Shape and Size Variation of Jenynsia Lineata (Jenyns 1842) (Cyprinodontiformes: Anablepidae) from Different Coastal Environments
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Hydrobiologia (2019) 828:21–39 https://doi.org/10.1007/s10750-018-3794-6 (0123456789().,-volV)(0123456789().,-volV) PRIMARY RESEARCH PAPER Shape and size variation of Jenynsia lineata (Jenyns 1842) (Cyprinodontiformes: Anablepidae) from different coastal environments Giselle Xavier Perazzo . Fabiano Correˆa . Pablo Calvin˜o . Felipe Alonso . Walter Salzburger . Adriana Gava Received: 6 April 2018 / Revised: 4 October 2018 / Accepted: 5 October 2018 / Published online: 12 October 2018 Ó Springer Nature Switzerland AG 2018 Abstract A key question in ecological speciation is and these differences are specific to each sex. While to understand the causes and consequences of pheno- females showed a variation in the caudal peduncle typic divergence among populations. In this work, we correlated with water current, we did not find such trait analyzed the body shape and size variation in Jenynsia variation and correlation in males. Alternatively, lineata across different coastal habitats along the individuals from marine rocky pools have a convex Atlantic coast of South America. We hypothesized body curvature along the dorsal profile and larger body that J. lineata presents morphological variations to sizes, in both sexes. With these results, we describe the inhabit contrasting environments and that these adap- shape and size morphological variation of J. lineata tations are sex specific. We analyzed 13 populations and discuss this uncommon habitat-dependent sexual from five coastal habitats, using linear and geometric dimorphism in a Neotropical livebearer fish. morphometry, and tested the correlation of body shape variation with environmental variables to understand Keywords Geometric and linear morphometrics Á which environmental factors may influence body Jenynsia multidentata Á Local adaptation Á Phenotypic shape and size variation. Jenynsia lineata showed plasticity Á Sexual dimorphism differences in body shape and size among populations, Handling editor: I. A. Nagelkerken G. X. Perazzo (&) Á A. Gava F. Alonso Instituto de Cieˆncias Biolo´gicas, PPG Biologia de CONICET - Instituto de Bio y Geociencias del NOA Ambientes Aqua´ticos Continentais, Universidade Federal (IBIGEO), Avenida 9 de Julho 14, do Rio Grande, Avenida Ita´lia: km 8, Campus Carreiros, 4405 Rosario De Lerma, Salta, Argentina Rio Grande, RS, Brazil e-mail: [email protected] W. Salzburger Zoological Institute, University of Basel, Vesalgasse 1, F. Correˆa 4051 Basel, Switzerland Laborato´rio de Ictiologia e Ecologia Aqua´tica, Universidade Federal do Acre, BR364, km 4, Campus Universita´rio, Rio Branco, AC, Brazil P. Calvin˜o Á F. Alonso Grupo de Investigacio´n y Conservacio´n de Killis (GICK), Calle 122, 2324 Berisso, Argentina 123 22 Hydrobiologia (2019) 828:21–39 Introduction freshwater fish in the subtropical regions of South America (Garcia et al., 2004; Goyenola et al., 2011) Morphological variation in populations of fish inhab- and has recently been recognized as a senior synonym iting divergent environments provides important of J. multidentata (Jenyns, 1942) (see Amorim, 2018). examples of the processes related to evolution This species is omnivorous (Bastos et al., 2017), with (Langerhans & DeWitt, 2004; Haas et al., 2010; viviparous reproduction, and shows a remarkable Torres-Dowdal et al., 2012; Theis et al., 2014; sexual dimorphism whereby females are larger than ´ Rowinski et al., 2015). Different environments across males, while males feature a copulatory organ a species’ distribution range may generate an array of (gonopodium) formed by a modification of the anal distinct selection regimes, which could promote fin (Betito, 2006; Lopez-Rodriguez et al., 2017). adaptive variation among populations (Townsend Popularly known as ‘barrigudinho’ (Brazil), ‘overito’, et al., 2008), driving plastic responses and/or genetic or ‘madrecita’ (Argentina and Uruguay), J. lineata is adaptive divergence (Crispo, 2008). In the absence of widely distributed and occurs in a variety of habitats, other evolutionary mechanisms and constraints, these such as estuaries (Ramos & Vieira, 2001; Garcia et al., individuals with local trait variation would have, on 2004; Mai et al., 2007; Bastos et al., 2017), coastal average, a higher relative fitness in their local envi- washouts (Bastos et al., 2013), lagoons (Fontoura ronment than individuals from other habitats et al., 1994), freshwater streams (Volcan et al., 2012; (Kawecki & Ebert, 2004). Correˆa et al., 2015), and marine rocky pools (Calvin˜o A key question in the research about ecological & Alonso, 2016). This variability of environments, speciation is to understand the causes and conse- associated with its abundance, makes J. lineata an quences of phenotypic divergence among populations. interesting organism to understand local adaptation to In fishes, some environmental conditions have been Neotropical coastal habitats. recognized as important causes of morphological Heterogeneous aquatic environments, such as variation and are often related to locomotion (Haas coastal habitats, have long been in the focus of et al., 2010; Theis et al., 2014; Gaston & Lauer, 2015; research related to adaptive divergence in fish, and Lauder, 2015) or feeding (Langerhans et al., 2004; body variation is often correlated with a salinity ´ Gomes & Monteiro, 2008;Araujo et al., 2014; Zanella gradient characteristic for such habitats (Norris et al., et al., 2015; Ingley et al., 2016). Another common 2010; Olsen et al., 2016; Dennenmoser et al., 2017). In observation is that fishes show convergence in body J. lineata, for example, specimens are larger in shape when populations occur along similar environ- brackish populations than in those from freshwater mental gradients, allowing the elaboration of an eco- environments (Fontoura et al., 1994; Mai et al., 2005). morphological paradigm for the correlation between Other Cyprinodontiformes, such as Poecilia vivipara body shape and environmental selective pressure (Bloch & Schneider, 1801) (Gomes & Monteiro, 2008; (Langerhans et al., 2004). For example, different fish Arau´jo et al., 2014) and Gambusia affinis (Baird & species tend to have a more compressed body shape Girard, 1853) (Langerhans et al., 2004), or even fishes (longer dorsal–ventral axis and shorter anterior–pos- from other orders, such as Clupea harengus (Linnaeus, terior axis) in populations of lentic water environ- 1758) (Clupeiformes) (Jørgensen et al., 2008)or ments compared to those of lotic environments, where Gasterosteus aculeatus (Linnaeus, 1758) (Gas- body shape is typically more fusiform (Haas et al., terosteiformes) (Marchinko & Schluter, 2007; Berner 2010; Gaston & Lauer, 2015). Such an eco-morpho- et al., 2008, 2009; Baker et al., 2015; Foster et al., logical paradigm has also been established for differ- 2015), show a similar variation in body size and shape ent predation pressures. In this case, populations of along salinity gradients. Different environments are an phylogenetically or geographically distinct species important source of divergent natural selection, and feature a pattern of variation in the body shape, adaptation to those habitats may, under some circum- according to the presence or absence of predators, that stances, lead to speciation (see, e.g., Schluter, 2009; is related to the ability of predator escape (burst-swim) Nosil, 2012). To understand the dynamics of adapta- (Langerhans et al., 2004). tion to different habitats, it is important to characterize The one-sided livebearer Jenynsia lineata (Jenyns, morphological variation at the level of individuals and 1842) is one of the most abundant brackish and 123 Hydrobiologia (2019) 828:21–39 23 populations as well as at ecological scales (Shukla & the variation in body shape and size (through centroid Bhat, 2017). size, a composite size measure based on all landmarks An important issue when one is interested in (Mitteroecker et al., 2013)), with the aim to investigate understanding the contribution of habitat environ- the phenotypic variation in J. lineata among distinct ments to body shape variation is to consider the habitats. We used linear measurements to improve the patterns of sex differences in body shape (Mokodon- size analyses and to obtain information regarding the gan et al., 2018). Since body shapes could be specific size of specific structures of the body (such as fins and to each sex, species with remarkable sexual dimor- body lengths), not available from geometric morpho- phism might show males and females with distinct metrics data. We then related body shape with habitat-related body shape variation. In such cases, environmental variables to understand which environ- trade-offs between natural and sexual selection often mental factors could influence body shape variation. underlie the diversification of sexes (Heinen-Kay Beyond, we investigated how each sex responds et al., 2015), especially because evolutionary forces morphologically to the habitat variation. With this that have shaped the breeding success of males are study, we aimed to determine how a fish species with fundamentally different from those acting on females remarkable sexual dimorphism could be phenotypi- (Bronson, 1985). Species with marked sexual dimor- cally adapted to distinct environments. Specifically, phism are the primer evidence that sexual selection is a we wanted to understand whether J. lineata presents strong force in the evolution of this intraspecific phenotypic variation between environments, what divergence (Kocher, 2004). However, habitat choice varies in body size