DOI: 10.5281/zenodo.8357530
title: Negative density-regulated contest performance promotes conflict resolution in a tree lizard

description: This project includes the raw data of the research article 'Negative density-regulated contest performance promotes conflict resolution in a tree lizard' by Hsu et al. Data are in the file <code>negative-density-regulated-contest-performance.ods</code> (a OpenDocument spreadsheet). Download and open it by using spreadsheet software (e.g. Microsoft Office Excel, Libreoffice Calc) Sheet <code>covariates by population</code> Column Description Site Lizard population log.female.over.male.ratio Natural logarithm of sex ratio (famel over male) n.injured Number of injured males n.not.injured Number of not injured males injury.ave Injury ratio selectDiff Standardized selection differential of male snout-vent length Comp.1 1st principle component of habitat composition Comp.2 2nd principle component of habitat composition Comp.3 3rd principle component of habitat composition Comp.4 4th principle component of habitat composition invSimpsonTrapAbundance Food items (inverse Simpson index) in item abundance from pitfall trap invSimpsonTrapWeight Food items (inverse Simpson index) in item dry mass from pitfall trap totalTrapWeight Total dry mass of food in pitfall trap (g) invSimpsonStomachAbundance Dietary breadth (inverse Simpson index) in abundance from stomach items invSimpsonStomachWeight Dietary breadth (inverse Simpson index) in dry mass from stomach items totalStomachWeight Total dry mass of items in stomach (g) Sheet <code>covariates by population and sex</code> Column Description Site Lizard population Sex Sex density Number of lizard in 1250 m^2 Sheet <code>stage fight</code> Column Description Site Lizard population resident (SVL) Snout-vent length of resident lizard intruder (SVL) Snout-vent length of intruder lizard max.aggresive Resident highest agressive behavior is.R.win Resident as winner rScore Rank level of resident highest agressive behavior Sheet <code>bite force</code> Column Description Site Lizard population Sex Sex Body weight Lizard body weight (g) Head length Lizard head length (mm) Head width Lizard head width (mm) Head height Lizard head height (mm) SVL Lizard snout-vent length (mm) Bite Force Lizard bite force (N) Abstract Territoriality is a behavioral adaptation resulting from intraspecific competition and reflects the strategy of how individuals share limited resources in the environment. As a consequence, territorial contests and levels of aggressiveness are strongly influenced by population density. The positive relationship between population density and the intensity of intraspecific competition may appear straightforward. However, empirical evidence regarding this association remains inconclusive. This ambiguity may be attributed to studies that have predominantly focused on specific fight-associated traits while overlooking the comprehensive assessment of multiple phenotypic characteristics. To examine the effects of population density and other ecological factors on the variation in fight behavior as well as fight-associated morphology and performance. We conducted population surveys and behavioral experiments using the Swinhoe’s tree lizard across eight populations. Our findings revealed that males from higher-density populations tended to engage in less intense fights and exhibited a weaker resident advantage in fights, which coincided with our findings on lower rates of injuries, weaker bite forces, and smaller body sizes (and vice versa). Male-specific plasticity in fight behavior, morphology, and performance along a density gradient suggests different evolutionary equilibria in territoriality influenced by local costs and benefits. Our study supports the significant role of negative density dependence as a fundamental regulator of eco-evolutionary dynamics. The observed phenotypic plasticity emphasizes the importance of ecological and social factors in shaping ontogenetic growth and life-history strategies. Our findings provide a basis for future investigations into pace-of-life syndromes and shed light on how phenotypic adaptation may shape population structure.