Fast-start swimming performance and reduction in lateral plate number in threespine stickleback

Abstract

Threespine stickleback (Gasterosteus aculeatus) have colonized freshwater habitats in circumboreal coastal regions, resulting in populations with variable but generally reduced lateral plate numbers compared with marine ancestors. Several abiotic and ecological factors associated with variation in lateral plate number among freshwater populations of G. aculeatus have been found, including large-scale climatic effects, variation in water-flow rates and levels of dissolved calcium, and the presence or absence of predatory fish. In addition, it has been proposed that plate reduction might be an adaptation for evading predator pursuit that enhances fast-start performance. If this hypothesis is correct, one would predict that fast-start performance would improve as lateral plate numbers decrease. I tested this prediction by comparing fast-start performance among stickleback with different numbers of lateral plates within two freshwater populations. Fast-starts of individual stickleback were video-recorded at 60 Hz and maximum velocity, maximum acceleration, displacement, and body curvature were calculated for each fish. Lateral plate number was significantly negatively correlated with velocity and displacement but not with acceleration or curvature. These results suggest that reduction in lateral plate number has the potential to be advantageous in some predation regimes because of its association with enhanced fast-start performance.

Morphometric and meristic variation in Galician threespine stickleback populations, northwest Spain

“…Given that swimming in the threespine is dependent upon pectoral sculling, the swimming ability of these fishes may be limited. The general trends of variation of Girona sticklebacks fit the profile of populations adapted to life in a standing-water habitat with abundant vegetation, where the manoeuvring and the stereoscopic vision is most important than the ability swimming, being this model comparable with stickleback populations from the littoral zone (Baumgartner 1992, Walker 1996, Bergstrom 2002. This trend was supported by the variation of meristic traits, since Girona fishes had a lower number of vertebrae and dorsal fin rays.…”

“…For example, there is a trend within Europe for northern threespine populations to possess a large number of lateral plates than southern ones (Mu¨nzing 1963). Lateral plate number may directly affect swimming velocity and displacement (Bergstrom 2002), so that the presence of completely plated sticklebacks in northern Europe may be an adaptation to wide displacements because these populations are anadromous. Fishes that are widely displaced across different habitats may, in turn, be more exposed to the action of predators, so is interesting to note that the Danish populations also have longer spines than their more southerly relatives.…”

Hydrodynamics of the bluegill sunfish C-start escape response: three-dimensional simulations and comparison with experimental data

“…Consequently, studies of fast starts have been pivotal in evolutionary and ecological studies of predatory-prey interactions (Bergstrom, 2002;Domenici, 2001;Ghalambor et al, 2004;Hale, 1996;Harper and Blake, 1988;Harper and Blake, 1991). In fact, fish with slower or less-efficient fast starts tend to get captured more frequently than fish with a higher escape performance (Walker et al, 2005).…”

Context‐dependent variability in the components of fish escape response: integrating locomotor performance and behavior

“…More recent work addresses this issue by comparing swimming performance while considering within-population variation and plate numbers, and found that there was a negative relationship between displacement, speed (but not curvature and acceleration), and lateral plate number (Bergstrom, 2002). Because curvature was not affected, there may be other factors rather than limited flexibility (such as increased drag) causing the trade off between locomotor performance and morphological defense (Bergstrom, 2002). Regardless of the specific proximate causes, defensive armor and escape locomotion do appear to trade off.…”