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Fusion of locomotor maneuvers, and improving sensory capabilities, give rise to the flexible homing strikes of juvenile zebrafish.

Westphal RE, O'Malley DM - Front Neural Circuits (2013)

Bottom Line: At 5 days post-fertilization and 4 mm in length, zebrafish larvae are successful predators of mobile prey items.Neomycin ablation of lateral line hair cells reduced the accuracy of strikes and overall feeding rates, especially when neomycin-treated larvae and juveniles were placed in the dark.Darkness by itself reduced the distance from which strikes were launched, as visualized by infrared imaging.

View Article: PubMed Central - PubMed

Affiliation: Department of Natural Sciences, North Shore Community College Lynn, MA, USA.

ABSTRACT
At 5 days post-fertilization and 4 mm in length, zebrafish larvae are successful predators of mobile prey items. The tracking and capture of 200 μm long Paramecia requires efficient sensorimotor transformations and precise neural controls that activate axial musculature for orientation and propulsion, while coordinating jaw muscle activity to engulf them. Using high-speed imaging, we report striking changes across ontogeny in the kinematics, structure and efficacy of zebrafish feeding episodes. Most notably, the discrete tracking maneuvers used by larval fish (turns, forward swims) become fused with prey capture swims to form the continuous, fluid homing strikes of juvenile and adult zebrafish. Across this same developmental time frame, the duration of feeding episodes become much shorter, with strikes occurring at broader angles and from much greater distances than seen with larval zebrafish. Moreover, juveniles use a surprisingly diverse array of motor patterns that constitute a flexible predatory strategy. This enhances the ability of zebrafish to capture more mobile prey items such as Artemia. Visually-guided tracking is complemented by the mechanosensory lateral line system. Neomycin ablation of lateral line hair cells reduced the accuracy of strikes and overall feeding rates, especially when neomycin-treated larvae and juveniles were placed in the dark. Darkness by itself reduced the distance from which strikes were launched, as visualized by infrared imaging. Rapid growth and changing morphology, including ossification of skeletal elements and differentiation of control musculature, present challenges for sustaining and enhancing predatory capabilities. The concurrent expansion of the cerebellum and subpallium (an ancestral basal ganglia) may contribute to the emergence of juvenile homing strikes, whose ontogeny possibly mirrors a phylogenetic expansion of motor capabilities.

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Effect of darkness on juvenile feeding success and strike distance. Juveniles were observed striking at Artemia under IR illumination and this behavior was compared with feeding strikes made in the light. (A) The success rate of strikes on Artemia are roughly 90% in the light, but substantially lower in the dark for these 39-day-old juveniles. (B) Strikes made in the dark are initiated from shorter distances than those in the light (t-test, p = 0.02), which fits with the suggested involvement of lateral line. n = 9 fish.
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Figure 13: Effect of darkness on juvenile feeding success and strike distance. Juveniles were observed striking at Artemia under IR illumination and this behavior was compared with feeding strikes made in the light. (A) The success rate of strikes on Artemia are roughly 90% in the light, but substantially lower in the dark for these 39-day-old juveniles. (B) Strikes made in the dark are initiated from shorter distances than those in the light (t-test, p = 0.02), which fits with the suggested involvement of lateral line. n = 9 fish.

Mentions: Strike distances and success rates were compared in light vs. dark conditions, as shown for feeding episodes of nine 39-dpf juvenile zebrafish recorded under IR vs. normal illumination (Figure 13A). Of nine feeding events recorded in the dark, five were successful (55%), compared with 9/10 (90%) successful feeding episodes from the same fish in the light. During dark feeding episodes, juveniles initiated feeding at 1.55 ± 1.11 mm from the prey, but launched strikes from 4.29 ± 1.96 mm in the light (p-value = 0.02) (Figure 13B). This fits with the longer range of vision vs. lateral line, which functions better at short distances. While sustained tracking movements were not apparent in the dark, in agreement with data of Patterson et al. (2013) on larvae, our modest set of recorded dark feeds precludes strong conclusions on juveniles.


Fusion of locomotor maneuvers, and improving sensory capabilities, give rise to the flexible homing strikes of juvenile zebrafish.

Westphal RE, O'Malley DM - Front Neural Circuits (2013)

Effect of darkness on juvenile feeding success and strike distance. Juveniles were observed striking at Artemia under IR illumination and this behavior was compared with feeding strikes made in the light. (A) The success rate of strikes on Artemia are roughly 90% in the light, but substantially lower in the dark for these 39-day-old juveniles. (B) Strikes made in the dark are initiated from shorter distances than those in the light (t-test, p = 0.02), which fits with the suggested involvement of lateral line. n = 9 fish.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675323&req=5

Figure 13: Effect of darkness on juvenile feeding success and strike distance. Juveniles were observed striking at Artemia under IR illumination and this behavior was compared with feeding strikes made in the light. (A) The success rate of strikes on Artemia are roughly 90% in the light, but substantially lower in the dark for these 39-day-old juveniles. (B) Strikes made in the dark are initiated from shorter distances than those in the light (t-test, p = 0.02), which fits with the suggested involvement of lateral line. n = 9 fish.
Mentions: Strike distances and success rates were compared in light vs. dark conditions, as shown for feeding episodes of nine 39-dpf juvenile zebrafish recorded under IR vs. normal illumination (Figure 13A). Of nine feeding events recorded in the dark, five were successful (55%), compared with 9/10 (90%) successful feeding episodes from the same fish in the light. During dark feeding episodes, juveniles initiated feeding at 1.55 ± 1.11 mm from the prey, but launched strikes from 4.29 ± 1.96 mm in the light (p-value = 0.02) (Figure 13B). This fits with the longer range of vision vs. lateral line, which functions better at short distances. While sustained tracking movements were not apparent in the dark, in agreement with data of Patterson et al. (2013) on larvae, our modest set of recorded dark feeds precludes strong conclusions on juveniles.

Bottom Line: At 5 days post-fertilization and 4 mm in length, zebrafish larvae are successful predators of mobile prey items.Neomycin ablation of lateral line hair cells reduced the accuracy of strikes and overall feeding rates, especially when neomycin-treated larvae and juveniles were placed in the dark.Darkness by itself reduced the distance from which strikes were launched, as visualized by infrared imaging.

View Article: PubMed Central - PubMed

Affiliation: Department of Natural Sciences, North Shore Community College Lynn, MA, USA.

ABSTRACT
At 5 days post-fertilization and 4 mm in length, zebrafish larvae are successful predators of mobile prey items. The tracking and capture of 200 μm long Paramecia requires efficient sensorimotor transformations and precise neural controls that activate axial musculature for orientation and propulsion, while coordinating jaw muscle activity to engulf them. Using high-speed imaging, we report striking changes across ontogeny in the kinematics, structure and efficacy of zebrafish feeding episodes. Most notably, the discrete tracking maneuvers used by larval fish (turns, forward swims) become fused with prey capture swims to form the continuous, fluid homing strikes of juvenile and adult zebrafish. Across this same developmental time frame, the duration of feeding episodes become much shorter, with strikes occurring at broader angles and from much greater distances than seen with larval zebrafish. Moreover, juveniles use a surprisingly diverse array of motor patterns that constitute a flexible predatory strategy. This enhances the ability of zebrafish to capture more mobile prey items such as Artemia. Visually-guided tracking is complemented by the mechanosensory lateral line system. Neomycin ablation of lateral line hair cells reduced the accuracy of strikes and overall feeding rates, especially when neomycin-treated larvae and juveniles were placed in the dark. Darkness by itself reduced the distance from which strikes were launched, as visualized by infrared imaging. Rapid growth and changing morphology, including ossification of skeletal elements and differentiation of control musculature, present challenges for sustaining and enhancing predatory capabilities. The concurrent expansion of the cerebellum and subpallium (an ancestral basal ganglia) may contribute to the emergence of juvenile homing strikes, whose ontogeny possibly mirrors a phylogenetic expansion of motor capabilities.

Show MeSH
Related in: MedlinePlus