Extended spider cognition

HFJ received a visiting professor fellowship from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq - Brazil) (PDE PDE232691/2014-2). Research supported in part by a Grant from the John Templeton Foundation to KNL.There is a tension between the conception of cognition as a central nervous system (CNS) process, and a view of cognition as extending towards the body or the contiguous environment. The centralised conception requires large or complex nervous systems to cope with complex environments. Conversely, the extended conception involves the outsourcing of information processing to the body or environment, thus making fewer demands on the processing power of the CNS. The evolution of extended cognition should be particularly favoured among small, generalist predators such as spiders, and here we review the literature to evaluate the fit of empirical data with these contrasting models of cognition. Spiders do not seem to be cognitively limited, displaying a large diversity of learning processes, from habituation to contextual learning, including a sense of numerosity. To tease apart the central from the extended cognition, we apply the mutual manipulability criterion, testing the existence of reciprocal causal links between the putative elements of the system. We conclude that the web threads and configurations are integral parts of the cognitive systems. The extension of cognition to the web helps to explain some puzzling features of spider behaviour and seems to promote evolvability within the group, enhancing innovation through cognitive connectivity to variable habitat features. Graded changes in relative brain size could also be explained by outsourcing information processing to environmental features. More generally, niche-constructed structures emerge as prime candidates for extending animal cognition, generating the selective pressures that help to shape the evolving cognitive system.Publisher PDFPeer reviewe

A simpler way to organize society : response to a risky stimulus is related to the spatial distribution of the individuals within a spider colonial web

Acknowledgments We thank Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) grant (nº 1583297) that supported this work. We also thank all Núcleo de Etologia e Evolução (NuEVo) colleagues that gave insights and precious suggestions to improve the work. We finally thank Rafael Paulino and Sidnei Sampaio for their help during field work.Peer reviewe

A comparison between affiliative and agonistic behaviours in wild and captive Sapajus libidinosus (Spix, 1823) (Mammalia, Primates, Cebidae)

Organisms modulate the expression of their behaviours through environmental contexts. Several studies have suggested that the frequencies of social behaviours may differ between captive and free-living primates. In the present study, we compared the social behaviours displayed by captive and free-living groups of the bearded capuchin monkey (Sapajus libidinosus), describing and analysing their social behaviours. We observed through focal animal sampling 59 animals distributed in 10 social groups, analysing 191:45 h of videos of their behaviours. Captivity reduced the frequency of agonistic, but not of affiliative behaviours. Furthermore, neither group size nor sex could explain the overall variability in affiliative behaviour. We conclude that captivity has indeed an important impact only on some aspects of social behaviour, namely, on agonistic behaviours

Who dares does not always win: risk-averse rockpool prawns are better at controlling a limited food resource

This is the author accepted manuscript. The final version is available from Elsevier Masson via the DOI in this record.Animal ‘personality’ – the phenomenon of consistent individual differences in behaviour within populations – has been documented widely, yet its functional significance and the reasons for its persistence remain unclear. One possibility is that among-individual behavioural variation is linked to fitness-determining traits via effects on resource acquisition. In this study, we test this idea, using rockpool prawns (Palaemon elegans) to test for a correlation between ‘high-risk exploration’ and the ability to monopolise a limited resource. Modified open field trials (OFTs) confirmed that consistent among-individual (co)variation in high-risk exploratory behaviours does exist in this species, and multivariate analysis shows trait variation is consistent with a major axis of personality variation. Subsequent feeding trials in size-matched groups where competition was possible revealed a high repeatability of feeding duration, used here as a proxy for RHP (resource holding potential). We found significant negative correlations between feeding duration and two ‘risky’ behaviours, such that individuals that took fewer risks fed more. Our results are not consistent with the widely hypothesised idea of a ‘proactive syndrome’ in which bolder, risk-taking personalities are positively associated with RHP. Rather they suggest the possibility of a trade-off, with some individuals successful at monopolising limited, high-value resources, while others are more willing to engage in potentially risky exploration (which may increase the likelihood of encountering novel resource patches). We speculate that alternative strategies for acquiring limited resources might thereby contribute to the maintenance of personality variation observed in wild populationsTH and AJW were supported by a grant from the Biotechnology and Biological Sciences Research Council awarded to AJW (BBSRC, grant BB/L022656/1)

The evolution of prey‐wrapping behaviour in spiders

We traced the evolution of silk use by spiders in attacks on prey by combining previous publications with new observations of 31 species in 16 families. Two new prey‐wrapping techniques are described. One, in which the spider holds a tense line (often covered with viscid silk) with both legs IV and applies it to the prey with a simultaneous movement of both legs, may be a synapomorphy linking Theridiidae, Nesticidae, and Synotaxidae. The other, in which the spider stands over the prey and turns in place, is apparently very ancient; it occurs in Theraphosidae, Tengellidae, and Agelenidae. The use of legs IV to wrap prey is described for the first time in Filistatidae and Scytodidae. Using a recent phylogeny of spiders, we propose that prey wrapping with legs IV has evolved convergently at least four times. We propose that prey wrapping originally evolved from egg‐sac construction behaviour.Instituto Smithsoniano de Investigaciones Tropicales (STRI)Universidad de Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí