Spider assemblage (Arachnida: Araneae) associated with canopies of Vochysia divergens (Vochysiaceae) in the northern region of the Brazilian Pantanal

Abstract

ABSTRACT. This study describes the composition and temporal variation of the spider assemblage (Arachnida: Araneae) The spider assemblage is affected by changes in the habitat structure, especially by the seasonal hydrological regime and variations in the phenology of V. divergens. The assemblage is composed of different groups of spiders. The dominant taxa and behavioral guilds differ in the different seasonal periods. Spiders were more abundant during the dry and rising water seasons, most likely reflecting a greater supply of potential prey, associated with new foliage and flowering at the canopy.The displacement of soil dwelling spiders to the trunks and canopies before and during the seasonal floods can change the structure and composition of the canopy assemblages. Oonopidae, Gnaphosidae and Caponiidae, were more frequent during the rising and high water seasons, which indicates that these taxa use the canopies of V. divergens as a refuge during the seasonal flooding in the Pantanal.

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

“…The assemblage was characterized by the predominance of hunting over weaving spiders, similar to the results of Battirola et al (2004Battirola et al ( , 2016, Castilho et al (2005), Sena et al (2010), and Morais et al (2007). The great variety of guilds present in the assemblage demonstrates the share and the lower overlapping of niches by the spiders.…”

“…Regarding the composition of the spider assemblage, Anyphaenidae, Pisauridae, Araneidae, and Salticidae were the most representative taxa, as was already observed in the Pantanal (Santos et al, 2003;Battirola et al, 2004Battirola et al, , 2016, and in other ecosystems (Morais et al, 2007;Carvalho & Avelino, 2010;Sena et al, 2010). The assemblage was characterized by the predominance of hunting over weaving spiders, similar to the results of Battirola et al (2004Battirola et al ( , 2016, Castilho et al (2005), Sena et al (2010), and Morais et al (2007).…”

“…The greatest variations were found to be in relation to the terrestrial (receding water and dry season) and aquatic (rising water and high water) stages, which are distinct because of the periodicity of alterations in the hydrological regimen (Heckman, 1998). These variations characterize the marked seasonality present in the Pantanal biome of Mato Grosso, which greatly influences the structure of habitats and consequently the fauna that makes use of them (Junk et al, 1989(Junk et al, , 2006Battirola et al, 2009Battirola et al, , 2016Nunes-da-Cunha & Junk, 2014).…”

“…This structural variation consequently can affect the distribution of resources and habitats for the fauna, considering that these habitats offer a three-dimensional array of substrates, physical and chemical, wet and dry, exposed or not, that directly receive the sun's energy (Erwin, 2013). Variations in the distribution of abundance and richness of arthropods as a function of the type of forest and/or host, seasonal period, and taxonomic group evaluated were observed in studies of canopy assemblages in the Pantanal of Mato Grosso (Santos et al, 2003;Battirola et al, 2004Battirola et al, , 2005Battirola et al, , 2014Battirola et al, , 2016Marques et al, 2006Marques et al, , 2007Yamazaki et al, 2016). Spiders generally do not have a direct relationship with plant hosts; however, they can be influenced indirectly by the structural conditions of the host (Raizer & Amaral, 2001;Souza & Martins, 2004Souza & Módena, 2004), as well as by the presence as potential preys, often represented by herbivorous insects that feed on this host (Costello & Daane, 1995;Rinaldi & Forti, 1997;Arango et al, 2000).…”

Individual niche trajectories drive fitness variation

“…The overall positive relationship between niche trajectory length and individual‐level fitness could be due to the higher feeding rate of predators when environmental prey availability fluctuates. Indeed, our study system is dynamic and gradual changes in temperature, humidity and vegetation structure over the summer lead to shifts in the presence and abundance of important invertebrate prey for frogs (Battirola, Batistella, Rosado‐Neto, Brescovit, & Marques, ; Santos‐Silva, Pinheiro, Chagas‐Jr, Marques, & Battirola, ; Soares et al, ). Therefore, these temporal changes in prey availability may provide the scope for temporal niche variation, favouring individuals that can plastically adjust their diets to the best foraging options at a given time.…”