Full general simulation R script

Simulation model R script. Includes host-parasite encounter for different infective stage aggregation levels, condition-linked immunity (CLI)/removal of parasites, deaths of lowest condition hosts, and generalized linear models analyzing host condition-parasitism relations at the population and sample level. Data output from running the model is approximately 1.4 GB

Main model - R script from Host species exploitation and discrimination by animal parasites

Host exploitation and discrimination model R scrip

Sex Differences in Mercury Contamination of Birds: Testing Multiple Hypotheses with Meta-Analysis

The sex of a bird can, in principle, affect exposure and accumulation of mercury. One conventional explanation for sex differences in mercury burden suggests female birds should have lower concentrations than conspecific males, because breeding females can depurate methylmercury to their eggs. However, sex differences in body burden of mercury among birds are not consistent. We used meta-analysis to synthesize 123 male–female comparisons of mercury burden from 50 studies. For breeding birds, males had higher concentrations of mercury than did females, supporting egg depuration as a mechanism. However, the percentage of female body mass represented by a clutch did not significantly predict the magnitude of the sex difference in mercury contamination, as predicted. Furthermore, whether species were semialtrical or altrical versus semiprecocial or precocial also did not explain sex differences in mercury burden. Foraging guild of a species did explain near significant variation in sex differences in mercury burden where piscivores and invertivores showed significant sex differences, but sex differences were not detected for carnivores, herbivores, insectivores, and omnivores. The magnitude and direction of sexual size dimorphism did not explain variation in sex differences in mercury burden among breeding birds. We reveal targeted research directions on mechanisms for sex differences in mercury and confirm that sex is important to consider for environmental risk assessments based on breeding birds

Population model for Common eiders breeding at the East Bay colony, Southampton Island, Canada.

<p><b>A.</b> Life cycle of common eiders (Southampton Island, Nunavut, Canada) based on three age classes. The population matrix <i>A</i> contains the vital rates and projects the population from time <i>t</i> to <i>t</i>+1. The fertility parameter was calculated as the product between the breeding probability (<i>BP</i>), the average breeding success (<i>BS</i>) and the average number of hatchlings per breeding female (<i>f</i>). <i>S_A</i> represents adult survival (survival from 2 years of age onwards), <i>S_Y</i> survival of yearlings (from 1 to 2 years of age) and <i>S_H</i> survival of hatchlings (from hatching to 1 year of age). We considered four different periods based on cholera severity; demographic parameters for each period are shown in <b>B.</b></p

Differential Water Mite Parasitism, Phenoloxidase Activity, and Resistance to Mites Are Unrelated across Pairs of Related Damselfly Species

<div><p>Related host species often demonstrate differences in prevalence and/or intensity of infection by particular parasite species, as well as different levels of resistance to those parasites. The mechanisms underlying this interspecific variation in parasitism and resistance expression are not well understood. Surprisingly, few researchers have assessed relations between actual levels of parasitism and resistance to parasites seen in nature across multiple host species. The main goal of this study was to determine whether interspecific variation in resistance against ectoparasitic larval water mites either was <i>predictive of</i> interspecific variation in parasitism for ten closely related species of damselflies (grouped into five “species pairs”), or was <i>predicted by</i> interspecific variation in a commonly used measure of innate immunity (total Phenoloxidase or potential PO activity). Two of five species pairs had interspecific differences in proportions of individuals resisting larval <i>Arrenurus</i> water mites, only one of five species pairs had species differences in prevalence of larval <i>Arrenurus</i> water mites, and another two of five species pairs showed species differences in mean PO activity. Within the two species pairs where species differed in proportion of individuals resisting mites the species with the higher proportion did not have correspondingly higher PO activity levels. Furthermore, the proportion of individuals resisting mites mirrored prevalence of parasitism in only one species pair. There was no interspecific variation in median intensity of mite infestation within any species pair. We conclude that a species’ relative ability to resist particular parasites does not explain interspecific variation in parasitism within species pairs and that neither resistance nor parasitism is reflected by interspecific variation in total PO or potential PO activity.</p></div

Female common eider carcasses following an avian cholera outbreak, East Bay colony, Southampton Island, Canada (photo: S. Descamps).

<p>Female common eider carcasses following an avian cholera outbreak, East Bay colony, Southampton Island, Canada (photo: S. Descamps).</p

Details of <i>Arrenurus</i> spp. parasitism, resistance and innate immunity measures in 10 species of damselflies sampled at five sites.

<p>N₁ = total sample size used for estimating prevalence and intensity of infection and proportion of resisting individuals by water mites</p><p>N_i = number of the total number of hosts that were infected</p><p>N_r = number of total number of infected hosts that resisted one or more mites, %dead = proportion of attached mites being dead and</p><p>N₂ = Total sample size for innate immunity part of the study.</p><p>Innate immunity is estimated as phenoloxidase (PO) activity, presented by the slope of the kinetic reaction (Δod485/min) and by PO corrected for protein content by using absolute values of the residuals of PO activity by total protein content regression within each species pair. Mean ± 1 SE is given.</p><p>Details of <i>Arrenurus</i> spp. parasitism, resistance and innate immunity measures in 10 species of damselflies sampled at five sites.</p

Differences between (A) Prevalence of <i>Arrenurus</i> water mites parasitism, (B) intensity of <i>Arrenurus</i> water mite parasitism, (C) proportion of <i>Arrenurus</i> resisting individuals, and (D) the measurement of PO activity that is activated as an immune response in ten coenagrionid damselfly species grouped by species pair.

<p>Prevalence of resisted mites (error bars ±95% Clopper-Pearson confidence intervals) is defined as the percent of the proportion of infected damselflies which resisted at least one water mite parasite. PO activity (error bars ±SE) is based on mean values from the PO assay controlled for by thoracic protein content. Grey bars = significant differences within a species pair.</p

GLMM results of species determining the differences in PO activity within each damselfly species pair.

<p>GLMM results include the full factorial effect of species, sex and thoracic protein content. Significant differences for the species differences are in bold. Sex was not included in the <i>Enallagma E</i> and <i>Enallagma C</i> species pairs because no females were collected for those species.</p><p>GLMM results of species determining the differences in PO activity within each damselfly species pair.</p

Comparison between live and resisted <i>Arrenurus</i> water mites, left image represents engorged live water mites on a <i>Nehalennia irene</i> individual, the right picture represents resisted dead water mites on a <i>Nehalennia gracilis</i> individual.

<p>Comparison between live and resisted <i>Arrenurus</i> water mites, left image represents engorged live water mites on a <i>Nehalennia irene</i> individual, the right picture represents resisted dead water mites on a <i>Nehalennia gracilis</i> individual.</p