The Spider Exposure Pathway and the Potential Risk to Arachnivorous Birds

Abstract

There is growing concern over the health of North American birds, with evidence suggesting substantial population declines. Spiders are prominent dietary items for many bird species and mediate the transfer of contaminants to arachnivorous birds that consume them. Few studies have investigated the potential risk the spider exposure pathway poses to these birds because most studies have focused on piscivores. In the present study, we developed new chronic and acute As, Cd, Cu, Pb, Ni, Se, Zn, and MeHg spider-based avian wildlife values (SBAWVs) for multiple adult and nestling birds (primarily passerines) and then used the newly generated SBAWVs to characterize the risk to birds across 2 study areas: 1) 5 reaches in the southern Appalachian Mountains, an area with substantial mercury deposition but minimal anthropogenic impact, and 2) 4 reaches adjacent to the Emory River, an area impacted by the largest fly coal-ash spill in US history. We identified MeHg and Cu, Pb, Se, and Zn as contaminants of potential concern (COPC) at the Appalachian Mountain and Emory River study areas, respectively, based on dietary exposure of aquatic contaminants via riparian spiders. The identification of COPC at both study areas due to dietary spider exposure is notable not only because the spider exposure pathway has largely been uninvestigated at these sites but also because the aquatic systems in both areas have been studied extensively. Significant differences in MeHg concentrations were detected among spider taxa and suggest that the selection of spider taxa can impact risk characterization. These results indicate that the spider exposure pathway is important to consider when assessing potential risk, particularly for passerine birds.

Use of Riparian Spiders as Sentinels of Persistent and Bioavailable Chemical Contaminants in Aquatic Ecosystems: A Review

“…The retention or bioaccumulation of Hg, PCBs, and Se in the tissues of riparian spiders has been demonstrated repeatedly (Table 1). The algal toxin microcystin (Moy et al, 2016), organic contaminants including per‐ and polyfluoroalkyl substances (PFAS), along with several pharmaceuticals and endocrine‐disrupting compounds (Koch et al, 2020; Previšić et al, 2021; Richmond et al, 2018), and some metals including Cd, Cu, Cr, Zn, and Pb have been less well studied but have been found to be retained in the tissues of riparian spiders (Beaubien et al, 2020; Cetinić et al, 2021; Du Laing et al, 2002; Hendrickx et al, 2004; Kim & Kim, 2016; Kraus et al, 2021; Maelfait & Hendrickx, 1998; Otter et al, 2013; Ramirez et al, 2011; Schipper et al, 2008; Tojal et al, 2002; Torres & Johnson, 2001; Zhang et al, 2009). This suggests that riparian spiders may be suitable sentinels for these contaminants as well (but see Cetinić et al, 2021; Kim & Kim, 2016; Kraus et al, 2021; Torres & Johnson, 2001).…”

“…Twelve studies have statistically assessed taxonomic differences in contaminant concentrations (Abeysinghe et al, 2017; Bartrons et al, 2015; Beaubien et al, 2020; Hannappel et al, 2021; Hendrickx et al, 2004; Kraus et al, 2017; Ortega‐Rodriguez et al, 2019; Sullivan et al, 2016; Tavshunsky et al, 2017; Tojal et al, 2002; Walters et al, 2008, 2010; Walters et al, 2018). Among these, more than 80% (10 out of 12 studies) reported taxonomic differences in contaminant accumulation.…”

“…The most commonly collected taxa belong to the families Tetragnathidae and Araneidae. Two studies have reported greater contaminant concentrations in tetragnathids (Beaubien et al, 2020; Walters et al, 2018), three have reported equivalent concentrations (Abeysinghe et al, 2017; Hannappel et al, 2021; Kraus et al, 2017); and one reported that tetragnathid spiders had lower PCB concentrations than araneids consuming mostly emergent insects, but higher concentrations than a particular species of araneid ( Mecynogea lemniscata ) which consumes a greater proportion of terrestrial insects (Walters et al, 2010). These studies illustrate the importance of reporting the lowest taxonomic resolution of riparian spiders possible and taking taxonomic differences into account when selecting study species.…”

“…Walters et al (2010) developed a risk assessment approach for PCB‐contaminated riparian spiders that was later extended by Gann et al (2015) for Hg. Beaubien et al (2020) developed an additional risk assessment technique for a large number of birds and heavy metal contaminants. Future studies could be expanded to incorporate arachnivorous bird species living in other regions of the world and other contaminants.…”

“…Factors in column 1 are defined and reviewed in the text and in Supporting Information, Table S3. 1, Anderson et al, 1973; 2, Maelfait and Hendrickx, 1998; 3, Torres and Johnson, 2001; 4, Du Laing et al, 2002; 5, Tojal et al, 2002; 6, Hendrickx et al, 2004; 7, Cristol et al, 2008; 8, Schipper et al, 2008; 9, Walters et al, 2008; 10, Zhang et al, 2009; 11, Walters et al, 2010; 12, Zhang et al, 2010; 13, Raikow et al, 2011; 14, Ramirez et al, 2011; 15, Wyman et al, 2011; 16, Edmonds et al, 2012; 17, Tsui et al, 2012; 18, Otter et al, 2013; 19, Tweedy et al, 2013; 20, Wang et al, 2013; 21, Marr et al, 2014; 22, Speir et al, 2014; 23, Bartrons et al, 2015; 24, Gann et al, 2015; 25, Kwon et al, 2015; 26, Ortiz Jr. et al, 2015; 27, Pennuto and Smith, 2015; 28, Alberts and Sullivan, 2016; 29, Chaves‐Ulloa et al, 2016; 30, Kim and Kim, 2016; 31, Laws et al, 2016; 32, Moy et al, 2016; 33, Sullivan et al, 2016; 34, Abeysinghe et al, 2017; 35, Hepp et al, 2017; 36, Kraus et al, 2017; 37, Tavshunsky et al, 2017; 38, Archer et al, 2018; 39, Howie et al, 2018; 40, Richmond et al, 2018; 41, Walters et al, 2018; 42, Beaubien et al, 2019; 43, Ortega‐Rodriguez et al, 2019; 44, Qiu et al, 2019; 45, Rodenhouse et al, 2019; 46, Beaubien et al, 2020; 47, Bergmann and Graça, 2020; 48, Gerson et al, 2020; 49, Koch et al, 2020; 50, Naslund et al, 2020; 51, Cetinić et al 2021; 52, Hannappel et al, 2021; 53, Kraus et al, 2021; 54, Ku et al, 2021; 55, Previšić et al, 2021.…”