Zebrafish learn to forage in the dark

Abstract

A large diversity of fishes struggle early in life to forage on zooplankton while under the threat of predation. Some species, such as zebrafish (Danio rerio), acquire an ability to forage in the dark during growth as larvae, but it is unclear how this is achieved. We investigated the functional basis of this foraging by video-recording larval and juvenile zebrafish as they preyed on zooplankton (Artemia sp.) under infrared illumination. We found that foraging improved with age, to the extent that 1-month-old juveniles exhibited a capture rate that was an order of magnitude greater than that of hatchlings. At all ages, the ability to forage in the dark was diminished when we used a chemical treatment to compromise the cranial superficial neuromasts, which facilitate flow sensing. However, a morphological analysis showed no developmental changes in these receptors that could enhance sensitivity. We tested whether the improvement in foraging with age could instead be a consequence of learning by raising fish that were naïve to the flow of prey. After 1 month of growth, both groups foraged with a capture rate that was significantly less than that of fish that had the opportunity to learn and indistinguishable from that of fish with no ability to sense flow. This suggests that larval fish learn to use water flow to forage in the dark. This ability could enhance resource acquisition under reduced competition and predation. Furthermore, our findings offer an example of learning in a model system that offers promise for understanding its neurophysiological basis.

Contested Paradigm in Raising Zebrafish (Danio rerio)

“…The fish fed from 7 to 32 dpf under constant light reached 6 mm, suggesting extremely unfavorable food conditions. There is, however, an agreement that zebrafish larvae cannot feed in the dark, even on prey as small and slow as Paramecium, 27 although Carrillo and McHenry 28 argued to the contrary. The latter authors performed experiments where zebrafish larvae initially fed with rotifers (5-10 dpf) were then forced into dark conditions in 3 mm deep containers and offered Artemia nauplii.…”

The effects of lateral line ablation and regeneration in schooling giant danios

“…Fishes make up about 50% of all existing vertebrate species, and most of them have a sensory system called the mechanosensory lateral line that detects flow in the water (Coombs and Van Netten, 2005;Mogdans and Bleckmann, 2012;Coombs et al, 2014;Webb et al, 2014). In fish, the lateral line system is involved in many behaviors such as detection of predators (McHenry et al, 2009;Stewart et al, 2013;Nair et al, 2017) and prey (Schwalbe et al, 2012;Carrillo and McHenry, 2016;Schwalbe et al, 2016), rheotaxis (Patton et al, 2010;Oteiza et al, 2017), obstacle avoidance (Teyke, 1985;Windsor et al, 2008), and local interactions within groups of fish (Partridge and Pitcher, 1980;Coombs and Van Netten, 2005;Chicoli et al, 2014;Coombs et al, 2014). In particular, most fishes and other aquatic amphibians seem to rely on the lateral line system, along with the visual system, for schooling behavior (Pitcher et al, 1976;Partridge and Pitcher, 1980;Mogdans and Bleckmann, 2012;Coombs et al, 2014).…”

Ecologia De Ictioplâncton: Uma Abordagem Cienciométrica

“…Entre as medidas bem sucedidas que poderiam ser estimuladas para promover avanços na área, especialmente nos ecossistemas de água doce, que são menos estudados do que os marinhos, estão os experimentos, que permitem detectar as habilidades que as larvas desenvolvem mediante uma pequena mudança em uma variável, que dificilmente seriam percebidas em campo (e.g. Carrillo & McHenry 2016). As modelagens também devem ser estimuladas, pois viabilizam analisar, por exemplo, as probabilidades das desovas de uma determinada espécie ocorrerem em determinados habitats (Schismenou et al 2008), fornecendo uma ampla noção dos possíveis locais de ocorrência dos ovos de uma determinada espécie para gestores e pesquisadores.…”