The reaction distance of a planktivorous fish (Scardinius erythrophthalmus) and the evasiveness of its prey (Daphnia pulex × pulicaria) under different artificial light spectra

Abstract

Artificial light at night may affect mortality risk in prey from visually oriented predators because the effect of the artificial light spectrum may differ for a predator's visual prey detection and for prey evasiveness. To test this, we conducted two types of experiment. First, we assessed the reaction distance and swimming speed of juvenile rudd (Scardinius erythrophthalmus) allowed to forage on juvenile Daphnia pulex × pulicaria under three artificial light sources: halogen, high pressure sodium (HPS), and metal halide bulbs, at the same light intensity. Second, we assessed the evasiveness of D. pulex × pulicaria under the same artificial light sources and in darkness (as a control), in the presence and absence of chemical information on predation risk (kairomones) of juvenile rudd. We found that while both reaction distance and swimming speed of fish was greater under halogen compared to HPS, and similar under metal halide light compared to halogen and HPS, the evasiveness of Daphnia was greater under halogen and HPS-generated light than under metal halide light. The results suggest a possible mismatch of Daphnia's behavioural response under metal halide light to predicted predation risk, and thus a possible threat to predator-prey balance in a lake ecosystem.

Daphnia depth selection in gradients of light intensity from different artificial sources: An evolutionary trap?

“…Experiments to assess the light‐spectral‐ and light‐intensity‐dependent visual field volume of the fish (i.e., experiments to determine the parameters for the model) revealed another quite interesting results, that is, the reaction distance (as a behavioral proxy for visual prey detection) and swimming speed of planktivorous fish depend not only on light intensity but also on its spectral composition. Our results showed that the reaction distance and swimming speed of juvenile rudd were greater in halogen and metal‐halide lights than in high pressure sodium light, which is consistent with the results of our earlier study (Tałanda et al 2018). The similar effect of different light sources on reaction distance and swimming speed is consistent with the results obtained in earlier studies, in which the greater swimming speed of fish correlated with better visual conditions (e.g., higher light intensity), which was attributed to better visibility and greater foraging activity (Utne‐Palm 1999).…”

“…In conclusion, the results of our study confirmed the suggestions presented in the earlier studies that changes in light intensity due to the presence of artificial light at night may force Daphnia to select greater depths in the water column, which results in a decrease in their individual growth rates and, in turn, decreases their fitness (Moore et al 2006, Tałanda et al 2018). Moreover, the results also suggest that another feature of artificial light, that is the specificity of its spectral characteristics (which largely differs from the spectral characteristics of natural light), may affect the fitness of Daphnia individuals, since Daphnia in the experiments were not able to correctly assess the spectrum‐dependent mortality risk due to predation by fish in the vertical gradient of several artificial light sources (i.e., halogen and metal halide lamps).…”

“…On the other hand, it may be expected that Daphnia adequately respond to this risk because they are constantly experiencing large spatial (horizontal and vertical within and between lakes) and temporal (diurnal and seasonal) variability in the spectral composition of the natural light in their environment, and therefore would have adapted to a wide range of combinations of light spectra, even those produced by artificial light sources. Indirect evidence supporting this prediction comes from a recent study by Tałanda et al (2018). In this study, it was found that the escape response of Daphnia pulex × pulicaria from a pipette mimicking the attack of a planktivorous fish was different in the spectral composition of various artificial light sources (halogen, high pressure sodium, and metal‐halide).…”

Effects of light and artificial fish shelter (PVC pipe) on some phenotypic traits of stinging catfish (Heteropneustes fossilisBloch, 1794)

“…All these factors are species‐specific and light intensity‐dependent (Batty, ; Tian, Zhang, Xu, Wang, & Liu, ). Light intensity enables fish to see diets for feeding (Boeuf & Le Bail, ; Elliott, ), escape from predators (James & Heck, ; Tałanda, Maszczyk, & Babkiewicz, ), hunt suitable preys (Cerri, ; Granqvist & Mattila, ) and find out habitats (Harvey, Butler, McLean, & Shand, ; Mol & Ouboter, ). Light can also influence the skin colour of some fishes which may be changed by the absorption, reflection and scattering of light by the pigments and microstructures within the fish integument (Leclercq, Taylor, & Migaud, ; Sugimoto, ).…”

Using a new high-throughput video-tracking platform to assess behavioural changes in Daphnia magna exposed to neuro-active drugs

“…It is well known that negative phototaxisis together with being smaller at first reproduction are fish anti-predator defence Daphnia mechanisms, and that these defences are more effective under low light intensities of 37-153 lux (Effertz and von Elert, 2014;Effertz and von Elert, 2017). At higher light intensities, fish predation efficiencies towards Daphnia preys are high and hence anti-predatory defences are less effective (Tałanda et al, 2018). This means that in the present study the higher reported effects at low than at high light intensity agree with reported cost-benefits of anti-predatory defences.…”