New Results

Where have all the spiders gone? Observations of a dramatic population density decline in the once very abundant garden spider, Araneus diadematus (Araneae: Araneidae), in the Swiss midland

Martin Nyffeler, Dries Bonte
doi: https://doi.org/10.1101/2020.03.03.975912

Abstract

Aerial web-spinning spiders (including large orb-weavers) depend, as a group of insectivores, completely on flying insects as a food source. The recent widespread loss of flying insects across large parts of western Europe, both in terms of diversity and biomass, can therefore be anticipated to have a drastic negative impact on survival and abundance of this type of spiders. To test the putative importance of such a to date neglected trophic cascade, a survey of population densities of the European garden spider Araneus diadematus – a large orb-weaving spider – was conducted in late summer 2019 on twenty sites of the Swiss midland. The data from this survey were compared with published population densities for this species from the previous century. The study verifies above-mentioned hypothesis that this spider’s present-day overall mean population density has declined alarmly to densities much lower than can be expected from normal population fluctuations (0.7% of the historical densities). Review of other available records suggests this pattern is widespread and not restricted to this region. In conclusion, the here documented abundance decline of this once so abundant spider in the Swiss midland is evidently revealing a bottom-up trophic cascade in response to the widespread loss of flying insect prey in recent decades.

1. Introduction

When the Entomological Group Krefeld along with colleagues published their famous long-term study (the “Krefeld study”) in 2017, it became known that the flying insect biomass had declined by approx. 75% over the past three decades in over 60 nature protection areas of Germany [1]. Another long-term study (the “Munich study”) basically confirmed the results of the Krefeld study, providing evidence that strong abundance declines of insect populations had occurred in farmland and forests across vast areas of Germany and Switzerland [2]. Similar abundance declines of insect populations were documented by means of other long-term studies for other European and North American regions [3–9]. Meanwhile, it is generally accepted as scientifically proven that in many parts of the globe insect population densities had drastically decreased in recent decades and that we now live in an era of global insect meltdown [9–13]. This has dramatic ecological implications due to the fact that insects comprise the base of many food chains and food webs [14,15] – in a world without insects countless insectivorous species would ultimately become extinct due to starvation [16].

In this context, aerial web-spinning spiders are a group of uttermost interest. This group of spiders (including the orb-weaving spiders in the families Araneidae) trap flying insects with the aid of aerial webs [17–19]. In the temperate climate zone, aerial web-spinning spiders feed for the most part on small dipterans, aphids, and hymenopterans (Figure 1) which are exactly the type of insects known to have most dramatically decreased in abundance and biomass in recent decades [1]. With other words, because of their reliance upon flying insects as their principal food source, aerial web-spinning spiders are a highly vulnerable predator group in regions characterized by high loss of flying insects such as Germany and Switzerland.

Figure 1.
Figure 1.

Prey composition (% by number) of the garden orb-weaver Araneus diadematus based on four field studies. A) Oat field near Zurich, Switzerland [21]. B) Fallow grassland near Zurich, Switzerland [21]. C) Fallow grassland near Jena, Germany [18]. D) Maize field margin near Munich [19]. Homoptera refers primarily to alate aphids.

While a larger number of studies on population declines of various groups of insects had been conducted in recent years (see references in [12]), potential cascading effects have been documented so far for insectivorous birds [6]. No studies of this type have so far considered potential declines due to trophic cascades among arthropods, like aerial web-spinning spiders. In the following we use the European garden spider Araneus diadematus as a model system to address the question whether evidence for population declines in aerial web-spinning spiders in the Swiss midland can be found. The female, 10–18 mm in length, reaches adulthood in late summer, at which time it spins (≈30 cm Ø) orbs [20–22]. The webs are built 0.5–2.5 m off the ground [21]. This animal with its conspicuous white, cross-shaped mark on the upper side of the abdomen is one of the best known spider species in western Europe.

By comparing historical abundance data (20th century) with present-day data (year 2019) it shall be examined whether the abundance of Araneus diadematus has changed over the past few decades. This work is based on extensive experience gathered during graduate research in the Swiss midland in the 20th century [20,21] and has since been supplemented by a present-day population density survey in the same geographical area. To make the comparison more robust, the data base was expanded by adding published population density values extracted from the scientific literature.

2. Materials and Methods

2.1. Assessment of population densities of Araneus diadematus in 2019

Population density assessments were conducted on 20 locations in the Swiss midland by walking transects and counting webs (see Table 1, Table S1 for details). The search focussed on webs of adult females in its typical habitats (gardens, parks, graveyards, hedgerows, forest edges, forest trails, fallow grassland patches). Transects of 200 to 1000 m2 ground area were used (area size depending upon the specific situation; see Table S1 for details). All counts were conducted on rain-free afternoons in August and September 2019.

View this table:
Table 1.

Population densities of adult female Araneus diadematus (18 historical vs. 20 recent values). *Adults/subadults in September

2.1. Literature search for historical data on Araneus diadematus population densities

Araneus diadematus population density values assessed in the 1970s have been taken from two graduate research theses which had been conducted in the Zurich area [20,21]. These data were supplemented by data taken from the literature. Overall, a total of 12 reports (including 18 population density values) could be gathered (see Table S1). In these studies, transects ranging from 100 to 5000 m2 ground area were used (see Table S1).

2.3. Statistical methods

The Mann–Whitney U test was applied to examine whether overall mean spider density in 2019 (N = 20) differed statistically significantly from overall mean spider density in the 20th century (N = 18). Mean values are followed by Standard Errors (± SE).

3. Results

In Table 1 population densities of Araneus diadematus assessed in the Swiss midland in August/September 2019 are compared with 20th century population density data for this species from a variety of European locations. The table reveals that present-day population densities of adult female Araneus diadematus in the Swiss midland were generally extremly low (overall mean = 0.0011 ± 0.0004 webs m-2 [range = 0.000–0.006 webs m-2]; Table 1). In 2/3 of the 20 investigated transects no webs of adult female Araneus diadematus could be found.

By contrast, historical population densities of Araneus diadematus in its typical habitats had been considerably higher (overall mean = 0.1560 ± 0.0552 webs m-2; Table 1. The difference between the 20th century European overall mean and the present-day Swiss overall mean (0.1560 vs. 0.0011 webs m-2) is statistically highly significant (Mann–Whitney U test, n1 = 18, n2 = 20, Z = −4.0637, p < 0.001). The present-day Swiss overall mean density of Araneus diadematus is roughly 140 times lower than the 20th century European overall mean (Table 1). [If the overall mean of exclusively the seven Swiss 20th century values (0.1564 webs m-2, Table 1) is compared with the overall mean of the twenty Swiss 21th century values (0.0011 webs m-2, Table 1), the ratio still remains 140 : 1, and the difference between the two overall means is still statistically significant at p < 0.05.]

In 2019, the webs appeared to be rather fragile (Figure 2A–B) compared with the stronger webs from previous decades, as is the case when malnourished spiders make webs with thinner threads (Nyffeler, pers. observations). This is in good agreement with laboratory experiments, in which the amount of produced thread was reduced if Araneus diadematus spiders were kept fooddeprived [23]. Furthermore, the webs contained few prey compared to previous studies (Table S2). The overall impression gained during this survey was that there was a paucity of prey throughout the entire study area in recent decades which is confirmed by the observations of other researchers [2,24,25].

Figure 2A–B.
Figure 2A–B.

Adult female Araneus diadematus in web in a garden in Flawil, northeastern Switzerland (courtesy: Rätus Fischer)

4. Discussion

This study revealed that the large orb-weaving spider Araneus diadematus occurred in extraordinarily low population densities in the Swiss midland in 2019 (Table 1). Araneus diadematus spiders take down their webs during the night and rebuild them early in the morning. However, as laboratory experiments and field observations had revealed, not the entire population is rebuilding its webs the following day [23,26]. Some spiders, which had consumed exceptionally large amounts of food at particularly favorable hunting sites, may cease feeding and rebuilding their webs for one or several days [23]. Thus, the percentage of spiders found with webs within a A. diadematus population is in general lower than 100% (usually ranging between about 66–88%) depending on the availability of food at a particular time and location [23,26]. The question arises whether the method of web counts applied in this study may have resulted in underestimating the true population densities by overlooking a certain percentage of satiated spiders which had not rebuilt their webs at the time when the counts were conducted. On this issue, it may be noted that densities assessed in the past century were for the most part also based on web counts [18,20,21,26–32] so that the same methodological bias was involved in both time periods. Furthermore, since insatiated spiders tend to rebuild their webs more frequently than fully satiated spiders [23,33], and since present-day spiders living in the era of insect loss are more likely to be insatiated compared with half a century ago (Table S2), the frequency of web building nowadays can be expected to be rather higher compared with the situation in the last century. Thus, the possibility that the extraordinarily low present-day population densities were underestimations due to this particular type of methodological bias can be ruled out.

The here documented abundance decline of this once so abundant spider in the Swiss midland is evidently revealing a bottom-up trophic cascade in response to prey scarcity recently documented in the Swiss midland and across vast areas of western Europe [1,2,24,25]. The hypothesis that the availability of flying insect prey in the study area had drastically declined over the past decades is confirmed by the “windshield phenomenon” noticed throghout the Swiss midland (i.e., nowadays many times less flying insects are killed on the front windshields of cars compared to previous decades; [9,34]. This is in sharp contrast to the situation a few decades ago, when fairly frequently “wasteful killing” (and coupled with it “partial consumption”) of insects in Araneus diadematus webs at favorable web sites could be witnessed (with capture rates of sometimes up to 1000 prey web-1 day-1; [35]). The reduced food intake of Araneus diadematus in recent years (Table S2) is assumed to have negatively impacted the fecundity and survival of this spider [36,37) which in turn led to the abundance decline documented in this study (Table 1). Sublethal effects of chemical pollution may have additionally negatively affected this spider’s survival [38–43].

Aside from food scarcity due to insect population declines and chemical pollution, other negative environmental developments additionally contributed to the decreasing population densities of large orb-weaving spider species in the western European landscape. This includes adverse effects of modern forestry practices (e.g., removal of forest understory and of shrubs at forest margins, large-scale aerial spraying for the purpose of caterpillar or bark beetle control), the transformation of traditional farmland into large-scale depauperate monocultures (accompanied by the deletion of weedy field margins and hedges), the transformation of fallow grassland patches into construction sites, and the removal of shrubs and trees in urban and suburban gardens. That habitat conversion and degradation can have a strong detrimental effect on large orb-weaving spider abundance has impressivly been demonstrated on the example of the fate of a plot of land located near Zurich-Oberenstringen (in between highway A3 and the Limmat riverbank). In the 1970s, tall grassland interspersed with shrubs covered this plot and at that time large orb-weaving spiders occurred there in high numbers (up to 6 m-2 in small local patches; [44]). During a visit of this site, 40 years later, it became apparent that the land had been converted to a highway rest area with short-cut lawns and, as a result, the density of large orb-weaving spiders had declined to a very low value of 0.002 m-2 (Nyffeler, pers. observations).

We of course realise that the recorded declines were not based on systematic long-term monitoring and that the declines could be attribited to normal population cycling. However, while we are not able to provide a smoking gun herein, several elements support a systematic decline. First of all, the dramatic decline up to <1% of the reference baseline from 40 years ago, has never been observed at shorter temporal time frames, and reach far beyond the typical natural fluctuations in population sizes (e.g., Green 2003), even when they are known to be linked to resource pulses (e.g., Wolf 1996). Second, records from other location show that this decline is occuring at such large spatial scales that can only be explained by large-scale, more global environmental drivers like land-use change, climate change or the global use of pollutants. Indeed, the extraordinarily low population densities in Araneus diadematus in the Swiss midland observed in the 2019 survey (Table 1) are validated by statements of biology students of the University of Basel according to which generally very few large orb-weaving spiders had been spotted in recent years during walks through forests and fields in the Basel region. Furthermore, in mid-June 2017, a group of over 40 biology experts conducted an extensive faunistic survey on the grounds of the Merian Gardens, a park-like area covering 180,000 m2 located in the outskirts of Basel ([47]). In the course of this survey only three specimens of A. diadematus could be found over a time period of 24 hours suggesting that nowadays this once so “abundant garden spider” ([48]) must have become rare in that park-like garden area. The only large orb-weaver species still found in high density during the 2019 survey in the Swiss midland was the bridge spider Larinioides sclopetarius (Nyffeler, pers. observations). This nocturnal species, which lives near water and frequently builds its webs on street lights and illuminated bridge railings, gets still sufficient amounts of food in the form of flying adults of semiaquatic insects (chironomids, ephemeropterans, trichopterans, etc.) attracted in large numbers to the artificial light [49–51]. Due to its capability to exploit this type of artificially high prey densities, L. sclopetarius is – contrary to other large orb-weavers – even in the 21th century extremely successful in colonizing urban habitats in high density, not only in Switzerland, but also in other parts of western Europe [50].

Similar extraordinarily low population densities of Araneus diadematus (0.0004 adult females m-2 at a landscape scale) were also recorded in an extensive survey in nine lanscapes of the Ghent region, northern Belgium, in summer of 2014 ([43]). Here as well, densities were one order of magnitude or more lower than those recorded one decade ago (e.g., during a survey in 2004–2006 densities at two locations were 10–20 times higher compared to ten years later; [52]; Bonte, pers. observations). Interestingly, while other orb-weaver species – especially the larger ones – showed dramatic declines in both abundance and species richness along an urbanisation gradient [53,54], A. diadematus was found to reach similar low densities across this land-use gradient. Or put conversely, local densities at spatial scales of approximately 100 km were alarmingly low in both the more natural and human impacted regions, demonstrating regional declines beyond the scale of local land-use. Thus, extraordinarily low present-day population densities of Araneus diadematus have been recorded in two different regions of western Europe, ≈500 km apart. These declines extend local environmental changes at small scales and suggest common negative impacts of intensive urbanization, climate change or any other large-scale stressor across the entire landscape over the past half-century [55,56].

The present study and that from northern Belgium suggest that the notion that Araneus diadematus is an abundant spider, as pointed out in much of the literature [57,58], has these days turned out to be a myth – at least in highly urbanized western European landscapes such as the Swiss midland and northern Belgium. But so far the apparent abundance decline of this species in western Europe had been ignored by faunists in charge of compiling local Red Lists for spiders (e.g., [57,58]). Red Lists are based on the number of different locations within a landscape from which a species has been recorded – and not on absolute population densities, and the fact that Araneus diadematus is still found in many places (although in strongly reduced densities) may explain why it is still labeled as an “abundant species” (e.g., [57,58]).

In contrast, present-day population densities of Araneus diadematus in some areas outside of continental western Europe appear to be still rather high. So for instance, exterminators of the pest control firm Senske Services removed more than 75 Araneus diadematus spiders from the exterior of a “2,500–square-foot home” in Seattle (USA) in August 2016, which translates to a population density of 0.32 spiders m-2 [59]. Evidently the spiders at this particular location were still capturing a sufficient amount of food in the form of flying insects enabling them to build up a population density roughly 290 times that of the present-day Swiss overall mean density. Future detailed assessments of the population densities of this spider species in the different parts of its geographic range are urgently needed and may provide important clues on the extent of the loss of flying insects in various regions of western Europe and of the globe. We would in this respect like to promote the use of new citizin-science tools such as SpiderSpotter [60] to achieve these highly needed insights, and especially to guide short-term action to mitigate these alarming declines in these sentinel arthropod top-predators.

5. Concluding Remarks

The drastic decline in the abundance of the orb-weaving spider Araneus diadematus over the past half-century documented in this study (Table 1) is apparently revealing a bottom-up trophic cascade in response to widespread insect losses that had occurred across large parts of Europe in recent decades [1,2,4,6,9,25,61,62]. There is evidence that other groups of aerial web-spinning spiders, which likewise depend on flying insects as food [17–19,21,63–65], have also become much rarer over the past decades (Nyffeler, pers. observations). So for instance, the mesh-web weaver Dictyna uncinata (along with other dictynid species) whose small, tangled webs were found in large numbers on the leaves of garden plants a few decades ago [65], has apparently become very rare these days (Nyffeler, pers. observations). The ongoing abundance decline of the spiders parallels the dramatic abundance declines in other insectivorous animals such as insectivorous birds, bats, frogs, and lizards documented in recent decades [66–68].

To sum this up, the findings of this study support the notion by other researchers that we now live in the midst of an ecological crisis in which trophic webs are being eroded and degraded as a result of man-made adverse environmental impacts [13,61,67,69,70]. If this disastrous trend cannot be halted or even reversed in the very near future, “entire ecosystems will collapse due to starvation” [16].

Supplementary Materials

Table S1 and Table S2 are available online at ………………..

Author Contributions

Conceptualization, M.N and D.B.; Methodology, M.N.; Validation: M.N. and D.B.; Formal Analysis: M.N. and D.B.; Investigation, M.N. (in Switzerland) and D.B. (in Belgium); Data Curation, M.N.; Writing – Original Draft Preparation, M.N.; Writing – Review & Editing, D.B.

Conflicts of Interest

The authors declare no conflict of interest.

Acknowledgements

The authors wish to extend their gratitude to Rätus Fischer and Christlinde Ruchti for assistance in the field.

References

  1. 1.↵
    Hallmann, C.A.; Sorg, M.; Jongejans, E.; Siepel, H.; Hofland, N.; Schwan, H. et al. More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLoS One 2017, 12, e0185809.
    OpenUrlCrossRefPubMed
  2. 2.↵
    Seibold, S.; Gossner, M.M.; Simons, N.K.; Blüthgen, N.; Müller, J.; Ambarli, D. et al. Arthropod decline in grasslands and forests is associated with landscape-level drivers. Nature 2019, 574, 671–674.
    OpenUrl
  3. 3.↵
    Schuch, S.; Wesche, K.; Schaefer, M. Long-term decline in the abundance of leafhoppers and planthoppers (Auchenorrhyncha) in Central European protected dry grasslands. Biol. Conserv. 2012, 149, 75–83.
    OpenUrl
  4. 4.↵
    Hallmann, C.A.; Zeegers, T.; van Klink, R.; Vermeulen, R.; van Wielink, P.; Spijkers, H. et al. Declining abundance of beetles, moths and caddisflies in the Netherlands. Insect. Conserv. Diver. 2019, doi: 10.1111/icad.12377.
    OpenUrlCrossRef
  5. 5.
    Harris, J.E.; Rodenhouse, N.L.; Holmes, R.T. Decline in beetle abundance and diversity in an intact temperate forest linked to climate warming. Biol. Conserv. 2019, 240, 108219.
    OpenUrl
  6. 6.↵
    Møller, A.P. Parallel declines in abundance of insects and insectivorous birds in Denmark over 22 years. Ecol. Evol. 2019, 9, 6581–6587.
    OpenUrl
  7. 7.
    Wepprich, T.; Adrion, J.R.; Ries, L.; Wiedmann, J.; Haddad, N. M. 2019 Butterfly abundance declines over 20 years of systematic monitoring in Ohio, USA. PLoS One 2019, 14, e0216270.
    OpenUrl
  8. 8.
    Stepanian, P.M.; Entrekin, S.A.; Wainwright, C.E.; Mirkovic, D.; Tank, J.L.; Kelly, J.F. Declines in an abundant aquatic insect, the burrowing mayfly, across major North American waterways. P. Natl. Acad. Sci. USA 2020, 117, 2987–2992.
    OpenUrlAbstract/FREE Full Text
  9. 9.↵
    Tinsley-Marshall, P.; Skilbeck, A. Riggs, A. Monitoring of Ecosystem Function at Landscape-Scale Demonstrates Temporal Difference in Invertebrate Abundance in Kent and South-East England; Report Kent Wildlife Trust: Maidstone, Kent, UK, 2020.
  10. 10.
    Leather, S.R. “Ecological Armageddon” – more evidence for the drastic decline in insect numbers. Ann. Appl. Biol. 2017, 172, 1–3.
    OpenUrl
  11. 11.
    Samways, M.J. Addressing global insect meltdown. Ecol. Citizen 2019, 3 (Suppl A), 23–6.
    OpenUrl
  12. 12.↵
    Sánchez-Bayo, F.; Wyckhuys, K.A. Worldwide decline of the entomofauna: A review of its drivers. Biol. Conserv. 2019, 232, 8–27.
    OpenUrl
  13. 13.↵
    Wagner, D.L. Insect declines in the Anthropocene. Annu. Rev. Entomol. 2020, 65, 457–480.
    OpenUrl
  14. 14.↵
    Nyffeler, M.; Birkhofer, K. An estimated 400–800 million tons of prey are annually killed by the global spider community. Sci. Nat. 2017, 104, 30.
    OpenUrl
  15. 15.↵
    Nyffeler, M.; Sekercioğlu, Ç.H.; Whelan, C.J. Insectivorous birds consume an estimated 400–500 million tons of prey annually. Sci. Nat. 2018, 105, 47.
    OpenUrl
  16. 16.↵
    Why insect populations are plummeting – and why it matters. Available online: https://www.nationalgeographic.com/animals/2019/02/why-insect-populations-are-plummeting-and-why-it-matters/ (accessed on 29 February 2020).
  17. 17.↵
    Nyffeler, M.; Dean, D.A.; Sterling, W.L. Prey selection and predatory importance of orb-weaving spiders (Araneae: Araneidae, Uloboridae) in Texas cotton. Environ. Entomol. 1989, 18, 373–380.
    OpenUrlCrossRef
  18. 18.↵
    Malt, S. (1996) Untersuchungen zur Rolle ausgewählter netzbauender Spinnen (Araneida) im trophischen Beziehungsgefüge von Halbtrockenrasen, Doctoral Dissertation, University of Jena, Germany, 1996.
  19. 19.↵
    Ludy, C. Prey selection of orb-web spiders (Araneidae) on field margins. Agr. Ecosyst. Environ. 2007, 119, 368–372.
    OpenUrl
  20. 20.↵
    Nyffeler, M. Diel Activity Patterns, Prey Composition, and Prey Consumption Rate of the Orb-Weaving Spiders Araneus diadematus and Nuctenea umbratica in a Garden in Höngg (Zurich), Master’s Thesis, Swiss Federal Institute of Technology Zurich, 1976.
  21. 21.↵
    Nyffeler, M. Field Studies on the Ecological Role of the Spiders as Insect Predators in Agroecosystems (Abandoned Grassland, Meadows and Cereal Fields), Doctoral Dissertation, Swiss Federal Institute of Technology Zurich, 1982.
  22. 22.↵
    Bee, L.; Oxford, G.; Smith, H. Britain’s Spiders: A Field Guide; Princeton University Press: Princeton, USA, 2017.
  23. 23.↵
    Witt, P.N.; Reed, C.F.; Peakall, D.B. A Spider’s Web: Problems in Regulatory Biology; Springer: New York, USA, 1968.
  24. 24.↵
    Insektenschwund in der Schweiz und mögliche Folgen für Gesellschaft und Wirtschaft. Available online: http://www.akademien-schweiz.ch/dms/D/Aktuell/News/Faktenblatt-Insekten/Faktenblatt%20Insekten.pdf (accessed on 29 February 2020).
  25. 25.↵
    Decline of insectivorous birds. Available online: https://www.vogelwarte.ch/en/atlas/focus/decline-of-insectivorous-birdsn (accessed on 29 February 2020).
  26. 26.↵
    Le Berre, M.; Ramousse, R.; Le Guelte, L. Eco-éthologie des Argiopidae: 1. Evolution temporelle d’une population d’Araneus diadematus Clerck dans son milieu naturel. Atti. Soc. Toscana Sci. Nat. P. V. Mem. Ser. B 1981, 88, 72–83.
    OpenUrl
  27. 27.
    Colebourn, P.H. The influence of habitat structure on the distribution of Araneus diadematus Clerck. J. Anim. Ecol. 1974, 43, 401–409.
    OpenUrl
  28. 28.
    Krzyzanowska, E. Field experiments on the filling of space with the community of Araneus diadematus (Clerck) (Aranei) in a pine stand. Mem. Zoologi. 1979, 30, 27–35.
    OpenUrl
  29. 29.
    Van der Hammen, L. The distribution of spiders and harvestmen (Chelicerata) in the Dutch National Park “De Hoge Veluwe”. Zool. Meded. 1983, 57, 325–338.
    OpenUrl
  30. 30.
    Pasquet, A. Distribution of two orb-weaving spiders Araneus marmoreus (Clerk) and Araneus diadematus (Clerk). Biol. Behav./Biol. Comport. 1984, 9, 321–331.
    OpenUrl
  31. 31.
    Fasola, M.; Mogavero, F. Structure and habitat use in a web-building spider community in northern Italy. Boll. Zool. 1995, 62, 159–166.
    OpenUrl
  32. 32.↵
  33. 33.↵
    Vollrath, F.; Samu, F. The effect of starvation on web geometry in an orb-weaving spider. Bull. Br. Arachnol. Soc. 1997, 10, 295–297.
    OpenUrl
  34. 34.↵
    Vogel, G. Where have all the insects gone? Science 2017, 356, 576–579.
    OpenUrlAbstract/FREE Full Text
  35. 35.↵
    Kirchner, W. Bisher Bekanntes über die forstliche Bedeutung der Spinnen—Versuch einer Literaturanalyse. Waldhygiene 1964, 5, 161–198.
    OpenUrl
  36. 36.↵
    Robinson, M.H.; Robinson, B. Prey caught by a sample population of the spider Argiope argentata (Araneae: Araneidae) in Panama: a year’s census data. Zool. J. Linn. Soc.-Lond. 1970, 49, 345–358.
    OpenUrl
  37. 37.↵
    Leborgne, R.; Pasquet, A. Time of oviposition and reproductive success in Argiope bruennichi (Araneae: Araneidae). Eur. J. Entomol. 2005, 102, 169–174.
    OpenUrl
  38. 38.↵
    Samu, F.; Vollrath, F. Spider orb web as bioassay for pesticide side effects. Entomol. Exp. Appl. 1992, 62, 117–124.
    OpenUrl
  39. 39.
    Lengwiler, U.; Benz, G. Effects of selected pesticides on web building behaviour of Larinioides sclopetarius (Clerck)(Araneae, Araneidae). J. Appl. Entomol. 1994, 117, 99–108.
    OpenUrl
  40. 40.
    Benamú, M.A.; Schneider, M.I.; Sánchez, N.E. Effects of the herbicide glyphosate on biological attributes of Alpaida veniliae (Araneae, Araneidae), in laboratory. Chemosphere 2010, 78, 871–876.
    OpenUrlCrossRefPubMedWeb of Science
  41. 41.
    Benamú, M.A.; Schneider, M.I.; González, A.; Sánchez, N.E. Short and long-term effects of three neurotoxic insecticides on biological and behavioural attributes of the orb-web spider Alpaida veniliae (Araneae, Araneidae): implications for IPM programs. Ecotoxicology 2013, 22, 1155–1164.
    OpenUrlCrossRef
  42. 42.
    Pasquet, A.; Tupinier, N.; Mazzia, C.; Capowiez, Y. Exposure to spinosad affects orb-web spider (Agalenatea redii) survival, web construction and prey capture under laboratory conditions. J. Pest Sci. 2016, 89, 507–515.
    OpenUrl
  43. 43.↵
    Dahirel, M.; De Cock, M.; Vantieghem, P.; Bonte, D. Urbanization-driven changes in web building and body size in an orb web spider. J. Anim. Ecol. 2019, 88, 79–91.
    OpenUrl
  44. 44.↵
    Nyffeler, M.; Benz, G. Bemerkenswerte Spinnenfunde in Wiesen und Getreidefeldern bei Zürich. Mitt. Schweiz. Ent. Ges. 1982, 55, 97–100.
    OpenUrl
  45. 45.
    Green, D.M. The ecology of extinction: population fluctuation and decline in amphibians. Biol. Conserv. 2003, 111, 331–343.
    OpenUrl
  46. 46.
    Wolff, J.O. Population fluctuations of mast-eating rodents are correlated with production of acorns. J. Mammal. 1996, 77, 850–856.
    OpenUrlCrossRefWeb of Science
  47. 47.↵
    Eggenschwiler, L.; Hänggi, A. 24 Stunden Forschung live: Ergebnisse vom GEO-Tag der Natur in den Merian Gärten in Basel. Mitt. Naturf. Ges. Basel 2018, 18, 19–37.
    OpenUrl
  48. 48.↵
    Nyffeler, M. Eine Notiz zur ökologischen Bedeutung der Radnetzspinnen als Blattlausprädatoren in Gärten. Mitt. Schweiz. Ent. Ges. 1983, 56, 200.
    OpenUrl
  49. 49.↵
    Kleinteich, A. Life History of the Bridge Spider, Larinioides sclopetarius (Clerck, 1757), Doctoral Dissertation, University of Hamburg, Germany, 2010.
  50. 50.↵
    Kleinteich, A.; Schneider, J.M. Developmental strategies in an invasive spider: constraints and plasticity. Ecol. Entomol. 2011, 36, 82–93.
    OpenUrlCrossRef
  51. 51.↵
    Richter, D.; Göbel, D.; Schmitt, M. Zum Beutespektrum der Brückenspinne (Larinioides sclopetarius; Araneae: Araneidae) im Ruhrgebiet. Elektronische Aufsätze der Biologischen Station Westliches Ruhrgebiet 2012, 22, 1–9.
    OpenUrl
  52. 52.↵
    Bonte, D.; Lanckacker, K.; Wiersma, E.; Lens, L. Web building flexibility of an orb-web spider in a heterogeneous agricultural landscape. Ecography 2008, 31, 646–653.
    OpenUrlCrossRef
  53. 53.↵
    Dahirel, M.; Dierick, J.; De Cock, M.; Bonte, D. Intraspecific variation shapes community-level behavioral responses to urbanization in spiders. Ecology 2017, 98, 2379–2390.
    OpenUrlCrossRef
  54. 54.↵
    Merckx, T.; Souffreau, C.; Kaiser, A.; Baardsen, L.; Backeljau, T.; Bonte, D. et al. Body-size shifts in aquatic and terrestrial urban communities. Nature 2018, 558, 113–116.
    OpenUrl
  55. 55.↵
    Antrop, M. Landscape change and the urbanization process in Europe. Landscape Urban Plan. 2004, 67, 9–26.
    OpenUrl
  56. 56.↵
    Urbanisierungsgrad in der Schweiz nach Kantonen am 31. Dezember 2018. Available online: https://de.statista.com/statistik/daten/studie/712490/umfrage/urbanisierung-in-der-schweiz-nach-kantonen/ (accessed on 29 February 2020).
  57. 57.↵
    Martin, D. Rote Liste der Spinnen (Araneae) Mecklenburg-Vorpommerns; Ministerium für Landwirtschaft, Umwelt und Verbraucherschutz Mecklenburg-Vorpommern: Schwerin, Germany, 2012.
  58. 58.↵
    Lemke, M.; Reinke, H.D.; Vahder, S.; Irmler, U. Die Spinnen Schleswig-Holsteins. Rote Liste; Ministerium für Energiewende, Landwirtschaft, Umwelt und ländliche Räume des Landes Schleswig-Holstein, Kiel, Germany, 2013.
  59. 59.↵
    Pest Control in the Pacific Northwest. Available online: https://www.pctonline.com/article/pest-control-pacific-northwest-allen/ (accessed on 29 February 2020).
  60. 60.↵
    SpiderSpotter. Available online: https://www.spinnenspotter.be/en/ (accessed on 29 February 2020).
  61. 61.↵
    Carrington, D. 2019 Plummeting insect numbers ‘threaten collapse of nature’. Available online: https://www.theguardian.com/environment/2019/feb/10/plummeting-insect-numbers-threaten-collapse-of-nature (accessed on 29 February 2020).
  62. 62.↵
    Møller, A.P. Quantifying rapidly declining abundance of insects in Europe using a paired experimental design. Ecol. Evol. 2020, doi: 10.1002/ece3.6070.
    OpenUrlCrossRef
  63. 63.↵
    Turnbull, A.L. The prey of the spider Linyphia triangularis (Clerck)(Araneae, Linyphiidae). Can. J. Zool. 1960, 38, 859–873.
    OpenUrl
  64. 64.
    Kajak, A. An analysis of food relations between the spiders Araneus cornutus and A. quadratus and their prey in meadows. Ekol. Pol. A 1965, 13, 717–768.
    OpenUrl
  65. 65.↵
    Nyffeler, M. Über den Beutefang der Netzspinne Dictyna uncinata Thorell, Semester Thesis, Department of Entomology, Swiss Federal Institute of Technology Zurich, 1974.
  66. 66.↵
    Inger, R.; Gregory, R.; Duffy, J.P.; Stott, I.; Voříšek, P.; Gaston, K.J. Common European birds are declining rapidly while less abundant species’ numbers are rising. Ecol. Lett. 2015, 18, 28–36.
    OpenUrlCrossRefPubMed
  67. 67.↵
    Lister, B.C.; Garcia, A. Climate-driven declines in arthropod abundance restructure a rainforest food web. P. Natl. Acad. Sci. USA 2018, 115, E10397–E10406.
    OpenUrlAbstract/FREE Full Text
  68. 68.↵
    Rosenberg, K.V.; Dokter, A.M.; Blancher, P.J.; Sauer, J.R.; Smith, A.C.; Smith, P.A. et al. Decline of the North American avifauna. Science 2019, 366, 120–124.
    OpenUrlAbstract/FREE Full Text
  69. 69.↵
    Dobson, A.; Lodge, D.; Alder, J.; Cumming, G.S.; Keymer, J.; McGlade, J. et al. Habitat loss, trophic collapse, and the decline of ecosystem services. Ecology 2006, 87, 1915–1924.
    OpenUrlCrossRefPubMedWeb of Science
  70. 70.↵
    Goulson, D. The insect apocalypse, and why it matters. Curr. Biol. 2019, 29, R967–R971.
    OpenUrl
  71. 71.
    Holzapfel, M. Die Gewächshausfauna des Berner Botanischen Gartens. Rev. Suisse Zool. 1932, 39, 325–374.
    OpenUrl
  72. 72.
    Turnbull, A.L. The spider population of a stand of oak (Quercus robur L.) in Wytham Wood, Berks., England. Can. Entomol. 1960, 92, 110–124.
    OpenUrl
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Posted March 05, 2020.
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Where have all the spiders gone? Observations of a dramatic population density decline in the once very abundant garden spider, Araneus diadematus (Araneae: Araneidae), in the Swiss midland
Martin Nyffeler, Dries Bonte
bioRxiv 2020.03.03.975912; doi: https://doi.org/10.1101/2020.03.03.975912
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