DOI: 10.5061/dryad.vdncjsz4w
title: Spider body size and longevity after exposure to lead-polluted soil

description: Heavy metal pollution is pervasive in urban soils, and it can negatively
 impact the fitness of arthropods. Arthropod populations can evolve to
 become more tolerant or resistant to metals, but the mechanisms of these
 processes are understudied. Here, we tested the hypotheses of fixed
 adaptation and facultative adaptation in a lead (Pb)-exposure experiment
 using the progeny of field-collected Pardosa
 milvina spiders from urban (elevated soil Pb) and rural
 (background soil Pb) habitats. We predicted that spiders from both
 populations that were reared in the elevated Pb treatment would exhibit
 decreased body size in comparison to individuals reared in background Pb
 soil due to a facultative shift in metabolic investment from growth to Pb
 resistance, or, alternatively, that urban spiders would exhibit no change
 in body size across treatments, supporting fixed adaptation as a
 consequence of a legacy effect of urban Pb pollution. We found no evidence
 that exposure to elevated Pb soil had an effect on P. milvina’s
 adult body size or survival, regardless of population origin. Our results
 indicate that the amount of Pb accumulated by the spiders was not
 sufficient to induce a measurable change in body size, or that there was a
 fitness cost that was not measured in the experiment, such as changes in
 fecundity or body condition. Overall, these findings do not provide
 support for fixed or facultative adaptation to Pb pollution in P.
 milvina; as such, future studies should investigate other possible
 tradeoffs, including changes in egg size, body weight, and foraging
 effort.
description: Offspring from field-collected spiders (<em>Pardosa
 milvina</em>) were reared on soil substrates with three
 concentration ranges of Pb. The spiders came from two populations (rural
 and urban) for a total of six experimental treatments. The spiderlings
 were reared on a diet of springtails and crickets until they matured and
 eventually died. We recorded the survival time of adult spiders (n =
 41-61) and measured the carapace width of a subset of specimens in each
 group upon death (n= 7-15). Measurements were made with an ocular
 micrometer (eye piece units) and converted to milimeters.
description: # Spider body size and longevity after exposure to lead-polluted soil
 [https://doi.org/10.5061/dryad.vdncjsz4w](https://doi.org/10.5061/dryad.vdncjsz4w) ## Description of the data and file structure Offspring from field-collected spiders (*Pardosa milvina*) were reared on soil substrates with three concentration ranges of Pb. The spiders came from two populations (rural and urban) for a total of six experimental treatments. Spiderlings were reared on a diet of springtails and crickets until they matured and eventually died. We recorded the survival time of adult spiders (n = 41-61) and measured the carapace width of a subset of specimens in each group upon death (n= 7-15). Measurements were made with an ocular micrometer (eye piece units) and converted to millimeters. Pb_concentrations_of_treatment_soils.docx: Pb concentrations of treatment soils. Values were obtained by performing nitric acid microwave digestion (EPA Method 3051) followed by Inductively Coupled Plasma analysis on five subsamples from each treatment. ### Files and variables #### File: Spiderling\_data.csv **Description:**  ##### Variables * Popul: Location where spiderling's mother was collected (rural = Wooster, OH, USA; urban = Cleveland OH, USA) * Treatment: Concentration of soil lead (high, low*, or background; see supplemental table for Pb ranges in mg/kg). * *"Low" was revised to "elevated" in the published manuscript; this is reflected in the supplemental table. * Longevity: Days that the spider lived (day 0 being when a spiderling was placed in its treatment soil). Missing values indicated by "NA". * Sex: Male or Female. Missing values indicated by "NA". * Age: Adult, penultimate, or immature. Missing values indicated by "NA" or blank cells. * Body_Size: Carapace width in millimeters (converted from eyepiece units). Missing values indicated by "NA". ## Code/software No software is needed.