Whistle repertoire and structure reflect ecotype distinction of pantropical spotted dolphins in the Eastern Tropical Pacific

Manali Rege-Colt; Julie N. Oswald; Joelle De Weerdt; Jose David Palacios-Alfaro; Maia Austin; Emma Gagne; Jacqueline Maythé Morán Villatoro; Catherine Teresa Sahley; Gilma Alvarado-Guerra; Laura J. May-Collado

doi:10.1038/s41598-023-40691-8

Whistle repertoire and structure reflect ecotype distinction of pantropical spotted dolphins in the Eastern Tropical Pacific

Manali Rege-Colt, Julie N. Oswald, Joelle De Weerdt, Jose David Palacios-Alfaro, Maia Austin, Emma Gagne, Jacqueline Maythé Morán Villatoro, Catherine Teresa Sahley, Gilma Alvarado-Guerra, Laura J. May-Collado^*

^*Corresponding author for this work

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Abstract

The pantropical spotted dolphin in the Eastern Tropical Pacific (ETP) is found in two genetically and phenotypically diverged ecotypes, coastal and offshore. These habitats have distinct acoustic characteristics, which can lead to the evolution of distinct acoustic communication. Whistles are sounds widely used by dolphins to mediate species and individual recognition and social interactions. Here, we study the whistle acoustic structure and repertoire diversity of offshore and coastal pantropical spotted dolphins. Our results show that there is significantly more within- and across-group variation in whistle fundamental frequency between ecotypes than between offshore groups and between coastal groups. A Random Forest classification analysis performed with an accuracy of 83.99% and identified duration, peak and minimum frequency as the most informative variables for distinguishing between ecotypes. Overall, coastal spotted dolphins produced significantly shorter whistles that were significantly lower in frequency (peak, minimum and maximum, and start and end) than offshore dolphins. Ecotypes produced whistle repertoires that were similar in diversity, but different in contour composition, with the coastal ecotype producing more upsweep whistles than offshore dolphins. The results of this study suggest that acoustic adaptations to coastal and offshore environments could be important contributors to intraspecific variation of dolphin whistle repertoires.

Original language	English
Journal	Scientific Reports
Volume	13
DOIs	https://doi.org/10.1038/s41598-023-40691-8
Publication status	Published - 18 Aug 2023

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Rege-Colt, M., Oswald, J. N., De Weerdt, J., Palacios-Alfaro, J. D., Austin, M., Gagne, E., Morán Villatoro, J. M., Sahley, C. T., Alvarado-Guerra, G., & May-Collado, L. J. (2023). Whistle repertoire and structure reflect ecotype distinction of pantropical spotted dolphins in the Eastern Tropical Pacific. Scientific Reports, 13. https://doi.org/10.1038/s41598-023-40691-8

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title = "Whistle repertoire and structure reflect ecotype distinction of pantropical spotted dolphins in the Eastern Tropical Pacific",

abstract = "The pantropical spotted dolphin in the Eastern Tropical Pacific (ETP) is found in two genetically and phenotypically diverged ecotypes, coastal and offshore. These habitats have distinct acoustic characteristics, which can lead to the evolution of distinct acoustic communication. Whistles are sounds widely used by dolphins to mediate species and individual recognition and social interactions. Here, we study the whistle acoustic structure and repertoire diversity of offshore and coastal pantropical spotted dolphins. Our results show that there is significantly more within- and across-group variation in whistle fundamental frequency between ecotypes than between offshore groups and between coastal groups. A Random Forest classification analysis performed with an accuracy of 83.99% and identified duration, peak and minimum frequency as the most informative variables for distinguishing between ecotypes. Overall, coastal spotted dolphins produced significantly shorter whistles that were significantly lower in frequency (peak, minimum and maximum, and start and end) than offshore dolphins. Ecotypes produced whistle repertoires that were similar in diversity, but different in contour composition, with the coastal ecotype producing more upsweep whistles than offshore dolphins. The results of this study suggest that acoustic adaptations to coastal and offshore environments could be important contributors to intraspecific variation of dolphin whistle repertoires.",

author = "Manali Rege-Colt and Oswald, {Julie N.} and {De Weerdt}, Joelle and Palacios-Alfaro, {Jose David} and Maia Austin and Emma Gagne and {Mor{\'a}n Villatoro}, {Jacqueline Mayth{\'e}} and Sahley, {Catherine Teresa} and Gilma Alvarado-Guerra and May-Collado, {Laura J.}",

note = "Boat surveys and acoustic data collection for Nicaragua were funded by The Rufford Foundation to JDW. Research permits in Nicaragua: DGPNB – IC – 011 – 2016, DGPNB – IC – 011 – 2017, DGPNB – IC – 011 – 2018, DGPNB – IC – 011 – 2019. Energ{\'i}a del Pac{\'i}fico, a subsidiary of Invenergy LLC headquartered in Chicago, funded El Salvador{\textquoteright}s boat surveys and acoustic data in collection as part of their Marine Biodiversity Monitoring and Evaluation Program. Offshore boat surveys in the Eastern Tropical Pacific were funded by NOAA Southwest Fisheries Science Center and the U.S Navy. Other resources needed for this project were funded by the May-Collado Lab.",

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doi = "10.1038/s41598-023-40691-8",

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T1 - Whistle repertoire and structure reflect ecotype distinction of pantropical spotted dolphins in the Eastern Tropical Pacific

AU - Rege-Colt, Manali

AU - Oswald, Julie N.

AU - De Weerdt, Joelle

AU - Palacios-Alfaro, Jose David

AU - Austin, Maia

AU - Gagne, Emma

AU - Morán Villatoro, Jacqueline Maythé

AU - Sahley, Catherine Teresa

AU - Alvarado-Guerra, Gilma

AU - May-Collado, Laura J.

N1 - Boat surveys and acoustic data collection for Nicaragua were funded by The Rufford Foundation to JDW. Research permits in Nicaragua: DGPNB – IC – 011 – 2016, DGPNB – IC – 011 – 2017, DGPNB – IC – 011 – 2018, DGPNB – IC – 011 – 2019. Energía del Pacífico, a subsidiary of Invenergy LLC headquartered in Chicago, funded El Salvador’s boat surveys and acoustic data in collection as part of their Marine Biodiversity Monitoring and Evaluation Program. Offshore boat surveys in the Eastern Tropical Pacific were funded by NOAA Southwest Fisheries Science Center and the U.S Navy. Other resources needed for this project were funded by the May-Collado Lab.

PY - 2023/8/18

Y1 - 2023/8/18

N2 - The pantropical spotted dolphin in the Eastern Tropical Pacific (ETP) is found in two genetically and phenotypically diverged ecotypes, coastal and offshore. These habitats have distinct acoustic characteristics, which can lead to the evolution of distinct acoustic communication. Whistles are sounds widely used by dolphins to mediate species and individual recognition and social interactions. Here, we study the whistle acoustic structure and repertoire diversity of offshore and coastal pantropical spotted dolphins. Our results show that there is significantly more within- and across-group variation in whistle fundamental frequency between ecotypes than between offshore groups and between coastal groups. A Random Forest classification analysis performed with an accuracy of 83.99% and identified duration, peak and minimum frequency as the most informative variables for distinguishing between ecotypes. Overall, coastal spotted dolphins produced significantly shorter whistles that were significantly lower in frequency (peak, minimum and maximum, and start and end) than offshore dolphins. Ecotypes produced whistle repertoires that were similar in diversity, but different in contour composition, with the coastal ecotype producing more upsweep whistles than offshore dolphins. The results of this study suggest that acoustic adaptations to coastal and offshore environments could be important contributors to intraspecific variation of dolphin whistle repertoires.

AB - The pantropical spotted dolphin in the Eastern Tropical Pacific (ETP) is found in two genetically and phenotypically diverged ecotypes, coastal and offshore. These habitats have distinct acoustic characteristics, which can lead to the evolution of distinct acoustic communication. Whistles are sounds widely used by dolphins to mediate species and individual recognition and social interactions. Here, we study the whistle acoustic structure and repertoire diversity of offshore and coastal pantropical spotted dolphins. Our results show that there is significantly more within- and across-group variation in whistle fundamental frequency between ecotypes than between offshore groups and between coastal groups. A Random Forest classification analysis performed with an accuracy of 83.99% and identified duration, peak and minimum frequency as the most informative variables for distinguishing between ecotypes. Overall, coastal spotted dolphins produced significantly shorter whistles that were significantly lower in frequency (peak, minimum and maximum, and start and end) than offshore dolphins. Ecotypes produced whistle repertoires that were similar in diversity, but different in contour composition, with the coastal ecotype producing more upsweep whistles than offshore dolphins. The results of this study suggest that acoustic adaptations to coastal and offshore environments could be important contributors to intraspecific variation of dolphin whistle repertoires.

U2 - 10.1038/s41598-023-40691-8

DO - 10.1038/s41598-023-40691-8

M3 - Article

SN - 2045-2322

VL - 13

JO - Scientific Reports

JF - Scientific Reports

ER -

Whistle repertoire and structure reflect ecotype distinction of pantropical spotted dolphins in the Eastern Tropical Pacific

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