Ontogenetic Changes in Web Design in Two Orb‐Web Spiders

Abstract

The first orb web built by newly hatched spiders resembles the adult web in its overall form and structure. However, many details show ontogenetic changes. One possible explanation for these changes is that the tiny early‐instar spiders with their minute brains will make more mistakes and build less ‘perfect’ orb webs than older and larger juveniles and adults. To test this hypothesis, known as the size limitation hypothesis, I analysed orb webs from three developmental stages, spiderlings, juveniles and adult females, in two neotropical orb‐web spiders, the araneid Eustala illicita and the nephilid Nephila clavipes. Neither species showed clear signs of being behaviourally limited or more prone to committing errors as spiderlings than were older juveniles or adults. These findings therefore do not support the size limitation hypothesis in either species. Finally, I looked for evidence of the ‘biogenetic law’, which predicts that juveniles should build less derived orb webs than the adults. Evidence for this was found in E. illicita, but not in N. clavipes.

Are smaller animals behaviourally limited? Lack of clear constraints in miniature spiders

“…In general, the results of this study, as well as those of previous studies of behavioural precision (Eberhard 2007;Hesselberg 2010), contradict the size-limitation hypothesis that smaller animals are more limited in their behavioural capabilities. In the present study, there were four trends that were opposite those predicted by the hypothesis, three cases in which the predicted trends did not occur, and only three partial confirmations (Table 6).…”

“…Thus, I did not make interspecific comparisons, but only intraspecific comparisons of adults versus small nymphs; these showed no differences. Similar comparisons between adults and nymphs of the araneid Eustala illicita also showed no differences (Hesselberg 2010).…”

Imperfections in perfect architecture: The orb web of spiders

“…It is not related to the physical characteristics of the spiders (mass and size), but to web characteristics (size of the capture area, length of silky thread deposited, inter-spiral distance). It is known that the web characteristics vary depending on the space available (Ades, 1986;Krink & Vollrath, 2000;Barrantes & Eberhard, 2012; previous prey capture (Lubin & Henschel, 1992;Henshel & Lubin, 1996;Pasquet et al, 1999), prey size (Thevenard et al, 2004;Blackledge & Zevenbergen, 2006;Abrenicot-Adamat et al, 2009), presence of conspecifics (Leborgne & Pasquet, 1986), internal state of the spider (Venner et al, 2003) and experience Venner et al, 2000;Sensenig et al, 2010), or stage of development of the spider (Eberhard, 2007(Eberhard, , 2011Hesselberg, 2010). As the number of anomalies is linked to web characteristics, it might be affected by these different factors, but under controlled laboratory conditions, the influence of these environmental factors was reduced or negligible.…”

“…Variations in the structures and geometry of the webs are used to quantify the influence of environmental factors such as space constraints (Ades, 1986;Krink & Vollrath, 2000;Barrantes & Eberhard, 2012;, parasite attacks (Eberhard, 2001(Eberhard, , 2010Gonzaga et al, 2010), or physiological factors such as stage of development (Eberhard, 2007(Eberhard, , 2011Hesselberg, 2010). There are other studies that take into account the regularity, irregularity or asymmetry, which result in the web being an imperfect orb Ap Rhisart & Vollrath, 1994;Vollrath et al, 1997;Hesselberg & Vollrath, 2004;Coslovsky & Zschokke, 2009;Nakata & Zschokke, 2010, Eberhard, 2011.…”

Cues guiding uloborid construction behavior support orb web monophyly

“…Spiders were induced to build orbs in small containers that severely restricted the spaces in which they could build, and this resulted in changes in several design features of the orbs they built in the araneids Eustala illicita (O. P.-Cambridge 1889) and Cyclosa caroli (Hentz 1850), the nephilid Nephila clavipes (Linnaeus 1767), and the tetragnathid Leucauge argyra (Walckenaer 1841) (Hesselberg 2010;Barrantes & Eberhard 2012). This technique has the disadvantage that the precise cue or cues that are used by the spider to sense the size of the space are not known; but it elicits up to seven apparently independent behavioral responses (Barrantes & Eberhard 2012).…”