Evolution of the fast start response in the cavefish Astyanax mexicanus

Hoke, Kim L.; Schwartz, Adina; Soares, Daphne

doi:10.1007/s00265-012-1368-6

Cited by 6 publications

(8 citation statements)

References 48 publications

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“…The C‐start responses of Pachón cavefish are characterized by a decrease in angular speed and peak bend angle compared to surface fish, with Pachón turning approximately 3°/ms more slowly and to a peak bend angle that is smaller in magnitude by almost 20° relative to surface fish (Figure 2c,d). This increase in peak bend angle is consistent with work done in adults (Hoke et al, 2012). Pachón larvae also displayed significantly longer response latencies than surface fish larvae (Figure 2e).…”

Section: Resultssupporting

confidence: 91%

“…In surface fish, the shortest latency C‐starts were initiated 7–9 ms after stimulus onset, in contrast to Pachón larvae in which the shortest latency C‐starts were initiated 11–13 ms after stimulus onset (Figure 2f). Previous work in adult surface and cave fish did not identify any significant differences in response latency, however this study was done at 500 fps, which may have been ineffective for capturing this difference (Hoke et al, 2012). Together, these data illustrate the substantial differences that have developed in the C‐start responses of surface fish and Pachón cave fish.…”

Section: Resultsmentioning

confidence: 81%

“…While a previous study found that cave populations do not exhibit diminished escape performance, the work was conducted in adults, introducing the confounding variable of learned behavior (Hoke, Schwartz, & Soares, 2012). Here, we characterize differences in the C‐start responses of 6 day postfertilization (dpf) larvae from multiple A. mexicanus populations using acoustic stimuli and high speed videography.…”

Section: Introductionmentioning

confidence: 99%

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Evolution of the acoustic startle response of Mexican cavefish

et al. 2020

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The ability to detect threatening stimuli and initiate an escape response is essential for survival and under stringent evolutionary pressure. In diverse fish species, acoustic stimuli activate Mauthner neurons, which initiate a C-start escape response. This reflexive behavior is highly conserved across aquatic species and provides a model for investigating the neural mechanism underlying the evolution of escape behavior. Here, we characterize evolved differences in the C-start response between populations of the Mexican cavefish, Astyanax mexicanus. Cave populations of A. mexicanus inhabit an environment devoid of light and macroscopic predators, resulting in evolved differences in various morphological and behavioral traits. We find that the C-start is present in river-dwelling surface fish and multiple populations of cavefish, but that response kinematics and probability differ between populations. The Pachón population of cavefish exhibits an increased response probability, a slower response latency and speed, and reduction of the maximum bend angle, revealing evolved differences between surface and cave populations. Analysis of the responses of two other independently evolved populations of cavefish, revealed the repeated evolution of reduced angular speed. Investigation of surface-cave hybrids reveals a correlation between angular speed and peak angle, suggesting these two kinematic characteristics are related at the genetic or functional levels. Together, these findings provide support for the use of A. mexicanus as a model to investigate the evolution of escape behavior.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

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Evolution of the acoustic startle response of Mexican cavefish

et al. 2020

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“…We mainly evaluated three aspects of wall-following level in Sinocyclocheilus genus: time, speed and distance with being the most important, as distance is a product of speed and time. However, we further considered speed and time also, for they can explain more subtle aspects of behaviour (Hoke et al, 2012). We noted the enhancement in wall-following ability going from Normal-eyed to Eyeless species.…”

Section: Discussionmentioning

confidence: 99%

Wall-following – phylogenetic context of an enhanced behaviour in stygomorphicSinocyclocheilus(Cypriniformes: Cyprinidae) cavefishes

Chen,

Dai,

et al. 2023

Preprint

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With 75 known species, the freshwater fish genus Sinocyclocheilus is the largest cavefish radiation in the world, emerging as a model system for evolutionary studies. They show multiple adaptations for cave dwelling (stygomorphic adaptations), which include a range of traits such as eye degeneration (Normal-eyed, Microeyed and Eyeless), depigmentation of skin, and in some species, the presence of horns. Their behavioural adaptations to subterranean environments, however, are poorly understood. Wall-following (WF) behaviour, where an organism remains in close contact with the boundary demarcating its habitat when in the dark, is a peculiar behaviour observed in a wide range of animals and is enhanced in some cave dwellers. Hence, we hypothesize wall-following to be present also in Sinocyclocheilus, possibly enhanced in Eyeless species compared to species with visual cues (Normal / Microeyed species). Using 13 species representative of Sinocyclocheilus radiation and eye-morphs, we designed a series of assays, based on preexisting methods for Astyanax mexicanus behavioural experiments, to examine wall-following behaviour under three stimulation conditions. Our results indicate that eyeless species exhibit significantly enhanced levels of WF compared to Normal-eyed species, with Micro-eyed forms demonstrating intermediate levels. Using a mtDNA based dated phylogeny (chronogram with four clades A to D), we traced the degree of WF of these forms to outline common patterns. We show that intensity of WF behaviour is high in the subterranean clades (B & C) compared to clades with free-living species (A & D). Experiments on WF behaviour revealed that eyeless species are highly sensitive to vibrations, whereas normal-eyed species are the least sensitive. Since WF behaviour is present to some degree in all Sinocyclocheilus species, and given that these fishes evolved in the late Miocene, we identify this behaviour as being ancestral with WF enhancement related to cave occupation. Our results from this diversification scale study of cavefish behaviour suggest that enhanced wall-following behaviour may be a convergent trait across all stygomorphic cavefish lineages.

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“…Like morphology, neural circuits can adapt to the environment. Of these, many circuits are sensory and regulate essential behaviors such as foraging, navigation, and escapes ( Blin et al, 2018 ; Hoke et al, 2012 ; Hüppop, 1987 ; Paz et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Evolutionary convergence of a neural mechanism in the cavefish lateral line system

Lunsford

Paz

Keene

et al. 2022

eLife

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Animals can evolve dramatic sensory functions in response to environmental constraints, but little is known about the neural mechanisms underlying these changes. The Mexican tetra, Astyanax mexicanus, is a leading model to study genetic, behavioral, and physiological evolution by comparing eyed surface populations and blind cave populations. We compared neurophysiological responses of posterior lateral line afferent neurons and motor neurons across A. mexicanus populations to reveal how shifts in sensory function may shape behavioral diversity. These studies indicate differences in intrinsic afferent signaling and gain control across populations. Elevated endogenous afferent activity identified a lower response threshold in the lateral line of blind cavefish relative to surface fish leading to increased evoked potentials during hair cell deflection in cavefish.. We next measured the effect of inhibitory corollary discharges from hindbrain efferent neurons onto afferents during locomotion. We discovered that three independently-derived cavefish populations have evolved persistent afferent activity during locomotion, suggesting for the first time that partial loss of function in the efferent system can be an evolutionary mechanism for neural adaptation of a vertebrate sensory system.

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Evolution of the fast start response in the cavefish Astyanax mexicanus

Cited by 6 publications

References 48 publications

Evolution of the acoustic startle response of Mexican cavefish

Evolution of the acoustic startle response of Mexican cavefish

Wall-following – phylogenetic context of an enhanced behaviour in stygomorphicSinocyclocheilus(Cypriniformes: Cyprinidae) cavefishes

Evolutionary convergence of a neural mechanism in the cavefish lateral line system

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