This ReadMe contains descriptions of all data files pertaining to the paper "Parasitism in early life: environmental conditions shape within-brood variation in responses to infection"
by Granroth-Wilding, Burthe, Lewis, Reed, Herborn, Newell, Takahashi, Daunt & Cunningham
published in Ecology & Evolution, 2014

All files are in tab-separated csv format.
The "Description of files" sections outlines contents of the file and "Details of files" explains column headings in the files, gives units etc. For full details of protocol, see main text of the paper.



**Summary of study**

Using experimental reduction of nematode burden, we show that individual hosts' responses to parasitism depend simultaneously but non-additively on prevailing environmental conditions, indicated by population productivity, and a chick's hatching order. These between-individual differences appear driven by changes to how parents allocate food among the brood.




**Description of files**

ChickGrowthRates.csv
Growth rates of all individual chicks in the experiment with all explanatory variables tested, including treatment, productivity, rank, sex, nest etc.

BroodGrowthRates.csv
Growth rates of the brood as a whole (i.e. sum of all siblings) with all explanatory variables tested.

FECs.csv
Faecal egg counts from chicks in three of our experimental years with all explanatory variables tested.




**Details of files**

ChickGrowthRates.csv
Year - year of study
Nest - nest site (each nest site in the colony is individually and uniquely numbered as part of the long-term study)
NestYear - nest & year concatenated to give a meaningful random factor to group families (accounting for repeated use of nest sites in different years)
ChickID - unique identifier for each chick
Productivity - colony-wide average breeding success in each year as number of chicks fledged per incubated nest, derived from regular checks at undisturbed monitoring plots. Our proxy for prevailing environmental conditions.
ChickGrowthRate - growth rate (g/day) for the linear growth phase, calculate by fitting a linear regression through 2-7 weight measurements throughout the linear growth phase
Rank - hatching order, oldest sibling A, youngest C
Treatment - experimental anti-parasite treatment: control broods are unmanipulated or sham-treated, dosed broods were given ivermectin
Sex - male or female
Dosing mass - mass (g) at dosing, to control for size differences between siblings
SurvivalToFledge - binary, 1 = fledged, 0 = died

BroodGrowthRates.csv
As above except:
BroodGrowthRate - growth rate (g/day) of the brood as a whole, an indicator of total parental provisioning, calculated as the sum of all individual siblings' growth rate
BroodSize - number of chicks in the brood at the end of the linear growth phase, to account for mortality after treatment
SexRatio - number of males / brood size

FECs.csv
As above except:
Storage - samples were either frozen at -20, or kept in the preservative DESS at room temperature
PrePostDose - whether the faecal sample was collected before or after treatment
EggCount - number of nematode eggs in the examined sample