Alternative reproductive tactics and life history phenotypes

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.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2018-0340 ◽

2019 ◽

Vol 76 (9) ◽

pp. 1562-1570 ◽

Cited By ~ 3

Author(s):

Erin S. McCallum ◽

Aneesh P.H. Bose ◽

Naylor Lobban ◽

Julie R. Marentette ◽

Harri Pettitt-Wade ◽

...

Keyword(s):

Life History ◽

Round Goby ◽

Neogobius Melanostomus ◽

Alternative Reproductive Tactics ◽

Gut Contents ◽

Isotopic Niche ◽

Life History Variation ◽

Reproductive Tactics ◽

Wide Range ◽

Diet Analyses

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.

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Immunoecology of species with alternative reproductive tactics and strategies

10.1101/062083 ◽

2016 ◽

Author(s):

G. A. Lozano ◽

A. F. H. Ros

Keyword(s):

Life History ◽

Alternative Reproductive Tactics ◽

Reproductive Tactics ◽

Sexual Competition ◽

Factors Affecting ◽

Physiological Profiles ◽

Handicap Hypothesis ◽

The Many ◽

Level Of Understanding ◽

The Cost

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.

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Brain Transcriptional Profiles of Male Alternative Reproductive Tactics and Females in Bluegill Sunfish

10.1101/025916 ◽

2015 ◽

Author(s):

Charlyn G. Partridge ◽

Matthew D. MacManes ◽

Rosemary Knapp ◽

Bryan D. Neff

Keyword(s):

Life History ◽

Candidate Genes ◽

Ampa Receptors ◽

Life Histories ◽

Alternative Reproductive Tactics ◽

Bluegill Sunfish ◽

Potential Candidate ◽

Reproductive Tactics ◽

Brain Transcriptome ◽

Responsive Element

AbstractBluegill sunfish are one of the classic systems for studying male alternative reproductive tactics (ARTs) in teleost fishes. In this species, there are two distinct life histories: parental and cuckolder, encompassing three reproductive tactics, parental, satellite, and sneaker. The parental life history is fixed, whereas individuals who enter the cuckolder life history transition from the sneaker to the satellite tactic as they grow. For this study, we used RNAseq to characterize the brain transcriptome of the three male tactics and females during spawning to identify gene categories associated with each tactic and identify potential candidate genes influencing their different spawning behaviors. We found that sneaker males had higher levels of gene differentiation compared to the other two male tactics. Sneaker males also had high expression in ionotropic glutamate receptor genes, specifically AMPA receptors, which may be important for increased working spatial memory while attempting to cuckold parental males at their nests. Larger differences in gene expression also occurred among male tactics than between males and females. We found significant expression differences in several candidate genes that were previously identified in other species with ARTs and suggest a previously undescribed role for cAMP-responsive element modulator (crem) in influencing parental male behaviors during spawning.

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