Social modulation of spatial dynamics in treefrog choruses

**Social modulation of spatial dynamics in treefrog choruses** Leverett, M.C., McLister, J.D., Desaivre, S.S., Conway, S., and Boyd, S.K. Social modulation of spatial dynamics in treefrog choruses. Behav Ecol Sociobiol 76, 54 (2022). https://doi.org/10.1007/s00265-022-03163-z Mary Chang Leverett a, James D. McLister b, Stève S. Desaivre a, Shane Conway a, and Sunny K. Boyd a, c a Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA b Department of Biological Sciences, Indiana University, South Bend, IN, USA c Corresponding author: S.K. Boyd; boyd.1@nd.edu ; phone: 574-631-5021 Keywords: Hyla versicolor; mate choice; anuran; acoustic signal; lek; spatial point pattern analysis Acknowledgements: The authors gratefully acknowledge the support of the National Science Foundation, https://www.nsf.gov/ (IOS #1257777 to SKB). We are also grateful to the University of Notre Dame Environmental Research Center, https://underc.nd.edu/, for providing facilities and financial support for this project. The Arthur J. Schmitt Foundation, http://www.schmittfoundation.org generously supported MCL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. **Abstract:** In anuran amphibians, as well as many other animals, it is common for males to form breeding aggregations where they advertise to females of the same species. For female gray treefrogs (*Hyla versicolor*), the characteristics of male calls are integral to their preferences while the distance to the males represents a key feature of the required investment. Therefore, the spatial arrangement of males and the quality of their advertisement calls can influence sexual selection processes. We recorded the calls of male gray treefrogs, as well as the spatial position of individuals in the chorus, for aggregations in northern Michigan over three breeding seasons. Males were not randomly distributed across the chorus, but showed both clustered and dispersed patterns, depending on the scale of analysis. On active chorus nights, we identified clusters of males and individual males closest to the centers of those clusters (“medoids”) using a novel analysis approach. Medoids displayed some call characteristics that are preferred by females significantly more often than the other members of their clusters and thus may represent “hotshot” males. Non-medoid males in the clusters displayed less preferred call features. Irrespective of overall cluster membership, the size of the chorus (number of males calling per night) and nearest neighbor distances were also correlated with specific call features. We suggest that the smaller clusters within choruses that we identified may represent the spatial scale over which female gray treefrogs sample and choose male mates. **Characteristics of the dataset:** This dataset (Leverettetal_SpatialMappingData_6-28-21.csv) is a file (37 KB) containing the averaged and temperature-corrected characteristics of recorded male Eastern gray treefrog (*Hyla versicolor*) advertisement calls and associated identifying information. It contains 17 columns and 394 rows (1 header row plus 393 rows of data). Data were collected from active breeding choruses in the upper peninsula of Michigan (USA), over three consecutive breeding seasons. For each night of chorus activity, the spatial positions of each male within the chorus (as x and y coordinates) and their advertisement calls were recorded. Calls were analyzed using RavenPro software v1.4 (Cornell Bioacoustics Research Program, Ithaca, New York, USA) to extract their temporal characteristics. Details of the temperature correction are contained in the supplementary materials of the article. **Descriptions of Column Headings:** Date = The day and month the frog was recorded (d-Mmm format) Year = The year the frog was recorded FrogToeClip = Frog ID number based on toe clipping SVL = The snout-vent-length of the frog recorded in mm AirT = The air temperature at the time of recording in °C WaterT = The water temperature at the time of recording in °C BodyT = The body temperature of the individual frog at time of recording in °C X = The x coordinate position of the frog within the study site Y = The y coordinate position of the frog within the study site CallDuration = Call duration in seconds measured as the time between the onset of the first note and offset of the last note, average of 10 calls per male IntercallInterval = Average intercall interval in seconds measured from the offset of the last note of a call to the onset of the first note of the next call, average of 10 calls per male CallPeriod = Call period in seconds calculated as the sum of each call duration and its subsequent intercall interval, average of 10 calls per male CDC = Average call duty cycle computed by taking each call duration divided by the sum of each call duration and its subsequent intercall interval, average of 10 calls per male InstantCallRate = Average call rate in calls per minute computed as the instantaneous call rate for each call by dividing 60 sec by the sum of each call duration and its subsequent intercall interval (= 60 s/call duration + intercall interval) NotesPerCall = Average number of notes in each call, for 10 calls per male NoteRate = Average note rate in notes per second, calculated by dividing the number of notes in a call by the call duration, in seconds, over 10 calls per male NotePeriod = Average time in seconds between the offset of a peak note to the offset of the following peak note, calculated first for the 5 peak notes in one call; averaged across 10 calls per male.