Evidence of local adaptation in a waterfall-climbing Hawaiian goby fish derived from coupled biophysical modeling of larval dispersal and post-settlement selection

Abstract

Background Local adaptation of marine and diadromous species is thought to be a product of larval dispersal, settlement mortality, and differential reproductive success, particularly in heterogeneous post-settlement habitats. We evaluated this premise with an oceanographic passive larval dispersal model coupled with individual-based models of post-settlement selection and reproduction to infer conditions that underlie local adaptation in Sicyopterus stimpsoni , an amphidromous Hawaiian goby known for its ability to climb waterfalls. Results Our model results demonstrated that larval dispersal is spatio-temporally asymmetric, with more larvae dispersed from the southeast (the Big Island) to northwest (Kaua‘i) along the archipelago, reflecting prevailing conditions such as El Niño/La Niña oscillations. Yet connectivity is nonetheless sufficient to result in homogenous populations across the archipelago. We also found, however, that ontogenetic shifts in habitat can give rise to adaptive morphological divergence when the strength of predation-driven post-settlement selection crosses a critical threshold. Notably, our simulations showed that larval dispersal is not the only factor determining the likelihood of morphological divergence. We found adaptive potential and evolutionary trajectories of S. stimpsoni were greater on islands with stronger environmental gradients and greater variance in larval cohort morphology due to fluctuating immigration. Conclusions Contrary to expectation, these findings indicate that immigration can act in concert with selection to favor local adaptation and divergence in species with marine larval dispersal. Further development of model simulations, parameterized to reflect additional empirical estimates of abiotic and biotic factors, will help advance our understanding of the proximate and ultimate mechanisms driving adaptive evolution, population resilience, and speciation in marine-associated species. Electronic supplementary material The online version of this article (10.1186/s12862-019-1413-4) contains supplementary material, which is available to authorized users.

Morphology and growth pattern of Nike fish (amphidromous goby larvae) in Gorontalo Waters, Indonesia

“…Therefore, comprehensive studies of Nike species are needed to show the form of the alteration. Local adaptation of marine and diadromous species is estimated to be a product of larval dispersal, settlement mortality, and differential reproductive success, particularly in heterogeneous post-settlement habitats (Moody et al, 2019).…”

Migratory flexibility in native Hawai'ian amphidromous fishes

“…This study underscores the importance of understanding the propensity and nature of migration in order to sustain native Hawai'ian amphidromous gobies (Hogan et al ., ). Larvae, especially early‐stage larvae, are thought to experience high mortality rates as a consequence of exposure to heterogeneous and dynamic conditions in both marine and stream ecosystems (Cushing, ; Cushing, 1990; Hjort, ; Houde, ; Lasker, ; Moody et al ., ). Increasing pressures in both environments may further depress survival and recruitment (Cushing, ; Hjort, , ; Lisi et al ., ; Moody et al ., ; Walter et al ., ).…”

“…Marine migration has long been considered a defining dimension of the ecology and evolutionary biology of native Hawai'ian amphidromous gobies (Alda et al ., ; McDowall, ; Moody et al ., , ). Amphidromy allows for the colonisation of newly formed streams or recolonisation of areas that have been disturbed by volcanic or human activity (McDowall, ).…”

“…This inference is largely based on evidence of little to no neutral genetic structure in native gobies throughout the Hawai'ian Archipelago, suggesting that marine larval dispersal results in widespread population connectivity among streams and across islands (Alda et al ., ; Chubb et al ., ; McDowall, ; Moody et al ., ). Archipelago‐wide stream surveys (Blum et al ., ) as well as morphometric and simulation studies (Moody et al ., ; Moody et al ., ) indicate, however, that larval dispersal is more constrained, perhaps scaling to all catchments (Blum et al ., ) or to one or a handful of proximate catchments (Moody et al ., ; Moody et al ., ) on an island. Evidence of partial migration in all but one species also indicates that obligate marine larval dispersal is not as prevalent as has been previously supposed.…”

Invasion and rapid adaptation of guppies (Poecilia reticulata) across the Hawaiian Archipelago

“…These conditions are more akin to those that have given rise to adaptive radiations of terrestrial Hawaiian biota, such as Drosophila, silverswords, honeycreepers, and spiders (Gillespie et al, 1994;Lerner et al, 2011;Montgomery, 1975;Witter & Carr, 1988) than native Hawaiian stream fishes (Moody et al, 2015(Moody et al, , 2019Moody, Kawano, et al, 2017).…”