Red Silver Spider

Argyrodes flavescens (Pickard-Cambridge) 1880

Figure 1. Gif image from

How many spiders are there on the web?
Look closely at the sides of the web! Are these red spiders the spiderlings of the big spider in the middle of the web? Are these spiders the male spiders instead?

Read on to find out more!

combined figure of argyrodes.png
Figure 2. A close up look of Argyrodes flavescens hanging on the periphery of a web (Copyright © 2009 Starmer, F.)

1. Introduction of Argyrodes flavescens (Red silver spider)

These small red-brown spiders are not the spiderlings nor males of the host spider. They are instead another species of spiders that behave as kleptoparasites and lives on the web of a larger web building spider host (Commonly Nephila spp.). The term kleptoparasitism or cleptoparasitism originated from Greek root words kleptēs thief + parasite, which means parasitism by theft [10]. In terms of etymology, kleptoparasitism should refer to the generalized theft of any resource, not just food [11]. Therefore from the term itself, it describes Argyrodes flavescens' dependent relationship on the host spider for resources. An additional information is that within the spiders of the genus Argyrodes, all except //Argyrodes flagellum// live on the webs of the larger web building spiders [2]!

In the Gif above (Figure 2), it showcases how small these kleptoparasite are as compared to the web building host spider. The host spider Nephila pilipes abdomen is approximately 5cm long while these small kletoparasites' abdomen are only approximately 3mm!

2. Distribution

2.1 Local distribution

Argyrodes flavescens are found in locations where the large web building host could be found. The common host would be the golden orb weavers which are found in secondary and primary forest in Singapore such as Pulau Ubin, Sungei Buloh Nature Reserve, Labrador Park etc. Refer to //Nephila pilipes// species page for the details of their local distribution.

2.2 Asia distribution

Figure 4. Global distribution point map of Argyrodes flavescens indicated by the yellow dots (Picture from Encyclopedia of Life © Discover Life and original sources).jpg
Figure 3. Distribution point map of Argyrodes flavescens indicated by the yellow dots (Picture from Encyclopedia of Life © Discover Life and original sources). Last updated on 22/7/2012.

The distribution of Argyrodes flavescens reflected in Figure 3 above were based on occurrence reports by the Global Biodiversity Information Facility (GBIF) network as of 22nd July 2012. The distribution includes countries in Asia: Malaysia [3], Thailand, Lao People's Democratic Republic [4], South Korea [5]. However, the list is not exhaustive as throughout the years Argyrodes flavescens has been recorded in other parts of Asia:Japan [6], China [7], Taiwan [8] and Singapore [9] (Figure 4 below) .

Distribution of Argyrodes flavescens Maptive.png
Figure 4. Distribution map of Argyrodes flavescens in Asia. (Created by Lim Zhi Yun using Maptive).

3. Biology

3.1 Kleptoparasitism

Figure 5. Numerous Argyrodes flavescens hanging on the web of a Nephila host (Copyright © 2007 Starmer, F.).png
Figure 5. Numerous Argyrodes flavescens hanging on the web of a Nephila host (Copyright © 2007 Starmer, F.)

As mentioned in the introduction, Kleptoparasitism or cleptoparasitism orginated from Greek root words kleptēs thief + parasite, means parasitism by theft [10]. In terms of etymology, kleptoparasitism should refer to the generalized theft of any resource, not just food [11].

Kleptoparasitism is one of the most common form of exploitation between animals which involves stealing of already captured food items from another animal [12,13]. In the past, most kleptoparsitic studies focused mainly on birds but the prevalence of this behavior is widespread in many animal taxa [14].

For the interaction to be termed kleptoparasitism, the kleptoparasite must incur a benefit and the host must be negatively affected by the loss of food [14]. In the case that the host does not incur any energetic cost via the loss of the resource, the interaction is not considered to be kleptoparasites [14]. In general, kleptoparasites do not injure the hosts in any direct way other than through loss of nourishment [14].

3.1.1 Kleptoparasitism in web building spiders

A spider web serves as a microhabitat to obligatory kleptoparasites and provides them with a variety of resources, such as captured prey, prey remains, and silk [9,15]. The Theridiidae spider, Argyrodes flavescens, is known to conduct nearly all their activities on webs of other spiders and is commonly associated to the large web-weaving spider from the genus Nephila [9,16]. Figure 6 showcases a few scenarios of the different behaviors of Argyrodes inhabitants on a Nephila web.

Edited diagram of kleptoparsitism in spiders.png
Figure 6. A pictorial diagram to show how a Nephila clavipes hostweb serves as a habitat for other web associates. Note that the Argyrodes in this diagram are Argyrodes elevatus and Argyrodes caudatus. (Copyright © 1987 Vollrath.F[17]) (Image edited with wordings by Lim Zhi Yun).

3.1.2 Argyrodes-Nephila Kleptoparasitism relationship

Previous studies have shown that the presence of A. flavescens is detrimental to N. pilipes in terms of reduced weight gain, increased web damage, rate of web relocation and ultimately mortality [9]. Susceptibility of Nephila to kleptoparasitism

Although Argyrodes kleptoparasites are found to occupy other web building spiders, spiders from the genus Nephila are especially susceptible to kleptoparasites [18–20]. There exist a variety of reasons behind why Nephila webs are suitable or favourable for Argyrodes [17]. Factors such as the web being a relatively permanent fixture and having an extensive three-dimensional barrier web helps to provides ample shelter with a large carrying capacity for Argyrodes to live on [17] (Refer to Figure 7).The significance of barrier webbing for Argyrodes were also proposed by several researchers [21,22]. Moreover, the mesh of the Nephila web is very fine and able to trap even the smallest insects [17]. The capture area of the orb web is also large, extremely stiff, and has diverging radii rendering it difficult for Nephila to monitor [17].

In Singapore, there are two Nephila species that are susceptible to kleptoparsities: Nephila pilipes and //Nephila antipodiana//. Readers can refer to the Nephila pilipes species page for other reasons on why the genus Nephila are susceptible to kleptoparasitism.

Figure to show Nephila web barrier.gif
Figure 7. A picture of a Nephila pilipes web with web barriers by the side (Copyright © 2010 Kuntner et al. [57]). (Image edited with wordings by Lim Zhi Yun). Factors influencing Argyrodes-Nephila relationships

The Argyrodes-Nephila relationships are known to be influenced by many factors, such as life stage, web characteristics, prey availability and environmental conditions [9]. In general, larger webs (and hence sub adult- adult Nephila) are found to carry a higher load of kleptoparasites [9]. Abundance of Argyrodes
It is well known that the abundance of Argyrodes considerably varies within host species and web characteristics, web structure and occupancy of host webs [8,18,23,24].

In the case of the golden orb weavers Nephila clavipes (from Neotropics), the abundance of kleptoparasites on the clustered webs is entirely predictable based on the size of the host’s web. However, it has been shown that on the isolated webs of N. clavipes, there exists a considerable variation in the number of kleptoparasites and host web size is a poor indicator of the kleptoparasite load [36]. In Singapore context, previous studies have shown that the number of A. flavescens is positively correlated with body size, web size and ambient light intensity surrounding the webs of host spider Nephila pilipes [9]. Host availability
A study in Japan have demonstrated the seasonal dynamics of Nephila-Argyrodes systems by showing that host availability influences the abundance and dynamics of kleptoparasites [25].

Argyrodes flavescens in sub-tropical Japan were observed to prefer different hosts at different period of the year due to the availability of the host (Differing life stages of the two different Nehpila species) [25]. In August and November, Nephila clavate was preferred while Nephila maculata was preferred in July. This was attributed to the larger size of Nephila maculata than Nephila clavate in July [25]. A study by Grostal & Walter revealed a similar result that Nephila spp. were the preferred hosts for Argyrodes antipodianus [24]. Inter-specific competition
In the same study, the authors found out that the peak density of two Argyrodes (A. flavescens and A. bonadea) were different due to inter-specific competitions. The authors demonstrated experimentally, that in a small spatial scale, the number of individuals of A. flavescens removed from the group was positively correlated with the rate of increase in A. bonadea [25]. As of 2016, A. bonadea sighting has yet to be recorded in Singapore.

New Argyrodes bonadea combined image.jpg
Figure 8. Argyrodes bonadea (Left image by Akio Tanikawa, available under a Creative Commons Attribution-Noncommercial-Share Alike license) (Right image by Patrick Randall, available under a Creative Commons Attribution-Noncommercial-Share Alike license. Copyright © 2013 Patrick Randall. )

3.2 Feeding Behaviour (Foraging strategies)

Kleptoparasitic spiders in the genus Argyrodes are known to form social groups around their host spider’s web [26]. It is potentially hazardous to forage as a kleptoparasite on the host web as the host spider itself is a potential predator [27]. Host spiders are known to readily eat Argyrodes [22] and often chase them away [21,28,29].

Argyrodes spider not only utilise a range of kleptoparasitic foraging techniques to exploit host spiders, they are also known to utilise araneophagic techniques such as attacking the vulnerable hosts that are moulting or lunging at spiderlings [26]. Kleptoparsitic foraging techniques such as “feeding with the host” are riskier than the other tactics such as “silk stealing” and they are known to give the most benefit to the kleptoparasites [21].

Argyrodes are known to display the following foraging strategies:
1. Collect small prey which are apparently ignored by hosts or eat prey remains which were abandoned by hosts [8,9] (Refer to Figure 9)
Figure 7. Argyrodes flavescens consuming a small prey.png
Figure 9. Argyrodes flavescens consuming a small prey (Copyright © 2007 Starmer, F.)

2. Steal freshly captured or freshly stored prey by hosts [9,30] (Refer to Figure 10)
Figure 8. Argyrodes flavescens stole a freshly captured or freshly stored prey by hosts.png
Figure 10. Argyrodes flavescens stole a freshly captured or freshly stored prey by hosts (Copyright © 2007 Starmer, F.)

3. Feed with the host to exploit digested food [9,21,23,24,26] (Refer to Figure 11)
Fig 9.jpg
Figure 11. Argyrodes flavescens feeding with hosts to exploit digested food (Copyright © 2009 Starmer, F.)

Video 1. Argyrodes flavescens feeding with hosts to exploit digested food (Copyright © 2009 Starmer, F.)
4. Silk stealing [9,31] (Tso & Severinghaus 1998; Koh & Li 2002) (Refer to Figure 12)
Figure 10. Argyrodes flavescens feeding on silk stealing silk.jpg
Figure 12. Argyrodes flavescens feeding on silk/ stealing silk (Copyright © 2009 Starmer, F.)

5. Hunt for spiderlings of host or attack the moulting host [21,26,32] (Rarely observed)
No image was found for this at the moment.

3.4. Reproduction

Figure 11. Close up image of how a male (top of the image) A.flavescens head fits into the female (bottom of the image) A. flavescens chelicerae during mating.jpg
Figure 13. Image of a male and female Argyrodes flavescens engaged in mating. The smaller sized male head is being grabbed by the larger sized female chelicerae (pair of appendages in front of the mouth). (Copyright © 2008 Starmer, F.)

Argyrodes flavescens conduct nearly all their activities on webs of their host spider, which includes reproduction.

During mating, the adult female grabs the head of the adult male A. flavescens with her chelicerae while , the male repeatedly prod his pedipalp one at a time into the female sexual organ (epigynum) (Refer to video 2 and 3). During their mating process, the male and female relaxes and back off from time to time (Refer to video 2 and 3). There was no publication found on the consequences of mating on the host web or if it makes them more vulnerable to the host detection.

There are also very limited publications on the exact time it takes for A. flavescens to reach sexual maturity but one publication mentioned that with the consistent high prey availability, spiderlings of A. flavescens are able to reach maturity and produce egg case in a month [25].

Video 2. A male and female A. flavescens mating (Copyright © 2008 Starmer, F.)

Video 3. A close up look of a male and female A. flavescens mating (Copyright © 2016 Su Yong-Chao)

3. 4.1 Egg case

Eggcase of argyrodes flavescens.png
Fig 14. Egg case of Argyrodes flavescens (Copyright © 2016 Lim Zhi Yun)

As mentioned previously, Argyrodes flavescens is known to conduct nearly all their activities on webs of their host spider, which includes laying of egg case.

In the wild, A. flavescens builds a small tent web away from the host web or use the abandoned portion of the host web to place their egg sac [33].

The egg case of A. flavescens are pale white to light brown in appearance and spherical, suspended by a long stalk [33]. The upper part of the eggcase is cone shaped, rounded and tapers well into a point. Inside the egg sac, the eggs are loosely deposited into the middle of a little puff of flossy silk [33]. After hatching, the offsprings crawl through the hole at the bottom of the egg sac [33].

3.4.2 Life stages

There are 4 instars stage in A. flavescens before the final moult to become the adult. The sex of the A. flavescens is only distinguishable at the third instar onwards. Notice the pedipalps on the third and fourth instar image (Figure 15).

compiled instars.png
Figure 15. Different stages of instars (1st to 4th) of A. flavescens (Copyright © Su Yong-Chao)

3.5 Dragline and Locomotion

Figure 14. Close up image of how the support web of A. flavescens in between the Nephila web.jpg
Figure 16. Close up image of the support web of A. flavescens in between the Nephila web (Copyright © 2009 Starmer, F.)

Draglines are important for Argyrodes as they have been observed to escape and run away from the attack of the host via its dragline [34]. Dragline are stiff strand of silk produced by spiders especially to form the framework of its web and as a means of lowering itself and returning to a height [54]. In addition, Argyrodes has been observed to swing from their draglines to get closer to the prey item [34].

Rotary probe movement are also observed in Argyrodes, including A. flavescens. They perform investigative behaviors as “rotary probe” by rotating the first pair of legs, because the host web is an unknown environment to the invader [34]. (Refer to Video 4 to observe the rotary probe action and the dragline from their spinnerets.)

Video 4. A.flavescens pulling out dragline from its spinnerets and performing rotary probing (Copyright © 2009 Starmer, F.)
Figure 6 from section 3.1.1 has showcased some but not all of the scenarios of Argyrodes behavioural activities on the host's web. To facilitate reader's experience, Figure 6 is inserted below this section for easy reference.

In general, eight behavioral activities of Argyrodes (Specifically Argyrodes Ululans) were recognized and recorded [30]:
“(1) Rotary probing (rotating the first pair of legs at the coxatrochanter joint);(Refer to video 4 above)
(2) Feeding (extracting food from prey); (Refer to Feeding behaviour section 3.2)
(3) Folded (resting or inactive position in which the spider remains motionless in the web with the legs folded up near the body; (Refer to Figure 6)
(4) Still (also an inactive state in which the spider sits in the web motionless with the legs outstretched, (Refer to Figure 6)
(5) Grooming (cleaning legs by passing them through the chelicerae); (Refer to Figure 6)
(6) Mating (courtship and copulation); (Refer to Reproduction section 3.4 )
(7) Stealing behaviors (including leg waving, web shaking, and clearing silk); and (Refer to Feeding behaviour section 3.2)
(8) Walking (locomotion)” [30]

Edited diagram of kleptoparsitism in spiders.png
Figure 6. A pictorial diagram to show how a Nephila clavipes hostweb serves as a habitat for other web associates. Note that the Argyrodes in this diagram are Argyrodes elevatus and Argyrodes caudatus. (Copyright © 1987 Vollrath.F[17]) Image edited with wordings by Lim Zhi Yun.

4. Morphology

This section describes the morphology of A. flavescens. There are limited detailed description or drawings on the morphology of A. flavescens, hence this section does not consist of full comparison between the male and female A. flavescens.

4.1 Morphology of A. flavescens (Male and Female)

Fig 15. male and female argyrodes.png
Figure 17. Male (left) and female (right) Argyrodes flavescens (Copyright © 2014 Taiwan Spider Picture Data)

Figure 16. Epigynum of female Argyrodes flavescens.jpg
Figure 18. Epigynum of female Argyrodes flavescens (Copyright © 2014 Taiwan Spider Picture Data)

Figure 17. Pedipalps of male Argyrodes flavescens.jpg
Figure 19. Pedipalps of male Argyrodes flavescens (Copyright © 2014 Taiwan Spider Picture Data)

4.1.1 Legs (Tarsus)

Although most of the Theridiid ae family members have a "comb like structure" of serrated bristles on the last segment (Tarsus) of their fourth leg (Figure 20), a look under the dissection microscope shows that Argyrodes flavescens lack such structures or that it is indistinguishable (Figure 21). Only tarsal claws were distinctively found on their leg instead.
Figure 18. Drawings of Tarsal comb in spiders (Copyright © Brandeis University Field Biology Electronic Field Guides).jpg
Figure 20. Drawings of Tarsal comb in spiders (Copyright © Brandeis University Field Biology Electronic Field Guides) (Permission to publish image sought but not granted because author is uncontactable. Image will be taken down if the author requests to.)

Figure 19. Image of A.flavescens 4th tarsal under the dissection microscope (Copyright © 2016 Lim Zhi Yun).png
Figure 21. Image of A.flavescens 4th tarsal under the dissection microscope (Copyright © 2016 Lim Zhi Yun)

5. Diagnosis

5.1 Male Nephila VS Argyrodes flavescens

As A. flavescens (Figure 22) and males N. pilipes (Figure 23) are commonly found on the same web of the host (female) N. pilipes,there is a need to know how to differentiate the two species. At first glance, they may be mistaken to be same species since both are much smaller than female N. pilipes host, of similar reddish brown colour and are commonly observed at the periphery of the web. However, they can be clearly differentiated in a few ways (Figure 24).
Figure 20. Male A. flavescens.jpg
Figure 22. Male A. flavescens (Copyright © 2016 Lim Zhi Yun)

Figure 21. Male N. pilipes.jpg
Figure 23. Male N. pilipes (Copyright © 2016 Lim Zhi Yun)

The following features
can be used to distinguish
between the two species:
Figure 22. Male A. flavescens in Singapore.png
Figure 24. Male A. flavescens in Singapore and Male N.pilipes in Singapore (Copyright © 2009 Starmer, F.)

Approximately 2mm smaller than male N.pilipes
Approximately 2mm larger
than male A.flavescens
Legs morphology: size and colour
Slender, deep blackish brown hue and the extremity of the femora yellow
Thicker and of reddish brown hue throughout.
Legs morphology: spinations
No spinations
Visible spinations
Smaller and less visible
Larger and more visible
Abdomen shape
Extremity produced into a somewhat cylindrical prominence,
rounded at its extremity with a black spot at the end of the
prominence region and one at the spinneret
Conical shape and is uniformly colored
Abdomen colour
The distinctive silvery markings
No silvery markings

5.2 Argyrodes miniaceus VS Argyrodes flavescens

Argyrodes miniacius argyrodes comparision.jpg
Figure 25. Argyrodes miniaceus (Left) photo by Nick Monaghan under Creative Commons 3.0 Australia License and Argyrodes flavescens (Right) (Copyright © 2014 Taiwan Spider Picture Data)

Argyrodes flavescens and Argyrodes miniaceus are of similar coloration and both have silvery markings on their abdomen. Therefore A.flavescens closely resembles A. miniaceus but it can be distinguished by examining the structure of female genitalia and the shape of embolus of male palps [6] (Figure 26).

Figure 23. Morphology diagrams of Argyrodes flavescens vs Argyrodes miniaceus ( Tanikawa etal, 1996) [6].png
Figure 26. Morphology diagrams of Argyrodes flavescens vs Argyrodes miniaceus ( Tanikawa etal, 1996) [6]

6. Taxonomy

The spider family Theridiidae, popularly known as comb-footed spiders, ranks as one of the most species-rich families of spiders [35]. One of the reason for the high species number in the Theridiidae is due the diversity of foraging and lifestyle strategies [35].

The taxonomy of the subfamily Argyrodinae has always been challenging [36] [37]. The current spider subfamily Argyrodinae (family Theridiidae) comprises of 239 named species [38] in six genera, Argyrodes, Faiditus, Neospintharus, Ariamnes, Rhomphaea, and Spheropistha [35]

Two montoypic genera, Argyrodella and Deelemanella were proposed by their authors to be members of the Argyrodinae [39][40]. There are limited information known about the biology of either species and the authors mentioned that their genitalia and other anatomical structures that are somewhat different from typical Argyrodines [39][40][41]. (Note that these two genera were not included in the phylogeny tree below.)

In 1894, Simon regarded the genera Argyrodes, Ariamnes and Rhomphaea as a group he named Argyrodeae [43]. Subsequently in 1962, the New World species was revised by Exline and Levi. Argyrodes, Ariamnes and Rhomphaea were lumped into a single genus, Argyrodes [36]. Within this genus, Exline and Levi recognised six species groups: Argyrodes, Ariamnes, Cancellatus, Cordillera, Trigonum and Rhomphaea [36]. In 1998, Tanikawa added Spheropistha to the genus Argyrodes [42].

In 2001, Exline and Levi’s one genus system was elevated to the subfamily level (Argyrodinae) by Yoshida [44]. In this subfamily Argyrodinae, Yoshida retained the genus Argyrodes and resurrected the following genera: Ariamnes, Rhomphaea and Spheropistha [44]. In 2004, Agnarsson’s morphological phylogeny of Theridiidae strongly supported the monophyly of the Argyrodinae which also aligned to Yoshida’s genera [35][44]. A molecular phylogeny of the Theridiidae family showed similar result [45]. In 2004, Agnarsson also elevated the Cancellatus and Cordillera species groups to a single genus, Faiditus, and elevated the Trigonum species group to genus Neospintharus [35]. This then formed the modern six genus system of Argyrodinae (which excluded the consideration of the two monotypic genera Argyrodella and Deelemanella mentioned previously).

The genera Ariamnes and Neospintharus utilise araneophagy as their main foraging strategy. Rhomphaea mainly utilises araneophagy and occasionally kleptoparasitism. The foraging strategies or habits of Spheropistha remain understudied. The genera Argyrodes and Faiditus use kleptoparasitism as their main foraging strategy [46][47].

6.1 Phylogenetics

In 2014, Su and Smith conducted the first study of group-living behaviour among kleptoparasitic spiders in a molecular phylogenetic context [16]. This is also the only paper (as of 2016) that included Argyrodes flavescens in the phylogeny tree of Argyrodinae as other authors worked mainly with Neotropical species. Their study included 41 species of Argyrodinae in their analyses: 23 species in Argyrodes, six species in Faiditus, five species in Rhomphaea, two species in Neospintharus, two in Ariamnes and three Spheropistha [16]. They also used published DNA sequence data from five species [45].

The DNA was extracted from the legs and prosoma of the specimens. In their analyses, they utilised 2511 bp of DNA sequence data from two mitochondrial genes, cytochrome c oxidase subunit I (COI, 776 bp) and 16S rRNA (16S, 633 bp), two nuclear genes, 28S rRNA (28S, 777 bp) and histone 3 (H3, 325 bp) [16]. They used published data and personal observations to character code three behavioural characters – foraging strategy, sociality and size of host web used – into discrete character states [16]. They categorised foraging strategies into "kleptoparasitism", "araneophagy", or ‘typical’ predation using self-constructed webs.

Su and Smith estimated the divergence time using the concatenated data matrix under a gene-tree framework using BEAST v. 1.8.0 [50]. In the concatenated analyses , the clock models and substitution rates of each gene was unlinked and the substitution models were set up in MrBayes. The oldest fossil occurrence for the Argyrodines, Argyrodes parvipatellaris [51][52] , was used as the reference calibration time for the divergence time estimations. The phylogenetic trees constructed by Su and Smith were then inferred using a Bayesian method in MrBayes v. 3.2.1 [48] and maximum likelihood in GARLI v. 2.0 [49].

In Figure 27, both Bayesian and maximum likelihood (ML) analyses of concatenated data strongly support monophyly of the Argyrodinae (Bayesian posterior probability = 1.00 and ML bootstrap support = 100; Figure. 27) [16]. Both analyses also show that three genera – Ariamnes, Neospintharus and Rhomphaea – are each supported as clades, while the other three – Faiditus, Argyrodes and Spheropistha – are not [16]. There are multiple well-supported species groups within the Argyrodes + F. xiphias+ Spheropistha clade (Fig. 27, consensus tree), but the relationships among these groups are not resolved in the ML analysis (refer to Figure. 28 for summary tree) [16].

Argyrodes flavscens falls under one of this unresolved clade, Miniaceus clade, which is indicated by the consensus and summary trees (Figures 27 and 28); this clade contains seven species, including Argyrodes flavescens and three species currently in the genus Spheropistha [16]. However, due to the uncertainty in the placement of the Spheropistha species, this clade is not recovered in the maximum clade credibility tree illustrated in Figure. 29 [16].

The Bayesian stochastic search variable selection (BSSVS) reconstruction of the foraging strategy (Figure. 29) indicates that the ancestral foraging strategy in Argyrodinae is araneophagy [16]. BSSVS allowed the authors to evaluate that a single origin of kleptoparsitism in the the Argyrodes + Spheropistha + Faiditus + Ariamnes clade with a secondary loss of kleptoparasitism in the genus Ariamnes is more likely as compared to two origins of kleptoparasitism, one in the genus Faiditus and one at the base of the Argyrodes + F. xiphias + Spheropistha clade [16].

Fig 24.png
Fig. 27 . Consensus tree. Molecular phylogenetic tree of Argyrodinae based on the concatenated data from four genes. The tree shown is the Bayesian tree from the MrBayes analyses. The labels on the nodes are the statistical supports provided by two tree analysis methods. The first number is the posterior probability of Bayesian analysis and the second number is the bootstrap value of the likelihood method (ML). (Su and Smith 2014)

Fig. 25.png
Fig. 28 . Summary cladogram of the Bayesian and maximum likelihood (ML) analyses of four individual genes and the concatenated data. The authors used the five boxes to present the posterior probability supports and to present the bootstrap supports of the nodes on the cladogram (see the upper right legend for the gene that each box represents). The cladogram shown is the result of Bayesian analyses as in Fig. 27. A black box shows the posterior probability support of a node is larger than 0.9 in Bayesian analyses and larger than 70 in ML analyses in the individual gene data or in concatenated data. The empty boxes show the supports are lower than 0.9 in Bayesian analyses and lower than 70 in ML analysis (Su and Smith 2014).
Fig 26.png
Fig. 29 . Reconstruction of ancestral foraging strategies using the Bayesian stochastic search variable selection model. The evolution of three foraging strategies – araneophagy, kleptoparasitism and web-weaving predation (outgroups) – were reconstructed, and their times of origin were estimated using the age of the oldest fossil record of an Argyrodes for calibration (see asterisk). (Su and Smith 2014).

6.2 Vernacular (Common) Names

Argyrodes flavescens is commonly called the "red and silver spider" or "red and silver dewdrop spider" due to the their colouration and the shape of its' abdomen [2].

6.3 Etymology

There are limited resources online that explains the etymology behind the family “Theridiidae”. Many sources simply gave it the definition of “Theridiidae-a family of comb-footed spiders”[2].

The genus name Argyrodes is derived from Greek where argyros represent "silver" and -odes represent "like" [55]. Although this "silver like" coloration does not match Argyrodes flavescens's reddish-brown colouration, it is likely named due to the other silvery Argyrodes species. In Latin, flavescens means ‎“become yellow” [56], which could be due to the yellow colouration on their femora or their reddish-brown colouration.

Argyrodes flavescens name derivation.png
Figure 30. Explanation of how the name Argyrodes flavescens was derived. (Created by Lim Zhi Yun)

6.4 Type Specimen

Argyrodes flavescens was first described by Pickard-Cambridge, O. in 1880 (Refer to Figure 28) [53]. The syntypes used in the description was from Sri Lanka, and preserved in British Museum of Natural History (BMNH) [6] There was no information found on the lectotypes.

fig 27.png
Figure 31. Original description of Argyrodes flavescens by Pickard-Cambridge, O. in 1880.

7. Conservation Status

This taxon has not yet been assessed for the IUCN Red List.

8. Literature and References

1. E. Sue Andersen 2014 Captive Breeding and Husbandry of The Golden Orb Weaver Nephila inaurata madagascariensis at Woodland Park Zoo.
2. Joseph K. H. Koh 2000 A Guide to Common Singapore Spiders. BP Guid. to Nat. Ser. Publ. by Singapore Sci. Cent. Spons. by Br. Pet.
3. Nasir, D. M., Su, S., Mohamed, Z. & Yusoff, N. C. 2014 New distributional records of spiders (Arachnida: Araneae) from the west coast of Peninsular Malaysia. Pakistan J. Zool 46, 1573–1584.
4. Peter Jäger & Bounthob Praxaysombath 2011 Spiders of Laos part 3.pdf.
5. Namkung, J., Yoo, J. S., Lee, S. Y., Lee, J. H., Paek, W. K. & Kim, S. T. 2009 Bibliographic Check list of Korean Spiders (Arachnida: Araneae) ver. 2010. J. Korean Nat. 2, 191–285. (doi:
6. Tanikawa, A., Chida, T. & Kumada, K. 1996 New Records of A rgyrodes flavescens ( Araneae : Theridiidae ) from Japan. 45, 47–52.
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