders (Araneae: Theridiidae) on364
harvester ants (Hymenoptera: Formicidae). Oecologia 53(3):406–411.365
Monzó, C., M. Juan-Blasco, S. Pekár, Ó. Mollá, P. Castañera & A. Urbaneja. 2013. Pre-adaptive366
shift of a native predator (Araneae, Zodariidae) to an abundant invasive ant species367
(Hymenoptera, Formicidae). Biological invasions 15(1):89–100.368
Nentwig, W. 1987. The prey of spiders. Pp. 249–263. In Ecophysiology of Spiders. (W. Nentwig,369
ed.). Springer-Verlag, Berlin.370
Novakowski, G. C., N. S.Hahn & R. Fugi. 2008. Diet seasonality and food overlap of the fish371
assemblage in a pantanal pond. Neotropical Ichthyology 6(4):567-576.372
17
Nørgaard, E. 1956. Environment and behaviour of Theridion saxatile. Oikos 7(2): 159–192.373
Nyffeler M., D.A. Dean & W.L. Sterling. 1988. The southern black widow spider, Latrodectus374
mactans (Araneae, Theridiidae), as a predator of the red imported fire ant, Solenopsis invicta375
(Hymenoptera, Formicidae), in Texas cotton fields. Journal of Applied Entomology 106(1–376
5):52–57.377
Oliveira, P.S. & I. Sazima. 1984. The adaptive bases of ant‐mimicry in a neotropical378
aphantochilid spider (Araneae: Aphantochilidae). Biological Journal of the Linnean Society379
22(2):145–155.380
Pekár, S. 2004. Predatory behavior of two European ant-eating spiders (Araneae, Zodariidae).381
Journal of Arachnology 32:31–41.382
Pekár, S. 2005. Predatory characteristics of ant-eating Zodarion spiders (Araneae: Zodariidae):383
potential biological control agents. Biological Control 34(2):196–203.384
Pekár, S., T. Bilde & M. Martišová. 2011a. Intersexual trophic niche partitioning in an ant-eating385
spider (Araneae: Zodariidae). PloS one 6(1):e14603.386
Pekár, S. & M. Brabec. 2016. Modern analysis of biological data. Generalized linear models in R.387
Masarykova univerzita.388
Pekár, S. & M. Cárdenas. 2015. Innate prey preference overridden by familiarisation with389
detrimental prey in a specialised myrmecophagous predator. The Science of Nature 102(1–390
2):8.391
Pekár, S., J.A. Coddington & T. Blackledge. 2012. Evolution of stenophagy in spiders (Araneae):392
evidence based on the comparative analysis of spider diets. Evolution 66:776–806.393
Pekár, S. & J. Král. 2001. A comparative study of the biology and karyotypes of two central394
European zodariid spiders (Araneae, Zodariidae). Journal of Arachnology 29(3):345–353.395
18
Pekár, S. & J. Král. 2002. Mimicry complex in two central European zodariid spiders (Araneae:396
Zodariidae): how Zodarion deceives ants. Biological Journal of the Linnean Society397
75(4):517–532.398
Pekár, S., J. Král & Y. Lubin. 2005. Natural history and karyotype of some ant-eating zodariid399
spiders (Araneae, Zodariidae) from Israel. Journal of Arachnology 33(1):50–62.400
Pekár, S., J. Šobotník & Y. Lubin. 2011. Armoured spiderman: morphological and behavioural401
adaptations of a specialised araneophagous predator (Araneae: Palpimanidae).402
Naturwissenschaften 98(7):593–603.403
Pekár, S. & S. Toft. 2009. Can ant‐eating Zodarion spiders (Araneae: Zodariidae) develop on a404
diet optimal for euryphagous arthropod predators?. Physiological Entomology 34(2):195–405
201.406
Pekár, S. & S. Toft. 2015. Trophic specialisation in a predatory group: the case of prey‐407
specialised spiders (Araneae). Biological Reviews 90:744–761.408
Pekár, S., S. Toft, M. Hrušková & D. Mayntz. 2008. Dietary and prey-capture adaptations by409
which Zodarion germanicum, an ant-eating spider (Araneae: Zodariidae), specialises on the410
Formicinae. Naturwissenschaften 95(3):233–239.411
Porter, S.D. & C.D. Jorgensen.1980. Recapture studies of the harvester ant, Pogonomyrmex412
owyheei Cole, using a fluorescent marking technique. Ecological Entomology 5(3):263–413
269.414
R Development Core Team. 2010. R: A Language and environment for statistical computing.415
Vienna: R Foundation for Statistical Computing. http://www.R-project.org.416
Robinson, M.H. & B. Robinson. 1976. Discrimination between prey types: an innate component417
of the predatory behaviour of araneid spiders. Ethology 41(3):266–276.418
19
Stephens, D.W. & J.R. Krebs. 1986. Foraging theory. Princeton University Press. Princeton, 247419
pp.420
Thompson, J.N. 1994. The coevolutionary process. University of Chicago Press, Chicago.421
Whitehouse, M.E.A. 1987. ‘Spider Eat Spider’: the predatory behavior of Rhomphaea sp. from422
New Zealand. Journal of Arachnology 15:355–362.423
424
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Table 1: List of prey items found in seven bundles in the retreat of Euryopis episinoides females.425
Prey species (number of individuals)
Tapinoma erraticum (13)
Messor marocanus (1), Tapinoma erraticum (15)
Aphaenogaster senilis (1), Tapinoma erraticum (15)
Aphaenogaster senilis (1), Tapinoma erraticum (11)
Messor marocanus (2), Tapinoma erraticum (25)
Tapinoma erraticum (9)
Tapinoma erraticum (1)
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
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Table 2: Probability of acceptance of different prey types by Euryopis episinoides females.443
Prey type Prey taxon
Acceptance frequency
(n=number of observations)
Araneae Thomisidae 0.0% (n=42)
Collembola Sinella curviseta 6.5% (n=31)
Blattodea Paratemnopteryx couloniana 0.0% (n=16)
Isoptera Reticulitermes sp. 95.2% (n=21)
Orthoptera Gryllus asimilis 40.0% (n=15)
Thysanoptera 0.0% (n=17)
Heteroptera Miridae 3.7% (n=27)
Hymenoptera Myrmicinae (Messor sp., Myrmica sp.) 85.3% (n=34)
Formicinae (Lasius sp.) 89.6% (n=48)
Coleoptera Curculionidae 0.0% (n=26)
Diptera Drosophila melanogaster 52.4% (n=42)
444
445
446
447
448
449
450
451
452
453
454
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Fig. 1. Euryopis episinoides spider attacking a Messor ant: A. Throwing silk from spinerrets. B.455
Biting into base of antennae.456
Fig. 2.: Kinematic diagrams of prey capture behaviour of Euryopis episinoides used against four457
prey types with the relative frequencies of transitions. A. Formicinae ants (n=11), B. Myrmicinae458
ants (n=14), C. termites (n=10), D. fruit flies (n=10). The transition frequencies between events459
are also indicated by the width of the line.460
Fig. 3: Comparison of the wrapping time (A), the number of bites (B), and the waiting time (C) of461
Euryopis episinoides for four different prey types: fruit flies (n=20), Formicinae ants (n=39),462
Myrmicinae ants (n=27), and termites (n=17).463
464
465
466
467
468
469
470
23
471
472
Fig. 1473
A B
24
474
Fig. 2475
476
25
477
Fig. 3478
479
480
481
482
Video 1. Capture and handling of Messor ant by Euryopis episiniodes female.483