Animal behaviour: task differentiation by personality in spider groups Article (Published Version) Grinsted, Lena and Bacon, Jonathan P (2014) Animal behaviour: task differentiation by personality in spider groups. Current Biology, 24 (16). R749-R751. ISSN 0960-9822 This version is available from Sussex Research Online: http://sro.sussex.ac.uk/id/eprint/49617/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher’s version. Please see the URL above for details on accessing the published version. Copyright and reuse: Sussex Research Online is a digital repository of the research output of the University. Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available. Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. http://sro.sussex.ac.uk Dispatch R749 15. Marcet, B., Chevalier, B., Luxardi, G., Dougherty, G.W., et al. (2014). Mutations in 20. Spektor, A., Tsang, W.Y., Khoo, D., and Coraux, C., Zaragosi, L.E., Cibois, M., CCNO result in congenital mucociliary Dynlacht, B.D. (2007). Cep97 and CP110 Robbe-Sermesant, K., Jolly, T., Cardinaud, B., clearance disorder with reduced generation of suppress a cilia assembly program. Cell 130, Moreilhon, C., et al. (2011). Control of multiple motile cilia. Nat. Genet. 46, 646–651. 678–690. vertebrate multiciliogenesis by miR-449 18. Boon, M., Wallmeier, J., Ma, L., Loges, N.T., through direct repression of the Delta/Notch Jaspers, M., Olbrich, H., Dougherty, G.W., pathway. Nat. Cell Biol. 13, 693–699. Raidt, J., Werner, C., Amirav, I., et al. (2014). Swiss Institute for Experimental Cancer 16. Song, R., Walentek, P., Sponer, N., Klimke, A., MCIDAS mutations result in a mucociliary Research (ISREC), School of Life Sciences, Lee, J.S., Dixon, G., Harland, R., Wan, Y., clearance disorder with reduced generation Swiss Federal Institute of Technology (EPFL), Lishko, P., Lize, M., et al. (2014). miR-34/449 of multiple motile cilia. Nat. Commun. 5, 4418. Lausanne, Switzerland. miRNAs are required for motile ciliogenesis 19. Chen, Z., Indjeian, V.B., McManus, M., by repressing cp110. Nature 510, 115–120. Wang, L., and Dynlacht, B.D. (2002). CP110, *E-mail: pierre.gonczy@epfl.ch 17. Wallmeier, J., Al-Mutairi, D.A., Chen, C.T., a cell cycle-dependent CDK substrate, Loges, N.T., Pennekamp, P., Menchen, T., regulates centrosome duplication in human Ma, L., Shamseldin, H.E., Olbrich, H., cells. Dev. Cell 3, 339–350. http://dx.doi.org/10.1016/j.cub.2014.07.006 Animal Behaviour: Task Perhaps some individuals are just inherently better than others at certain Differentiation by Personality tasks, or they become better over time with more practice [8]. If, at the same in Spider Groups time, other group members are, or become better at other tasks, and individuals mostly perform the tasks In social animals, group efficiency is often assumed to increase with task they are good at, each group member differentiation, but this requires that individuals are better than generalists may gain the benefits of improved at the task they specialize in. A new study finds that individual Anelosimus group efficiency. For example, in the studiosus spiders do predominantly perform the task they excel at, in line cooperatively breeding cichlid fish with their individual personality type, when they are placed in groups. Neolamprologus pulcher, task participation varies with body size Lena Grinsted* raising the young. Hence, when groups and age, perhaps because smaller and Jonathan P. Bacon contain a mix of both types, emergent fish are better at defending the nest task differentiation increases overall while larger fish are better at removing Did you think that all spiders are group performance benefitting all sand from the nest [9]. However, ferocious predators, which attack any group members. the assumption that task participation other spider or bug they come across? Consider a leafcutter ant nest. Some actually correlates with individual Well, think again. Sure, it is true that worker ants are tiny, while others are task performance in non-polymorphic many spiders will eat their own huge. It is easy to imagine how an ant social animals has rarely been proven. offspring if they get in the way, and yes, colony can benefit from this extreme Social spiders provide a good some females will happily snack on polymorphism; tiny workers will example of highly cooperative their partners during mating. But efficiently feed and clean the fungus societies in which female group some spiders form cooperative gardens, while large soldiers with members are non-polymorphic and communities where they live peacefully gigantic mandibles are superior at yet show reproductive skew and task side by side [1]. Darwin himself defending the nest against larger differentiation within groups [10,11]. expressed surprise when he came predators [6]. Task specialization Only about 25 species bear the title across a group-living spider in 1832 accompanied by polymorphism leads ‘social’ out of almost 45,000 spider (Parawixia bistriata) [2]. One spider that to more efficient and successful species described [12]. These are facultatively forms small groups is groups. Why task differentiation would cooperative breeders that live in Anelosimus studiosus. Within an be beneficial within societies of extremely inbred societies. In the Anelosimus studiosus group some cooperative breeders that lack evolution of permanent sociality from females show an aggressive morphological castes, such as the subsociality, a pre-mating dispersal personality type and participate more social spiders, birds and mammals, is stage has been lost, leaving brothers in colony defense and prey capture, harder to imagine. For example, why do and sisters to mate generation after while others are docile and engage helpers in the cooperatively breeding generation (within-group relatedness: more in brood care [3]. Experimental noisy miner, Manorina melanocephala, r > 0.5 [13]). Subsocial species, such groups containing a mix of these two often specialize in either chick as A. studiosus, show cooperation at different personalities outperform provisioning or mobbing nest the juvenile stage, after which siblings groups of only one personality type, predators, rather than participating disperse to breed alone, maintaining using egg-case weight as a proxy for equally in all tasks [7]? Individuals an outbred mating system [1]. The new fitness [4]. An elegant new study by within these types of social groups findings by Wright et al. [5] showing Colin M. Wright and colleagues [5] has are all morphologically capable of that A. studiosus specialize on tasks found the reason why. Aggressive performing any task. So why do some they are efficient at when placed in females are simply more efficient group members engage in riskier groups may be key to understanding at foraging, web construction and activities, such as colony defense, why social spiders show individual defense, while docile females excel at more than others? behavioral variation. Current Biology Vol 24 No 16 R750 characteristic of social cooperative breeders. All females within the groups reproduce and mothers will aggressively chase away other adult group members [17]. Hence, A. studiosus is a subsocial species that sometimes occurs in groups. This makes it an ideal species for studies on the costs and benefits of group living, as group sizes are easily manipulated in the lab. Studies asking whether behavioral variation is an adaptation to sociality are now needed in fully social spider species. All populations of A. studiosus studied to date have contained a mix of aggressive and docile phenotypes [15], personality traits have been found to be heritable [18], and group forming behavior is non-plastic in solitary populations [14]. Therefore, different personalities are maintained even in populations that exist purely of solitary spiders with no behavioral plasticity to naturally form groups. Thus, it seems Figure 1. Social spiders. unlikely that mixed phenotypes is an Six Stegodyphus sarasinorum attack an ant prey, while their more timid nestmates (not shown) remain in the safety of the nest. (Photo: Virginia Settepani.) adaptation to group living or sociality in this species. Consistent personalities and In some Amazonian social spiders, area of behavioral types. Interestingly, behavioral syndromes have been such as Anelosimus eximius [11], instead of showing gradual, normally documented in a diverse range of both task differentiation is age related, as distributed individual personality social and non-social species, individuals acquire more colony tasks scores, this spider shows a bimodal including insects, spiders, fish, birds with age, while in Old World social distribution [14]. This allows and mammals [19]. Behavioral spiders, something more intriguing researchers to group individual spiders differences may occur