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Lisondro-Arosemena AK, Salazar-Nicholls MJ, Warkentin KM. Elevated ammonia cues hatching in red-eyed treefrogs: A mechanism for escape from drying eggs. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2024; 342:406-411. [PMID: 38708813 DOI: 10.1002/jez.b.23253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 02/01/2024] [Accepted: 04/02/2024] [Indexed: 05/07/2024]
Abstract
Egg dehydration can kill terrestrial frog embryos, and this threat is increasing with climate change and deforestation. In several lineages that independently evolved terrestrial eggs, and retained aquatic tadpoles, embryos accelerate hatching to escape from drying eggs, entering the water earlier and less developed. However, the cues that stimulate drying-induced early hatching are unknown. Ammonia is a toxic, water-soluble metabolic waste that accumulates within eggs as embryos develop and concentrates as eggs dehydrate. Thus, increasing ammonia concentration may be a direct threat to embryos in drying eggs. We hypothesized that it could serve as a cue, stimulating embryos to hatch and escape. The embryos of red-eyed treefrogs, Agalychnis callidryas, hatch early to escape from many threats, including dehydration, and are known to use mechanosensory, hypoxia, and light cues. To test if they also use high ammonia as a cue to hatch, we exposed stage-matched pairs of hatching-competent, well-hydrated sibling embryos to ammonia and control solutions in shallow water baths and recorded their behavior. Control embryos remained unhatched while ammonia-exposed embryos showed a rapid, strong hatching response; 95% hatched, on average in under 15 min. This demonstrates that elevated ammonia can serve as a hatching cue for A. callidryas embryos. This finding is a key step in understanding the mechanisms that enable terrestrial frog embryos to escape from egg drying, opening new possibilities for integrative and comparative studies on this growing threat.
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Affiliation(s)
| | | | - Karen M Warkentin
- Gamboa Laboratory, Smithsonian Tropical Research Institute, Panamá, Panamá
- Department of Biology, Boston University, Boston, Massachusetts, USA
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2
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Güell BA, McDaniel JG, Warkentin KM. Egg-Clutch Biomechanics Affect Escape-Hatching Behavior and Performance. Integr Org Biol 2024; 6:obae006. [PMID: 38585155 PMCID: PMC10995723 DOI: 10.1093/iob/obae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 03/05/2024] [Accepted: 03/11/2024] [Indexed: 04/09/2024] Open
Abstract
Arboreal embryos of phyllomedusine treefrogs hatch prematurely to escape snake predation, cued by vibrations in their egg clutches during attacks. However, escape success varies between species, from ∼77% in Agalychnis callidryas to just ∼9% in A. spurrelli at 1 day premature. Both species begin responding to snake attacks at similar developmental stages, when vestibular mechanosensory function begins, suggesting that sensory ability does not limit the hatching response in A. spurrelli. Agalychnis callidryas clutches are thick and gelatinous, while A. spurrelli clutches are thinner and stiffer. We hypothesized that this structural difference alters the egg motion excited by attacks. Since vibrations excited by snakes must propagate through clutches to reach embryos, we hypothesized that the species difference in attack-induced hatching may reflect effects of clutch biomechanics on the cues available to embryos. Mechanics predicts that thinner, stiffer structures have higher free vibration frequencies, greater spatial attenuation, and faster vibration damping than thicker, more flexible structures. We assessed clutch biomechanics by embedding small accelerometers in clutches of both species and recording vibrations during standardized excitation tests at two distances from the accelerometer. Analyses of recorded vibrations showed that A. spurrelli clutches have higher free vibration frequencies and greater vibration damping than A. callidryas clutches. Higher frequencies elicit less hatching in A. callidryas, and greater damping could reduce the amount of vibration embryos can perceive. To directly test if clutch structure affects escape success in snake attacks, we transplanted A. spurrelli eggs into A. callidryas clutches and compared their escape rates with untransplanted, age-matched conspecific controls. We also performed reciprocal transplantation of eggs between pairs of A. callidryas clutches as a method control. Transplanting A. spurrelli embryos into A. callidryas clutches nearly tripled their escape success (44%) compared to conspecific controls (15%), whereas transplanting A. callidryas embryos into different A. callidryas clutches only increased escape success by 10%. At hatching competence, A. callidryas eggs are no longer jelly-encapsulated, while A. spurrelli eggs retain their jelly coat. Therefore, we compared the hatching response and latency of A. spurrelli in de-jellied eggs and their control, jelly-encapsulated siblings using manual egg-jiggling to simulate predation cues. Embryos in de-jellied eggs were more likely to hatch and hatched faster than control siblings. Together, our results suggest that the properties of parentally produced egg-clutch structures, including their vibration biomechanics, constrain the information available to A. spurrelli embryos and contribute to interspecific differences in hatching responses to predator attacks.
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Affiliation(s)
- B A Güell
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - J G McDaniel
- Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA
| | - K M Warkentin
- Department of Biology, Boston University, Boston, MA 02215, USA
- Gamboa Laboratory, Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá
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3
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Salica MJ, Goldberg J, Akmentins MS, Candioti FV. Exceptional features of the embryonic ontogeny of a direct‐developing Robber frog. J Zool (1987) 2023. [DOI: 10.1111/jzo.13060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Affiliation(s)
- M. J. Salica
- Instituto de Ecorregiones Andinas (Consejo Nacional de Investigaciones Científicas y Técnicas – Universidad Nacional de Jujuy) San Salvador de Jujuy Argentina
| | - J. Goldberg
- Instituto de Diversidad y Ecología Animal (Consejo Nacional de Investigaciones Científicas y Técnicas – Universidad Nacional de Córdoba); Facultad de Ciencias Exactas, Físicas y Naturales (Universidad Nacional de Córdoba) Córdoba Argentina
| | - M. S. Akmentins
- Instituto de Ecorregiones Andinas (Consejo Nacional de Investigaciones Científicas y Técnicas – Universidad Nacional de Jujuy) San Salvador de Jujuy Argentina
| | - F. Vera Candioti
- Unidad Ejecutora Lillo (Consejo Nacional de Investigaciones Científicas y Técnicas – Fundación Miguel Lillo) San Miguel de Tucumán Argentina
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4
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Effect of natural abiotic soil vibrations, rainfall and wind on anuran calling behavior: a test with captive-bred midwife toads (Alytes obstetricans). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:105-113. [PMID: 36508004 PMCID: PMC9742647 DOI: 10.1007/s00359-022-01596-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 12/14/2022]
Abstract
Anurans are known to detect vibrations, but few studies explore relationships between vibrations and resultant behaviors. We studied the reaction of calling captive-bred male midwife toads (Alytes obstetricans) to the randomized playback of a vibrational crescendo stimulus train. We considered two sources of natural abiotic vibrational stimuli: rainfall and wind. Rainfall was expected to induce calling and wind was expected to inhibit it. Playback experiments with two synthetic tones (200 Hz and 300 Hz) tested the sensitivity to pure tones and could possibly reveal a hearing sensitivity trend between these frequencies. The toads did not increase call rate in response to rainfall vibrations and only one of the five wind stimulus levels caused a significant decrease in call rate. This limited response could be explained, because the tested toads came from a captive population, where emergence may not be mediated by rainfall vibrations. We found that A. obstetricans is highly sensitive to very low frequencies, which could explain the sensitivity observed to vibrational stimuli. Playback of a random crescendo stimulus train proves to be a valid approach for addressing behavioral questions. However, the use of a captive population may have been a limitation in the clarity of the results.
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Griffis‐Kyle KL, LeVering K, Vega A, Perez‐Martinez CA, Barun A, Perry G. Reproductive niche differentiation in syntopic tropical tree frogs (
Agalychnis
). Biotropica 2022. [DOI: 10.1111/btp.13162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
| | | | | | - Christian A. Perez‐Martinez
- Museum of Comparative Zoology Harvard University Cambridge Massachusetts USA
- Division of Biological Sciences University of Missouri Columbia Missouri USA
| | - Arijana Barun
- Metropolitan State University of Denver Denver Colorado USA
| | - Gad Perry
- Texas Tech University Lubbock Texas USA
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6
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Jung J, Guo M, Crovella ME, McDaniel JG, Warkentin KM. Frog embryos use multiple levels of temporal pattern in risk assessment for vibration-cued escape hatching. Anim Cogn 2022; 25:1527-1544. [PMID: 35668245 DOI: 10.1007/s10071-022-01634-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 05/02/2022] [Accepted: 05/06/2022] [Indexed: 12/01/2022]
Abstract
Stereotyped signals can be a fast, effective means of communicating danger, but animals assessing predation risk must often use more variable incidental cues. Red eyed-treefrog, Agalychnis callidryas, embryos hatch prematurely to escape from egg predators, cued by vibrations in attacks, but benign rain generates vibrations with overlapping properties. Facing high false-alarm costs, embryos use multiple vibration properties to inform hatching, including temporal pattern elements such as pulse durations and inter-pulse intervals. However, measures of snake and rain vibration as simple pulse-interval patterns are a poor match to embryo behavior. We used vibration playbacks to assess if embryos use a second level of temporal pattern, long gaps within a rhythmic pattern, as indicators of risks. Long vibration-free periods are common during snake attacks but absent from hard rain. Long gaps after a few initial vibrations increase the hatching response to a subsequent vibration series. Moreover, vibration patterns as short as three pulses, separated by long periods of silence, can induce as much hatching as rhythmic pulse series with five times more vibration. Embryos can retain information that increases hatching over at least 45 s of silence. This work highlights that embryo behavior is contextually modulated in complex ways. Identical vibration pulses, pulse groups, and periods of silence can be treated as risk cues in some contexts and not in others. Embryos employ a multi-faceted decision-making process to effectively distinguish between risk cues and benign stimuli.
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Affiliation(s)
- Julie Jung
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA.
| | - Ming Guo
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA
| | - Mark E Crovella
- Department of Computer Science, 111 Cummington Mall, Boston, MA, 02215, USA
| | - J Gregory McDaniel
- Department of Mechanical Engineering, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Karen M Warkentin
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA.,Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama, Republic of Panama
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7
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Escape-hatching decisions show adaptive ontogenetic changes in how embryos manage ambiguity in predation risk cues. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03070-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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Jung J, Serrano-Rojas SJ, Warkentin KM. Multimodal mechanosensing enables treefrog embryos to escape egg-predators. J Exp Biol 2020; 223:jeb236141. [PMID: 33188064 DOI: 10.1242/jeb.236141] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/03/2020] [Indexed: 01/05/2023]
Abstract
Mechanosensory-cued hatching (MCH) is widespread, diverse and important for survival in many animals. From flatworms and insects to frogs and turtles, embryos use mechanosensory cues and signals to inform hatching timing, yet mechanisms mediating mechanosensing in ovo are largely unknown. The arboreal embryos of red-eyed treefrogs, Agalychnis callidryas, hatch prematurely to escape predation, cued by physical disturbance in snake attacks. When otoconial organs in the developing vestibular system become functional, this response strengthens, but its earlier occurrence indicates another sensor must contribute. Post-hatching, tadpoles use lateral line neuromasts to detect water motion. We ablated neuromast function with gentamicin to assess their role in A. callidryas' hatching response to disturbance. Prior to vestibular function, this nearly eliminated the hatching response to a complex simulated attack cue, egg jiggling, revealing that neuromasts mediate early MCH. Vestibular function onset increased hatching, independent of neuromast function, indicating young embryos use multiple mechanosensory systems. MCH increased developmentally. All older embryos hatched in response to egg jiggling, but neuromast function reduced response latency. In contrast, neuromast ablation had no effect on the timing or level of hatching in motion-only vibration playbacks. It appears only a subset of egg-disturbance cues stimulate neuromasts; thus, embryos in attacked clutches may receive unimodal or multimodal stimuli. Agalychnis callidryas embryos have more neuromasts than described for any other species at hatching, suggesting precocious sensory development may facilitate MCH. Our findings provide insight into the behavioral roles of two mechanosensory systems in ovo and open possibilities for exploring sensory perception across taxa in early life stages.
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Affiliation(s)
- Julie Jung
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Shirley J Serrano-Rojas
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá
| | - Karen M Warkentin
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá
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9
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Caorsi V, Guerra V, Furtado R, Llusia D, Miron LR, Borges-Martins M, Both C, Narins PM, Meenderink SWF, Márquez R. Anthropogenic substrate-borne vibrations impact anuran calling. Sci Rep 2019; 9:19456. [PMID: 31857629 PMCID: PMC6923410 DOI: 10.1038/s41598-019-55639-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/20/2019] [Indexed: 11/10/2022] Open
Abstract
Anthropogenic disturbance is a major cause of the biodiversity crisis. Nevertheless, the role of anthropogenic substrate vibrations in disrupting animal behavior is poorly understood. Amphibians comprise the terrestrial vertebrates most sensitive to vibrations, and since communication is crucial to their survival and reproduction, they are a suitable model for investigating this timely subject. Playback tests were used to assess the effects of substrate vibrations produced by two sources of anthropogenic activity– road traffic and wind turbines– on the calling activity of a naïve population of terrestrial toads. In their natural habitat, a buried tactile sound transducer was used to emit simulated traffic and wind turbine vibrations, and changes in the toads’ acoustic responses were analyzed by measuring parameters important for reproductive success: call rate, call duration and dominant frequency. Our results showed a significant call rate reduction by males of Alytes obstetricans in response to both seismic sources, whereas other parameters remained stable. Since females of several species prefer males with higher call rates, our results suggest that anthropogenically derived substrate-borne vibrations could reduce individual reproductive success. Our study demonstrates a clear negative effect of anthropogenic vibrations on anuran communication, and the urgent need for further investigation in this area.
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Affiliation(s)
- Valentina Caorsi
- Programa de Pós-Graduação em Biologia Animal, Dep. de Zoologia, Inst. de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, RS, 91540-000, Brazil. .,Research and Innovation Centre, Fondazione Edmund Mach, via Mach 1, S. Michele all'Adige, 38010, TN, Italy. .,Laboratório de Herpetologia e Comportamento Animal, Departamento de Ecologia, Inst. de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil.
| | - Vinicius Guerra
- Programa de Pós-Graduação em Ecologia e Manejo de Recursos Naturais, Centro de Ciências Biológicas e da Natureza, Universidade Federal do Acre, Rio Branco, AC, Brazil.,Laboratório de Herpetologia e Comportamento Animal, Departamento de Ecologia, Inst. de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Raíssa Furtado
- Programa de Pós-Graduação em Ecologia, Dep. de Ecologia, Inst. de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, CP 15007, RS, 91501-970, Brazil
| | - Diego Llusia
- Departamento de Ecología, Terrestrial Ecology Group, Universidad Autónoma de Madrid (UAM), C/Darwin 2, E-28049, Ciudad Universitaria de Cantoblanco, Madrid, Spain.,Laboratório de Herpetologia e Comportamento Animal, Departamento de Ecologia, Inst. de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Lívia Roese Miron
- Curso de Ciências Biológicas, Universidade Federal de Santa Maria, Avenida Roraima, n 1000, 97105-900, Santa Maria, RS, Brazil
| | - Márcio Borges-Martins
- Programa de Pós-Graduação em Biologia Animal, Dep. de Zoologia, Inst. de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, RS, 91540-000, Brazil
| | - Camila Both
- Departamento Interdisciplinar, Universidade Federal do Rio Grande do Sul, Campus Litoral Norte, Av. Tramandaí, 976, 95625-000, Imbé, RS, Brazil
| | - Peter M Narins
- Departments of Integrative Biology & Physiology, and Ecology & Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive S., Los Angeles, CA, 90095, USA
| | | | - Rafael Márquez
- Fonoteca Zoológica. Dept. de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales-CSIC, José Gutiérrez Abascal 2, 28006, Madrid, Spain
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10
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Jung J, Kim SJ, Pérez Arias SM, McDaniel JG, Warkentin KM. How do red-eyed treefrog embryos sense motion in predator attacks? Assessing the role of vestibular mechanoreception. ACTA ACUST UNITED AC 2019; 222:jeb.206052. [PMID: 31586019 DOI: 10.1242/jeb.206052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 09/28/2019] [Indexed: 01/18/2023]
Abstract
The widespread ability to alter timing of hatching in response to environmental cues can serve as a defense against threats to eggs. Arboreal embryos of red-eyed treefrogs, Agalychnis callidryas, can hatch up to 30% prematurely to escape predation. This escape-hatching response is cued by physical disturbance of eggs during attacks, including vibrations or motion, and thus depends critically on mechanosensory ability. Predator-induced hatching appears later in development than flooding-induced, hypoxia-cued hatching; thus, its onset is not constrained by the development of hatching ability. It may, instead, reflect the development of mechanosensor function. We hypothesize that vestibular mechanoreception mediates escape-hatching in snake attacks, and that the developmental period when hatching-competent embryos fail to flee from snakes reflects a sensory constraint. We assessed the ontogenetic congruence of escape-hatching responses and an indicator of vestibular function, the vestibulo-ocular reflex (VOR), in three ways. First, we measured VOR in two developmental series of embryos 3-7 days old to compare with the published ontogeny of escape success in attacks. Second, during the period of greatest variation in VOR and escape success, we compared hatching responses and VOR across sibships. Finally, in developmental series, we compared the response of individual embryos to a simulated attack cue with their VOR. The onset of VOR and hatching responses were largely concurrent at all three scales. Moreover, latency to hatch in simulated attacks decreased with increasing VOR. These results are consistent with a key role of the vestibular system in the escape-hatching response of A. callidryas embryos to attacks.
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Affiliation(s)
- Julie Jung
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA
| | - Su J Kim
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA
| | - Sonia M Pérez Arias
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA
| | - James G McDaniel
- Department of Mechanical Engineering, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Karen M Warkentin
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA.,Gamboa Laboratory, Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá
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