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Table 1 Predicted association, and justification of candidate variables used in modeling baseline fecal glucocorticoid (GC) metabolite concentrations

From: Effect of food limitation and reproductive activity on fecal glucocorticoid metabolite levels in banded mongooses

Putative fixed effect and justification, mechanism, or examplePredicted association with GCs
A. Food limitation
   1. General 
      (a) GCs increase in response to natural food limitation 
         (i) GCs increase in the dry season and are negatively correlated with rainfall in African elephant (Loxodonta africana) [12] 
         (ii) GCs were higher in a food-limited group versus a food-abundant group in black-legged kittiwakes (Rissa tridactyla) [25] 
      (b) GCs increases in response to experimental food limitation 
         (i) GCs increase under food limitation in black-legged kittiwakes (Rissa tridactyla) [27] 
         (ii) Food limitation during development increases GCs in western scrub-jays (Aphelocoma californica) [28] 
         (iii) Food limitation and unpredictability increase GCs in mountain chickadees (Poecile gambeli) [29] 
         (iv) Food limitation increases GCs in barn swallows (Hirundo rustica) [30] 
   2. Access to anthropogenic food resourcesNegative
     (a) GCs decrease during anthropogenic food provisioning in Sykes’ monkeys (Cercopithecus mitis albogularis) [18] 
      (b) Refuse-feeding banded mongooses exhibit better physical condition than non-refuse-feeders [54] 
      (c) Banded mongoose area use is concentrated around refuse sites [39, 55] 
         (i) GCs increase with increased foraging travel time in Mexican howlers (Alouatta palliata mexicana) [23] 
         (ii) GCs increase under high food search demand effort in squirrel monkeys (Saimiri sciureus) [22] 
      (d) Banded mongoose escorts lose body mass while provisioning pups and exhibit increased fGCMs, but fGCMs are reduced in these animals if fed supplementally [43] 
   3. Fecal organic matterNegative
      (a) Indicator of organic matter intake in cattle (Bos taurus) and goats (Capra aegagrus) [56] 
      (b) Complementary measures, fecal ash and ingested soil, also indicate food limitation 
         (i) Domestic sheep (Ovis aries) increase soil ingestion as forage [57] and food supplementation [58, 59] decrease and stocking rates increase [60] 
         (ii) Aardwolves (Proteles cristata) have more fecal sand when termites are scarce [61] 
         (iii) Tamanduas (Tamandua tetradactyla) ingest more substrate during behavioral or dietary deficits [62] 
         (iv) Three-banded armadillos (Tolypeutes tricinctus) ingested more soil in dry seasons [63] 
         (v) Giant anteater (Myrmecophaga tridactyla) fecal nutrition markers were inversely related to fecal ash [64] 
   4. Recent rainfallNegative
      (a) Millipedes and (at times) termite alates dominate banded mongoose diet [65] 
      (b) Rainfall affects banded mongoose prey availability: soil macroinvertebrates [66]; millipedes [67]; termite alates [68] 
         (i) Residual effect of rain on millipede availability may last up to 8 days [67] 
   5. Soil macrofauna densityNegative
      (a) Soil macrofauna densities at our study site vary by habitat type [66] 
B. Reproduction
   1. Breeding statusPositive
         (a) GCs increase in female meerkats (Suricata suricatta) as pregnancy progresses [8] 
         (b) GCs increase in mate-guarding male long-tailed macaques (Macaca fascicularis) [69] 
         (c) Mating, parturition, associated agonistic encounters, and pup depredations increase GCs in captive banded mongooses [38] 
         (d) Alloparental care (pup provisioning) in banded mongoose is associated with increased fGCMs (although this may be driven by energetic losses) [43] 
         (e) Subordinate female banded mongoose have higher fGCM concentrations in late pregnancy than higher ranked females (although this may be driven by exclusion from food resources and resulting energetic losses) [50] 
C. Predation risk
   1. Group sizeNegative
      (a) GCs increase under higher predation risk in European rabbits (Oryctolagus cuniculus) [10] 
         (i) Larger groups should lower per capita predation risk—dilution effect [70,71,72,73] 
         (ii) Larger groups should lower per capita vigilance—detection effect [74, 75] 
         (iii) Larger group sizes do exhibit lower per capita vigilance in banded mongooses [76] 
         (iv) GCs are positively associated with vigilance in meerkats [11] 
   2. Canopy coverNegative
      (a) Aerial predators are putatively important, if not predominant natural predators of banded mongooses e.g. martial eagles (Polemaetus bellicosus) [77] 
         (i) Hunting success for large raptors is diminished in areas of higher canopy cover e.g. Bonelli’s eagle (Aquila fasciata) [78, 79] 
  1. Candidate models modeled fecal glucocorticoid metabolite concentrations in banded mongooses (Mungos mungo), northeastern Botswana (2008–2011)