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Martinez-Rivera N, Serrano-Velez JL, Torres-Vazquez II, Langerhans RB, Rosa-Molinar E. Are superficial neuromasts proprioceptors underlying fast copulatory behavior? Front Neural Circuits 2022; 16:921568. [PMID: 36082109 PMCID: PMC9446510 DOI: 10.3389/fncir.2022.921568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
In male Poeciliid fishes, the modified anal fin (i.e., gonopodium) and its axial and appendicular support are repositioned within the axial skeleton, creating a novel sexually dimorphic ano-urogenital region. During copulation, the relative location of the gonopodium is crucial for successful insemination. Therefore, the repositioning of these structures and organ relied on the reorganization of the efferent circuitry that controls spinal motor neurons innervating appendicular muscles critical for the movement of the gonopodium, including the fast and synchronous torque-trust motion during insemination attempts. Copulation occurs when a male positions himself largely outside a female's field of view, circumducts his gonopodium, and performs a rapid, complex maneuver to properly contact the female urogenital sinus with the distal tip of the gonopodium and transfers sperm. Although understanding of the efferent circuitry has significantly increased in the last 24 years, nothing is known about the cutaneous receptors involved in gonopodium movement, or how the afferent signals are processed to determine the location of this organ during copulation. Using Western mosquitofish, Gambusia affinis, as our model, we attempt to fill this gap in knowledge. Preliminary data showed cutaneous nerves and sensory neurons innervating superficial neuromasts surrounding the base of adult male gonopodium; those cutaneous nerves projected ventrally from the spinal cord through the 14th dorsal root ganglion and its corresponding ventral root towards the base and fin rays of the gonopodium. We asked what role the cutaneous superficial neuromasts play in controlling the positioning and timing of the gonopodium's fast and synchronous movements for effective sperm transfer. First, we found a greater number of superficial neuromasts surrounding the base of the male's gonopodium compared to the base of the female's anal fin. Second, we systemically removed superficial neuromasts surrounding the gonopodium base and observed significant impairment of the positioning and timing of gonopodial movements. Our findings provide a first step to supporting the following hypothesis: during radical reorganization of the Poeciliid body plan, superficial neuromasts have been partially co-opted as proprioceptors that allow the gonopodium to control precise positioning and timing during copulatory attempts.
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Affiliation(s)
- Noraida Martinez-Rivera
- Biological Imaging Group, Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, United States
- Biology Department, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
- Puerto Rico Center for Environmental Neuroscience, Institute of Neurobiology, University of Puerto Rico-Medical Sciences, Old San Juan, Puerto Rico
| | | | - Irma I. Torres-Vazquez
- Biology Department, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
- Bi-campus Neuroscience Graduate Program, The University of Kansas, Lawrence, KS, United States
| | - R. Brian Langerhans
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States
| | - Eduardo Rosa-Molinar
- Biological Imaging Group, Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, United States
- Biology Department, University of Puerto Rico-Rio Piedras, San Juan, Puerto Rico
- Puerto Rico Center for Environmental Neuroscience, Institute of Neurobiology, University of Puerto Rico-Medical Sciences, Old San Juan, Puerto Rico
- Bi-campus Neuroscience Graduate Program, The University of Kansas, Lawrence, KS, United States
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Vinterstare J, Ekelund Ugge GMO, Hulthén K, Hegg A, Brönmark C, Nilsson PA, Zellmer UR, Lee M, Pärssinen V, Sha Y, Björnerås C, Zhang H, Gollnisch R, Herzog SD, Hansson LA, Škerlep M, Hu N, Johansson E, Langerhans RB. Predation risk and the evolution of a vertebrate stress response: Parallel evolution of stress reactivity and sexual dimorphism. J Evol Biol 2021; 34:1554-1567. [PMID: 34464014 DOI: 10.1111/jeb.13918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 08/12/2021] [Indexed: 11/29/2022]
Abstract
Predation risk is often invoked to explain variation in stress responses. Yet, the answers to several key questions remain elusive, including the following: (1) how predation risk influences the evolution of stress phenotypes, (2) the relative importance of environmental versus genetic factors in stress reactivity and (3) sexual dimorphism in stress physiology. To address these questions, we explored variation in stress reactivity (ventilation frequency) in a post-Pleistocene radiation of live-bearing fish, where Bahamas mosquitofish (Gambusia hubbsi) inhabit isolated blue holes that differ in predation risk. Individuals of populations coexisting with predators exhibited similar, relatively low stress reactivity as compared to low-predation populations. We suggest that this dampened stress reactivity has evolved to reduce energy expenditure in environments with frequent and intense stressors, such as piscivorous fish. Importantly, the magnitude of stress responses exhibited by fish from high-predation sites in the wild changed very little after two generations of laboratory rearing in the absence of predators. By comparison, low-predation populations exhibited greater among-population variation and larger changes subsequent to laboratory rearing. These low-predation populations appear to have evolved more dampened stress responses in blue holes with lower food availability. Moreover, females showed a lower ventilation frequency, and this sexual dimorphism was stronger in high-predation populations. This may reflect a greater premium placed on energy efficiency in live-bearing females, especially under high-predation risk where females show higher fecundities. Altogether, by demonstrating parallel adaptive divergence in stress reactivity, we highlight how energetic trade-offs may mould the evolution of the vertebrate stress response under varying predation risk and resource availability.
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Affiliation(s)
- Jerker Vinterstare
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Gustaf M O Ekelund Ugge
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden.,School of Bioscience, University of Skövde, Skövde, Sweden
| | - Kaj Hulthén
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Alexander Hegg
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Christer Brönmark
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Per Anders Nilsson
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Ursula Ronja Zellmer
- Animal Ecology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Marcus Lee
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Varpu Pärssinen
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Yongcui Sha
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Caroline Björnerås
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Huan Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Raphael Gollnisch
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Simon D Herzog
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Lars-Anders Hansson
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Martin Škerlep
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Nan Hu
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Emma Johansson
- Aquatic Ecology Unit, Ecology Building, Department of Biology, Lund University, Lund, Sweden
| | - Randall Brian Langerhans
- Department of Biological Sciences, W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA
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