Univoltine and Semivoltine Life Histories in Senecella calanoides (Copepoda: Calanoida) and Their Relationship to Body Size

1984 ◽  
Vol 41 (8) ◽  
pp. 1167-1175 ◽  
Author(s):  
J. C. H. Carter ◽  
M. J. Dadswell ◽  
K. Goudie
Keyword(s):  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Eastern Canada ◽  
Southern Ontario ◽  
Limited Food

Most populations of Senecella calanoides Juday in eastern Canada are univoltine. However, in Lake Mazinaw, southern Ontario, and probably in three additional lakes in western Quebec it has a 2-yr life history (semivoltine) with two fractions, different in age by 1 yr, developing together. The additional year of development in Mazinaw is spent almost entirely in the fourth and fifth copepodite instars. Slower development in semivoltine populations is tentatively attributed to colder waters resulting from extensive hypolimnia, with limited food as a possible secondary cause. Later copepodites of semivoltine populations were smaller than their univoltine counterparts, possibly because of poorer nutrition.

The life histories of north-temperate populations of the crayfish Cambarus robustus and Cambarus bartoni

1985 ◽  
Vol 63 (10) ◽  
pp. 2313-2322 ◽  
Author(s):  
Premysl Hamr ◽  
Michael Berrill
Keyword(s):  
Life History ◽  
Life Histories ◽  
Carapace Length ◽  
Late Summer ◽  
Temperate Climate ◽  
Free Living ◽  
Southern Ontario ◽  
The Third ◽  
Early Fall ◽  
First Time

The life histories of the crayfish Cambarus robustus and Cambarus bartoni were studied in the Kawartha Lakes region of southern Ontario. There were marked differences in their breeding and molting cycles compared with the familiar pattern of the Orconectes species of this region. Egg extrusion occurred later (July in C. robustus, June in C. bartoni), and juveniles therefore did not become free living until late summer or early fall. With little growing time in their first summer, they measured only 5–10 mm in carapace length (CPL) before growth ceased for the winter. At the end of their second summer the still immature crayfish measured 17–26 mm CPL in C. robustus and 13–20 mm CPL in C. bartoni. Maturity was therefore not attained until the end of the third summer, when most C. robustus matured at 34–45 mm CPL and C. bartoni at 25–30 mm CPL. The majority of individuals apparently reproduced for the first time during their fourth summer; a few apparently survived into another summer, reaching carapace lengths greater than 50 mm in C. robustus and 30 mm in C. bartoni. In males of both species, form 1 and form 2 occur throughout the summer. Although lacking the synchrony of Orconectes species, breeding and molting activities are still confined to the period between April and October. The timing of the life-history events observed in these two Cambarus species may be adaptations to seasonal stresses of the swift water environments that these species inhabit as well as to the relative harshness of the northern temperate climate.

scholarly journals Foundress Number, But Not Queen Size or Boldness, Predicts Colony Life-History in Wild Paper Wasps

2019 ◽  
Author(s):  
Colin M. Wright ◽  
David N. Fisher ◽  
Wayne V. Nerone ◽  
James L.L. Lichtenstein ◽  
Elizabeth A. Tibbetts ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Life History Traits ◽  
Positive Association ◽  
Paper Wasps ◽  
Trade Offs ◽  
Behavioral Tendencies ◽  
Queen Size

AbstractColonies of social insects exhibit a spectacular variety of life histories. Here we documented the degree of variation in colony life-history traits, mostly related to productivity, in two species of wild paper wasps. We then tested for associations between colony life-history traits to look for trade-offs or positively associated syndromes, and examined whether individual differences in the behavioral tendencies of foundresses (Polistes metricus) or the number of cofoundresses (P. fuscatus) influenced colony life-history. The majority of our measures of colony life-history were positively related, indicating no obvious resource allocation trade-offs. Instead, the positive association of traits into a productivity syndrome appears to be driven by differences in queen or microhabitat quality. Syndrome structure differed only marginally between species. Queen boldness and body size were not associated with colony life-history inP. metricus. Colonies initiated by multipleP. fuscatusfoundresses were generally more productive, and this advantage was approximately proportional to the number of cofoundresses. These findings demonstrate that colony life-history traits can be associated together much like individual life-history traits, and the associations seen here convey that differences in overall productivity drive between-colony differences in life-history.

Modelling fishing-induced adaptations and consequences for natural mortality

2010 ◽  
Vol 67 (7) ◽  
pp. 1086-1097 ◽  
Author(s):  
Christian Jørgensen ◽  
Øyvind Fiksen
Keyword(s):  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Life History Traits ◽  
Reproductive Behaviour ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Trade Offs ◽  
Wide Range ◽  
Investment In Reproduction

When trade-offs involving predation and mortality are perturbed by human activities, behaviour and life histories are expected to change, with consequences for natural mortality rates. We present a general life history model for fish in which three common relationships link natural mortality to life history traits and behaviour. First, survival increases with body size. Second, survival declines with growth rate due to risks involved with resource acquisition and allocation. Third, fish that invest heavily in reproduction suffer from decreased survival due to costly reproductive behaviour or morphology that makes escapes from predators less successful. The model predicts increased natural mortality rate as an adaptive response to harvesting. This extends previous models that have shown that harvesting may cause smaller body size, higher growth rates, and higher investment in reproduction. The predicted increase in natural mortality is roughly half the fishing mortality over a wide range of harvest levels and parameter combinations such that fishing two fish kills three after evolutionary adaptations have taken place.

Egg production in adult trematodes: adaptation or constraint?

Parasitology ◽  
1997 ◽  
Vol 114 (2) ◽  
pp. 195-204 ◽  
Author(s):  
R. POULIN
Keyword(s):  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Egg Production ◽  
Egg Size ◽  
Life History Traits ◽  
Sampling Site ◽  
Consistent Difference ◽  
Host Body Mass ◽  
Trematode Parasites

Parasite life-history traits should reflect past environmental and host-related selective pressures acting to produce strategies that maximize transmission success. The evolution of adult body size and egg production in 804 species of trematode parasites was investigated using independent contrasts derived from a phylogeny of trematodes. Contrasts in trematode body size were positively correlated with contrasts in egg size, and almost significantly correlated with contrasts in numbers of uterine eggs. After controlling for body size, no relationship existed between egg size and egg numbers, suggesting that there is no trade-off between the two components of egg production. Average host body mass and latitude of the sampling site did not correlate with either trematode body size or egg size. Contrasts between trematode taxa exploiting ectotherm hosts and their sister taxa exploiting endotherms showed no consistent difference in either body size or egg size. The effect of other variables on trematode life-histories, such as the nature of the habitat in which eggs are released, the site of attachment within the host's body, or the number of hosts involved in the life-cycle, could not be evaluated statistically. The similarity in life-history traits among members of given clades suggests that phylogenetic constraints may have acted to limit or mask any adaptive changes expected from changes in host-related or environmental conditions.

Can commercial fishing cause evolution? Answers from guppies (Poecilia reticulata)

2005 ◽  
Vol 62 (4) ◽  
pp. 791-801 ◽  
Author(s):  
David N Reznick ◽  
Cameron K Ghalambor
Keyword(s):  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Life History Theory ◽  
Poecilia Reticulata ◽  
Mortality Rates ◽  
Adult Mortality ◽  
Commercial Fisheries ◽  
Commercial Fishing ◽  
Rate Of Evolution

Life history theory predicts that high adult mortality rates select for earlier maturity and increased reproduction. If such evolution occurs in response to the commercial exploitation of natural fish populations, then the correlated reduction in body size would reduce the yield of the fishery. Earlier maturity and reduced body size are seen in commercially exploited populations. Here, we compare the life histories of natural populations of guppies (Poecilia reticulata) from Trinidad that live in either high- or low-predation environments, which serve as surrogates for the presence or absence of commercial fishing. We can quantify mortality rate and life history variables, including age and size at maturity, in the laboratory and in nature. We have manipulated mortality rates in nature and measured the rate of evolution. High mortality selects for earlier maturity at a smaller size, as observed in commercial fisheries and as predicted by theory. Furthermore, the nature and magnitude of predator-induced mortality are comparable to those caused by commercial fishing. The rate of evolution in guppies predicts similar evolution in commercial fisheries on a time scale of decades. These attributes support arguments that humans, like predators, have acted as an agent of selection when exploiting populations of fish.

Fast and slow life histories of carnivores

2011 ◽  
Vol 89 (8) ◽  
pp. 692-704 ◽  
Author(s):  
Evi Paemelaere ◽  
F. Stephen Dobson
Keyword(s):  
Life History ◽  
Body Size ◽  
Litter Size ◽  
Life Histories ◽  
Life History Traits ◽  
Life Cycles ◽  
Age At Maturity ◽  
Negatively Associated ◽  
Trade Offs ◽  
Body Sizes

The fast–slow continuum hypothesis explains life-history traits as reflecting the causal influence of mortality patterns in interaction with trade-offs among traits, particularly more reproductive effort at a cost of shorter lives. Variation among species of different body sizes produce more or less rapid life cycles (respectively, from small to large species), but the fast–slow continuum remains for birds and mammals when body-size effects are statistically removed. We tested for a fast–slow continuum in mammalian carnivores. We found the above trade-offs initially supported in a sample of 85 species. Body size, however, was strongly associated with phylogeny (ρ = 0.79), and thus we used regression techniques and independent contrasts to make statistical adjustments for both. After adjustments, the life-history trade-offs were not apparent, and few associations of life-history traits were significant. Litter size was negatively associated with age at maturity, but slightly positively associated with offspring mass. Litter size and mass were negatively associated with the length of the developmental period. Gestation length showed weak but significant negative associations with age at maturity and longevity. We conclude that carnivores, despite their wide range of body sizes and variable life histories, at best poorly exhibited a fast–slow continuum.

scholarly journals Scaling the risk landscape drives optimal life-history strategies and the evolution of grazing

2019 ◽  
Vol 117 (3) ◽  
pp. 1580-1586 ◽  
Author(s):  
Uttam Bhat ◽  
Christopher P. Kempes ◽  
Justin D. Yeakel
Keyword(s):  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Extinction Risk ◽  
Life History Strategies ◽  
Allee Effects ◽  
Resource Distributions ◽  
Stochastic Fluctuations ◽  
Demographic Risk ◽  
Energetic Reserves

Consumers face numerous risks that can be minimized by incorporating different life-history strategies. How much and when a consumer adds to its energetic reserves or invests in reproduction are key behavioral and physiological adaptations that structure communities. Here we develop a theoretical framework that explicitly accounts for stochastic fluctuations of an individual consumer’s energetic reserves while foraging and reproducing on a landscape with resources that range from uniformly distributed to highly clustered. First, we show that the selection of alternative life histories depends on both the mean and variance of resource availability, where depleted and more stochastic environments promote investment in each reproductive event at the expense of future fitness as well as more investment per offspring. We then show that if resource variance scales with body size due to landscape clustering, consumers that forage for clustered foods are susceptible to strong Allee effects, increasing extinction risk. Finally, we show that the proposed relationship between resource distributions, consumer body size, and emergent demographic risk offers key ecological insights into the evolution of large-bodied grazing herbivores from small-bodied browsing ancestors.

Parasite Abundance, Body Size, Life Histories, and the Energetic Equivalence Rule

1998 ◽  
Vol 151 (6) ◽  
pp. 497 ◽  
Author(s):  
Arneberg ◽  
Skorping ◽  
Read
Keyword(s):  
Body Size ◽  
Life Histories ◽  
Parasite Abundance

Correlates of Species Richness in Mammals: Body Size, Life History, and Ecology

2005 ◽  
Vol 165 (5) ◽  
pp. 600
Author(s):  
Nick J. B. Isaac ◽  
Jones ◽  
Gittleman ◽  
Purvis
Keyword(s):  
Life History ◽  
Species Richness ◽  
Body Size

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

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