Spatial, sexual, and rapid temporal differentiation in neuromast expression on lateral plates of Haida Gwaii threespine stickleback (Gasterosteusaculeatus)

Abstract

Lateral lines, a major sensory modality in fishes, are diverse among taxa, but their intraspecific variation has received limited attention. We examined numbers of superficial neuromasts on the buttressing lateral plates (LP) of 1910 threespine stickleback (Gasterosteus aculeatus Linnaeus, 1758) from 26 ecologically and morphologically diverse populations on the Haida Gwaii archipelago, western Canada. Extending from previous studies, we predicted that (i) highly stained dystrophic localities would have threespine stickleback with elevated numbers of neuromasts per plate due to a greater reliance on non-visual sensory modalities and (ii) that LP count and neuromast numbers per plate would functionally covary with predatory assemblage. We found that there were no differences in neuromast count across major habitats (marine, lake, stream), but clear-water populations and those with predatory fish had significantly more neuromasts per plate than most populations in highly stained dystrophic lakes, the effects being accentuated on the first buttressing plate (LP4). We also report the first evidence that neuromast counts per plate are sexually dimorphic, with males having a greater density of neuromasts in most populations. Two transplant experiments between ecologically opposite habitats indicate that within 12 generations, neuromast counts per plate can rapidly shift in response to a change in habitat.

Ecological predictors of lateral line asymmetry in stickleback (Gasterosteus aculeatus)

“…On average, neuromast counts are greater in freshwater than oceanic populations and benthic versus limnetic population pairs (Wark and Peichel 2010;Ahnelt et al 2021). Furthermore, populations subject to peat-stained waters develop fewer neuromasts on their lateral plates, as do females relative to males (Planidin and Reimchen 2019).…”

“…Many life history traits are associated with the lateral line, such as predator prey interaction (Coombs and Patton 2009;Junges et al 2010;Schwalbe et al 2012), rheotaxis (Baker and Montgomery 1999;Suli et al 2012;Brown and Simmons 2016;Jiang et al 2017), schooling (Middlemiss et al 2017;Mekdara et al 2018) and conspecific interaction (Butler and Maruska 2016). There is also a growing body of evidence showing that lateral line morphology is variable within species, particularly among populations in different habitats (Wark and Peichel 2010;Trokovic et al 2011;Fischer et al 2013;Planidin and Reimchen 2019). This intraspecific divergence presents a useful model system to study the mechanisms driving the diversification of the lateral line system.…”

“…Threespine stickleback, Gasterosteus aculeatus (Linnaeus 1758), exhibit highly variable numbers of neuromasts (Wark and Peichel 2010;Wark et al 2012;Planidin and Reimchen 2019;Ahnelt et al 2021). The lateral line of threespine stickleback is comprised entirely of superficial neuromasts, which differ in their number in association with habitat characteristics and life history.…”

Diversity and sexual dimorphism in the head lateral line system in North Sea populations of threespine sticklebacks, Gasterosteus aculeatus (Teleostei: Gasterosteidae)

“…In the investigated threespine sticklebacks, the posttemporal bone forms a short longitudinal groove which carries a row of neuromasts. This is contrary to the typical trunk lateral line of this fish which generally consists of small groups of pits on the bony lateral plates (Wark and Peichel 2010;Planidin and Reimchen 2019), or, if the plates are missing, of single neuromasts free standing on the skin (Wark and Peichel 2010). Nevertheless, it has to be noted that the separation of PO, PT and ST is just functional.…”

“…Jollie 1975;Ahnelt and Göschl 2003;Fischer et al 2013). But recently, this phenomenon has received more attention, especially concerning gasterosteid fishes (Wark and Peichel 2010;Jiang et al 2015;Trokovic et al 2011;Planidin and Reimchen 2019). These authors found that the LLS of the threespine stickleback varies in the number of its neuromasts among populations (Wark and Peichel 2010) and among sexes (Planidin and Reimchen 2019) and suggest that these numerical differences are the results of environmental constraints.…”