The spatiotemporal dynamics of rheotactic behavior depends on flow speed and available sensory information

Abstract

SUMMARY

Sedentary behavior as a factor in determining lateral line contributions to rheotaxis

“…Similarly, epaulette sharks (Hemiscyllium ocellatum) exhibit rheotaxis when they are located on the benthos, but not when they are higher in the water column (Peach, 2001). Finally, our blind cavefish results are consistent with the absence of lateral line effects observed in other species with non-sedentary behaviors, such as the surface-dwelling giant danio (Bak-Coleman et al, 2013). In giant danio, lateral line deprivation did not cause a significant reduction in the rheotactic performance of visually deprived giant danio; however, it did alter the spatiotemporal dynamics of rheotactic behavior.…”

“…According to Stewart et al (Stewart, 2013), this should decrease the flow stimulus to the lateral line from a suction predator by as much as 80% (Stewart et al, 2013), suggesting that adult zebrafish may be less dependent on their lateral line than larval fish. The fact that adults of a closely related species (giant danio) do not rely on their lateral line for rheotaxis (Bak-Coleman et al, 2013) is consistent with this idea. Future studies of how the sensory basis of rheotaxis changes during development, especially during critical transition phases such as the inflation of the swimbladder, are needed.…”

“…The rheotactic index (RI) (Bak-Coleman et al, 2013) increased as a function flow speed for each treatment group in both species (Fig. 4).…”

“…Rheotaxis is a taxonomically widespread behavior that occurs throughout the life cycle of fish under widely varying behavioral, flow and sensory conditions (Arnold, 1974). For example, rheotaxis has been observed in the diurnal, stream-dwelling giant danio (Devario aequipinnatus) (Bak-Coleman et al, 2013;McClure et al, 2006) and in blind cavefish [Astyanax mexicanus (De Fillippi 1853)], which inhabit lightless, subterranean cave pools (Baker and Montgomery, 1999b).…”

“…One reason is that there is presently no good way to block the vestibular system without disrupting the ability of fish to maintain an upright posture, making it difficult, if not impossible, to assess the unique contribution of the vestibular system. A second reason is that there is conflicting evidence for (Montgomery et al, 1997;Baker and Montgomery, 1999a;Baker and Montgomery, 1999b;Suli et al, 2012;Olszewski et al, 2012) and against (Lyon, 1904;Dijkgraaf, 1933;Dijkgraaf, 1963;Van Trump and McHenry, 2013;Bak-Coleman et al, 2013) a substantial role of the lateral line in rheotaxis. All of these studies together raise questions about the precise circumstances under which the lateral line may or may not play a role in rheotaxis.…”