Social familiarity modulates group living and foraging behaviour of juvenile predatory mites

Abstract

Environmental stressors during early life may have persistent consequences for phenotypic development and fitness. In group-living species, an important stressor during juvenile development is the presence and familiarity status of conspecific individuals. To alleviate intraspecific conflicts during juvenile development, many animals evolved the ability to discriminate familiar and unfamiliar individuals based on prior association and use this ability to preferentially associate with familiar individuals. Assuming that familiar neighbours require less attention than unfamiliar ones, as predicted by limited attention theory, assorting with familiar individuals should increase the efficiency in other tasks. We assessed the influence of social familiarity on within-group association behaviour, development and foraging of juvenile life stages of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. The observed groups consisted either of mixed-age familiar and unfamiliar juvenile mites or of age-synchronized familiar or unfamiliar juvenile mites or of pairs of familiar or unfamiliar larvae. Overall, familiar mites preferentially grouped together and foraged more efficiently, i.e. needed less prey at similar developmental speed and body size at maturity, than unfamiliar mites. Preferential association of familiar mites was also apparent in the inter-exuviae distances. Social familiarity was established by imprinting in the larval stage, was not cancelled or overridden by later conspecific contacts and persisted into adulthood. Life stage had an effect on grouping with larvae being closer together than nymphal stages. Ultimately, optimized foraging during the developmental phase may relax within-group competition, enhance current and future food supply needed for optimal development and optimize patch exploitation and leaving under limited food.

Habitat-dependent olfactory discrimination in three-spined sticklebacks (Gasterosteus aculeatus)

“…The influence of familiarity on group-joining decisions has recently received increasing interest as it has been shown to enhance the benefits of grouping: advanced foraging efficiency (Griffiths et al 2004;Strodl and Schausberger 2012a), enhanced anti-predator behavior (Chivers et al 1995;Griffiths et al 2004;Strodl and Schausberger 2012b), stable dominance ranks within the group (Höjesjö et al 1998), reduced food competition (Utne-Palm and Hart 2000), better growth (Gerlach et al 2007), improved information transfer (Swaney et al 2001) and raised reproductive success (Strodl and Schausberger 2013).…”

Social Recognition in the Arachnida

“…Arachnid species that show social behaviour are characterised by high intra-and often interspecific tolerance when forming groups (spiders: Wickler 1987/scorpions: Shivashankar 1994;Cloudsley-Thompson 2011/pseudoscorpions: Weygoldt 1969;Tizo-Pedroso 2009/harvestmen: Machado andMacías-Ordoñez 2007;Chelini et al 2012/mites, Mori andSaito 2006;Mailleux et al 2011;Strodl and Schausberger 2012b). Unless there is indiscriminate tolerance of any foreign individual, these species must have developed recognition abilities to discriminate acceptable group members from those that will be refused.…”

“…Kin recognition has been revealed for various species but has not (yet) been found in the group of highly social spider mites. The advantages of group living in mites include reduction of evaporative water loss (Glass et al 1998), increased foraging efficiency (Strodl and Schausberger 2012a) and increased survival by cooperative defence against predators (Mori and Saito 2005;Strodl and Schausberger 2012b). The latter is particularly evident for species that build common nests Saito 2004, 2005).…”

“…An association early in life will reduce cannibalistic behaviours against familiar individuals in later juvenile stages, irrespective of whether they are kin or non-kin. Staying in a group of familiar individuals increases foraging efficiency (Strodl and Schausberger 2012a;Zach et al 2012) and reduces response time to predatory attacks (Strodl and Schausberger 2012b), which is suggested to be mediated by the reduced time needed for the assessment of conspecifics (Strodl and Schausberger 2012a, b). The advantage of a familiarity-based recognition mode in P. persimilis is that it allows mothers to lay eggs next to clutches of unrelated females, and still juvenile cannibalism after hatching remains low (Schausberger 2007).…”

Mites on Plants

“…Although Phytoseiulus mites do not hunt together, numbers of them often penetrate the same webs and they are able to recognise familiar conspecifi cs and this increases their hunting effi ciency (Strodl and Schausberger 2012 ). Chilean Predatory Mites have elongate dorsal shield setae that help them to penetrate the dense silken webs of Tetranychus (Sabelis and Bakker 1992 ) and use their chelicerae and palps to cut prey webbing (Shimoda et al 2009 ).…”