Global Patterns of Guild Composition and Functional Diversity of Spiders

Abstract

The objectives of this work are: (1) to define spider guilds for all extant families worldwide; (2) test if guilds defined at family level are good surrogates of species guilds; (3) compare the taxonomic and guild composition of spider assemblages from different parts of the world; (4) compare the taxonomic and functional diversity of spider assemblages and; (5) relate functional diversity with habitat structure. Data on foraging strategy, prey range, vertical stratification and circadian activity was collected for 108 families. Spider guilds were defined by hierarchical clustering. We searched for inconsistencies between family guild placement and the known guild of each species. Richness and abundance per guild before and after correcting guild placement were compared, as were the proportions of each guild and family between all possible pairs of sites. Functional diversity per site was calculated based on hierarchical clustering. Eight guilds were discriminated: (1) sensing, (2) sheet, (3) space, and (4) orb web weavers; (5) specialists; (6) ambush, (7) ground, and (8) other hunters. Sixteen percent of the species richness corresponding to 11% of all captured individuals was incorrectly attributed to a guild by family surrogacy; however, the correlation of uncorrected vs. corrected guilds was invariably high. The correlation of guild richness or abundances was generally higher than the correlation of family richness or abundances. Functional diversity was not always higher in the tropics than in temperate regions. Families may potentially serve as ecological surrogates for species. Different families may present similar roles in the ecosystems, with replacement of some taxa by other within the same guild. Spiders in tropical regions seem to have higher redundancy of functional roles and/or finer resource partitioning than in temperate regions. Although species and family diversity were higher in the tropics, functional diversity seems to be also influenced by altitude and habitat structure.

Habitat associations of epigeal spiders in upland calcareous grassland landscapes: the importance for conservation

“…Following identification to species, spiders were separated into five guilds based on hunting strategies suggested by Cardoso et al (2011): sheet web weavers, ground hunters, space web weavers, ambush hunters and other hunters. However, whilst Cardoso et al's (2011) classification includes Pachygnatha degeeri as an orb web spinner, in this study since only adult specimens were identified, it is placed in the ground hunter guild in recognition of its active hunting strategy as an adult.…”

Spider community responds to litter complexity: insights from a small-scale experiment in an exotic pine stand

“…We classified all the spiders in families and, based on family affiliation, in two different major foraging strategies: webbuilding (the ones that must anchor their hunting webs to the substrate) and hunting predators (the ones that actively pursue or use a sit-and-wait strategy for prey capture, not using webs to trap prey). To classify the groups, we checked Dias et al (2010) and Cardoso et al (2011).…”

“…Spiders can display a range of diff erent foraging strategies (Cardoso et al, 2011). Web-building (the ones that anchor prey-capture webs to the substrate) and hunting spiders (the ones actively pursuing or using a sit-and-wait strategy for prey capture, not using webs to trap prey) interact diff erently with habitat structure, but studies have revealed that the densities of both groups are commonly enhanced when habitat complexity increases (Langellotto & Denno, 2004).…”

Temporal variation in the spider assemblage (Arachnida, Araneae) in canopies of Callisthene fasciculata (Vochysiaceae) in the Brazilian Pantanal biome

“…Many of these herbivores are distributed according to the plant phenology (flowering, fructification, and change of foliage), as well as changes in environmental conditions (Wolda, 1988). Therefore, areas with high complexity in vegetation can present a larger variety of preys or more diversified sites for spiders to build traps and shelters (Cardoso et al, 2011). Spiders are generalist and have varied strategies for hunting and capturing their preys, many of which are species-specific (Höfer & Brescovit, 2001;Morais et al, 2007).…”

“…Spiders are generalist and have varied strategies for hunting and capturing their preys, many of which are species-specific (Höfer & Brescovit, 2001;Morais et al, 2007). These different strategies increase their dominance and adaptability in different habitats, reducing the competition between species that compose the assemblage (e.g., Moran & Southwood, 1982, Pianka, 1994, which characterizes spiders as the main predators in these communities (Cardoso et al, 2011) and thereby influences the dynamics of different populations in these habitats (Finke & Denno, 2004).…”