Quantitative variables related to color, territory, behavior, and morphology for male lesser prairie-chickens used in discrete choice models in mate choice study

Sexual selection theory maintains that traits under selection honestly advertise qualities of signaling individuals and that only individuals in the best condition can survive while displaying maximally elaborated secondary sexual ornaments. Recent trends in mate choice studies have favored the consideration of the effects of multiple traits on mating success, including suites of traits transmitted in different sensory modalities. Sexual selection is expected to be especially strong in lek-mating species. The lesser prairie-chicken (Tympanuchus pallidicinctus) is a grouse species which breeds on leks. Males of this species perform audio and locomotor displays and exhibit two pairs of brightly colored ornaments. We performed an observational study of mate choice in spring 2016-2018 and noted 40 copulations on seven leks. We quantified behavioral, territorial, and morphological characteristics of males along with ornament color properties. We found that variables from all categories considered predicted female choice. Age had the strongest effect, with adult males experiencing higher female choice relative to yearlings. Allocation of aggressive behavior and comb color properties were also strongly correlated with female choice. Our results show that modulating behavior depending on whether females are present contributes to male mating success and highlight the importance of the size and color properties of secondary ornaments. Further research is required to determine how the variables most strongly associated with mate choice relate to one another and which aspects of individual quality, if any, are signaled by color ornaments. Future studies could also incorporate variables related to females to determine if selection on females occurs.

Methods
The data was collected in the field and is based on readings and measurements taken from wild Lesser Prairie-Chickens. The variables beginning with "pc" resulted from a principal components analysis of several behavioral variables. The raw values of the other variables were standardized (mean = 0,  SD=1).

The columns beginning with "as" and "cmb" represent color readings from air sacs and combs respectively. The raw spectra obtained with spectrometry were processed using color space models in the R package pavo.

Dist and mcp are spatial variables which were determined through the use of GIS software.