scholarly journals The age and evolution of sociality in Stegodyphus spiders: a molecular phylogenetic perspective

2006 ◽  
Vol 274 (1607) ◽  
pp. 231-237 ◽  
Author(s):  
Jes Johannesen ◽  
Yael Lubin ◽  
Deborah R Smith ◽  
Trine Bilde ◽  
Jutta M Schneider

Social, cooperative breeding behaviour is rare in spiders and generally characterized by inbreeding, skewed sex ratios and high rates of colony turnover, processes that when combined may reduce genetic variation and lower individual fitness quickly. On these grounds, social spider species have been suggested to be unstable in evolutionary time, and hence sociality a rare phenomenon in spiders. Based on a partial molecular phylogeny of the genus Stegodyphus , we address the hypothesis that social spiders in this genus are evolutionary transient. We estimate the age of the three social species, test whether they represent an ancestral or derived state and assess diversification relative to subsocial congeners. Intraspecific sequence divergence was high in all of the social species, lending no support for the idea that they are young, transient species. The age of the social lineages, constant lineage branching and the likelihood that social species are independently derived suggest that either the social species are ‘caught in sociality’ or they have evolved into cryptic species.

1998 ◽  
Vol 76 (12) ◽  
pp. 2137-2147 ◽  
Author(s):  
L Avilés ◽  
G Gelsey

The transition to permanent-sociality in spiders is thought to have involved the suppression of the dispersal phase characteristic of hypothetical subsocial or periodic-social ancestral species. Extant periodic-social species may provide insights into this transition. The periodic-social Anelosimus jucundus in southern Arizona was found to form mother-offspring and sibling associations that disintegrate prior to the mating season. Following the breakdown of the social phase, more than twice as many females as males became established within a few metres of the natal nest. Given that the predispersal sex ratio was 1:1, a fraction of the males may have dispersed beyond the local area. The short dispersal distances of at least a fraction of individuals of both sexes, the clustering of nests in local areas, and at least two possible cases of sibling mating suggest, however, that dispersal may not eliminate the possibility of close inbreeding in this species. Estimated transition probabilities between life-history stages show that the heaviest loss of individuals occurs during dispersal. Once established, 41% of the females that reached maturity succeeded in producing grown progeny. We discuss the implications of these findings in terms of the transition from periodic to permanent sociality in spiders and of current models that consider the interplay between competition and inbreeding avoidance in the evolution of dispersal.


1994 ◽  
Vol 42 (2) ◽  
pp. 237 ◽  
Author(s):  
MF Downes

Aspects of the biology of the social spider Phryganoponrs candidus (=Badumna candida) (L. Koch) in relation to its life history are described, based on data from a field and laboratory study conducted over several years at Townsville, Queensland. Host plant records and preferences are given, and an analysis made of the effects of nest height and ecotone proximity on nest occurrence. Founded between October and February as a chambered silk funnel by a solitary subadult female, the nest was enlarged by the female and her progeny into a complex retreat area and an outlying prey-trapping area. The architecture of the retreat was not an aggregation of repeated subunits. Closely adjacent nests sometimes united their prey-capture webbing to form compound nests. From a tagged sample of new-founded nests, 31% reached a stage at which thriving spiderlings were present. Numbers of spiders in nests ranged from 9 to 224 and correlated with nest size, which ranged from 70 to more than 20 000 cm(2). At the peak of nest growth in October, the stage at which subadult spiders began to disperse, about 90 spiders inhabited each nest; only 12% of new-founded nests reached this stage. Summer dispersal left nests empty; they degenerated under rain and became moribund by March. The main host plants were Zizyphus mauritiana (the chinee apple) and Dolichondrone heterophylla. Most nests occurred between 0.5 and 2.5 m from the ground but height did not influence nest success. Nests were prevalent at ecotones, although they did not thrive better there. Because so much of the social biology of spiders is integrated with the structure and function of their nests, these findings are relevant to an understanding of the evolution of sociality in spiders.


2011 ◽  
Vol 366 (1574) ◽  
pp. 2155-2170 ◽  
Author(s):  
Guy Bloch ◽  
Christina M. Grozinger

Bees provide an excellent model with which to study the neuronal and molecular modifications associated with the evolution of sociality because relatively closely related species differ profoundly in social behaviour, from solitary to highly social. The recent development of powerful genomic tools and resources has set the stage for studying the social behaviour of bees in molecular terms. We review ‘ground plan’ and ‘genetic toolkit’ models which hypothesize that discrete pathways or sets of genes that regulate fundamental behavioural and physiological processes in solitary species have been co-opted to regulate complex social behaviours in social species. We further develop these models and propose that these conserved pathways and genes may be incorporated into ‘social pathways’, which consist of relatively independent modules involved in social signal detection, integration and processing within the nervous and endocrine systems, and subsequent behavioural outputs. Modifications within modules or in their connections result in the evolution of novel behavioural patterns. We describe how the evolution of pheromonal regulation of social pathways may lead to the expression of behaviour under new social contexts, and review plasticity in circadian rhythms as an example for a social pathway with a modular structure.


2021 ◽  
Vol 75 (3) ◽  
Author(s):  
Nick A. R. Jones ◽  
Helen C. Spence-Jones ◽  
Mike Webster ◽  
Luke Rendell

Abstract Learning can enable rapid behavioural responses to changing conditions but can depend on the social context and behavioural phenotype of the individual. Learning rates have been linked to consistent individual differences in behavioural traits, especially in situations which require engaging with novelty, but the social environment can also play an important role. The presence of others can modulate the effects of individual behavioural traits and afford access to social information that can reduce the need for ‘risky’ asocial learning. Most studies of social effects on learning are focused on more social species; however, such factors can be important even for less-social animals, including non-grouping or facultatively social species which may still derive benefit from social conditions. Using archerfish, Toxotes chatareus, which exhibit high levels of intra-specific competition and do not show a strong preference for grouping, we explored the effect of social contexts on learning. Individually housed fish were assayed in an ‘open-field’ test and then trained to criterion in a task where fish learnt to shoot a novel cue for a food reward—with a conspecific neighbour visible either during training, outside of training or never (full, partial or no visible presence). Time to learn to shoot the novel cue differed across individuals but not across social context. This suggests that social context does not have a strong effect on learning in this non-obligatory social species; instead, it further highlights the importance that inter-individual variation in behavioural traits can have on learning. Significance statement Some individuals learn faster than others. Many factors can affect an animal’s learning rate—for example, its behavioural phenotype may make it more or less likely to engage with novel objects. The social environment can play a big role too—affecting learning directly and modifying the effects of an individual’s traits. Effects of social context on learning mostly come from highly social species, but recent research has focused on less-social animals. Archerfish display high intra-specific competition, and our study suggests that social context has no strong effect on their learning to shoot novel objects for rewards. Our results may have some relevance for social enrichment and welfare of this increasingly studied species, suggesting there are no negative effects of short- to medium-term isolation of this species—at least with regards to behavioural performance and learning tasks.


2005 ◽  
Vol 24 (3) ◽  
pp. 185-195
Author(s):  
Mike Metcalfe

This paper is about knowledge sharing vision appropriate for a complex environment. In these environments, traditional views of knowledge sharing as informing a hierarchical, centralised leadership may be misleading. A complex environment is defined as one that emerges unpredictable changes that require organisations to reconnect, to reorganise. Organisations need to be able to rapidly reconnect relationships so as to reflect new priorities, and to do so without causing change “bottlenecks”. The empirical biologists have observed that some social species have evolved structures that enable them to do this automatically what ever the environmental change. These organisational forms have survived for millions of years without central planning; rather they use local knowledge is reconnect as required overall providing an appropriate strategic response. These organisational forms seem to result from the small-worlds phenomenon and it is self organising. Specifically, this paper will argue that this small-worlds, self organisation, phenomena is a useful vision for designing a knowledge sharing vision appropriate for a complex environment. The supportive evidence is provided in the form of identifying the empirical attributes of self organisation and small worlds to provide an explanation of how and why it works. The system thinking, biology (insect) and the social-network literature are used.


1993 ◽  
Vol 41 (5) ◽  
pp. 441 ◽  
Author(s):  
MF Downes

A two-year study of the social spider Badumna candida at Townsville, Queensland, provided information on colony size and changes over time, maturation synchrony, temperature effects on development, sex ratio, dispersal, colony foundation, fecundity and oviposition. Key findings were that B. candida outbred, had an iteroparous egg-production cycle between March and October, had an even primary sex ratio and achieved maturation synchrony by retarding the development of males, which matured faster than females at constant temperature. There was no overlap of generations, the cohort of young from a nest founded by a solitary female in summer dispersing the following summer as subadults (females) or subadults and adults (males). These findings confirm the status of B. candida as a periodic-social spider (an annual outbreeder), in contrast to the few known permanent-social spider species whose generations overlap. Cannibalism, normally rare in social spiders, rose to 48% when spiders were reared at a high temperature. This may be evidence that volatile recognition pheromones suppress predatory instincts in social spiders.


Behaviour ◽  
2014 ◽  
Vol 151 (10) ◽  
pp. 1367-1387 ◽  
Author(s):  
Tessa K. Solomon-Lane ◽  
Madelyne C. Willis ◽  
Devaleena S. Pradhan ◽  
Matthew S. Grober

In many social species, there are important connections between social behaviour and reproduction that provide critical insights into the evolution of sociality. In this study, we describe associations between agonistic behaviour and male reproductive success in stable social groups of bluebanded gobies (Lythrypnus dalli). This highly social, sex-changing species forms linear hierarchies of a dominant male and multiple subordinate females. Males reproduce with each female in the harem and care for the eggs. Since aggression tends to be associated with reduced reproduction in social hierarchies, we hypothesized that males in groups with high rates of aggression would fertilise fewer eggs. We also hypothesized that a male’s agonistic behaviour would be associated with his reproductive success. Dominants often exert substantial control over their harem, including control over subordinate reproduction. To address these hypotheses, we quantified egg laying/fertilisation over 13 days and observed agonistic behaviour. We show that there was a significant, negative association between male reproductive success and the total rate agonistic interactions by a group. While no male behaviours were associated with the quantity of eggs fertilised, female agonistic behaviour may be central to male reproductive success. We identified a set of models approximating male reproductive success that included three female behaviours: aggression by the highest-ranking female and approaches by the lowest-ranking female were negatively associated with the quantity of eggs fertilised by males in their groups, but the efficiency with which the middle-ranking female displaced others was positively associated with this measure. These data provide a first step in elucidating the behavioural mechanisms that are associated with L. dalli reproductive success.


2007 ◽  
Vol 73 (3) ◽  
pp. 183-234 ◽  
Author(s):  
Javier Francisco-Ortega ◽  
Eugenio Santiago-Valentín ◽  
Pedro Acevedo-Rodríguez ◽  
Carl Lewis ◽  
John Pipoly ◽  
...  

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