Cost of complex behaviour and its implications in antipredator defence in orb-web spiders
Section snippets
Time Cost of Building Asymmetric Webs
We used Cyclosa argenteoalba to examine the effect of web asymmetry on the time required for laying the capture spirals. Cyclosa argenteoalba is a diurnal orb-web spider, which is common in suburbs and rural areas in Japan. Adult females are approximately 5–6 mm long and weigh 5–20 mg. The spider builds its web around dawn and collapses the web at the end of the day, rebuilding it on a daily basis. From 4 May to 7 August 2008, we collected C. argenteoalba adult females in and around the campus of
Time Cost of Building Asymmetric Webs
The coefficients of constrained regression were significantly positive for the spider weight and absolute value of AI, and significantly negative for observation date (Table 1). On average, the spider took 1860.2 s ± 600.5 SD to construct a capture spiral. While web asymmetry was significantly correlated with spiral spacing asymmetry (r49 = 0.579, N = 51, P < 0.001), the correlation between web asymmetry and the number of U-turns was not significant (r49 = 0.192, N = 51, P = 0.531).
Effect of Predator Cue on Web Asymmetry
In C. argenteoalba, the
Discussion
The observations of web-building behaviour of C. argenteoalba revealed that the time taken for capture spiral construction took longer when the web asymmetry was larger, the spider was heavier, the spiral length was longer and the observation was conducted earlier in the season (i.e. mean temperature was lower). The effects of spider weight, spiral length and observation date were not surprising because spiders have to move greater distances to lay longer spirals, heavy spiders move slower, and
Acknowledgments
We thank Chiharu Wako for her help in measuring web parameters. This work was partly supported by Japan Society for the Promotion of Science grants-in-aid for Scientific Research (C) (no. 20570025, 23570037, and 26440251).
References (35)
Are smaller animals behaviourally limited? Lack of clear constraints in miniature spiders
Animal Behaviour
(2011)- et al.
Grade changes in brain–body allometry: Morphological and behavioural correlates of brain size in miniature spiders, insects and other invertebrates
- et al.
Time is money—Time pressure, incentives, and the quality of decision-making
Journal of Economic Behavior & Organization
(2006) - et al.
Predator-induced plasticity in web-building behavior
Animal Behaviour
(2004) An analysis of the orientation of an orb-web spider
Journal of Theoretical Biology
(2010)- et al.
A functional explanation of top-bottom asymmetry in vertical orb webs
Animal Behaviour
(1983) To be or not to be conspicuous: The effects of prey availability and predator risk on spider's web decoration building
Animal Behaviour
(2009)Plasticity in an extended phenotype and reversed up-down asymmetry of spider orb webs
Animal Behaviour
(2012)Brain evolution: Getting better all the time?
Current Biology
(2005)- et al.
A new method for evaluating the complexity of animal behavioral patterns based on the notion of Kolmogorov complexity, with ants' hunting behavior as an example
Neurocomputing
(2012)