How non-nestmates affect the cohesion of swarming groups in social spiders

Abstract

In social biology, it is often considered that an organized society cannot exist without exclusion behaviour towards newcomers from another nest. Unlike most vertebrate and invertebrate social species, social spiders such as Anelosimus eximius accept unrelated migrants without agonistic behaviour. Does it imply that spiders cannot recognize non-nestmates from nestmates or is there any evidence of recognition without aggression ? In order to answer this question, we studied behavioural differences between groups coming from single and mixed-nests in the overall context of swarming.Our study shows that the presence of non-nestmate conspecifics reduces the cohesion of the swarm groups during the settlement process and increases the spatial dispersion of spiders, the asymmetry in the spatial distribution being less pronounced. Individuals belonging to different nests are not as mutually attractive. This paper shows that, during the induced migration, two processes counteract each other: the amplification process resulting from the addition of silk drives individuals to form groups with non-nestmates and the recognition process reduces the cohesion of groups composed of nonnestmates. The collective decision-making during migration results from the balance between these two trends.

Reaching the Ball or Missing the Flight? Collective Dispersal in the Two-Spotted Spider Mite Tetranychus urticae

“…First, the recognition abilities can be overruled by other mechanisms such as aggregation [22,25,47]. Silk as an attractive and cohesion cue [25] could be stronger than discrimination among individuals in a group of mites (as already shown in cockroaches and spiders) [22,47]. Second, behaviour can change when mites are faced with different environmental situations.…”

“…This mite exhibits some levels of social life, such as collective web building [17,18] and a positive group effect [19]. Moreover, T. urticae , like other arthropod species [20-22] can discriminate between kin and non-kin [23-26]. …”

Collective behaviors of two-component swarms

“…This type of model studies is applicable to various problems, such as collective decision making, collective intelligence, pest control through robots, and leader-follow problems in flocks (Couzin et al, 2005;Am e et al, 2006;Couzin, 2007;Halloy et al, 2007;Mailleux et al, 2008;Schmickl et al, 2009;Couzin, 2009). In the present case, the particular environment is the existence of two different types of shelters.…”

“…In order to understand this problem, we introduce a simple two-component swarm and employ a particle based simulation approach. Although there exist various different approaches to study the motion of the swarm (Vicsek et al, 1995;Levine et al, 2000;Couzin et al, 2002;Krause and Ruxton, 2002;Schweitzer, 2003;Erdmann et al, 2005;Am e et al, 2006;Chen and Leung, 2006;Levine et al, 2006;Sumpter, 2006;Mach and Schweitzer, 2007;Li and Wang, 2007;McInnes, 2007;Halloy et al, 2007;Mailleux et al, 2008;Schmickl et al, 2009), common essential ingredients are mutual attractions, self-propelling forces, and responses to environmental attractions such as food and shelters. Here, we choose a particle-based simulation model, which employs simple forms of the essential ingredients (Chen and Leung, 2006).…”

Social Recognition in Invertebrates

“…Evans (1998), (4)Evans (1999), (5)Faraji et al (2000), (6)Johannesen and Lubin (2001), (7)Mahsberg (1990), (8)Mailleux et al (2008), (9)Roberts et al (2003), (10)Rowell and Avilés (1995),(11)Ruch et al (2009), (12) Schausberger (2005), (13) Schausberger (2007), (14) Schausberger and Croft (2001), (15) Schneider (1996), (16) Schneider and Bilde (2008), (17) Strodl and Schausberger (2012a), (18) Strodl and Schausberger (2012b), (19) Walsh and Rayor (2008), (20) Yip et al (2009), (21) Zach et al (2012)…”