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Social spider defense against kleptoparasites
Abstract
Because of the large amount of webbing they provide, social spider colonies often host other satellite spider species referred to as kleptoparasites or food stealers. Such kleptoparasites may take advantage of increased prey capture rates associated with large spider aggregations. This study investigated the relationship between a cooperatively social spider species, Anelosimus eximius (Araneae: Theridiidae), which lives in the undergrowth of tropical rainforests in Peru, and its kleptoparasite, Argyrodes ululans (Araneae: Theridiidae), which specializes in foraging in An. eximius webs. Although large aggregates of spiders may be more attractive to kleptoparasites, the benefits of group defense may offset this cost. Natural colonies were observed, and enclosed field colonies containing fixed numbers of host spiders were manipulated in order to determine whether kleptoparasite success is affected by the number of social spiders that are available for defense. Prey was less likely to be stolen by Ar. ululans when a greater number of host An. eximius spiders were involved in prey capture. When hosts detected a kleptoparasite earlier and chased it more often, prey was more likely to be successfully defended. Ar. ululans was more successful in stealing small prey items in all colonies and gave up more readily on very large prey (> 11 mm). I conclude that communal living and group defense in An. eximius confer protection from the kleptoparasite Ar. ululans.
... Other inquilines may simply take advantage of the protection provided by the host's nest, without damaging the host. Here, we will focus on inquilines of social spider colonies that steal food resources from their hosts, referring to them as "kleptoparasites" (Cangialosi, 1990). Specifically, we investigate how the incidence of social spider kleptoparasites is influenced by host and habitat characteristics, including potential host hygiene behaviours. ...
... Previous work in the lowland tropics found that nests of social Anelosimus spiders harbour communities of foreign spider species (Cangialosi, 1990(Cangialosi, , 1991Fernandez-Fournier & Avilés, 2018). Studies on Anelosimus eximius in Peru found that kleptoparasitic spiders steal prey from their host in antagonistic interactions (Cangialosi, 1991) and that hosts employ behaviours to defend prey (Cangialosi, 1990). ...
... Previous work in the lowland tropics found that nests of social Anelosimus spiders harbour communities of foreign spider species (Cangialosi, 1990(Cangialosi, , 1991Fernandez-Fournier & Avilés, 2018). Studies on Anelosimus eximius in Peru found that kleptoparasitic spiders steal prey from their host in antagonistic interactions (Cangialosi, 1991) and that hosts employ behaviours to defend prey (Cangialosi, 1990). ...
Group living animals are likely to attract more parasites than solitary ones. Parasite loads, however, should also depend on environmental conditions and on host characteristics and behaviours. Previous work has found that social spider colonies harbour communities of kleptoparasitic spiders that forego building their own web and, instead, steal prey from their social host.
We examined kleptoparasite loads and host hygiene behaviours in colonies of social and subsocial spiders in the genus Anelosimus along an elevation gradient in eastern Ecuador.
We found that kleptoparasite loads declined dramatically with increasing elevation. Host hygiene behaviours, such as debris removal, web repair and interactions with the parasites, also declined with elevation. Within elevations, species with more frequent hygiene behaviours appeared more successful at keeping parasites at bay. Contrary to our predictions, parasite density declined with host nest and colony size.
The decline in parasite loads at higher elevations likely reflects a lower rate of energy exchange between colonies and their environments, where colder temperatures mean fewer and smaller prey for colonies to process. The decline in parasite density with host colony size may reflect a decline in the number of accessible prey in larger host colonies, as larger colonies should capture fewer but larger insects due to scaling properties of their three‐dimensional webs.
Social immunity, whereby a social host uses social behaviour to fight against parasites, has been studied in eusocial and non‐eusocial insects. This study opens up social spiders as a novel system in which to study how host characteristics interact with environmental factors to affect parasite loads. It also introduces the concept of group‐level immunity to social spiders and suggests a role for colony‐level metabolism in determining ecological patterns in parasitism.
A plain language summary is available for this article.
... Egg cannibalism may also be involved (Christenson, 1984;Pruitt & Goodnight, 2014). Finally, much evidence suggests that social parasites, which are often other species of nonsocial spiders, contribute to colony extinction (Cangialosi, 1990(Cangialosi, , 1991Perkins, Riechert, & Jones, 2007). These interlopers may be intimately coevolved with the social spiders (Avil es, . ...
... The evolutionary costs of these links are most apparent in how social spiders interact with foreign spiders. Foreign spiders exploit this tolerance to lay their egg cases within colonies, steal prey from the social spiders, compromise colony architecture by adding alternative web types, and even consume the social spiders themselves (Cangialosi, 1990;Perkins et al., 2007;Pruitt & Riechert, 2011b). Social spiders therefore do not always appear to be able to differentiate their innocuous colony mates from dangerous invaders, with some exceptions (Cangialosi, 1990), and this tendency is problematic (Pruitt, 2013). ...
... Foreign spiders exploit this tolerance to lay their egg cases within colonies, steal prey from the social spiders, compromise colony architecture by adding alternative web types, and even consume the social spiders themselves (Cangialosi, 1990;Perkins et al., 2007;Pruitt & Riechert, 2011b). Social spiders therefore do not always appear to be able to differentiate their innocuous colony mates from dangerous invaders, with some exceptions (Cangialosi, 1990), and this tendency is problematic (Pruitt, 2013). ...
In some ways, social spiders are a biological novelty item. They are not extraordinarily successful either evolutionarily or ecologically, and their societies suffer a variety of disadvantages that render them more brittle than other social systems. Yet, from an empiricist's perspective, these attributes make them uniquely poised for addressing a variety of research questions. Here we provide a brief overview of the biology of social spiders for the general reader. We then highlight a variety of ecological and evolutionary challenges suffered by these animals that renders them at risk of extinction in the short and long term. We finally discuss how these hardships have given rise to a variety of individual and group level adaptations that are rare or entirely absent in other spiders, as well as in most other social animals. Throughout this article, we highlight gaps in our current understanding of these creatures and draw attention to some of the more promising frontiers for future research. To this end, we have two goals. First, we would like to draw the attention of general behavioural ecologists interested in social evolution to the biology of social spiders, and emphasize a variety of reasons why one might consider these animals for their next research question. Second, for those already inculcated in the social spider literature, we hope that this article will raise the reader's consciousness to various underexplored but promising avenues for future research. With the right research question, social spiders promise to be a high-profile and high-throughput model system.
... Host spiders are generally larger orb-web building species like Nephila (Nephilidae) or Argiope (Araneidae). Argyrodes species either built a web at the periphery of the host web with silken lines attached to it in order to detect vibratory signals by the host [22] [23] or they live directly on the web of the host spider. The vernacular name 'dew drop spiders' refers to the triangular shaped and silver colored body that makes the small spiders (3 -12 mm) appear like dew drops in the large host web. ...
... The only related compounds from spiders are branched propyl esters with a chain length between C 24 and C 36 , present on the cuticle of another but distantly related theridiid Anelosimus eximius, together with hydrocarbons and other components [14]. Interestingly, a relative of A. elevatus, A. ululans is a cleptoparasite of An. eximus [23]. The sexual dimorphism observed in the wax ester blend of A. elevatus is surprising and suggests that the compounds may serve a function in chemical communication of this species. ...
... Methyl Undecanoate (23). To a soln. of undecanoic acid (22, 2 g, 10.7 mmol) in abs. ...
... We suggest that these highly cooperative social ants found it easier to counter predator attack when flies attempted to steal the 50-mg bread crumbs because many workers were carrying the food and could retaliate against the fly when it attacked. Similar results have been reported from predation in other species of ants (Cangialosi 1990;Peeters & De Greef 2015). There was no significant change in the frequency of flies attempting to steal bread crumbs of different weights (Fig. 2b), suggesting that the size of the prey does not affect the number of robberies by the predator. ...
... There was no significant change in the frequency of flies attempting to steal bread crumbs of different weights (Fig. 2b), suggesting that the size of the prey does not affect the number of robberies by the predator. This has also been reported in the kleptoparasitic spider Argyrodes ululans (Cangialosi 1990). ...
Examples of predator-prey interactions in which flies rob ants are uncommon. To date, this behavior has only been recorded in the genus Bengalia Robineau-Desvoidy (Bengaliinae, Diptera, Calliphoridae). These predatory flies ambush ants, and rob them of the food or offspring that they are carrying. However, because of the rarity of this behavior, the reasons and consequences (evolutionary advantages) are unknown, and indeed, the behavior has been sometimes considered anecdotal. In this study, we employed field investigations and behavioral analyses to investigate whether the sex of the fly Bengalia varicolor, or the weight and quality of the food carried by Pheidole nodus ants influenced fly-ant interactions in their natural habitats. We show that food weight and quality influenced the behavior of B. varicolor independent of the fly's sex. Robbing behavior by the flies was more successful when the food robbed was of high-quality and light in weight. Furthermore, the weight of the food robbed modulated the escape distance the flies could carry it. This then may affect the food quality and weight transported by the ants. This is a novel example of deciphering the relationship between highwayman flies and their ant victims. Given the widespread distribution of Bengalia flies, we suggest that such interspecific predator-prey encounters may shape the robbery interactions and the carrying behavior of further ant species in nature.
... Invasive ants are known to compete with local fauna for resources (Drsya-Mohan et al. 2019). In the present case, competition might manifest in the form of kleptoparasitism, in which the ant steals prey that has been captured and killed by the spider (Cangialosi 1990), and this would result in a reduction of food availability for the spider colony. Social spiders usually capture several prey items that are often larger than themselves and therefore, they need to store the food in their web or nest for later consumption (Nentwig 1985). ...
... Social spiders usually capture several prey items that are often larger than themselves and therefore, they need to store the food in their web or nest for later consumption (Nentwig 1985). This foodhandling behaviour makes social spiders frequent targets of kleptoparasites (Cangialosi 1990;Drisya-Mohan et al. 2019). We believe that it is likely that this behavior is being exploited by M. floricola, which would explain why we found small ant colonies inside the spiders' nest. ...
Invasive ant species are a serious threat to native fauna, especially in highly diverse tropical countries. Therefore, new distribution reports and information on the interactions with other species are essential to understand the potential effects of invasive ants on biodiversity. Here we report for the first time the presence of colonies of Monomorium floricola (Jerdon, 1851) in the nest of the Neotropical social spider Anelosimus eximius (Keyserling, 1884) in the southern part of the Ecuadorian Amazon. Our report extends the known distributional range of M. floricola to the southern Ecuador.
... Not uncommonly, however, an eagle that has caught a fish finds itself beset upon by another eagle who attacks it until the first eagle releases the fish to defend itself, thereby creating an opportunity for its tormentor to seize the fish and usurp it from the producer. Behavioral biologists call this type of behavior "kleptoparasitism," or parasitism by "theft," sometimes also called "piracy" (e.g., Barnard 1984;Elgar 1986;Cangialosi 1990;Tershey et al. 1990;Forbes 1991). Hansen's research revealed that, of all fish consumed by eagles, 42% are acquired by fishing, and 58% are acquired by "stealing" fish caught by other eagles as they transport them (1986: 791). ...
... In addition to bald eagles, spiders are also vulnerable to kleptoparasitism. Spiders capture food by spinning webs and trapping prey which is sometimes usurped by others (Cangialosi 1990;Elgar 1989). Among mammals, hyenas have been observed to expropriate prey killed by other predators and even observed following these predators as they hunt, seizing prey once it is killed (Estes and Goddard 1967). ...
... Second, the evolution of sociality is associated with a decrease in cross-contextual aggressiveness (e.g., towards conspecifics, heterospecifics, prey, and potential predators/parasites) and increased conspecific densities that together render social spiders susceptible to a diversity of ecological pressures . These pressures include invasion by foreign species of spiders (Cangialosi 1990, Pruitt 2012, increased detection rate by ant predators (Purcell & Aviles 2008, Keiser et al. 2015, increased susceptibility to starvation and local resource competition (Aviles et al. 2002, Yip et al. 2008, Majer et al. 2018, and an increased propensity to spread socially transmitted microbes (Henschel 1998, Keiser et al. 2018. Different habitats may vary in the severity of these pressures based on local conditions (e.g., prey availability, predator abundance). ...
... Prior work over a smaller spatial scale (Henschel et al. 1996, Henschel 1998) more exhaustively documents the various agents of mortality in S. dumicola. Potential sources of our undiagnosed extinctions are numerous but include biotic factors such as predatory birds, wasps (Rayor & Uetz 1990, Rayor 1996, and kleptoparasitic or araneophagous spiders (Cangialosi 1990, Rypstra & Tirey 1991, as well as abiotic factors (e.g., stochastic damage to the deployment tree). However, prior work on S. dumicola (Henschel 1996) identified predatory ants and fungal outbreaks as the most potent agents of colony extinctions in this system (e.g., predation by ants accounting for 45% of mortalities, compared with predation by birds and araneophagous spiders at 3% each and predation by wasps at 1%), which served as motivation for our focusing on these sources of mortality. ...
Many animal societies are susceptible to mass mortality events and collapse. Elucidating how environmental pressures determine patterns of collapse is important for understanding how such societies function and evolve. Using the social spider Stegodyphus dumicola, we investigated the environmental drivers of colony extinction along two precipitation gradients across southern Africa, using the Namib and Kalahari deserts versus wetter savanna habitats to the north and east. We deployed experimental colonies (n = 242) along two ~ 800-km transects and returned to assess colony success in the field after 2 months. Specifically, we noted colony extinction events after the 2-month duration and collected environmental data on the correlates of those extinction events (e.g., evidence of ant attacks, no. of prey captured). We found that colony extinction events at desert sites were more frequently associated with attacks by predatory ants as compared with savanna sites, while colony extinctions in wetter savannas sites were more tightly associated with fungal outbreaks. Our findings support the hypothesis that environments vary in the selection pressures that they impose on social organisms, which may explain why different social phenotypes are often favored in each habitat.
Significance statement
Many social animals are susceptible to group extinction events. Identifying the factors that precipitate these events can help us to understand how societies function and evolve. We used a social spider model to evaluate whether the drivers of group extinction events may vary with habitat type. We found that ant attacks were more commonly associated with colony demise at arid sites, whereas fungal outbreaks were associated with collapse in wetter environments. If maintained temporally, these contrasting selection pressures could facilitate the evolution of local adaptation in individual- and colony-level phenotypes and aid in the maintenance of intraspecific trait diversity.
... The only related compounds from spiders are branched propyl esters with a chain length between C 24 and C 36 , present on the cuticle of another but distantly related theridiid Anolesimus eximus, together with hydrocarbons and other components [14]. Interestingly, a relative of A. elevatus, A. ululans is a cleptoparasite of An. eximus [23]. ...
... Methyl undecanoate (23). To a solution of undecanoic acid (22, 2 g, 10.7 mmol) in abs. ...
The analysis of cuticular extracts from the cleptoparasitic spider Argyrodes elevatus revealed the presence of unusual esters, new for arthropods. These novel compounds proved to be methyl-branched long chain fatty acid esters with methyl branches located either close or remote from the internally located ester group. GC/MS analysis of the prosoma lipid blend from the male cuticle contained one major component, undecyl 2-methyltridecanoate (1). In contrast, four major wax type esters, 2-methylundecyl 2,8-dimethylundecanoate (2), 2,8-dimethylundecyl 2,8-dimethylundecanoate (3), heptadecyl 4-methylheptanoate (4), and 14-methylheptadecyl 4-methylheptanoate (5), were identified in the lipid blend of female prosomata. Structure assignments were based on mass spectra, gas chromatographic retention indices, and microderivatization. Unambiguous proof of postulated structures was ensured by independent synthesis of all five esters. Preferentially odd-numbered carbon chains pointed to a distinct biosynthetic pathway, different from that of common fatty acids, because one or two C3 starter units are incorporated during the biosynthesis of all acid and alcohol building blocks present in the five esters. The striking sexual dimorphism together with the unique biosynthesis points to a function of the esters in chemical communication of the spiders, although no behavioral data are currently available to test this assumption. This article is protected by copyright. All rights reserved.
... The main sequence of events for stealing attempts by adult females is summarized in Fig. 5. (The individual behaviors of the kleptoparasites and of An. eximius are described in more detail in Cangialosi 1990a andCangialosi 1990b). A female Ar. ...
... Because it is social, groups of An. eximius make this host "bigger" than At. ,lhdans (and therefore defensively stronger, Cangialosi, 1990b) making kleptoparasitism more likely than predation. ...
This study investigated the life cycle and behavior of Argyrodes ululans which is a specialist kleptoparasite in the communal webs of its social spider host, Anelosimus exiraius. Observations of natural and enclosed colonies of An. eximius revealed that large An. eximius colonies maintain steady populations of high numbers of differently aged At. ululans individuals whereas small colonies contain fewer kleptoparasites less predictably. Adult female At. uhdans forage almost exclusively by stealing newly captured prey directly from their hosts and were never observed to prey on host spiders. Although male and juvenile Ar. uhdans will sometimes steal prey from An. eximius, they tend to scavenge more and feed on prey scraps abandoned by their hosts.
... La vie grégaire telle qu'elle existe à la sortie du cocon chez les araignées pourrait procurer un certain nombre d'avantages tels qu'une protection face aux prédateurs (Cangialosi 1990;Henschel 1998;Pruitt & Riechert 2011) ; la possibilité de coopérer pour la chasse (Rypstra & Tirey 1991;Pasquet & Krafft 1992) ; ou encore un partage dans la construction de la toile et donc une économie de soie (Jakob 1991 (Rypstra 1986;Gundermann et al. 1993). Chez l'araignée solitaire Zodarion cyrenaicum, les individus présentent peu d'agressivité vis-à-vis de leurs congénères. ...
La transition entre vie solitaire et vie sociale est une transition évolutive majeure, apparue indépendamment dans de nombreux taxons. Les araignées offrent une gamme étendue d'organisations sociales, différant par la complexité et la durée des interactions entre congénères. Parmi les 48 000 espèces d'araignées, une trentaine a développé une vie sociale élaborée caractérisée par la construction d'une toile commune, l'existence de soins coopératifs aux juvéniles et la présence de chasses collectives. Cependant, les juvéniles de toutes les espèces d'araignées solitaires présentent une phase grégaire temporaire suite à leur émergence du cocon maternel. Cette phase grégaire, dont la durée est variable entre les espèces, aboutit à la dispersion des juvéniles et l'initiation d'interactions agonistiques. La caractérisation de cette transition est cruciale pour identifier les mécanismes ayant présidé au développement d'une vie sociale permanente chez les araignées. Une première partie est consacrée à la caractérisation des mécanismes impliqués dans l'initiation de la dispersion chez les juvéniles de l'espèce solitaire Agelena labyrinthica. Nos résultats indiquent que l'agressivité est une conséquence, non la cause, de la dispersion. Dans une seconde partie, nous montrons l'influence du contexte social sur les comportements de prédation des juvéniles au cours de leur phase grégaire. Finalement, la troisième partie de cette thèse aborde les chasses collectives chez l'araignée sociale Anelosimus eximius. Nos résultats montrent que l'émergence d'une synchronisation dans les déplacements des araignées repose sur une modulation des comportements individuels dépendante de l'activité des congénères. En combinant approches expérimentales et théoriques, cette thèse suggère que la communication joue un rôle déterminant dans le maintien de la cohésion sociale et l'expression de formes sophistiquées de coopération chez les araignées.
... Few species of spiders can be considered truly social, but more species, particularly web-building spiders, live in close proximity to one another, potentially gaining benefits by this association. Among these benefits are sharing of frame threads (Kullman 1959), improved defense against predators and parasites (Cangialosi 1990), improved prey capture efficiency (Rypstra 1979;Uetz 1989), and greater egg production (Smith 1983). ...
Few species of spiders can be considered truly social, but a greater number of species, particularly web-building spiders, live in close proximity to one another. One species which has become highly successful through a lifestyle of colonial aggregation is the orbweaver Cyrtophora citricola Forskål. This 6-page fact sheet was written by Lionel A. Stange, and published by the UF Department of Entomology and Nematology, October 2012. http://edis.ifas.ufl.edu/in966
... Although most of the studies have dealt with the diversity, evolution, and behavior of kleptoparasites, the knowledge about its effect on the web-building and foraging behavior of social spiders are insufficient, due to lack of studies except a few (Cangialosi 1990;Leborgne et al. 2011). A pioneering study conducted by Leborgne et al. (2011), showed that in Eresid subsocial spider, Stegodyphus lineatus kleptoparasites negatively influenced the web building behavior and was independent of the success in the spider's previous foraging. ...
The term kleptoparasitism is used to describe the stealing of nest material or prey of one animal by another. Foraging and food handling behaviors of social spiders increase the vulnerability to klepto- parasitism. Kleptoparasites of the social spider Stegodyphus sarasinorum Karsch 1891 were identified based on the observations done in the field. Four species of spiders and two species of ants were observed as kleptoparasites and collected from the nest and webs of this social spider. The ants were found to be the most dominant among them. The influence of a facultative kleptoparasitic ant, Oecophylla smaragdina on the foraging behavior of S. sarasinorum was studied in laboratory conditions. The experiments suggested that the web building behavior of S. sarasinorum was influenced by the exposure to ants. However, exposure to ants caused no significant effect in the prey capture, handling time of prey and prey ingestion behaviors of the spider.
... indicating a high prey availability in this area (Vollrath and Houston 1986;Hodge 1987;Nakata and Ushimaru 1999;Hellmann 2006). High food availability provides one major precondition for the occurrence of kleptoparasites (Cangialosi 1990). Indeed, in addition to the wasps, large numbers of kleptoparasitic spiders (Argyrodes sp.) were observed in Nephilengys webs at Sibaliw. ...
Stealing prey items from other animals entails obvious benefits for the thief. However, this so-called kleptoparasitic behavior can also involve costs including injury or even death, especially when stealing from a potential predator. Here, we examined how kleptoparasitic hover wasps (Parischnogaster sp.) that steal prey items out of spider webs handle the risk of falling prey to their hosts. We tested the wasps’ ability to evade different webs under natural and experimental conditions and whether webs are perceived visually. Further, we tested whether wasps learn about web position and are able to avoid them in future trajectories as well as how quick wasps escape from webs once entangled. Additionally, we recorded the attack time for different spider species towards prey items placed into their webs, to estimate the risk of being attacked when entangled. Our results provide strong support for visual web perception by wasps facilitating the successful evasion of webs in flight trajectories, learning capability, and quick escape from webs once entangled. At the same time, the results, together with our observations in the field, suggest a specialization of kleptoparasitizing spider webs with overall lower risk of predation.
Significance statement:
Stealing prey from other predators often entails significant risk of injury and death. Yet, most research on such kleptoparasitism focused on the benefits to the kleptoparasite or the cost to the host, thereby overlooking an important component to explain the evolution and maintenance of kleptoparasitism. Here, we examine the potential costs for hover wasps when stealing prey from spider webs and test how wasps reduce the potential risks of this kleptoparasitic foraging behavior. While often described from casual observations, kleptoparasitism in hover wasps is so far unstudied. We show that kleptoparasitism from spider webs is associated with costs for hover wasps, but that visual detection of webs, avoidance learning, and rapid escape behavior mitigate those costs. Our study hints at hover wasps targeting certain host species where their mitigating strategies are most effective.
... Clustered spacing patterns of hosts have been observed across many host-parasite combinations in Argyrodinae, including Anelosimus eximius hosting F. ululans [70], N. clavipes hosting A. elevatus and A. caudatus, and Nephila clavipes hosting Argyrodes spp. [71]. ...
Group-living behavior is taxonomically widespread but rare in spiders. The conventional view is that the main pathways to group-living in spiders are either sub-social, where extended maternal care leads to prolonged sibling association; or communal living, where individuals aggregate to exploit a common resource. Female egg-sac guarding behavior occurs throughout kleptoparasitic spiders in the subfamily Argyrodinae (Theridiidae), while individuals in group-living species cohabit in the resource rich webs of their host spiders. These attributes fit both sub-social and communal routes to group-living, which offers new insights to study the early stages of social evolution. We investigated whether members of kleptoparasitic groups in natural populations comprise related individuals by comparing the population structure of two group-living species, Argyrodes miniaceus and A. cf. fissifrons, and two solitary species, A. fasciatus and Neospintharus trigonum. We found that: (1) genetic-spatial autocorrelation in group-living species was highest among spiders sharing the same host web and declined steeply with increasing distance, but no significant autocorrelation at any scale for solitary species; (2) there was high relatedness among group members in two cases of group-living species, which indicated relatedness was not an adhesive agent in most of the groups, but no high relatedness in solitary species; and (3) the host web boundary was not the sole predictor of genetic structures in group-living species. These results suggest that population genetic structure in the group-living species is caused by limited dispersal of group members that is favored by ecological conditions, including the nature and size of resources. In contrast, the absence of genetic structuring in populations of solitary species indicates a high level of dispersal with individual interactions unlikely to have fitness benefits.
... Third, group size increases due to late or no dispersal from the group (Riechert and Roeloffs, 1993). When dispersal does occur, so does often group budding, which increases the survival chances of the daughter group and leads to group reproduction and group inheritance (Cangialosi, 1990). ...
Some of the debates over the evolution of altruism and social groups can be tackled empirically, and criteria have been offered to decide between competing selection processes that might underlie the evolution of sociality. However, the typical model considers one selection process to be the main cause of the evolution of cooperation and cooperative groups. I argue, however, that at least in some cases, the evolution of cooperative groups can be better explained as the outcome of several selection processes, whether concurrent or sequential, rather than a single unifying process. Several examples from social spiders illustrate that selection processes cannot be reduced to particular instances of one overall process. I argue that seeking a unifying selection process for the evolution of altruism can reduce research productivity, generate misleading expectations and lead to false conclusions. On the other hand, looking at a combination of selection processes leads to new insights which are particularly relevant for the study of evolutionary transitions.
... Characteristically, social spider colonies cooperate in prey capture, web repair, and alloparental care, and colony members are highly related (e.g., r≈ 0.30 Anelosimus studiosus ) (Avilés 1997;Lubin and Bilde 2007;Duncan et al. 2010). Despite the finding that colonies are commonly encumbered by a rich community of kleptoparasites and colony-level predators (typically heterospecific spiders, hereafter termed "foreign spiders"), few investigations have considered the role of colony defense for individual and colony-level fitness (but see Cangialosi 1990Cangialosi , 1991. Instead, recent work on social spiders has focused on the foraging consequences of cooperative behavior Guevara and Avilés 2007;Powers and Avilés 2007;Purcell and Avilés 2008;Yip et al. 2008). ...
The social spider Anelosimus studiosus exhibits a behavioral polymorphism where colony members express either a passive, tolerant behavioral tendency (social) or an aggressive, intolerant behavioral tendency (asocial). Here we test whether asocial individuals act as colony defenders by deflecting the suite of foreign (i.e., heterospecific) spider species that commonly exploit multi-female colonies. We (1) determined whether the phenotypic composition of colonies is associated with foreign spider abundance, (2) tested whether heterospecific spider abundance and diversity affect colony survival in the field, and (3) performed staged encounters between groups of A. studiosus and their colony-level predator Agelenopsis emertoni (A. emertoni)to determine whether asocial females exhibit more defensive behavior. We found that larger colonies harbor more foreign spiders, and the number of asocial colony members was negatively associated with foreign spider abundance. Additionally, colony persistence was negatively associated with the abundance and diversity of foreign spiders within colonies. In encounters with a colony-level predator, asocial females were more likely to exhibit escalatory behavior, and this might explain the negative association between the frequency of asocial females and the presence of foreign spider associates. Together, our results indicate that foreign spiders are detrimental to colony survival, and that asocial females play a defensive role in multi-female colonies.
Electronic supplementary material
The online version of this article (doi:10.1007/s00265-010-1112-z) contains supplementary material, which is available to authorized users.
... [Behav Ecol 18:324–330 (2007)] I nterspecific kleptoparasitism is a well-known foraging tactic occurring across a wide range of bird species (for reviews, see Brockmann and Barnard 1979; Furness 1987). In many cases, hosts adopt defensive behaviors to avoid or minimize kleptoparasitism (Brockmann and Barnard 1979; Cangialosi 1990). Such defensive behaviors may inflict energetic costs on hosts such as lost foraging time, lower food intake rate, and higher levels of vigilance (Lima 1991; Beauchamp 1998; Giraldeau and Caraco 2000; Morissette and Himmelman 2000; Fritz et al. 2002). ...
In many cases of interspecific kleptoparasitism, hosts develop defensive behaviors to minimize the impact of kleptoparasites. Because vigilance and defensive behaviors are often costly, selection should favor hosts that adjust the amount of investment needed to minimize losses to kleptoparasitism. However, examples of such facultative responses are rare. Here, we investigate the response of cooperatively breeding pied babblers (Turdoides bicolor) to the drongo (Dicrurus adsimilis), an avian kleptoparasite that regularly follows pied babbler groups, often giving alarm calls to alert the group to predators but also occasionally giving false alarm calls in order to steal food items. We show that pied babbler response to drongos varies markedly according to babbler group size. In small groups, where there are few individuals available to act as sentinels, babblers sentinel less when a drongo is present and respond strongly to drongo alarm calls. However, in large groups, where there are many individuals available to participate in predator vigilance, babblers sentinel more often when a drongo is present, rarely respond to drongo alarm calls, and aggressively displace drongos, with a consequent decline in the number of successful kleptoparasitism events. This behavior represent a facultative response to a kleptoparasite according to the costs versus benefits of tolerating their presence. Copyright 2007, Oxford University Press.
... collective defense [34], [35]. This holds true as long as the costs associated with defense reactions are low compared to the benefits gained (for example [36], [37]). Collective defense is based on cooperating members of a group, and according to Hamilton's theory of kin selection [38] should be more likely to evolve in groups consisting of members with a high relatedness. ...
The prevalent way aphids accomplish colony defense against natural enemies is a mutualistic relationship with ants or the occurrence of a specialised soldier caste typical for eusocial aphids, or even both. Despite a group-living life style of those aphid species lacking these defense lines, communal defense against natural predators has not yet been observed there. Individuals of Aphis nerii (Oleander aphid) and Uroleucon hypochoeridis, an aphid species feeding on Hypochoeris radicata (hairy cat's ear), show a behavioral response to visual stimulation in the form of spinning or twitching, which is often accompanied by coordinated kicks executed with hind legs. Interestingly, this behaviour is highly synchronized among members of a colony and repetitive visual stimulation caused strong habituation. Observations of natural aphid colonies revealed that a collective twitching and kicking response (CTKR) was frequently evoked during oviposition attempts of the parasitoid wasp Aphidius colemani and during attacks of aphidophagous larvae. CTKR effectively interrupted oviposition attempts of this parasitoid wasp and even repelled this parasitoid from colonies after evoking consecutive CTKRs. In contrast, solitary feeding A. nerii individuals were not able to successfully repel this parasitoid wasp. In addition, CTKR was also evoked through gentle substrate vibrations. Laser vibrometry of the substrate revealed twitching-associated vibrations that form a train of sharp acceleration peaks in the course of a CTKR. This suggests that visual signals in combination with twitching-related substrate vibrations may play an important role in synchronising defense among members of a colony. In both aphid species collective defense in encounters with different natural enemies was executed in a stereotypical way and was similar to CTKR evoked through visual stimulation. This cooperative defense behavior provides an example of a surprising sociality that can be found in some aphid species that are not expected to be social at all.
... Kleptoparasitism, the stealing or sharing of food by individuals of the same or different species (Brockmann & Barnard 1979), is a form of direct competition (Curio 1976) used to reduce costs of searching and handling food (Barnard 1984;Osorno et al. 1992). It is well documented for birds (Brockmann & Barnard 1979;Furness 1987) and is also described for mammals (Kruuk 1972;Curio 1976;Wittenberger 1981;Parker & Ruttan 1988), predatory insects (Erlandsson 1988;Zamora 1990), spiders (Vollrath 1984;Cangialosi 1990Cangialosi , 1991 and fish (Pitcher 1986;Dominey & Snyder 1988). It has been reported for only a few species of marine invertebrates (Rosenthal 1971;Wobber 1975;Sloan 1979Sloan , 1984. ...
We used time-lapse underwater video systems in the subtidal zone of the Mingan Islands, eastern Canada, to examine behavioural interactions of four kleptoparasites with the sea star Leptasterias polaris when it was feeding on infaunal (buried) clams. Departures of L. polaris from its prey coincided with interactions with kleptoparasites in 10 out of 10 filmed feeding bouts on the large clam Spisula polynyma, compared with only four out of 10 of filmed bouts on the smaller clam Mya truncata. The sea star's abandoning of the prey was most often caused by interactions with another sea star, Asterias vulgaris, a potential predator. The whelk (a carnivorous snail), Buccinum undatum, and the crabs Hyas araneus and Cancer irroratus, also kleptoparasitized L. polaris, especially when A. vulgaris was present. Comparisons of feeding bouts in the presence and absence of kleptoparasites showed that at least 10.4% of the prey mass captured by L. polaris was lost to kleptoparasites. Simultaneous current meter data showed that the movement of A. vulgaris and B. undatum to sites where L. polaris was feeding on S. polynyma was upstream, suggesting chemodetection of food odours. Crabs in the vicinity may also use visual cues. Leptasterias polaris is the only carnivore that can efficiently extract large clams from the sediments and therefore its foraging may supply a substantial part of the diet of kleptoparasites. Copyright 2000 The Association for the Study of Animal Behaviour.
Evolutionary transitions from solitary to group-living are ubiquitous in animal systems. While the fitness consequences of group size changes are often investigated, the long-standing debate on whether kinship is a prerequisite of sociality is still ongoing. In the current study, we used kleptoparasitic spiders Argyrodes miniaceus (subfamily Argyrodinae, Theridiidae) as a model system to assess the role of group size on the foraging payoffs of kin and non-kin groups. We set up laboratory-manipulated kin and non-kin foraging groups and used feeding occurrence and duration as proxies for foraging benefits and feeding latency and the number of host attacks as estimates of foraging costs. Compared to solitary individuals, feeding durations of successfully fed individuals in groups was not significantly different from that of solitary foragers in both kin and non-kin groups. The occurrences of feeding decreased significantly in group sizes two and above, in non-kin groups, and in group sizes three and above, in kin groups. In kin groups, groups size two had significantly shorter feeding latencies compared to other group sizes, even though feeding duration did not change systematically with group size. Similarly, the number of attacks from the hosts were highest in non-kin groups with more than two individuals and in kin groups with more than three individuals. The juxtaposition of kin and non-kin group showed that A. miniaceus enjoyed the highest foraging payoffs when being solitary or in small groups (group size two). However, host attacks appeared to hamper feeding occurrences in kin groups, which was not observed in non-kin groups. Our results contrast sharply with the feeding benefits of kinship recorded in kin-based groups of sub-social species present in related subfamilies in the Theridiidae.
Spiders are famously aggressive and cannibalistic, and nearly all are solitary. Only about 20–25 out of over 46,000 known species display highly social behavior. Nevertheless, sociality has arisen in multiple families independently in spiders, probably via the ‘maternal care route’, with an apparent concentration of social species in the Neotropics. We review aspects of reproduction and maternal care and how these may interplay with the evolution and maintenance of social cooperative behavior, focusing on Neotropical spiders. We also discuss the behavioral, ecological, and evolutionary contexts in which these behaviors have evolved in spiders, and highlight the unique opportunities that exist for research due to the multiple independent evolutionary experiments that replicated origins of sociality offer. We ponder why social species appear concentrated in the Neotropics, with the outstanding example found in the genus Anelosimus. Curiously, highly social Anelosimus are restricted to the Neotropics, while the genus is distributed globally and ubiquitously displays extended maternal care. We discuss traits that are shared among these independently derived social species and thus form a part of a social ‘syndrome’. Such traits include absence of dispersal, inbreeding, biased sex ratios, and even shared patterns of colony composition of individuals differing in personality type. Ecologically, social Neotropical spiders are mostly restricted to tropical lowland and mid-elevation forests where prey size tends to be greater than in areas where sub-social species are found. They are especially common in areas of high rainfall, where their very dense 3-dimensional webs may not only allow capture of large prey, but also serve as a predator defense, for examples where ants are particularly common. Neotropical social spiders receive benefits from collaboration in web construction, care of young, nest defense, and prey capture, where they can handle much larger prey than other similarly sized spiders, and more effectively fend off predators. Colonies seem to benefit from a mix of personality types within colonies with both bold and shy individuals being crucial to colony success, but with larger colonies having more shy individuals and thus characterized by lower overall aggression. While sociality seems to offer short-term benefits in certain environments, a switch to an inbred breeding system that is tightly linked to sociality in spiders seems responsible for a loss of genetic variability that may restrict diversification due to vulnerability to climate change, disease, and parasitism.
Most web-building spiders build their webs solitary, and they usually prevent other individuals from invading their webs. However, some web-builders make their webs communally, and these are found mostly in tropical rain forests. The advantage of communal web building is thought to be improved prey capture. The communal capture of large insect prey has been observed in a number of social web-building spiders and communal spiders have been shown to capture larger prey than do solitary spiders. Philoponella raffrayi is a communal web-building uloborid spider that is distributed throughout southeastern Asia. This study describes the colony composition, and prey capture and handling behavior of the uloborid spider P. raffrayi. It determines whether the efficiency with which this species captures large insects is higher when spiders hunt cooperatively than when they hunt alone. Although most prey was captured by individual spiders, I occasionally observed two spiders cooperatively wrapping and capturing prey. Cooperation increased prey-capture efficiency when the prey was larger than half of a spider’s body length. Furthermore, interspecific associations of P. raffrayi in the Pasoh Forest Reserve (Pasoh FR) is described.
Argyrodes trigonum (Hentz 1850) can interact with its host as kleptoparasite, host predator, web-stealer, or commensal. This species can also capture insect prey in a web of its own construction. Which foraging strategy an individual A. trigonum exhibits certainly depends on a multitude of environmental factors, especially host availability. In this study, field surveys of populations of A. trigonum and its hosts and daily observations of individually marked host webs were made at sites in Ohio and New Hampshire. These observations together with a manipulation of A. trigonum density were performed in order to determine the influence of host species and abundance on the foraging strategy of A. trigonum. A. trigonum utilized Neriene radiata (Walckenaer 1841) to a greater extent than alternative hosts at both web sites even though many other host species were more abundant. The percentage of A. trigonum sharing a web with the host did not change with differing host/A. trigonum ratios; however, as a host/A. trigonum ratio increased, more A. trigonum were found in unoccupied host webs and fewer A. trigonum were found in webs of their own construction. A. trigonum is more likely to share a web with Pityohyphantes costatus (Hentz 1850) and to usurp the webs of Neriene radiata. Overall, A. trigonum behaved predominantly as a host predator; however, kleptoparasitism is more likely in host webs that last longer. Capturing prey in self-constructed or empty host webs is also important to A. trigonum foraging.
Brood parasitism is not well documented in arthropods. We studied interactions among two species of salticid spiders (Habronattus tranquillus and Metaphidippus manni) and a diguetid spider (Diguetia mojavea). Observations and experiments show that these salticids invade a web and deposit their own eggs after D. mojavea mothers die. Although salticid eggs are laid after diguetid eggs are produced, their eggs are larger than those of diguetids, develop much more rapidly, and invariably emerge before the first diguetid spiderlings hatch. Salticid spiderlings also emerge at a significantly larger size than diguetid spiderlings. Thus, the salticid spiderlings have both timing and size advantages over the diguetid hatchlings. In addition, salticid spiderlings prey on resident diguetid juveniles and thereby significantly reduce the host's fitness. We document experimentally that one defense against this parasitism is the mother's presence after her egg sacs are deposited. Other possible diguetid defenses include high fecundity and asynchronous hatching of egg sacs. Our results suggest that these salticids are obligate brood parasites of D. mojavea and provide one of the first experimental examples of host-parasite coupling among arthropods.
The kleptoparasitic spider subfamily Argyrodinae in Korea is reviewed with detailed illustrations and SEM photographs of male palpal organs. Five species belonging to four genera of Korean Argyrodinae spiders are redescribed and Argyrodes miltosus Zhu and Song, 1991 is synonymized with A. miniaceu. A key to the species of the Korean Argyrodinae spiders are also provided.
Argyrodes flavescens is a common theridiid spider species foraging in the web of a host spider Nephila pilipes in Singapore. In the present study, we investigated the factors that influence the relationship between kleptoparasites and host spiders and the impact of kleptoparasites on hosts. Field surveys were conducted to examine how host size, web size, and ambient light intensity around webs affect the abundance of A. flavescens. The results from the field study showed that the mean number of A. flavescens is positively correlated with body size and web size of host spiders, and ambient light intensity surrounding the webs. Laboratory experiments were carried out to examine the impact of A. flavescens on N. pilipes by manipulating the number of A. flavescens present on the webs. The experimental results demonstrated that A. flavescens reduces host weight gain, increases mortality of host spiders, rate of web relocation, and web damage. These findings suggest that A. flavescens is detrimental to host spiders, N. pilipes, by stealing freshly captured prey items from the host, forcing the hosts to relocate the webs more frequently, sharing the large prey item with the host, and removing large quantity of silk from the host web.
Cooperative social life originated independently at least 3 times in the eresid spider genus Stegodyphus. The ultimate and proximate factors for sociogenesis have been analyzed in two African social species, S. dumicola and S. mimosarum.
More profitable hunting as the ultimate benefit of sociality can explain group sizes up to 30 individuals. Most groups are much larger, reducing average female fecundity. They benefit mainly from the shelter against predators provided by the compact silk nest as a heritable resource.
Sociogenesis is not based on extended maternal care but on interattraction and tolerance of juvenile spiders, retained throughout life in females. Their neotenic sociality came to overlap with advanced (pedomorphic) sexual maturity. This evolutionary pathway towards sociality is called the “sibling‐route”.
Negative side effects, accumulating with group size, may make sociality in Stegodyphus evolutionarily unstable.
ABSTRAC7: -Argyrodes flavescens is a common theridiid spider species foraging in the web of a host spider Nephila pilipes in Singapore. In the present study, we investigated the factors that influence the relationship between kleptoparasites and host spiders and the impact of kleptoparasites on hosts. Field surveys were conducted to examine how host size, web size, and ambient light intensity around webs affect the abundance of A. flavescens. The results from the field study showed that the mean number of A. flavescens is positively correlated with body size and web size of host spiders, and ambient light intensity surrounding the webs. Laboratory experiments were carried out to examine the impact of A. flavescens on N. pilipes by manipulating the number of A. flavescens present on the webs. The experimental results demonstrated that A. flavescens reduces host weight gain, increases mortality of host spiders, rate of web relocation, and web damage. These findings suggest that A. flavescens is detrimental to host spiders, N. pili pes, by stealing freshly captured prey items from the host, forcing the hosts to relocate the webs more frequently, sharing the large prey item with the host, and removing large quantity of silk from the host web.
The Ecuadorian Amazon region is exceptionally rich in terms of the number and variety of social spiders it contains. In this area there are representatives of three of the four forms of social behavior described for spiders, comprising species in 10 genera and seven families. Here we review the natural history of the fourteen species from this area that we have identified as having some form of social behavior, including six species Cyclosa sp., Plesiometa sp., Tapinillus sp. 2, Achaearanea cf. mundula, a pholcid, and a sparassid whose sociality has not been previously described. In the introduction we review the characteristics of spider sociality, noting several significant differences with insect social systems. In particular, we note that social spiders have not developed reproductive castes and that in the species with the most complex social behaviors the social groups are also relatively isolated population lineages. We discuss how the Ecuadorian social spiders, in particular those recently discovered, may help test existing hypotheses for the evolution of sociality in spiders. We also outline some of the evolutionary and ecological problems that social spiders may help clarify, such as the evolution of female-biased sex ratios in subdivided populations, the levels of selection, and the patterns of extinction and dispersal of local populations in a metapopulation. An electronic Appendix with English descriptions of the six previously undescribed social species can be found at http://www.scielo.cl/
Argyrodes globosus (Keyserling, 1884) is a small kleptoparasite spider that steals prey from the web of web-building spiders. In coffee plantations in the south of Mexico it was observed to parasitize five species: Gasteracantha cancriformis (Linnaeus, 1785) and Verrucosa arenata (Walckenaer, 1841) (Araneidae), Leucauge mariana (Keyserling, 1881) and Leucauge venusta (Walckenaer, 1841) (morphologically indistinguishable species) and Leucauge argyra (White, 1841) (Tetragnathidae). G. cancriformis was more frequently parasitized than the other hosts. An analysis of web diameter for each host species indicated that for L. mariana/venusta, L. argyra and V. arenata the kleptoparasite was associated with webs of a certain size range (23-33cm diameter) although a far larger range of web sizes was available (17-50cm diameter). The average size of the web of G. cancriformis (~23cm) appeared to be close to the preferred size for the kleptoparasite and this, together with an apparent absence of host aggression, may explain the prevalence of A. globosus with this host. For the parasite, web size choice may involve a tradeoff among diverse factors including prey capture rate, ease of access to the web and aggressive behaviour by the host.
This study elucidates the homology of elements of the male palps in the spider family Theridiidae. We survey and illustrate 60 species from 29 out of the 86 currently recognized genera representing all subfamilies. The study is buttressed by a phylogenetic framework, and uses a new method to evaluate critically competing homology hypotheses based on various criteria. Among the classic criteria for homology, topology performed better than special similarity, and much better than function. Guided by those results, we propose names for and correspondences among the broad diversity of theridiid palpal tegular sclerites. We discuss the phylogenetic utility and distribution of key palpal characteristics, and evaluate existing evolutionary hypotheses of the theridiid palp and its components.
Argyrodes Simon 1864 is a large, cosmopolitan theridiid genus whose members exhibit a wide range of foraging techniques which usually involve exploiting other spiders, either by using their webs, stealing their food, or preying on them directly. We held a symposium on this genus at the 15th International Congress of Arachnology, Badplaas, South Africa in order to obtain a clearer perspective on the relationship between the phylogeny of the genus and the different foraging techniques. We concluded that Argyrodes forms a monophyletic group within the Theridiidae, and that there are clear monophyletic clades within the genus (already identified as species groups) that appear to share behavioral characteristics. We found no clear indication that foraging behaviors such as kleptoparasitism (stealing food) evolved from araneophagy (eating spiders) or vice versa. However, it appears that species that specialize in either kleptoparasitism or araneophagy use additional techniques in comparison to species that readily use both foraging modes. During our examination of Argyrodes/host interactions we noted the importance of Nephila species as hosts of Argyrodes species around the world and the impact of Argyrodes on Nephila. We also noted the fluid nature of the relationship between Argyrodes and the spiders with which they interact. For example, an Argyrodes/host relationship can change to an Argyrodes/prey relationship, and the type of kleptoparasitic behavior employed by an Argyrodes can change when it changes host species. The importance of eating silk was also noted and identified as an area for further research. We concluded that more work involving international collaboration is needed to fully understand the phylogeny of the genus and the relationships between the different types of foraging behaviors.
The spider genus Anelosimus Simon, 1891 (Theridiidae) currently contains over forty described species, found worldwide in tropical to warm temperate areas. American Anelosimus are all social, a rare trait among spiders, but social behaviour has not been reported for Anelosimus species elsewhere. Old World Anelosimus are poorly known, both behaviourally and taxonomically, and no Anelosimus species have yet been described from sub-Saharan Africa or Madagascar. Based on a preliminary phylogenetic analysis we predicted sociality in an undescribed Madagascar species because it grouped among social New World species. An expedition to Madagascar then found no less than five undescribed periodic-social (subsocial) Anelosimus species in Périnet reserve. A sixth species from the same locality is known from museum specimens and the Anelosimus diversity of Périnet is comparable with the most diverse single locality in the Americas. Subsocial species play a key role in understanding the evolution of permanent sociality (quasisociality). This increased pool of available subsocial study species demonstrates the utility of phylogenies as predictors of traits in species thus far unstudied. Here, A. andasibesp.n., A. may Agnarsson sp.n., A. nazarianisp.n., A. salleesp.n., A. salutsp.n. and A. vondronasp.n. are described. Anelosimus locketi Roberts, 1977 from Aldabra Atoll is a junior synonym of A. decaryi (Fage, 1930) comb.n. from Madagascar. Preliminary data on the behaviour of the new species are given, indicating a level of sociality similar to the American A.‘arizona’1. The phylogenetic analysis supports the monophyly of the Madagascar group and places it as sister to a clade containing the eximius lineage from the Americas, and a pair of undescribed Tanzanian species.
Argyrodes gibbosus is a kleptoparasitic spider in the web of spiders. It generally steals freshly captured prey from the web of its host. In Sicily, Argyrodes gibbosus parasitizes webs of the spider Cyrtophora citricola, a facultative colonial species.
When a C. citricola female was present in its web, Argyrodes caught small prey in the web or tried to rob prey captured by the host; in that case, we never observed successful attacks on host egg-sacs. When the host disappeared from its web, the kleptoparasite modified its foraging strategies and attacked the host egg-sacs and ate the eggs. The exploitation of this new resource could ensure rapid development for the kleptoparasite which was characterized by the presence of larger females and a higher mating rate.
Argyrodes flavipes illustrates a novel form of highly social behaviour in spiders. Although A. flavipes lives in groups, forages communally, and has parental care, it is also highly aggressive towards conspecifics. These observations, plus the relatively small group sizes, suggest that sociality in these animals may be more akin to that in social mammalian carnivores than in social insects. Most highly social spiders are thought to have developed sociality via the sub-social route because of their high level of parental care. Although A. flavipes also exhibits high levels of parental care, its phylogenetic background and the fact that it needs to defend its young from conspecifics, suggest that both sub-social and para-social factors may have influenced its social development.
The potential costs and benefits of foraging in aggregations are examined for the orb-spinning spider Gasteracantha minax. Web-site tenacity is low in this species; individuals frequently move among sites, thereby joining aggregations of different sizes. Female spiders in aggregations suffered lower predation rates and attracted more males than their solitary counterparts. However, aggregated eggsacs, probably produced by females in aggregations, experienced higher rates of parasitism than solitary eggsacs. We found no evidence of higher prey capture success rates among spiders in aggregations. However, we demonstrate a novel way in which spiders can increase their foraging efficiency by decreasing silk investment. A spider spinning a web within an existing aggregation can attach the support threads of its web to those of other webs, thereby exploiting the silk produced by other spiders.
The overwhelming majority of spiders are solitary and territorial. Of the handful of web-sharing social species, most belong to the cobweb genus Anelosimus Simon, 1891 (Theridiidae). Anelosimus species, especially those from the Americas, have therefore become model organisms in the study of spider sociality. However, lack of a phylogeny and outdated taxonomy have hindered progress in understanding the evolution of social behaviour. The identity of many species studied behaviourally is in doubt, and choice among the competing hypotheses on the course of evolution of sociality in Anelosimus requires a robust phylogeny. This paper offers a revision of the New World ‘eximius lineage’ containing the most intensely studied Anelosimus species, and a phylogenetic study including worldwide exemplars. Previous taxonomic work on the group was incomplete and oversimplified. Some species-level taxa, e.g. A. jucundus (O. P.-Cambridge, 1896) and A. studiosus (Hentz, 1850), as previously circumscribed represent a compendium of species and are here re-examined. Eight new species are here described: A. arizona, A. baeza, A. octavius and A. puravida, of the ‘jucundus group’, and A. gucamayos, A. oritoyacu, A. pantanal and A. tungurahua of the ‘studiosus group’. Furthermore, Enoplognatha dubia Chamberlin, 1916 and Theridion tosum Chamberlin, 1916 previously synonymized with A. jucundus, and Anelosimus fraternus Bryant, 1948, previously synonymized with A. studiosus, are here again considered valid. Enoplognatha dubia becomes a junior secondary homonym of Brattia dubia Tullgren, 1910 (= Anelosimus dubius) and the replacement name Anelosimus elegans Nomen Novum is here provided. The parsimony analysis of the morphological matrix (43 taxa, 147 characters) resulted in two equally most parsimonious trees, with four trichotomies in the strict consensus. Three of these lack character evidence to resolve them; one is a result of character conflict. One of the two trees is optimal under successive weighting. The New World Anelosimus are not monophyletic, but rather form three clades, the eximius lineage (20 species), the ‘rupununi group’ (two species) and the ‘ethicus group’ (six species). The phylogenetic results corroborate previous transfer of species to Kochiura and Selkirkiella. The following additional species are removed from Anelosimus: Styposis camoteensis (Levi, 1967) (comb. nov.), Styposis tepus (Levi, 1967) (comb. nov.), Chrosiothes episinoides (Levi, 1963) (comb. nov.) and Stemmops osorno (Levi, 1963) (comb. nov.). Four species are here treated as nomina dubia, Anelosimus nigrobaricus Barrion & Litsinger, 1995 (type in very bad condition, original description lacks sufficient detail for identification), and A. salaensis Barrion & Litsinger, 1995, Theridion fasciatum Holmberg, 1876 and T. sordidum Holmberg, 1876 (types lost, original descriptions lacks sufficient detail for identification). The results corroborate previous findings of convergent evolution of permanent sociality in the genus. However, instead of sociality evolving twice as previously suspected, the current phylogeny suggests no less than six, independent origins. Each time, the evolution of sociality seems to be responsible for a dramatic shift in population structure from outbred panmictic to strongly inbred subdivided populations. Perhaps as a consequence, once they are permanently social, species seem to fail to diversify; all social clades are small (one or two species) and usually smaller than their sister clade. No losses of social behaviour are inferred. The maternal care route hypothesis is again supported. To explain sociality in Anelosimus it seems sufficient to hypothesize a temporal extension of the juvenile web-sharing, co-operation and conspecific tolerance, displayed in basic maternal care, coupled with depression of dispersal. Given the most parsimonious phylogeny, the basal-most Anelosimus species occur in the Old World, and three Anelosimus clades occur in the New World. Sufficient data are not available to estimate the age of the Anelosimus lineage accurately, but the sparse fossil record hints at a relatively recent origin (20–40 mya). If true, vicariance could not account for this distribution; rather, the pattern may suggest three independent colonization events of Old World Anelosimus in the Americas. Support for most branches within Anelosimus is relatively low, especially the support for the relationships within species groups. Thus, although the forgoing conclusions are clearly implied by the phylogeny, weak support limits their force. © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society, 2006, 146, 453–593.
Spiders from the theridiid genus Argyrodes exhibit considerable variation in foraging tactics. However, little is known about the conditions under which Argyrodes spiders switch foraging tactics. Argyrodes flavescens (Pickard-Cambridge) is commonly found in the webs of another spider Nephila pilipes (Fabricius) in Singapore. In this study, a series of prey-choice tests were conducted for A. flavescens, both in the presence and absence of N. pilipes, to investigate the state-dependent prey type preference of A. flavescens. It was found that, in the absence of N. pilipes, well-fed A. flavescens took houseflies more than fruit flies, but starved A. flavescens took more fruit flies than houseflies. Whether N. pilipes spiders were present or absent, both well-fed and starved A. flavescens preferred living prey and rarely took wrapped prey of any kind. When well fed, A. flavescens rarely took mealworms. However, when starved, A. flavescens tended to take freshly captured prey, and also tended to feed together with N. pilipes on a housefly or mealworm captured by N. pilipes. Whether A. flavescens were absent or present, both well-fed and starved N. pilipes took mealworm larvae more often than they took houseflies, and they never attacked fruit flies. This is the first study to show that Argyrodes spiders alter their foraging tactics depending on hunger level, prey type, or the presence of the host. In doing so, Argyrodes spiders may maximize their energy gain and minimize predation risk in different circumstances.
Permanent cooperative sociality is rare in spiders. Here we describe sociality in a cobweb (Theridiidae) genus with no other known social species. In five areas of eastern Ecuador, we found nests of Theridion nigroannulatum containing from a single to several thousand adults living together in a communal web. Spiders cooperated in prey capture and shared their food. Subadult to young adult sex ratios were highly female biased, suggesting a strongly subdivided population structure as in other permanent-social spiders. Unusual aspects of T. nigroannulatum's biology include the existence of adult females of two discrete sizes, an extreme boom and bust pattern of colony growth, and the presence, within larger colonies, of populations of a predatory spider (Faiditus spp., Argyrodinae) that may play the role of a colony-level parasite. The existence of females of two sizes may be the result of alternative female reproductive strategies, intracolony competition for resources, or an incipient caste system in this species. A redescription and phylogenetic analysis corroborate the placement of this species in Theridion, indicating that sociality has evolved independently in at least three theridiid genera.
This paper offers the first cladistic analysis of a wide selection of theridiid genera based on morphological data. The analysis treats 53 theridiid taxa representing 32 genera (Achaearanea, Anelosimus, Ameridion, Argyrodes, Ariamnes, Carniella, Cerocida, Chrysso, Coleosoma, Dipoena, Emertonella, Enoplognatha, Episinus, Euryopis, Faiditus, Kochiura, Latrodectus, Neospintharus, Nesticodes, Pholcomma, Phoroncidia, Rhomphaea, Robertus, Selkirkiella, Spintharus, Steatoda, Stemmops, Theridion, Theridula, Thymoites, Thwaitesia, Tidarren) and eight outgroup taxa representing the families Nesticidae (Eidmanella and Nesticus), Synotaxidae (Synotaxus, two species), Pimoidae (Pimoa), Linyphiidae (Linyphia), Tetragnathidae (Tetragnatha) and Araneidae (Argiope). The parsimony analysis of 242 morphological and behavioural characters found a single, most parsimonious tree. The monophyly of theridiids and their sister relationship with nesticids is strongly supported. The recent resurrection of Ariamnes and Rhomphaea from Argyrodes made the latter paraphyletic. However, Ariamnes and Rhomphaea are characterized by an array of characters, and Argyrodes still contains dramatically distinct clades for which names are available: Faiditus (removed from synonymy − RS) and Neospintharus (RS). These revalidations provide a classification with greater information content and utility. These three genera, along with Ariamnes, Rhomphaea and Spheropistha, comprise the subfamily Argyrodinae. The monophyly and composition of the subfamilies Hadrotarsinae, Spintharinae, Pholcommatinae, Latrodectinae and Theridiinae are discussed. Theridion is paraphyletic and in need of revision. Anelosimus as currently circumscribed is paraphyletic, a problem resolved by revalidating Selkirkiella (RS) and Kochiura (RS). Numerous new combinations are established. The results suggest the monophyletic origin of both kleptoparasitism and araneophagy in the lineage leading to Argyrodinae, negating hypotheses that either arose from the other. Sociality evolved multiple times within the family, accounting for as much as one fourth of the origins of social behaviour among all spiders. No losses of sociality are implied. The hypothesis of maternal care as the pathway to sociality receives support. Evolution of theridiid webs is complex, with multiple modifications and loss of the basic theridiid cobweb. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 141, 447–626.
Summary: Among spiders, some species could be qualified as colonial. Individuals may live alone or in colonies where each spider exploits its own capture web in a communal network. We compared solitary with colonial life in Cyrtophora female populations from South-East Sicily in 1992 and 1993. We used 6 parameters to describe and compare the populations: spider size, web size, egg production, prey captured, presence of kleptoparasites and their size. Spiders living in colonies did not differ in size from solitary spiders. The webs of colonial spiders were smaller than those of solitary spiders. The number of prey captured and their size did not differ between the two types of spiders. Solitary spiders produced more eggs than colonial individuals. Kleptoparasite spiders Argyrodes gibbosus were more numerous in the webs of solitary spiders than in the webs of colonial spiders and there were more solitary webs infested by kleptoparasites in 1992. The kleptoparasites were larger in colonial webs than in solitary ones. Another species of spider, Holocnemus pulchei, spun its own web in the network of the web of Cyrtophora. The number of Holocnemus per web did not differ between solitary and colonial Cyrtophora. Results are discussed by referring to what it is known in other temporarily social spiders.
Argyrodes ululans, a kleptoparasitic spider that specializes in stealing prey from the social spider, Anelosimus eximius, faces a variety of foraging situations depending upon the number of host spiders involved in prey capture and defence, and prey availability. The ability of A. ululans to modify its mode of attack may therefore be essential to ensure its success in obtaining food. Kleptoparasite hunger level, host colony size and prey size were manipulated and detailed observations of behaviour were made to determine whether A. ululans modifies its stealing strategy in response to these changing conditions. Argyrodes ululans initiated an attack based on its hunger state and the size of the prey tackled, and altered the relative frequencies of its component stealing behaviour patterns according to the number of host spiders that responded to capture the prey. These adjustments in stealing tactics allow A. ululans to maximize its success in acquiring prey and to conserve energy used for foraging.
Argyrodes flavipes illustrates a novel form of highly social behaviour in spiders. Although A. flavipes lives in groups, forages communally, and has parental care, it is also highly aggressive towards conspecifics. These observations, plus the relatively small group sizes, suggest that sociality in these animals may be more akin to that in social mammalian carnivores than in social insects. Most highly social spiders are thought to have developed sociality via the sub-social route because of their high level of parental care. Although A. flavipes also exhibits high levels of parental care, its phylogenetic background and the fact that it needs to defend its young from conspecifics, suggest that both sub-social and para-social factors may have influenced its social development.
In this field study we investigated the impact of Argyrodes fissifrons (Araneae: Theridiidae)by studying several aspects of its population and foraging. We examined
1) if natural population variations of A.fissifrons occur with different web sizes of hosts
2) if A.fissifrons form long-term associations with particular hosts
3) if the size range of prey consumed by A.fissifrons overlaps with that of Cyrtophora hosts
Results from field surveys indicated that a positive relationship exists between the average number of A.fissifrons and the size of host webs. The number of A.fissifrons per host web changed daily, indicating the the daily occurrence of immigration-emigration events. However, as inferred from monitoring marked A.fissifrons for 3 nights, some individuals form a long-term association with a particular host. The sex ratio, body size, and prey intake of A.fissifrons spiders staying in a particular hosts' web during monitoring did not differ from those that left a web. A significant difference was found in prey size distribution between Cyrtophora hosts and A.fissifrons, and the average prey size of the former was far greater than the latter. This result suggests that A.fissifrons scavenge on webs of Cyrtophora hosts by collecting small prey ignored by their hosts
Brrod parasitism is not well documented in arthropods. We studied the interactions among two species of salticid spiders (Habronattus tranquillus & Metaphidippus manni) and a diguetid spider (Diguetia mojavea). Observations and experiments show that these salticids invade a web and deposit their own eggs after D.mojavea mother die. Although salticid eggs are laid after diguetid eggs, their eggs are larger than those of diguetids, develop much more rapidly, and invariably emerge before the first diguetid spiderlings hatch. Salticid spiderlings also emerge at a significantly larger size than diguetid spiderlings. Thus, the salticid spiderlings have both timing and size advantages over diguetid hatchlings. In addition, salticid spiderlings prey on resident diguetid juveniles and thereby significantly reduce the host's fitness. We document experimentally that one defense against this parasitism is the mother's presence after her egg sacs are deposited . Other possible diguetid defenses include high fecundity and asynchronous hatching of egg sacs. Our results suggest that these salticids are obligate brood parasites of D.mojavea and provide one of the first experimental examples of host-parasite coupling among arthropods.
The concept of colony-level life history evolution is introduced for the cooperative spiders by describing the life cycle and demography of Aebutina binotata(Araneae: Dictynidae), a species living in groups containing up to several dozen adult females plus their offspring. In a life cycle remarkably similar to army ants, the colonies of A.binotata were found to reproduce by fission and to alternate nomadic and sedentary phases in tight association with their internal demography. Colonies of other cooperative spiders, on the other hand, remain stationary as they grow for a number of generations before producing propagules that are relatively small subsets of the maternal colony. It is suggested that A.binotata's peculiar life cycle may have unfolded as a consequence of the two-dimensional architecture of its nests. Expanding two-dimensional nests may fragment more easily than the three-dimensional characteristic of other species. A long distance group migration or nomadic phase, described here for the first time, may have followed as a mechanism to cope with potential disadvantages of fission while selecting for strict synchronisation of individual life cycle stages within the nests. It is shown, however, that, as in other cooperative spiders, A.binotata's sex ratio is also highly female biased. The theoretical implications of biased sex ratios in species with fissioning colonies are discussed.
We investigated host specificity, the effects of host size, and the effects of the size, structure and occupancy of host webs on the abundance of the kleptobiotic spider Argyrodes antipodianus O.P.-Cambridge 1880. The kleptobiont is not host specific, but does prefer orb webs that are surrounded by a scaffold of threads (barrier-web). Across all hosts, host size had little effect on the abundance of the kleptobiont, while host density and the presence of other species of Argyrodes on webs had no effect. Web diameter, although not strongly related to the abundance of A. antipodianus in the field, limited kleptobiont numbers in greenhouse experiments. On webs of the Golden Orb Spider, Nephila plumipes (Latreille 1804), numbers of A. antipodianus were not affected by size of the scaffold or by aggregation of host webs. However, presence of host males was associated with a significantly higher abundance of A. antipodianus, suggesting that these kleptoparasites may take advantage of distracted females and impose a cost on mating in N. plumipes.
A high degree of mobility was observed in a population of Nephila clavipes (L.) (Araneae; Araneidae) in southeastern Peru, September-December, 1979. Prey capture and consumption were measured relative to the number of kleptoparasitic spiders (Araneae; Theridiidae; Argyrodes sp.) in the webbing. Those N. clavipes that moved their webs shortly after observation had consumed significantly fewer prey items than those that maintained their web site. However, total prey capture was not different between the two groups. Prey consumption was significantly reduced by each additional kleptoparasite in the web. Consequently, there was a complete correlation between the number of Argyrodes individuals in a spider's web and the percentage of those spiders that relocated their web. /// Высокая степень подвижности наблюдалась в популяции Nephila clavipes (L.) (Araneae, Araneidae) в юго-восточном Перу в сентябре-декабре 1979 г. Определяли скорость ловли жертв и потребление в зависимости от количества клептопаразитических пауков (Araneae, Theridiidae, Argyrodes sp.) в паутине. Те N. clavipes, которые перемещали свою сеть вскоре после наблюдений, потербляли значительно меньше жеств, чем те, которые сохраняли свои участки с паутиной. Однако, общее количество пойманных жертв не различается у двух грпп. Каждый дополнительный клептопаразит в паутине существенно снижает потребпение жертв. Следовательно, здесь имеется четкая корреляция между количеством Argyrodes в паутине и относительным количеством пауков, перемещающих чвою паутину.
The premise that a species will maximize its net energy intake over the short term was tested by studying the robbing behavior of the Great Egret. In wading-bird feeding aggregations of the southern Florida Everglades, the 5 most common species robbed other birds, and this behavior consumed 10% of the feeding time of the Great Egret. When an egret robbed other birds, it got larger prey, but it took longer, caught fewer prey, and expended more energy than it did feeding in more typical fashion by slow walking or standing. Nonrobbing behavior had a gross energy intake per time 3.1 x greater than robbing. The cost-benefit ratio of robbing was 70% larger than for standing feeding. The combined used of both standing feeding and robbing resulted in a cost-benefit ratio 10% larger than for standing feeding alone. The use of a nonoptimal behavior is interpreted to suggest that energy return need not always be optimized over the short term. Minimizing cost-benefit ratios, optimizing time budgets, or maximizing net energy gain may occur only intermittently during an animal's annual cycle. The existence of a less-than-optimal behavior within the egret's foraging repertoire suggests that, under circumstances other than those studied, it might contribute to foraging optimization. It is predicted that an animal should attempt to capture each prey that it encounters when the occurrence of a prey item is a relatively rare and random event and if the potential penalty were small. Under these conditions, which would occur during periods of nonrigorous foraging, an animal can use a nonoptimal behavior.
and Summary
Wild colonies of the social spider Anelosimus eximius (Araneae, Theridiidae) appear often to be food‐limited and not all females come to reproduction. Using a limited number of marked females in an artificial colony, set up in the laboratory, this study attempts a first analysis of the participation in prey capture and ingestion. Marked females of the same age and experience were observed during the attack of prey insects, the ensuing transportation of the prey to the retreat, and the feeding session. No correlation was found between the time females spent hunting and the time they spent feeding. Females that laid eggs had fed longer and imbibed more nutrients, but had not hunted more than those females that did not reproduce. These, it is speculated, were denied access to the prey by the reproducing females.
the theridiid spider Argyrodes elevatus lives as a kleptoparasite in the webs of two araneid spiders, Argiope argentata and Nephila clavipes, where it steals small insects from the orb web as well as pillages large prey-items that have already been caught and often predigested by the host spider. The prey-catching behaviour of the two host spiders and the stealing by the kleptoparasites are described. The success rate of raids on stored prey is given. Two raid strategies were observed in the kleptoparasites: either A. elevatus moved onto the hub during the first prey-catching sequence of the host (strategy PxP) or it moved onto the hub during the subsequent (second) prey-catching sequence (strategy PPx). Strategy PxP was employed more often than strategy PPx and the stealing success with strategy PxP was superior. The host spiders react to raid-strategy PxP by reducing the duration of prey-catching sequences. The advantage to the kleptoparasites of switching between strategies is discussed.
The normally solitary spider species, Achaearanea tepidariorum (C. L. Koch) (Aranae: Theridiidae), will cease cannibalism and forage in aggregations of webs when prey is very abundant. The circumstances of their shift from solitary to group foraging and the effect it has on capture efficiency and success were tested. Fabricated aggregations quickly dispersed at a site where captures were low, but these aggregations persisted for several months where the abundance of prey was high. When resources were abundant for the spiders, the number of prey captured per day by solitary individuals was not different from the number captured by individuals foraging in groups; however, the biomass of prey obtained per day was greater for those individuals in groups. The variance in daily capture was substantially less for grouped individuals. Prey introduction experiments using both house flies and fruit flies revealed that groups captured a greater proportion of the prey that entered their web because of local enhancement and ricochet effects. These factors are probably responsible for the different variances in prey capture observed between aggregated and solitary individuals because they tend to distribute insect prey across more individuals. The different variances in foraging success are consistent with the predictions of risk-sensitive foraging theory that group foraging should be the risk-averse (low variance) foraging mode and solitary foraging should be the risk-prone (high variance) foraging mode.
Kleptoparasitism refers to the interspecific stealing of already procured food, but this paper shows that intraspecific food-stealing is effectively the same behaviour. A comprehensive review of the literature shows that certain orders of birds contain a disproportionate number of kleptoparasitic species. Birds in these orders occupy a limited range of ecological niches and are most commonly either predatory or dietary opportunists. Kleptoparasitism is particularly associated with certain ecological conditions, such as the availability of hosts feeding on large, visible food items and periods of food shortage. Birds show a wide range of socially parasitic feeding interactions of which kleptoparasitism is one extreme. The parasitic pattern of food-stealing is likely to involve frequency-dependent selection and may be an example of an evolutionarily stable strategy.
Most Anelosimus eximius live in colonies, but a few females emigrate short distances and establish small, individual webs. Field studies were conducted on one colony and nearby smaller webs in order to describe communal activities and division of labour, and to note costs and benefits of remaining in the parental colony and emigrating. Adult and juvenile females repaired the web and captured prey. Adult females, rather than juveniles, cared for egg sacs and fed young. When colonial egg sacs were abundant, females moved from sac to sac. Several colonial females regurgitated food to spiderlings which had recently emerged from a particular sac. In smaller webs inhabited by two or three females, the mother cared for the sac but all females fed the young by regurgitation. Males rarely participated in communal activities. Advantages of colony living include protection from predators, the availability of large prey and, in the event of a female's death, the care of her egg sac and feeding of her young. Cannibalism of the egg sac is a potential cost of coloniality, affecting about 10–20% of colonial sacs. Cannibalism was not observed in the smaller webs. However, the costs of emigrating are very high: most of the solitary females disappeared, leading to interspecific predation on their eggs and young.
Based on three years of study in the Serengeti National Park, George B. Schallerâs The Serengeti Lion describes the vast impact of the lion and other predators on the vast herds of wildebeest, zebra, and gazelle for which the area is famous. The most comprehensive book available on the lion, this classic work includes the authorâs findings on all aspects of lion behavior, including its social system, population dynamics, hunting behavior, and predation patterns. âIf you have only enough time to read one book about field biology, this is the one I recommend.ââEdward O. Wilson, Science âThis book conveys not only the fascination of its particular study of lion behavior but the drama and wonder and beauty of the intimate interdependence of all living things.ââSaturday Review âThis is an important book, not just for its valuable information on lions, but for its broad, open, and intelligent approach to problems that cut across the fields of behavior, populations, ecology, wildlife management, evolution, anthropology, and comparative biology.ââRichard G. Van Gelder, Bioscience
An adaptation in one lineage (e.g. predators) may change the selection pressure on another lineage (e.g. prey), giving rise to a counter-adaptation. If this occurs reciprocally, an unstable runaway escalation or 'arms race' may result. We discuss various factors which might give one side an advantage in an arms race. For example, a lineage under strong selection may out-evolve a weakly selected one (' the life-dinner principle'). We then classify arms races in two independent ways. They may be symmetric or asymmetric, and they may be interspecific or intraspecific. Our example of an asymmetric interspecific arms race is that between brood parasites and their hosts. The arms race concept may help to reduce the mystery of why cuckoo hosts are so good at detecting cuckoo eggs, but so bad at detecting cuckoo nestlings. The evolutionary contest between queen and worker ants over relative parental investment is a good example of an intraspecific asymmetric arms race. Such cases raise special problems because the participants share the same gene pool. Interspecific symmetric arms races are unlikely to be important, because competitors tend to diverge rather than escalate competitive adaptations. Intraspecific symmetric arms races, exemplified by adaptations for male-male competition, may underlie Cope's Rule and even the extinction of lineages. Finally we consider ways in which arms races can end. One lineage may drive the other to extinction; one may reach an optimum, thereby preventing the other from doing so; a particularly interesting possibility, exemplified by flower-bee coevolution, is that both sides may reach a mutual local optimum; lastly, arms races may have no stable and but may cycle continuously. We do not wish necessarily to suggest that all, or even most, evolutionary change results from arms races, but we do suggest that the arms race concept may help to resolve three long-standing questions in evolutionary theory.
Sociobiology: the modern synthesis Animal social behavior
- Wilson
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Wilson EO (1975) Sociobiology: the modern synthesis. Harvard University Press, Cambridge Wittenberger JF (1981) Animal social behavior. Duxbury Press, Boston
Web building and prey capture in communal orb weavers. In: Shear WA (ed) Spiders: webs, behavior and evolution
- Uetz
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Uetz GW (1986) Web building and prey capture in communal orb weavers. In: Shear WA (ed) Spiders: webs, behavior and evolution. Stanford University Press, Stanford Vollrath F (1979) Behaviour of the kleptoparasitic spider Argyrodes elevatus (Araneae, Theridiidae). Anita Behav 27:515-521
The Serengeti lion: a study of predator-prey relations Predation by Argyrodes (Theridiidae) on solitary and eemmunal spiders
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Schaller GB (1972) The Serengeti lion: a study of predator-prey relations. University of Chicago Press, Chicago Smith Trail DS (1980) Predation by Argyrodes (Theridiidae) on solitary and eemmunal spiders. Psyche 87:349-355
Kleptobiotic interactions in invertebrates Producers and scroungers. Chrom Helm, Beckenham Vollrath F (1987) Kleptobiosis in spiders Eco-physiology of spiders Prey capture and feeding in the communal spider Anelosimus eximius
- Vollrath
Vollrath F (1984) Kleptobiotic interactions in invertebrates. In: Barnard CJ (ed) Producers and scroungers. Chrom Helm, Beckenham Vollrath F (1987) Kleptobiosis in spiders. In: Nentwig W (ed) Eco-physiology of spiders. Springer, Berlin Heidelberg New york Vollrath F, Rohde-Arndt D (1983) Prey capture and feeding in the communal spider Anelosimus eximius. Z Tierpsychol 61:313-324
Sociality in the Arachnida Social insects, vol II
- Re Buskirk
Living in groups: is there an optimal group size? Behavioral ecology: an evolutionary approach
- Hr Pulliam
- T Caraco
Web building and prey capture in communal orb weavers Spiders: webs, behavior and evolution
- Gw Uetz
The behavioral and ecological interactions of the kleptoparasitic spider, Argyrodes ululans, and its social spider host, Anelosimus eximius
- Kr Cangialosi
Kleptobiotis in spiders Ecophysiology of spiders
- F Vollrath
Sociobiology: the modern synthesis
- Eo Wilson