scholarly journals Immunoecology of species with alternative reproductive tactics and strategies

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.

Real options method in the assessment of mining industry investment

2014 ◽  
Vol 2 (6) ◽  
pp. 261-268
Author(s):  
Андрей Гусев ◽  
Andrey Gusev ◽  
Денис Нарулин ◽  
Denis Narulin
Keyword(s):  
Real Options ◽  
Mining Industry ◽  
Mathematical Basis ◽  
Factors Affecting ◽  
Valuation Model ◽  
Real Options Valuation ◽  
Option Pricing Model ◽  
Mining Projects ◽  
The Many ◽  
The Cost

Investment in mining projects involves significant costs, long period of time, consistent type of investment decisions and complex mosaic of the many unforeseen factors affecting the cost of the project. Real options valuation (ROV) is one of the modern methods of assessment that helps in adaptation and revision of mining projects under uncertainty. Application of the method is technically demanding and requires a certain knowledge of the mining industry, and also has three main barriers: the problem of marketing, analysis and consequences. The mathematical basis of this method is a valuation model based on option pricing model, invented by Black — Scholes. List of alternatives and opportunities in project phases discussed in the article demonstrates perfect suitability of the mining industry for practicing different types of real options.

scholarly journals Environmental Influence on Life-History Traits in Male Squid Uroteuthis Edulis With Alternative Reproductive Tactics

2021 ◽  
Author(s):  
Yumeng Pang ◽  
Chih-Shin Chen ◽  
Tomohiko Kawamura ◽  
Yoko Iwata
Keyword(s):  
Life History ◽  
Body Size ◽  
Growth Rates ◽  
Life History Traits ◽  
Environmental Influence ◽  
Life Stage ◽  
Energy Allocation ◽  
Alternative Reproductive Tactics ◽  
Reproductive Tactics ◽  
Somatic Energy

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.

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 ◽  
...  
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.

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

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.

Pescadores migrantes: análisis de su dinámica e integración Social

2019 ◽  
Vol 37 (3) ◽  
pp. 18
Author(s):  
Fernando González Laxe
Keyword(s):  
Renewable Resources ◽  
Sustainable Management ◽  
Social Groups ◽  
Technological Innovations ◽  
Social Competition ◽  
Factors Affecting ◽  
Fish Stocks ◽  
Fishery Resources ◽  
Migration Dynamics ◽  
The Many

The globalization of the economy encourages massive population displacements and inevitably generates a cosmopolitization of societies. This leads to concern, misunderstanding and rejection. The most vulnerable social groups in society can perceive the population as intruders and enemies in social competition. Undoubtedly, the extreme spatial instability of fishery resources is among the many factors affecting migration dynamics. Various reasons for the mobility of fishermen are relevant around this concept. These include aspect related to traditions, to the capitalisation of activity, to technological innovations, and to innovation exchanges concerning the location of fish stocks. This article reflects on spatial increase of fishermen’s. The analyse are part of the paradigm of the sustainable management of common renewable resources, in particular fishery resources. It presents three lines of analysis: the reason for mobility; the choice of destination; and are the integration into host units.

scholarly journals Factors Affecting the Rate of Fuel Consumption in Aircrafts

2021 ◽  
Vol 13 (14) ◽  
pp. 8066
Author(s):  
Thowayeb H. Hassan ◽  
Abu Elnasr E. Sobaih ◽  
Amany E. Salem
Keyword(s):  
Fuel Consumption ◽  
Positive Association ◽  
Pollutant Emissions ◽  
Aviation Industry ◽  
Factors Affecting ◽  
Fuel Flow ◽  
Homogeneity Of Variance ◽  
Strong Positive Association ◽  
Ground Distance ◽  
The Cost

The cost of fuel and its availability are among the most major concerns for aircrafts and the aviation industry overall. Environmental difficulties with chemical pollutant emissions emitted by aviation machines are also connected to fuel consumption. As a result, it is crucial to examine factors that affect the overall fuel usage and consumption in the airport-based aviation industry. Several variables were investigated related to the total fuel consumed, such as dry operating weight (DOW) (KG), zero-fuel weight (ZFW), take-off weight (TOW), air distance (AIR DIST) (KM), and ground distance (GDN DIST). Analysis of the correlation between total fuel consumed as well as the extra fuel and selected variables was conducted. The results showed that the most positively associated factors with the total used fuel were the air distance (r2 = 0.86, p < 0.01), ground distance (r2 = 0.78, p < 0.01), TOW (r2 = 0.68, p < 0.01), and flight time (r2 = 0.68, p < 0.01). There was also a strong positive association between the average fuel flow (FF) and actual TOW (r2 = 0.74, p < 0.01) as well as ZFW (r2 = 0.61, p < 0.01). The generalized linear model (GLM) was utilized to assess the predictions of total energy usage after evaluating important outliers, stability of the homogeneity of variance, and the normalization of the parameter estimation. The results of multiple linear regression revealed that the most significant predictors of the total consumed fuel were the actual ZFW (p < 0.01), actual TOW (p < 0.01), and actual average FF (p < 0.05). The results interestingly confirmed that wind speed has some consequences and effects on arrival fuel usage. The result reflects that thermal and hydrodynamic economies impact on the flying fuel economy. The research has various implications for both scholars and practitioners of aviation industry.

scholarly journals Factors Affecting Thanatosis in the Braconid Parasitoid Wasp Heterospilus prosopidis

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 48
Author(s):  
Mio Amemiya ◽  
Kôji Sasakawa
Keyword(s):  
Life History ◽  
Antipredator Behavior ◽  
Parasitoid Wasp ◽  
Ecological Perspective ◽  
Background Color ◽  
Factors Affecting ◽  
Death Feigning ◽  
Heterospilus Prosopidis ◽  
History Of

Thanatosis, also called death feigning, is often an antipredator behavior. In insects, it has been reported from species of various orders, but knowledge of this behavior in Hymenoptera is insufficient. This study examined the effects of sex, age (0 or 2 days old), temperature (18 or 25 °C), and background color (white, green, or brown) on thanatosis in the braconid parasitoid wasp Heterospilus prosopidis. Thanatosis was more frequent in 0-d-old individuals and in females at 18 °C. The duration of thanatosis was longer in females, but this effect of sex was weaker at 18 °C and in 0-d-old individuals. The background color affected neither the frequency nor duration. These results were compared with reports for other insects and predictions based on the life history of this species, and are discussed from an ecological perspective.

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