Intruder colour and light environment jointly determine how nesting male stickleback respond to simulated territorial intrusions

Abstract

Variation in male nuptial colour signals might be maintained by negative frequency-dependent selection. This can occur if males are more aggressive towards rivals with locally common colour phenotypes. To test this hypothesis, we introduced red or melanic three-dimensional printed-model males into the territories of nesting male stickleback from two optically distinct lakes with different coloured residents. Red-throated models were attacked more in the population with red males, while melanic models were attacked more in the melanic male lake. Aggression against red versus melanic models also varied across a depth gradient within each lake, implying that the local light environment also modulated the strength of negative frequency dependence acting on male nuptial colour.

Phenotypic plasticity drives a depth gradient in male conspicuousness in threespine stickleback,Gasterosteus aculeatus

“…Intriguingly, previous evidence suggests that color not only mediates intrasexual aggression in threespine stickleback, but that this affect varies across optical environments and depths (Bolnick et al. ).…”

“…Preliminary data from a series of GoPro cameras placed along a depth gradient in Gosling Lake (see Bolnick et al. ) suggest that trout and bellastomatid density are somewhat higher in deep and shallow environments, respectively. However, these results are not significant (Fig.…”

“…In situ mate choice trials, perhaps using model stickleback (e.g., Bolnick et al. ), could be employed to assess whether female detection and/or preference differs across depth. Additionally, nuptial color is also involved in intrasexual interactions in stickleback (Bakker and Sevenster ; McLennan and McPhail ; Baube ; Rick and Bakker ; but see Mckinnon and McPhail ), and thus a similar argument could be made that color‐mediated, male–male agonistic interactions drive depth gradients in male conspicuousness.…”

“…While we recognize this is a limitation of our study, previous evidence from both optomotor and behavioral studies indicate that stickleback are sensitive to a variety of colors, including those of both long (e.g., red) and short (e.g., ultraviolet) wavelengths(e.g., Milinski and Bakker ; Boughman ; Rick and Bakker ,b,c; Bolnick et al. ). Consequently, these results suggest the stickleback eye is at least partially transmissive to wavelengths between ∼300 and 700 nm.…”

Opsin expression predicts male nuptial color in threespine stickleback

“…For example, positive covariance between red coloration and sensitivity to red in males could drive greater antagonism between red males, leading to negative frequency‐dependent selection that could favor rare male color morphs and thus maintain variation in nuptial color (Djikstra, Seehausen, Gricar, Maan, & Groothuis, ; Djikstra, Seehausen, Pierotti, & Groothuis, ; Seehausen & Schluter, ; Bolnick et al. ; Djikstra & Border ). Bolnick et al.…”