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21.
Species with complex life cycles pose challenges for understanding what processes regulate population densities, especially if some life stages disperse. Most studies of such animals that are thought to be recruitment limited focus on the idea that juvenile mortality limits the density of recruits (and hence population density), fewer consider the possibility that egg supply may be important. For species that oviposit on specific substrata, environmental constraints on oviposition sites may limit egg supply. Female mayflies in the genus Baetis lay egg masses on the underside of stream rocks that emerge above the water’s surface. We tested the hypothesis that egg mass densities are constrained by emergent rock densities within and between streams, by counting egg masses on emergent rocks. All emergent rocks were counted along 1-km lengths of four streams, revealing significant variation in emergent rock density within streams and a more than three-fold difference between streams. In each stream, egg mass density increased with the density of emergent rocks in 30-m stretches. We used regression equations describing these small-scale relationships, coupled with the large-scale spatial variation of emergent rocks, to estimate egg mass densities for each 1-km stream length, a scale relevant to population processes. Scaled estimates were positively associated with emergent rock density and provided better estimates than methods that ignored environmental variation. Egg mass crowding was inversely related to emergent rock density at the stream scale, a pattern consistent with the idea that oviposition substrata were in short supply in streams with few emergent rocks, but crowding did not compensate entirely for differences in emergent rock densities. The notion that egg supply, not larval mortality, may limit population density is an unusual perspective for stream insects. Environmental constraints on egg supply may be widespread among other species with specialised oviposition behaviours. 相似文献
22.
Evan P. Lancaster Ejebagom J. Ojogbo Steven I. Rekant Janelle R. Scott Heidi Weimer 《Journal of applied animal welfare science : JAAWS》2016,19(4):396-407
To find management strategies for controlling the owned cat population in Knox County, TN, the authors formulated a mathematical model using biological properties of such nonhuman animals and spay actions on certain age classes. They constructed this discrete-time model to predict the future owned cat population in this county and to evaluate intervention strategies to surgically sterilize some proportion of the population. Using the predicted population size and the number of surgeries for specific scenarios, they showed that focusing on specific age classes can be an effective feature in spay programs. 相似文献
23.
24.
Lesley T. Lancaster Kathleen M. Kay 《Evolution; international journal of organic evolution》2013,67(4):1041-1054
The California Floristic Province exhibits one of the richest floras on the planet, with more than 5500 native plant species, approximately 40% of which are endemic. Despite its impressive diversity and the attention it has garnered from ecologists and evolutionary biologists, historical causes of species richness and endemism in California remain poorly understood. Using a phylogenetic analysis of 16 angiosperm clades, each containing California natives in addition to species found only outside California, we show that CA's current biodiversity primarily results from low extinction rates, as opposed to elevated speciation or immigration rates. Speciation rates in California were lowest among Arcto‐Tertiary lineages (i.e., those colonizing California from the north, during the Tertiary), but extinction rates were universally low across California native plants of all historical, geographic origins. In contrast to long‐accepted ideas, we find that California diversification rates were generally unaffected by the onset of the Mediterranean climate. However, the Mediterranean climate coincided with immigration of many desert species, validating one previous hypothesis regarding origins of CA's plant diversity. This study implicates topographic complexity and climatic buffering as key, long‐standing features of CA's landscape favoring plant species persistence and diversification, and highlights California as an important refuge under changing climates. 相似文献
25.
Cüneyt M. Serdar David T. Gibson Douglas M. Munnecke John H. Lancaster 《Applied microbiology》1982,44(1):246-249
An organism identified as Pseudomonas diminuta was found to hydrolyze parathion. Cells grown for 48 h contained 3,400 U of parathion hydrolase activity per liter of broth. Expression of enzymatic activity was lost at a high frequency (9 to 12%) after treatment with mitomycin C. Hydrolase-negative derivatives were missing a plasmid present in the wild-type organism. The molecular mass of this plasmid (pCS1), as determined by electron microscopy, was about 44 × 106 daltons. 相似文献
26.
CA Kalva-Filho EZ Campos VL Andrade ASR Silva AM Zagatto MCS Lima M Papoti 《Biology of sport / Institute of Sport》2015,32(4):333-337
The aims of the present study were to investigate the relationship of aerobic and anaerobic parameters with 400 m performance, and establish which variable better explains long distance performance in swimming. Twenty-two swimmers (19.1±1.5 years, height 173.9±10.0 cm, body mass 71.2±10.2 kg; 76.6±5.3% of 400 m world record) underwent a lactate minimum test to determine lactate minimum speed (LMS) (i.e., aerobic capacity index). Moreover, the swimmers performed a 400 m maximal effort to determine mean speed (S400m), peak oxygen uptake () and total anaerobic contribution (CANA). The CANA was assumed as the sum of alactic and lactic contributions. Physiological parameters of 400 m were determined using the backward extrapolation technique ( and alactic contributions of CANA) and blood lactate concentration analysis (lactic anaerobic contributions of CANA). The Pearson correlation test and backward multiple regression analysis were used to verify the possible correlations between the physiological indices (predictor factors) and S400m (independent variable) (p < 0.05). Values are presented as mean ± standard deviation. Significant correlations were observed between S400m (1.4±0.1 m·s-1) and LMS (1.3±0.1 m·s-1; r = 0.80), (4.5±3.9 L·min-1; r = 0.72) and CANA (4.7±1.5 L·O2; r= 0.44). The best model constructed using multiple regression analysis demonstrated that LMS and explained 85% of the 400 m performance variance. When backward multiple regression analysis was performed, CANA lost significance. Thus, the results demonstrated that both aerobic parameters (capacity and power) can be used to predict 400 m swimming performance. 相似文献
27.
Hillard S. Kaplan Jane B. Lancaster Sara E. Johnson John A. Bock 《Human nature (Hawthorne, N.Y.)》1995,6(4):325-360
Our objective is to test an optimality model of human fertility that specifies the behavioral requirements for fitness maximization
in order (a) to determine whether current behavior does maximize fitness and, if not, (b) to use the specific nature of the behavioral deviations from fitness maximization towards the development of models of evolved
proximate mechanisms that may have maximized fitness in the past but lead to deviations under present conditions. To test
the model we use data from a representative sample of 7,107 men living in Albuquerque, New Mexico, between 1990 and 1993.
The model we test proposes that low fertility in modern settings maximizes number of grandchildren as a result of a trade-off
between parental fertility and next generation fertility. Results do not show the optimization, although the data do reveal
a trade-off between parental fertility and offspring education and income.
We propose that two characteristics of modern economies have led to a period of sustained fertility reduction and to a corresponding
lack of association between income and fertility. The first is the direct link between costs of investment and wage rates
due to the forces of supply and demand for labor in competitive economies. The second is the increasing emphasis on cumulative
knowledge, skills, and technologies in the production of resources. Together they produce historically novel conditions. These
two features of modern economies may interact with evolved psychological and physiological mechanisms governing fertility
and parental investment to produce behavior that maximizes the economic productivity of lineages at the expense of fitness.
If cognitive processes evolved to track diminishing returns to parental investment and if physiological processes evolved
to regulate fertility in response to nutritional state and patterns of breast feeding, we might expect non-adaptive responses
when returns from parental investment do not diminish until extremely high levels are reached. With high economic payoffs
from parental investment, people have begun to exercise cognitive regulation of fertility through contraception and family
planning practices. Those cognitive processes maynot have evolved to handle fitness trade-offs between fertility and parental investment.
A preliminary presentation of this data was published in R. I. M. Dunbar, ed.,Human Reproduction Decisions: Biological and Social Perspectives. New York: St. Martin’s Press, 1995. Support for the research project, “Male Fertility and Parenting in New Mexico,” began
with two seed grants from the University of New Mexico’s Biomedical Research Grants Program, 1988 and 1989, and one from the
University of New Mexico Research Allocations Committee, 1988. Further seed money as well as interim funding came from the
William T. Grant Foundation (#89130589 and #91130501). The major support for the project came from the National Science Foundation
from 1990 to 1993 (#BNS-9011723 and #DBS-911552). Both National Science Foundation grants included Research Experience for
Undergraduates supplements.
Hillard S. Kaplan is an Associate Professor of Anthropology at the University of New Mexico. His earlier research and publications
focused on food sharing, time allocation, parental investment, and reproductive strategies among Ache hunter-gatherers in
Paraguay, Machiguenga and Piro forager-horticulturalists in Peru, and villagers of several ethnicities in Botswana. New research
and theory concern fertility, parental investment, and mating strategies in developed and developing nations. This research
formulates a new theory of reproductive decision-making and the demographic transition, integrating human capital and parental
investment theory in a synthesis of economic and evolutionary approaches.
Jane B. Lancaster is a Professor of Anthropology at the University of New Mexico. Her research and publications are on human
reproductive biology and behavior, especially human parental investment; women’s reproductive biology of pregnancy, lactation,
and child-spacing; and male fertility and investment in children. Current research with Hillard S. Kaplan is on male life
history strategies among a large sample of men in New Mexico. She has coedited three books on human parental investment:School-Age Pregnancy and Parenthood (with B. Hamburg),Parenting across the Life Span (with J. Altmann, A. Rossi, and L. Sherrod), andOffspring Abuse and Neglect (with R. Gelles). She is scientific editor of a quarterly journal,Human Nature: An Interdisciplinary, Biosocial Perspective published by Aldine de Gruyter. She is also a council member of the newly formed Human Behavior and Evolution Society.
John A. Bock is Andrew W. Mellon Post-Doctoral Fellow in Epidemiology and Population Health at the National Centre for Epidemiology
and Population Health, The Australian National University. His research focuses on the allocation of parental investment and
the determinants of children’s activities, integrating aspects of economic and evolutionary theory. He has ongoing field research
with Bantu and Bushmen agro-pastoralists and forager-horticulturalists in the Okavango Delta, Botswana. He is also collaborating
with Lancaster and Kaplan on the determinants of progeny distribution and homosexuality among New Mexican men.
Sara E. Johnson is a Ph.D. candidate at the University of New Mexico. Her major research trajectory focuses on trade-offs
in life history characters. Her research experience includes participation in a study of variation in growth and development
among children in a multi-ethnic community in the Okavango Delta, Botswana, in addition to her dissertation work on individual
variation in growth and mortality among juvenile baboons. She is collaborating with Lancaster and Kaplan on the association
between survival and fertility among Albuquerque men. 相似文献
28.
K. J. Killgore J. J. Hoover S. G. George B. R. Lewis C. E. Murphy W. E. Lancaster 《Zeitschrift fur angewandte Ichthyologie》2007,23(4):476-483
A multiyear study of pallid sturgeon distribution and relative abundance was conducted in the lower and middle Mississippi river (LMR and MMR, respectively). The LMR and MMR comprise the free‐flowing Mississippi River extending 1857 river kilometers (rkm) from its mouth at the Gulf of Mexico upstream to the mouth of the Missouri River. A total of 219 pallid sturgeon and 6018 shovelnose sturgeon was collected during the periods 1996–1997 and 2000–2006. Trotlines baited with worms were the primary collecting gear. The smallest pallid sturgeon captured on trotlines was 405 mm FL and the largest was 995 mm FL. Mean size of pallid sturgeon was statistically smaller in the Mississippi River below the Atchafalaya River near Baton Rouge, LA (621 mm FL). Mean abundance (catch per trotline night) of pallid sturgeon was highest at water temperatures around 10°C. There was a latitudinal trend in mean abundance of pallid and shovelnose sturgeon, but the pattern differed between species. Pallid sturgeon abundance was statistically (P < 0.05) higher (0.3 fish per trotline night) in the lower reach between the Atchafalaya River and New Orleans (rkm 154–507), and at the Chain of Rocks (COR), a low water dam near the mouth of the Missouri River. Pallid sturgeon abundance between these two locations was statistically the same (0.12–0.23). Shovelnose sturgeon abundance increased going upstream, but was disproportionally higher at the COR (22 fish per line compared with <6 fish per line in other reaches). Overall, the ratio between pallid and shovelnose sturgeon varied from a high of 1 : 6 at the lower reach, and gradually decreased upstream to a low of 1 : 77 at the COR. Based on differences in sturgeon abundance, size and habitat characteristics, the free‐flowing Mississippi River can be divided into two reaches in the MMR (i.e. COR is a separate location), and four reaches (i.e., including the Atchafalaya River) in the LMR where management goals may differ. 相似文献
29.
Pooranee K. Morgan Kevin Huynh Gerard Pernes Paula M. Miotto Natalie A. Mellett Corey Giles Peter J. Meikle Andrew J. Murphy Graeme I. Lancaster 《The Journal of biological chemistry》2021,297(6)
Adipose-tissue-resident macrophages (ATMs) maintain metabolic homeostasis but also contribute to obesity-induced adipose tissue inflammation and metabolic dysfunction. Central to these contrasting effects of ATMs on metabolic homeostasis is the interaction of macrophages with fatty acids. Fatty acid levels are increased within adipose tissue in various pathological and physiological conditions, but appear to initiate inflammatory responses only upon interaction with particular macrophage subsets within obese adipose tissue. The molecular basis underlying these divergent outcomes is likely due to phenotypic differences between ATM subsets, although how macrophage polarization state influences the metabolism of exogenous fatty acids is relatively unknown. Herein, using stable isotope-labeled and nonlabeled fatty acids in combination with mass spectrometry lipidomics, we show marked differences in the utilization of exogenous fatty acids within inflammatory macrophages (M1 macrophages) and macrophages involved in tissue homeostasis (M2 macrophages). Specifically, the accumulation of exogenous fatty acids within triacylglycerols and cholesterol esters is significantly higher in M1 macrophages, while there is an increased enrichment of exogenous fatty acids within glycerophospholipids, ether lipids, and sphingolipids in M2 macrophages. Finally, we show that functionally distinct ATM populations in vivo have distinct lipid compositions. Collectively, this study identifies new aspects of the metabolic reprogramming that occur in distinct macrophage polarization states. The channeling of exogenous fatty acids into particular lipid synthetic pathways may contribute to the sensitivity/resistance of macrophage subsets to the inflammatory effects of increased environmental fatty acid levels. 相似文献
30.
P Mastroiacovo B K?llén L B Knudsen P A Lancaster E E Castilla O Mutchinick E Robert 《Teratology》1992,46(5):455-464
The study is based on almost 10 million births and reports on 215 infants with two unusual malformations: amelia and gross body wall defect. Amelia without body wall defect was present in 116 cases, 67 had body wall defects without amelia, and 32 had both. The total rate was 2.2 per 100,000 births. The infants were divided into five mutually exclusive groups. There were 40 infants (0.4 per 100,000) with agenesis of the body stalk, 18 with amelia and other types of gross body wall defects (0.2 per 100,000), 56 with amelia and malformations other than gross body wall defects (0.6 per 100,000), 41 with amelia (with or without other limb reduction defects) but no nonlimb malformations (0.4 per 100,000), and 60 infants with gross body wall defects of a type other than agenesis of body stalk and without amelia (0.6 per 100,000). A weak trend of decreasing prevalence of these malformations was found during the observation period. Infants with agenesis of the body stalk and infants with amelia combined with other types of gross body wall defects occurred at an increased rate in infants of young women. This maternal age effect is also found with gastroschisis, but not with omphalocele, and may indicate etiological or pathogenetic similarities between gastroschisis and the two former groups of defect. In infants with amelia, additional limb reduction defects could be of any type: transverse, longitudinal, or intercalary. Therefore, amelia may be the end result of different types of disturbances of limb morphogenesis. There was an increased rate of twinning. The relationship with amniotic band syndrome is discussed. 相似文献