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Data for: Plasticity in mosquito size and thermal tolerance across a latitudinal climate gradient

Cite this dataset

Lyberger, Kelsey; Farner, Johannah; Couper, Lisa; Mordecai, Erin (2024). Data for: Plasticity in mosquito size and thermal tolerance across a latitudinal climate gradient [Dataset]. Dryad.


Variations in heat tolerance among populations can determine whether a species can cope with ongoing climate change. Such variation may be especially important for ectotherms whose body temperatures, and consequently, physiological processes, are regulated by external conditions. Additionally, differences in body size are often associated with latitudinal clines, thought to be driven by climate gradients. While studies have begun to explore variation in body size and heat tolerance within species, our understanding of these patterns across large spatial scales, particularly regarding the roles of plasticity and genetic differences, remains incomplete. Here, we examine body size, as measured by wing length, and thermal tolerance, as measured by the time to immobilization at high temperatures (“thermal knockdown”), in populations of the mosquito Aedes sierrensis collected from across a large latitudinal climate gradient spanning 1300 km (34-44 °N). We find that mosquitoes collected from lower latitudes and warmer climates were more tolerant of high temperatures than those collected from higher latitudes and colder climates. Moreover, body size increased with latitude and decreased with temperature, a pattern consistent with James’ rule, which appears to be a result of plasticity rather than genetic variation. Our results suggest that warmer environments produce smaller and more thermally tolerant populations.

README: Data for: Plasticity in mosquito size and thermal tolerance across a latitudinal climate gradient

The first dataset KD-lat.lon.csv includes information about the site locations including latitude, longitude, and mean annual temperature. The next dataset KD-time.wings.analysis.csv includes information from the main plasticity experiment in which we measured knockdown time, wing length, and thorax length. The final dataset lab_reared.csv is a subset of data from the experiment in Couper et al. 2024 on the size of individuals from 9 other locations reared in the lab at 13, 17, 24, or 28°C.

Description of the data and file structure

Use the code KD_analysis_submission_R2.R which pulls in the three datasets described in detail below to create the figures in the manuscript.

NA means that the measure was unavailable likely due to the thorax being damaged or that the measure was not relevant for that individual.


  • Population: the location identifier
  • Latitude and Longitude
  • Males: sample size of male mosquitoes
  • Females: sample size of female mosquitoes
  • Temp: the mean annual temperature degrees C
  • Precip: mean annual precipitation in mm


  • Sample.ID: an identifier for each mosquito
  • Treehole.ID: the location identifier
  • Sex: M=male and F=female
  • KD_diff: the knockdown time in minutes
  • block: the set of individuals run during the same knockdown trial
  • Right_winglength: wing length in mm
  • Thorax: thorax length in mm


  • X: a number for each mosquito
  • Population: the location identifier
  • SampleID: an identifier for each mosquito
  • Temp.Treatment: the temperature it was reared at either 13, 17, 24, or 28°C
  • Date.Adult.Eclosion: date the individual eclosed MM/DD/YYYY
  • Date.Adult.Death: date the individual died MM/DD/YYYY
  • Sex: M=male and F=female
  • Left.Wing.Length: wing length in mm
  • AdultLifespan: lifespan in days from eclosion to death
  • Latitude and Longitude
  • Temp: the mean annual temperature at the site of collection in degrees C
  • Wet.Temp: the mean temperature during the wettest quarter at the site of collection in degrees C
  • Thorax: thorax length in mm

Sharing/Access information

This data was created by the authors.


The R code was run using version 4.1.1 and uses the packages ggplot2, lme4, lmerTest, car, gridExtra, sf, effectsize, and lavaan. It creates all the plots for the manuscript and runs the mixed effect models and structural equation models.


This data on body size and thermal tolerance was collected by measuring the wing length and knockdown time of 13 populations of Aedes sierrensis across the Pacific Coast of North America. We also analyze a subset of the data from another experiment of 9 populations of laboratory-reared Aedes sierrensis from Couper et al. 2024


Directorate for Biological Sciences, Award: 2208947, Postdoctoral Research Fellowships in Biology Program

Division of Environmental Biology, Award: DEB-2011147

National Institutes of Health, Award: R35GM133439

National Institutes of Health, Award: R01AI102918

National Institutes of Health, Award: R01AI168097

Stanford University, Stanford Center for Innovation and Global Health

Stanford University, King Center on Global Development

Stanford University, Woods Institute for the Environment

Philippe Cohen Graduate Fellowship

Stanford Center for Computational, Evolutionary and Human Genomics

Bing-Mooney Fellowship