scholarly journals Facultative sex and reproductive strategies in response to male availability in the spiny stick insect, Extatosoma tiaratum

2010 ◽  
Vol 58 (4) ◽  
pp. 228 ◽  
Author(s):  
Angela Schneider ◽  
Mark A. Elgar
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Reproductive Strategies ◽  
Reproductive Output ◽  
Stick Insect ◽  
Model System ◽  
Life History Strategies ◽  
Evolutionary Significance ◽  
Social Environments ◽  
Reproductive State

Facultative thelytoky, in which females can reproduce both sexually and asexually, offers a promising model system to understand the evolutionary significance of sex, by providing insights into whether the different reproductive modes reflect an adaptive life-history response to varying environmental conditions. Females of the spiny stick insect, Extatosoma tiaratum, can reproduce both sexually or asexually. We show that virgin females signal their reproductive state: males respond to signals produced by virgin females that have not commenced ovipositing, but fail to respond to ovipositing virgin females. Virgin females reared under different social environments varied their reproductive output: virgin females reared in the absence of males laid more eggs over a seven-day period than virgin females reared in the presence of males. The reproductive output of mated females over a seven-day period was higher than that of virgin females. These data suggest that female E. tiaratum adjust several life-history strategies in conjunction with facultative thelytoky.

scholarly journals Contrasting effects of climate change on seasonal survival of a hibernating mammal

2020 ◽  
Vol 117 (30) ◽  
pp. 18119-18126 ◽  
Author(s):  
Line S. Cordes ◽  
Daniel T. Blumstein ◽  
Kenneth B. Armitage ◽  
Paul J. CaraDonna ◽  
Dylan Z. Childs ◽  
...  
Keyword(s):  
Climate Change ◽  
Population Dynamics ◽  
Life History ◽  
Environmental Conditions ◽  
Temporal Trends ◽  
Life History Strategies ◽  
Environmental Drivers ◽  
Age Classes ◽  
History Of ◽  
Colorado Rocky Mountains

Seasonal environmental conditions shape the behavior and life history of virtually all organisms. Climate change is modifying these seasonal environmental conditions, which threatens to disrupt population dynamics. It is conceivable that climatic changes may be beneficial in one season but result in detrimental conditions in another because life-history strategies vary between these time periods. We analyzed the temporal trends in seasonal survival of yellow-bellied marmots (Marmota flaviventer) and explored the environmental drivers using a 40-y dataset from the Colorado Rocky Mountains (USA). Trends in survival revealed divergent seasonal patterns, which were similar across age-classes. Marmot survival declined during winter but generally increased during summer. Interestingly, different environmental factors appeared to drive survival trends across age-classes. Winter survival was largely driven by conditions during the preceding summer and the effect of continued climate change was likely to be mainly negative, whereas the likely outcome of continued climate change on summer survival was generally positive. This study illustrates that seasonal demographic responses need disentangling to accurately forecast the impacts of climate change on animal population dynamics.

scholarly journals Cuckoos, cowbirds and hosts: adaptations, trade-offs and constraints

2006 ◽  
Vol 362 (1486) ◽  
pp. 1873-1886 ◽  
Author(s):  
Oliver Krüger
Keyword(s):  
Life History ◽  
Brood Parasitism ◽  
Reproductive Strategies ◽  
Life History Theory ◽  
Model Systems ◽  
Life History Strategies ◽  
Host System ◽  
Brood Parasites ◽  
Trade Offs ◽  
Evolution Of Life

The interactions between brood parasitic birds and their host species provide one of the best model systems for coevolution. Despite being intensively studied, the parasite–host system provides ample opportunities to test new predictions from both coevolutionary theory as well as life-history theory in general. I identify four main areas that might be especially fruitful: cuckoo female gentes as alternative reproductive strategies, non-random and nonlinear risks of brood parasitism for host individuals, host parental quality and targeted brood parasitism, and differences and similarities between predation risk and parasitism risk. Rather than being a rare and intriguing system to study coevolutionary processes, I believe that avian brood parasites and their hosts are much more important as extreme cases in the evolution of life-history strategies. They provide unique examples of trade-offs and situations where constraints are either completely removed or particularly severe.

Smelling the future: subtle life-history adjustments in response to environmental conditions and perceived transmission opportunities in a trematode

Parasitology ◽  
2016 ◽  
Vol 144 (4) ◽  
pp. 464-474 ◽  
Author(s):  
C. LAGRUE ◽  
R. RINNEVALLI ◽  
R. POULIN
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Intermediate Host ◽  
Definitive Host ◽  
Environmental Conditions ◽  
Life History Strategy ◽  
Host Density ◽  
Life Cycles ◽  
Life History Strategies ◽  
Priming Effects

SUMMARYA number of parasites with complex life cycles can abbreviate their life cycles to increase the likelihood of reproducing. For example, some trematodes can facultatively skip the definitive host and produce viable eggs while still inside their intermediate host. The resulting shorter life cycle is clearly advantageous when transmission probabilities to the definitive hosts are low. Coitocaecum parvum can mature precociously (progenesis), and produce eggs by selfing inside its amphipod second intermediate host. Environmental factors such as definitive host density and water temperature influence the life-history strategy adopted by C. parvum in their crustacean host. However, it is also possible that information about transmission opportunities gathered earlier in the life cycle (i.e. by cercariae-producing sporocysts in the first intermediate host) could have priming effects on the adoption of one or the other life strategy. Here we document the effects of environmental parameters (host chemical cues and temperature) on cercarial production within snail hosts and parasite life-history strategy in the amphipod host. We found that environmental cues perceived early in life have limited priming effects on life-history strategies later in life and probably account for only a small part of the variation among conspecific parasites. External cues gathered at the metacercarial stage seem to largely override potential effects of the environmental conditions experienced by early stages of the parasite.

scholarly journals Breeding biology of the Green-backed Tit (Parus monticolus) in southwest China

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ping Ye ◽  
Xiaogang Yao ◽  
Jianli Bi ◽  
Guangrong Li ◽  
Wei Liang ◽  
...  
Keyword(s):  
Life History ◽  
Reproductive Strategies ◽  
Southwest China ◽  
Parental Behavior ◽  
Egg Laying ◽  
Breeding Biology ◽  
Life History Strategies ◽  
Reproductive Outcome ◽  
Behavioral Patterns ◽  
Evolution Of Life

AbstractStudies on breeding biology enable us to broaden our understanding of the evolution of life history strategies. We studied the breeding biology of the Green-backed Tit (Parus monticolus) to provide comprehensive data on nest and egg characteristics, parental behavior throughout egg laying and nestling periods, and reproductive outcome. Our study reveals adaptive behavioral patterns and reproductive strategies for P. monticolus.

Latitudinal Variation in Reproductive Characteristics of American Shad (Alosa sapidissima): Evidence for Population Specific Life History Strategies in Fish

1978 ◽  
Vol 35 (11) ◽  
pp. 1469-1478 ◽  
Author(s):  
William C. Leggett ◽  
James E. Carscadden
Keyword(s):  
Environmental Conditions ◽  
Reproductive Strategies ◽  
Thermal Environment ◽  
Growth Parameters ◽  
Fine Tuning ◽  
American Shad ◽  
Latitudinal Variation ◽  
Life History Strategies ◽  
Alosa Sapidissima ◽  
Reproductive Characteristics

The reproductive characteristics of five populations of American shad (Alosa sapidissima) on the Atlantic coast were studied. The proportion of repeat spawners increased with the latitude of the home river. Relative and absolute fecundities decreased as the proportion of repeat spawners increased. These reciprocal trends in reproductive characteristics are independent of growth parameters. The principal factor influencing reproductive strategies in shad appears to be variability in the thermal regime of the home river which influences egg and larval survival. Northern populations, spawning in environments that are thermally harsh and variable, allocate a greater proportion of their energy reserves to migration thereby ensuring higher postspawning survival. This is accomplished by reducing the energy allocated to gonads. The pattern of reproductive responses of shad to the thermal environment of the natal river is consistent with existing ecological theory concerning the evolution of reproductive strategies in response to differing environmental conditions. Available literature for several other fishes suggests that fine tuning of reproductive strategies to local environmental conditions may be widespread among fish and may be the ultimate basis for the evolution of homing. Key words: American shad, Alosa sapidissima, reproductive strategies, fecundity, frequency of reproduction, energy allocation, latitudinal variation, theoretical ecology

Homeomorphy in Paleozoic bryozoans: a search for explanations

Paleobiology ◽  
1980 ◽  
Vol 6 (4) ◽  
pp. 451-465 ◽  
Author(s):  
Daniel B. Blake
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Convergent Evolution ◽  
Controlling Factors ◽  
Life History Strategies ◽  
Taxonomic Analysis ◽  
Ample Opportunity ◽  
Key Innovation

Many apparent homeomorphs have been recognized among genera assigned to the Paleozoic stenolaemate bryozoan orders Trepostomata and Cryptostomata. Morphologies are evaluated to determine whether such homeomorphy should be expected, or is likely to have resulted from incomplete taxonomic analysis. Historical and constructional constraints prevalent in the phylum appear to provide ample opportunity for adaptive convergence, a conclusion supported by the occurrence of similar morphologies in distantly related post-Paleozoic bryozoans.Cryptostomes are distinguished in part by the presence of restricted budding loci. Loci pattern is hypothesized to be the key innovation in the establishment of the clade and the pattern also is considered critical to the evolution of the relatively slender branches and short zooecia typical of cryptostomes.Loci development does not provide a taxonomic panacea. This is because the hypothesis does not preclude convergent evolution of broadly similar restricted loci in Paleozoic non-cryptostome groups, although presumably the cryptostomes in general would have been best equipped to succeed under conditions favoring restricted loci.Environmental conditions for the cryptostomes in general and changing life history strategies for rhabdomesoids in particular provide possible controlling factors for the evolution of these bryozoans.

Life history as an integrative theoretical framework advancing the understanding of the attachment system

2009 ◽  
Vol 32 (1) ◽  
pp. 34-35
Author(s):  
Daniel J. Kruger
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Reproductive Strategies ◽  
Life History Theory ◽  
Theoretical Framework ◽  
Behavioral Strategies ◽  
Life Conditions ◽  
Psychological System ◽  
Attachment Process

AbstractEvolutionary Life History Theory (LHT) is a powerful framework that can be used for understanding behavioral strategies as contingent adaptations to environmental conditions. Del Giudice uses LHT as a foundation for describing the attachment process as an evolved psychological system which evaluates life conditions and chooses reproductive strategies appropriate in the developmental environment, integrating findings across several literatures.

Reproductive strategies conferring species dominance in marine mysid (Peracarida, Mysida) species in coastal waters off Vancouver Island, BC

Crustaceana ◽  
2015 ◽  
Vol 88 (12-14) ◽  
pp. 1421-1438 ◽  
Author(s):  
R. E. Burnham
Keyword(s):  
Life History ◽  
Reproductive Strategies ◽  
Cold Water ◽  
Resource Limitation ◽  
Vancouver Island ◽  
Life History Strategies ◽  
Species Flock ◽  
Species Dominance ◽  
Clayoquot Sound ◽  
Growth And Reproduction

Cold-water mysid species are key components of north Pacific coastal ecosystems and yet much of their life history remains unknown. In Clayoquot Sound, on the west coast of Vancouver Island, a dozen or so species have been identified, with four occurring consistently in samples: Holmesimysis sculpta (W. Tattersall, 1933), Neomysis rayii (Murdoch, 1885), Telacanthomysis columbiae (W. Tattersall, 1933) (Fukuoka & Murano, 2001) and Columbiaemysis ignota Holmquist 1982. In this article growth and reproduction of these species over a 24-month period (May 2010-April 2012) is described, showing recovery from annual removal by the eastern Pacific grey whale (Eschrichtius robustus (Lilljeborg, 1861)) over winter, when pressure from this main predator has been relieved. Holmesimysis sculpta dominates the species flock by employing different life history strategies. It is less seasonal than sister species, overcoming a presumed resource limitation scenario and exhibits year-round reproduction, thereby demonstrating more rapid population rebound following predation and, therefore, retain dominance.

scholarly journals When the going gets tough, the tough get going: effect of extreme climate on an Antarctic seabird’s life history

2019 ◽  
Author(s):  
Stéphanie Jenouvrier ◽  
Lise Aubry ◽  
Silke van Daalen ◽  
Christophe Barbraud ◽  
Henri Weimerskirch ◽  
...  
Keyword(s):  
Life History ◽  
Individual Differences ◽  
Old Age ◽  
Environmental Conditions ◽  
Life History Strategies ◽  
Demographic Rates ◽  
Individual Traits ◽  
Evolution Of Life ◽  
Favorable Conditions ◽  
Seabird Population

1AbstractIndividuals differ in many ways. Most produce few offspring; a handful produce many. Some die early; others live to old age. It is tempting to attribute these differences in out-comes to differences in individual traits, and thus in the demographic rates experienced. However, there is more to individual variation than meets the eye of the biologist. Even among individuals sharing identical traits, life history outcomes will vary due to individual stochasticity, i.e., to chance. Quantifying the contributions of heterogeneity and chance is essential to understanding natural variability. Inter-individual differences vary across environmental conditions. Heterogeneity and stochasticity depend on environmental conditions. We show that favorable conditions increase the contributions of individual stochasticity, and reduce the contributions of heterogeneity, to variance in demographic outcomes in a seabird population. The opposite is true under poor conditions. This result has important consequence for understanding the ecology and evolution of life history strategies.

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