Alternative reproductive tactics, an overlooked source of life history variation in the invasive round goby

2019 ◽  
Vol 76 (9) ◽  
pp. 1562-1570 ◽  
Author(s):  
Erin S. McCallum ◽  
Aneesh P.H. Bose ◽  
Naylor Lobban ◽  
Julie R. Marentette ◽  
Harri Pettitt-Wade ◽  
...  

Alternative reproductive tactics (ARTs) can generate considerable within-species life history variation but are often overlooked. Here, we use the invasive round goby (Neogobius melanostomus) to address a number of ecological and evolutionary questions about ARTs. Making use of a 12-year, multisite Laurentian Great Lakes data set, we show that the guarder male tactic was twice as common as the sneaker male tactic but that nonreproductive males were the most common morph. The ratio of guarder to sneaker males did not vary spatially despite a wide range of resource densities across sites. Guarders and sneakers spanned similar age ranges, suggesting that the ARTs are nonsequentially expressed. Based on short-term (gut contents) diet analyses, both reproductive tactics consumed fewer types of food and tended to consume fewer items overall when compared with nonreproductive males. Long-term (isotope) diet analyses showed that guarder males fed at a higher trophic level (higher δ15N) and had a broader isotopic niche. Our results show that ARTs are an important aspect of this invasive species’ breeding system and should be accounted for when assessing and managing populations.

PLoS ONE ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. e0174828 ◽  
Author(s):  
Katinka Bleeker ◽  
Karen de Jong ◽  
Nils van Kessel ◽  
Camilla A. Hinde ◽  
Leopold A. J. Nagelkerke

Author(s):  
Artūras Skabeikis ◽  
Jūratė Lesutienė

AbstractFeeding activity and diet composition of round goby were investigated in the south-eastern Baltic Sea, the Lithuanian coastal waters during May-October 2012 in order to determine main feeding objects and seasonal periods when native fauna could be most affected by predation of this highly invasive species. In total, prey represented by 18 taxa was found in the gut contents of dissected fish. Feeding activity of round goby varied depending on the body size, sex and stage of the reproduction period. The gut contents of < 50 mm specimens were dominated by zooplanktonic and meiobenthic organisms, whereas larger individuals (50–99 mm) shifted to amphipods and mollusks. Individuals of the intermediate 100-200 mm length had a variable diet, changing depending on the season; in spring they mostly preyed on Macoma balthica, in summer − on polychaetes, while in autumn the contribution of Mytilus trossulus and fish considerably increased in their diet. Diet composition of individuals ≥ 200 mm was relatively constant in the course of the study with substantial preference to M. balthica. These findings imply that benthic fauna, particularly a newly settled generation of epibenthic mollusks in autumn is under strong predatory pressure of the round goby.


2021 ◽  
Vol 118 (17) ◽  
pp. e2014719118
Author(s):  
Kathryn M. Everson ◽  
Levi N. Gray ◽  
Angela G. Jones ◽  
Nicolette M. Lawrence ◽  
Mary E. Foley ◽  
...  

The North American tiger salamander species complex, including its best-known species, the Mexican axolotl, has long been a source of biological fascination. The complex exhibits a wide range of variation in developmental life history strategies, including populations and individuals that undergo metamorphosis; those able to forego metamorphosis and retain a larval, aquatic lifestyle (i.e., paedomorphosis); and those that do both. The evolution of a paedomorphic life history state is thought to lead to increased population genetic differentiation and ultimately reproductive isolation and speciation, but the degree to which it has shaped population- and species-level divergence is poorly understood. Using a large multilocus dataset from hundreds of samples across North America, we identified genetic clusters across the geographic range of the tiger salamander complex. These clusters often contain a mixture of paedomorphic and metamorphic taxa, indicating that geographic isolation has played a larger role in lineage divergence than paedomorphosis in this system. This conclusion is bolstered by geography-informed analyses indicating no effect of life history strategy on population genetic differentiation and by model-based population genetic analyses demonstrating gene flow between adjacent metamorphic and paedomorphic populations. This fine-scale genetic perspective on life history variation establishes a framework for understanding how plasticity, local adaptation, and gene flow contribute to lineage divergence. Many members of the tiger salamander complex are endangered, and the Mexican axolotl is an important model system in regenerative and biomedical research. Our results chart a course for more informed use of these taxa in experimental, ecological, and conservation research.


Parasitology ◽  
2017 ◽  
Vol 145 (8) ◽  
pp. 1020-1026 ◽  
Author(s):  
Gwendoline M. David ◽  
Cybill Staentzel ◽  
Olivier Schlumberger ◽  
Marie-Jeanne Perrot-Minnot ◽  
Jean-Nicolas Beisel ◽  
...  

AbstractThe round goby, Neogobius melanostomus, is a Ponto-Caspian fish considered as an invasive species in a wide range of aquatic ecosystems. To understand the role that parasites may play in its successful invasion across Western Europe, we investigated the parasitic diversity of the round goby along its invasion corridor, from the Danube to the Upper Rhine rivers, using data from literature and a molecular barcoding approach, respectively. Among 1666 parasites extracted from 179 gobies of the Upper Rhine, all of the 248 parasites barcoded on the c oxidase subunit I gene were identified as Pomphorhynchus laevis. This lack of macroparasite diversity was interpreted as a loss of parasites along its invasion corridor without spillback compensation. The genetic diversity of P. laevis was represented by 33 haplotypes corresponding to a haplotype diversity of 0·65 ± 0·032, but a weak nucleotide diversity of 0·0018 ± 0·00015. Eight of these haplotypes were found in 88·4% of the 248 parasites. These haplotypes belong to a single lineage so far restricted to the Danube, Vistula and Volga rivers (Eastern Europe). This result underlines the exotic status of this Ponto-Caspian lineage in the Upper Rhine, putatively disseminated by the round goby along its invasion corridor.


2018 ◽  
Vol 75 (5) ◽  
pp. 759-771 ◽  
Author(s):  
James A. Mumby ◽  
Timothy B. Johnson ◽  
Thomas J. Stewart ◽  
Edmund A. Halfyard ◽  
Brian C. Weidel ◽  
...  

The forage fish communities of the Laurentian Great Lakes continue to experience changes that have altered ecosystem structure, yet little is known about how they partition resources. Seasonal, spatial, and body size variation in δ13C and δ15N was used to assess isotopic niche overlap and resource and habitat partitioning among the five common offshore Lake Ontario forage fish species (n = 2037; alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), round goby (Neogobius melanostomus), and deepwater (Myoxocephalus thompsonii) and slimy (Cottus cognatus) sculpins). Round goby had the largest isotopic niche (6.1‰2, standard ellipse area), followed by alewife (3.4‰2), while rainbow smelt, slimy sculpin, and deepwater sculpin had the smallest and similar niche size (1.7‰2–1.8‰2), with only the sculpin species showing significant isotopic niche overlap (>63%). Stable isotopes in alewife, round goby, and rainbow smelt varied with location, season, and size, but did not vary in the sculpin species. Lake Ontario forage fish species have partitioned food and habitat resources, and non-native alewife and round goby have the largest isotopic niche, suggestive of a boarder ecological niche, and may contribute to their current high abundance.


2021 ◽  
Author(s):  
Yumeng Pang ◽  
Chih-Shin Chen ◽  
Tomohiko Kawamura ◽  
Yoko Iwata

Abstract Squid are characterized by flexible life-history traits (LHTs) that change in response to changing oceanic parameters. Male alternative reproductive tactics (ARTs), characterized by large-sized ‘consorts’ versus small-sized ‘sneakers’, are commonly observed in loliginid species. This study reports on LHTs flexibility in male squids displaying ARTs. LHTs of consorts and sneakers in Uroteuthis edulis, including body size, age, growth rate and gonado-somatic energy allocation, were compared among seasonal and geographical groups from Japan and Taiwan. The ratio of consorts to sneakers was highest in the group spawning in the ‘Japan-warm’ season (June-November), followed by that of the ‘Japan-cold’ season (December-May), and lowest in Taiwan (spring and autumn). LHTs were compared among cohorts separated by hatching season and catch location (Jwarm, Jcold and Taiwan cohorts). Mean body size of consorts showed no difference among cohorts, although Taiwan consorts were relatively younger than Japan consorts. Mean size and age of sneakers decreased with increased water temperature at hatching. Growth rates of consorts and sneakers were slightly different among cohorts, in accordance with differences of statolith increment widths during their early life stage (50-150 d). Growth rates of both consorts and sneakers were highest in the Taiwan cohort, followed by the Jwarm cohort, with the Jcold cohort lowest. Sneakers invested more both in mantle and gonadal weights than consorts in all cohorts. Gonado-somatic energy allocation patterns of consorts and sneakers were consistent at different temperatures. LHTs of U. edulis consorts and sneakers were strongly influenced by temperature, with higher flexibility in sneakers than consorts.


2016 ◽  
Author(s):  
G. A. Lozano ◽  
A. F. H. Ros

AbstractAlternative reproductive tactics and strategies (ARTS) refer to polymorphic reproductive behaviours in which in addition to the usual two sexes, there are one or more alternative morphs, usually male, that have evolved the ability to circumvent direct intra-sexual competition. Each morph has unique morphological, ecological, developmental, behavioural, life-history, and physiological profiles that shift the balance between reproduction and self-maintenance, one aspect being immunity. Immunoecological work on species with ARTS, which is the topic of this review, is particularly interesting because the alternative morphs make it possible to separate the effects of sex, per se, from other factors that in other species are inextricably linked with sex. We first summarize the evolution, development and maintenance of ARTS. We then review the main immunoecological hypotheses relevant to species with ARTS, dividing them into physiological, life-history, and ecological hypotheses. In context of these hypotheses, we critically review in detail all immunoecological studies we could find on species with ARTS. Several interesting patterns emerge. Oddly, there is a paucity of studies on insects, despite the many benefits that arise from working with insects: larger sample sizes, simple immune systems, and countless forms of alternative reproductive strategies and tactics. Of all the hypotheses reviewed, the immunocompetence handicap hypothesis and its derivatives have generated the greatest amount of work, but not necessarily the greatest level of understanding. Generally, greater understanding would occur if hypotheses and predictions were always explicitly articulated and several hypotheses with mutually exclusive predictions are addressed simultaneously. Integration has been a one-way street, with ecologists delving deeper into physiology, seemingly at the cost of ignoring their organisms’ evolutionary history and ecology. One possible useful framework is to divide ecological and evolutionary factors affecting immunity into those that stimulate the immune system, and those that depress it. Finally, the contributions of genomics to ecology are being increasingly recognized, including in species with ARTS, but we must ensure that evolutionary and ecological hypotheses drive the effort. There is no grandeur in the strict reductionist view of life.


2020 ◽  
Vol 10 (18) ◽  
pp. 9981-9999
Author(s):  
Leon Green ◽  
Jan Niemax ◽  
Jens‐Peter Herrmann ◽  
Axel Temming ◽  
Charlotta Kvarnemo

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