DOI: 10.5061/dryad.9kd51c5kh
title: Feeding mediated web-building plasticity in a cobweb spider

description: Behavioral plasticity has been proposed as a means by which animals alter
 their phenotypes in response to changing conditions. Animals may display
 behavioral plasticity as a consequence of environmental variation. The
 detritus-based, bell-shaped cobweb spider Campanicola campanulata is an
 ideal model to study behavioral plasticity, because its web architecture
 is easy to be quantified, and the functions of different parts of the web
 are clear. Though the plasticity of cobweb architecture has been reported
 in a few species, retreats as important defensive structures have rarely
 been considered before because retreats in most cobwebs are relatively
 small compared with the web size. We studied the web-building behaviors of
 C. campanulata under different feeding regimes. We set up 3 spider
 treatments with different feeding conditions: marginally well fed,
 moderately well fed, and extremely well fed, and observed the differences
 in the web architecture among them. In addition, we measured the
 mechanical properties of anchor silk, and also calculated the foraging and
 defense investment of the spiders. The results showed that marginally
 well-fed spiders build cobwebs with significantly longer length of anchor
 silk, lower retreat to the ground, more number and longer gumfooted lines,
 and larger capture area, while extremely well-fed spiders build cobwebs
 with significantly bigger retreat volume and higher height of retreat to
 the ground. In addition, marginally well-fed spiders invest significantly
 less during cobweb construction. However, there was no significant
 difference between the breaking force and elongation at break in anchor
 silk among different treatments. These results demonstrated that
 marginally well-fed spiders invest more in foraging, and extremely
 well-fed spiders invest more in defense, and the spider made a balance
 between foraging and predator avoidance in response to changes in
 physiological state. Our study strengthens the current understanding of
 web construction in cobweb spiders, especially those facing high costs
 during retreat construction.
description: <em>Study species</em>
 <em>Campanicola campanulata </em>(Araneae:
 Theridiidae) is widely distributed in South China, such as Hubei,
 Zhejiang, and Guizhou provinces (Chen 1993). It builds a web in cool
 but rain-proofed places such as concaves of rocks or earth walls, or under
 low overhanging branches (Figure 1A). It feeds mainly on ants, and usually
 lives in aggregation, building webs solitarily, with 1 spider per retreat
 (Figure 1B, C). The web consists of anchor silk, a bell-shaped retreat,
 and dozens of sticky gumfooted lines (Figure 1D). Anchor silks are usually
 made of strands of silk suspended from concave walls or tree roots. These
 structures prevent damage to the web by winds. The retreat is made of
 silk, sand, pebbles, debris, leaves, or shells, and has a small opening at
 the bottom. Its weight is usually 30–40 times the body weight of the
 spider. The gumfooted lines of the web emanate from the retreat edge and
 are fastened to coarse sand grains or fixed substrata, which are mainly
 used to form a capture web. When ants are intercepted by sticky gumfooted
 lines, the lines detach from the substrate and pull the prey up toward the
 retreat, making it difficult for the ants to gain the leverage needed for
 escape (Argintean et al. 2006). The configuration of the suspended retreat
 can significantly reduce the spider’s vulnerability to enemies because
 there are silken tunnels inside the retreat (Henschel and Jocqué 1994),
 which the enemies cannot tres-pass into. In addition, the sticky gumfooted
 lines also more or less prevent the invasion of enemies, such as parasitic
 wasps. <em>Spider and
 maintenance</em> From May to June 2019, we
 collected sub-adult (i.e., 1 molt before adulthood, ~2.4 mm in body
 length) <em>C. campanulata</em> from Hubei Dabie Mountain
 National Nature Reserve in Huanggang, Hubei Province, China (31°5ʹN,
 115°48ʹE), and raised them to adulthood in the laboratory. The spiders
 were maintained individually in a plastic box (length × width × height: 10
 cm × 5 cm × 10 cm) with bamboo sticks attached to their inner sides to
 allow them to build webs. The front and back sides of the box were made of
 removable transparent Perspex glass. All spiders were kept in the
 laboratory with controlled environmental conditions (temperature: 25 ± 1
 °C; relative humidity: 80  ±  5%; photoperiod: 14 h: 10  h L:D). The
 bottom of the box was covered with a layer of sand for the spider to
 collect to build a retreat, and a piece of sponge with absorbed water was
 placed at the bottom of the box to provide water for the spider. We fed
 each spider with 2 ants (Monomorium sp., ~2.2mm in body length) every 2
 days, and the developmental status (molting) of each spider was checked
 twice daily (09:00 and 21:00). <em>Experimental
 design and procedure</em> Sixty newly matured
 female spiders (~2 days after maturity) were randomly divided into 3
 treatments (N = 20 in each group): marginally well fed, control (normal
 feeding, i.e., moderately well fed), and extremely well fed. The body
 size (carapace width, body length, and body weight) of each spider was
 measured before the experiment. We fed Monomorium ants to them for 6 days
 (each spider was fed every 2 days with 2 ants at each time). Then, we
 measured the morphological parameters of their webs and examined the
 mechanical properties of the anchor silks (i.e., threads underlying the
 axial fibers). These data were considered as pretreatment data.
 After collecting these data, we destroyed all the webs, and let
 the spiders build new webs in another 6 days, and during this period of
 time, the spiders were fed differently. According to our field dissection
 of the retreat of the spiders, we found that the most normally developed
 adult spiders generally consumed about 6 ants in a week. Therefore, in
 this study, for those spiders in control treatment (moderately well fed),
 they were fed every 2 days with 2 ants at each time (6 ants in total). For
 those spiders in marginally well-fed treatment, they were fed only once
 with 2 ants (2 ants in total). For those spiders in extremely well-fed
 treatment, they were fed every 2 days with 5 ants at each time (15 ants in
 total). We observed and recorded the consuming process to make sure the
 ants were consumed. After these 6 days of different feedings, we measured
 the morphological parameters of the webs and examined the mechanical
 properties of the anchor silks again in each group. These data were
 considered as posttreatment data.
description: # Feeding mediated web-building plasticity in a cobweb spider This
 Zhang_et_al_CZ_Readme.txt was generated on 2022-06-22 by Haixin Zhang and
 Jie Liu. \--------------------General Information-------------------
 \#This is the dataset for Zhang, H.X., Li,G., L, C.C., Chen,
 J.,Zhao,Z.Y.,Zhang,S.C & Liu, J. 2022. Feeding mediated web-building
 plasticity in a cobweb spider. \#Principle Investigator Contact
 Information Shichang,Zhang,State Key Laboratory of Biocatalysis and Enzyme
 Engineering & Centre for Behavioural Ecology & Evolution, School
 of Life Sciences. Jie Liu, State Key Laboratory of Biocatalysis and Enzyme
 Engineering & Centre for Behavioural Ecology & Evolution, School
 of Life Sciences, Hubei University, Wuhan, China; Hubeiate Key Laboratory
 of Regional Development and Environmental Response, Faculty of Resources
 and Environmental Science, Hubei University, Wuhan, China; e-mail:
 [spider@hubu.edu](mailto:spider@hubu.edu) (S.Z) and
 [sparassidae@aliyun.com](mailto:sparassidae@aliyun.com) (J.L) \#Date of
 data collection March to June 2019 \#Location of data collection PR China
 \#Funding sources This work was supported by the National Natural Sciences
 Foundation of China?(NSFC-31970406/31772420/31573236),National Science
 & Technology Fundamental Resources Investigation Program of
 China(Grant No.2019FY101800),and CAS Key Laboratory of Tropical Forest
 Ecology,Xishuangbanna Tropical of Botanical Garden,Chinese Academy of
 Sciences(19CAS-TFE-3). \#Recommended citation Zhang, H.X., Li,G., L, C.C.,
 Chen, J.,Zhao,Z.Y.,Zhang,S.C & Liu, J. 2022. Feeding mediated
 web-building plasticity in a cobweb spider.
 \--------------------Methodological Information------------------- \#The
 data was collected following the protocol described in Zhang et al., 2022.
 \#Data was processed/analyzed with R 4.0.3. \--------------------Specific
 information in the csv data------------------- \#Number of variabes: 29
 \#Number of rows: 60 \#Variable List: 1. Group: Spiders in three
 groups(hungry, control and well-fed). 2. Num: number of each spider in
 three groups(hungry, control and well-fed). results of pretreatment
 3.BL(mm): body lengths of spiders in different groups. 3. CW(mm): carapace
 width of spiders in different groups. 4. BW(mg): body weight of spiders in
 different groups of pre-treatment. 5. ASL1(mm): length of anchor silk in
 different groups of pre-treatment. 6. RH1(mm): height of retreat in
 different groups of pre-treatment. 7. ED1(mm): diameter of retreat
 entrance in different groups of pre-treatment. 8. CRH1(mm): height of
 retreat center from the ground in different groups of pre-treatment. 9.
 RW1(mg): weight of retreat in different groups of pre-treatment. 10.
 10.GLN1: number of gumfooted lines in different groups of pre-treatment.
 11. RV1(mm3): volume of retreat in different groups of pre-treatment. 12.
 GTL1(mm): total length of gumfooted lines in different groups of
 pre-treatment. 13. EC1(10-6J): energy consumption during web-building in
 different groups of pre-treatment. 14. CA1(mm2): capture area in different
 groups of pre-treatment. 15. BF1(uN): breaking force of anchor silk in
 different groups of pre-treatment. 16. EB1(%): elongation at break of
 anchor silk in different groups of pre-treatment results of post-treatment
 17. ASL2(mm): length of anchor silk in different groups of post-treatment.
 18. RH2(mm): height of retreat in different groups of post-treatment. 19.
 ED2(mm): diameter of retreat entrance in different groups of
 post-treatment. 20. CRH2(mm): height of retreat center from the ground in
 different groups of post-treatment. 21. RW2(mg): weight of retreat in
 different groups of post-treatment. 22. GLN2: number of gumfooted lines in
 different groups of post-treatment. 23. V2(mm3): volume of retreat in
 different groups of post-treatment. 24. GTL2(mm): total length of
 gumfooted lines in different groups of post-treatment. 25. EC2(10-6J):
 energy consumption during web-building in different groups of
 post-treatment. 26. CA2(mm2): capture area in different groups of
 post-treatment. 27. BF2(‬uN): breaking force of anchor silk in different
 groups of post-treatment. 28. EB2(%): elongation at break of anchor silk
 in different groups of post-treatment. null - not found