Besides variation among animal species in ground colour and in the number, size, shape, and distribution of pattern elements, there is also considerable intraspecific variation in colour patterns that can manifest both between populations inhabiting different environments, and among individuals within populations. In previous investigations into the consequences of inter-individual variation in colour patterns in moths we have relied on a discrete classification with three categories: non-variable; variable; or highly variable colour patterns, as jointly assessed by Per-Eric Betzholtz and Markus Franzén (e.g., Forsman et al. 2015, 2016, Franzén et al. 2019). Here we provide the raw data from the anonymized assessments of colour pattern variation of 489 species of Erebidae and Noctuidae moths in Sweden performed by twelve lepidopterologists with extensive experience and expertise of the moth fauna in Sweden. In addition, the raw data (on a discrete scale) provided by the experts is used to generate a continuously distributed measure of the intra-specific colour pattern variation in moths. Despite variation among the independent scorers in their assessments of the average level of forewing colour pattern variation, there were statistically significant consistent differences in average colour pattern variation among the different species of moths (for details see Supporting Information I in Betzholtz et al. 2019).

References

Betzholtz, P.-E., A. Forsman, and M. Franzén. 2019. Inter-individual variation in colour patterns in noctuid moths characterizes long-distance dispersers and agricultural pests. Journal of Applied Entomology 143: 992-999.

Forsman, A., P. E. Betzholtz, and M. Franzén. 2015. Variable coloration is associated with dampened population fluctuations in noctuid moths. Proceedings of the Royal Society B 282: 20142922.

Forsman, A., P. E. Betzholtz, and M. Franzén. 2016. Faster poleward range shifts in moths with more variable colour patterns. Scientific Reports 6: 36265.

Franzén, M., P. E. Betzholtz, and A. Forsman. 2019. Variable color patterns influence continental range size and species-area relationships on islands. Ecosphere 10: e02577.

Data on expert assessments of colour pattern variation in moths

To obtain a quantitative measure of the inter-individual variation in colour pattern of moths a questionnaire with instructions was distributed together with an Excel file that contained a list of 489 moth species in the family Noctuidae and Erebidae (according to Aarvik et al. 2017) to 26 lepidopterologists with extensive experience and expertise of the moth fauna in Sweden (for details see Supporting Information I-II in Betzholtz et al. 2019). Respondents were asked to classify species for inter-individual colour pattern variability as 0 (non-variable), 1 (variable), or 2 (highly variable) based on their own personal experience of individuals observed or captured in Sweden until 2015. Species that were sexually dichromatic were classified as having variable coloration only if variation was apparent within one or both sexes, otherwise they were considered non-variable. Twelve of the expert lepidopterologists provided independent classifications of colour pattern variation for all or for a subset of the 489 moth species. To obtain a continuous measure of colour pattern variability for each species, a mean value of colour pattern variation was calculated for each species across the values assigned by the twelve independent experts. The mean values were then divided by 2 (the highest possible value) to generate a variable with a continuous distribution that ranges from 0 to 1. Finally, the resulting values (+0.1) were transformed to natural logarithms to generate an approximately normal distribution (see Supporting Information Fig S2 in Betzholtz et al. 2019).

References

Aarvik, L., B. Å. Bengtsson, H. Elven, P. Ivinskis, U. Jürivete, O. Karsholt, M. Mutanen, and N. Savenkov. 2017. Nordic-Baltic Checklist of Lepidoptera. Norwegian Journal of Entomology Supplement 3: 1-236.

Betzholtz, P.-E., A. Forsman, and M. Franzén. 2019. Inter-individual variation in colour patterns in noctuid moths characterizes long-distance dispersers and agricultural pests. Journal of Applied Entomology 143: 992-999.

The file includes information for 489 species of moths on family (Erebidae or Noctuidae), species identity, original colour pattern variation score (in three categories (non-variable=0; variable=1; or highly variable=2) as jointly assessed by Per-Eric Betzholtz and Markus Franzén, and as used in previous contributions), discrete classification of colour pattern variation as assessed by 12 anonymous expert lepidopterologists (scorer A-L), average colour pattern variation score across scorers A-L, average score divided by 2, and the natural log-transformed values (of average colour pattern variation score  + 0.1).