Age-specific residual reproductive value and reproductive effort in the Iceland scallop, Chlamys islandica (O.F. M�ller)

Oecologia ◽  
1981 ◽  
Vol 51 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Ola Vahl
Keyword(s):  
Reproductive Effort ◽  
Reproductive Value ◽  
Residual Reproductive Value ◽  
Chlamys Islandica ◽  
Iceland Scallop

scholarly journals The influence of male age and simulated pathogenic infection on producing a dishonest sexual signal

2012 ◽  
Vol 279 (1748) ◽  
pp. 4740-4746 ◽  
Author(s):  
Emily K. Copeland ◽  
Kenneth M. Fedorka
Keyword(s):  
Reproductive Effort ◽  
Reproductive Value ◽  
Female Fitness ◽  
Sexual Signal ◽  
Terminal Investment ◽  
Male Age ◽  
Residual Reproductive Value ◽  
Male Reproductive Effort ◽  
Allonemobius Socius ◽  
Pathogenic Infection

In recent years, studies have shown that reproductive effort decelerates in response to pathogenic infection. If infection substantially reduces a host's residual reproductive value (RRV), however, then an acceleration of effort may instead occur (e.g. terminal investment). Reproductive acceleration would theoretically allow hosts to maintain or exaggerate their sexual signal upon infection. This would create a deceptive message from the perspective of the chooser, who may unwittingly copulate with an infected mate to their detriment. Using the cricket Allonemobius socius , we assessed the potential for reduced RRV to accelerate male reproductive effort and create a dishonest signal. RRV was manipulated through male age and simulated pathogenic insult. Reproductive effort was measured as calling song energetics, mating success, latency to mate and nuptial gift size. We show that males adopted either an accelerated or decelerated reproductive strategy upon infection, and that this decision was probably mediated by RRV. Moreover, males who accelerated their effort produced a dishonest signal by increasing their song energetics while providing fewer paternal resources (i.e. smaller gifts). Our study is one of the few to document the existence of dishonest signals and relate dishonesty to a potential reduction in female fitness, underscoring the conflict inherent in sexual reproduction.

scholarly journals Collapse of the fishery for Iceland scallop (Chlamys islandica) in Breidafjordur, West Iceland

2006 ◽  
Vol 64 (2) ◽  
pp. 298-308 ◽  
Author(s):  
Jónas P. Jonasson ◽  
Gudrun Thorarinsdottir ◽  
Hrafnkell Eiriksson ◽  
Jon Solmundsson ◽  
Gudrun Marteinsdottir
Keyword(s):  
Stock Index ◽  
Steady Increase ◽  
Natural Mortality ◽  
Muscle Weight ◽  
Chlamys Islandica ◽  
Poor Recruitment ◽  
Low Levels ◽  
Iceland Scallop ◽  
Fishing Area ◽  
Very High

Abstract Jonasson, J. P., Thorarinsdottir, G., Eiriksson, H., Solmundsson, J., and Marteinsdottir, G. 2007. Collapse of the fishery for Iceland scallop (Chlamys islandica) in Breidafjordur, West Iceland. – ICES Journal of Marine Science, 64: 298–308. The stock index of the Iceland scallop (Chlamys islandica) in Breidafjordur on the west coast of Iceland has declined drastically in recent years. Total fishing mortality was very high throughout the study period from 1993 to 2003, a period characterized by a steady increase in summer sea surface temperature, in 2003 reaching the highest estimated level of the previous century. Between 1998 and 2005, estimates of chlorophyll a (food availability) fluctuated with periods of low chlorophyll followed by a reduction in muscle weight and high natural mortality. High levels of natural mortality were observed in the main fishing area in the southern part of Breidafjordur. There the stock index had been declining since 1994. Recruitment to the fishable stock was highly variable during the study period, with low recruitment towards the end of the 1990s. Subsequently the fishery has been on relatively few year classes, and the stock has been fragile because of several years of poor recruitment and high natural mortality. Consequently, the stock appeared unable to withstand the fishing pressure and declined to historically low levels, leading to a halt to fishing in 2004.

ARE BIOENERGETIC PROPERTIES LINKED WITH SHELL FLUCTUATING ASYMMETRY AND HETEROZYGOSITY IN ICELAND SCALLOP,CHLAMYS ISLANDICA?

2007 ◽  
Vol 26 (1) ◽  
pp. 17-23
Author(s):  
ISABELLE TREMBLAY ◽  
MARCEL FRÉCHETTE ◽  
JEAN-MARIE SÉVIGNY ◽  
HELGA E. GUDERLEY
Keyword(s):  
Fluctuating Asymmetry ◽  
Chlamys Islandica ◽  
Iceland Scallop

Use of Biochemical Genetic Markers to Discriminate between Adductor Muscles of the Sea Scallop (Placopecten magellanicus) and the Iceland Scallop (Chlamys islandica)

1993 ◽  
Vol 50 (6) ◽  
pp. 1222-1228 ◽  
Author(s):  
E. Kenchington ◽  
K. S. Naidu ◽  
D. L. Roddick ◽  
D. I. Cook ◽  
E. Zouros
Keyword(s):  
Genetic Markers ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Placopecten Magellanicus ◽  
Sea Scallop ◽  
Chlamys Islandica ◽  
Adductor Muscles ◽  
Enforcement Programme ◽  
Iceland Scallop ◽  
Species Specific

Three biochemical techniques were applied to adductor muscles of Placopecten magellanicus and Chlamys islandica, two commercially important scallops, to search for species-specific genetic markers. Allozyme electrophoresis identified two enzyme systems, mannose phosphate isomerase and glutamic oxaloacetate transaminase, which appear to be diagnostic. Sequencing of the 18S rRNA gene in each species showed 15 nucleotide differences over 1815 base pairs. Digestion of the gene with the restriction enzyme XHO I released two fragments in Placopecten and three in Chlamys. All three techniques could be developed for management purposes as part of an enforcement programme to identify illegally caught scallops.

scholarly journals Flirting with danger: predation risk interacts with male condition to influence sexual display

2019 ◽  
Vol 30 (5) ◽  
pp. 1265-1272
Author(s):  
Pedro Z de Moraes ◽  
Pedro Diniz ◽  
Esteban Fernandez-Juricic ◽  
Regina H Macedo
Keyword(s):  
High Risk ◽  
Predation Risk ◽  
Video Recording ◽  
Reproductive Value ◽  
Male Response ◽  
Residual Reproductive Value ◽  
Display Behavior ◽  
Sexual Display ◽  
Male Condition ◽  
Risk Of Predation

AbstractSexual signaling coevolves with the sensory systems of intended receivers; however, predators may be unintended receivers of sexual signals. Conspicuous aerial displays in some species may place males at high risk of predation from eavesdropping predators. There are three different hypotheses to explain how signaling males can deal with increased predation risk: (1) males invest in survival by decreasing signal conspicuousness; (2) males invest in reproduction by increasing signal conspicuousness; and (3) male response is condition-dependent according to his residual reproductive value. Here, we used blue-black grassquits (Volatinia jacarina) to test these hypotheses, asking whether males modify leap displays under different levels of predation risk. Grassquit males develop an iridescent nuptial plumage and spend considerable time emitting a multimodal signal: while leaping from a perch, males clap their wings above their heads and emit a high-pitched short song. We exposed males to predator and nonpredator playbacks while video recording their displays. We found interactions between predation risk and 2 male condition variables (ectoparasite infestation and proportion of nuptial plumage coverage) that influenced display behavior. Less parasitized males and those with higher proportion of nuptial plumage showed no change in display behavior, while more parasitized males and those with lower proportion of nuptial plumage increased the vigor of displays under predation risk. In other words, males with low residual reproductive value increased reproductive effort when there was a high risk of extrinsic death. Our study provides some empirical support for the terminal investment hypothesis.

Life histories of North American game birds: a reanalysis

1988 ◽  
Vol 66 (8) ◽  
pp. 1906-1912 ◽  
Author(s):  
Todd W. Arnold
Keyword(s):  
Life History ◽  
North American ◽  
Life Histories ◽  
Life History Traits ◽  
Reproductive Effort ◽  
Cost Of Reproduction ◽  
Reproductive Value ◽  
Trade Offs ◽  
Game Birds ◽  
The Cost

Recently, Zammuto (R. M. Zammuto. 1986. Can. J. Zool. 64: 2739–2749) suggested that North American game birds exhibited survival–fecundity trade-offs consistent with the "cost of reproduction" hypothesis. However, there were four serious problems with the data and the analyses that Zammuto used: (i) the species chosen for analysis ("game birds") showed little taxonomic or ecological uniformity, (ii) the measures of future reproductive value (maximum longevity) were severely biased by unequal sample sizes of band recoveries, (iii) the measures of current reproductive effort (clutch sizes) were inappropriate given that most of the birds analyzed produce self-feeding precocial offspring, and (iv) the statistical units used in the majority of analyses (species) were not statistically independent with respect to higher level taxonomy. After correcting these problems, I found little evidence of survival–fecundity trade-offs among precocial game birds, and I attribute most of the explainable variation in life-history traits of these birds to allometry, phylogeny, and geography.

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