scholarly journals Forensic post-mortem interval (PMI) estimates: variation in fly developmental times of individuals

2016 ◽  
Author(s):  
Mihály Földvári
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Developmental Time ◽  
Measurement Means ◽  
Post Mortem ◽  
Limited Sample ◽  
Post Mortem Interval ◽  
Forensic Practice ◽  
Wide Range ◽  
The Individual

ABSTRACTImmature stages of flies are paramount in establishing the post-mortem interval (PMI) in forensic practice. My focus is on differences in developmental time that can be influenced by genetic differences or individual life history traits, which latter may be interpreted as life history decisions.Data of a calliphorid fly species (Lucilia ampullacea) are presented: one female produced 300 eggs within an hour and the individual developmental time varied subsequently to a great extent – when the first flies emerged from their puparia there were still first instar larvae in the food (pig liver) provided.In conclusion the estimated PMI must be based on a wide range of collected flies (not simply the oldest or largest or widest individual), since a limited sample can be one extremity of a potentially bell shaped (Gaussian) frequency distribution of developmental times — unrepresentative sampling will bias the PMI in an unpredictable way. One possible solution can be to use large, randomized samples and their body measurement means.

scholarly journals Life-history variation of drosophila subobscura under lead pollution depends on population history

Genetika ◽  
2014 ◽  
Vol 46 (3) ◽  
pp. 693-703 ◽  
Author(s):  
Bojan Kenig ◽  
Aleksandra Patenkovic ◽  
Marko Andjelkovic ◽  
Marina Stamenkovic-Rada
Keyword(s):  
Heavy Metal ◽  
Life History ◽  
Metal Contamination ◽  
Life History Traits ◽  
Heavy Metal Contamination ◽  
Developmental Time ◽  
Drosophila Subobscura ◽  
Life History Variation ◽  
Laboratory Conditions ◽  
Coefficients Of Variation

Contamination represents environmental stress that can affect genetic variability of populations, thus influencing the evolutionary processes. In this study, we evaluate the relationship between heavy metal contamination (Pb) and phenotypic variation, assessed by coefficients of variation (CV) of life-history traits. To investigate the consequences of population origin on variation of life history traits in Drosophila subobscura in response to different laboratory conditions we compared populations from relatively polluted and unpolluted environments. Prior to experiment, flies from natural populations were reared for two generations in standard Drosophila laboratory conditions. Afterwards, all flies were cultured on three different media: one medium without lead as the control, and the other two with different concentrations of lead. Coefficients of variation (CV) of life- history traits (fecundity, egg-to-adult viability and developmental time) were analyzed on flies sampled in generations F2, F5 and F8 from these three groups. In later generations samples from both polluted and unpolluted environments showed the increased fecundity variation on media with lead. This increase is expressed more in population from unpolluted environment. On contrary, population from unpolluted environment had increased variation of developmental time in earlier, F2 generation, compared to the population from polluted environment. Our results showed that the response to heavy metal contamination depends on the evolutionary history of the populations regarding habitat pollution.

scholarly journals Early swelling response to phytohemagglutinin is lower in older toads

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e6104 ◽  
Author(s):  
Francisco Javier Zamora-Camacho ◽  
Mar Comas
Keyword(s):  
Immune Response ◽  
Time Series ◽  
Life History ◽  
Life History Traits ◽  
Area Under The Curve ◽  
Older Individuals ◽  
Innate Response ◽  
Early Immune Response ◽  
The Individual ◽  
Epidalea Calamita

The effects of age on performance of life-history traits are diverse, but a common outcome is senescence, an irreversible deterioration of physical and physiological capabilities of older individuals. Immune response is potentially bound to senescence. However, little is known about immune response ageing in amphibians. In this work, we test the hypothesis that amphibian early immune response is reduced in older individuals. To this end, we captured adult natterjack toads (Epidalea calamita) and inoculated them with phytohemagglutinin, an innocuous protein that triggers a skin-swelling immune response whose magnitude is directly proportional to the ability of the individual to mount an immune response. We measured early swelling immune response (corresponding to an innate-response stage) hourly, for six hours, and we calculated the area under the curve (AUC) for each individual’s time series, as a measure of immune response magnitude incorporating time. We estimated toad age by means of phalanx skeletochronology. Swelling and AUC decreased with age. Therefore, in accordance with our predictions, early immune response seems subject to senescence in these toads. Reduced ability to get over infections due to senescence of immune respose might be—together with a worse functioning of other organs and systems—among the causes of lower survival of older specimens.

scholarly journals Individual variability in life-history traits drives population size stability

2012 ◽  
Vol 58 (2) ◽  
pp. 358-362 ◽  
Author(s):  
Ned A. Dochtermann ◽  
C. M. Gienger
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Individual Variability ◽  
Population Variation ◽  
Sceloporus Undulatus ◽  
Natural Systems ◽  
Size Stability ◽  
Population Sizes ◽  
The Individual ◽  
Dynamics Of Populations

Abstract Understanding how population sizes vary over time is a key aspect of ecological research. Unfortunately, our understanding of population dynamics has historically been based on an assumption that individuals are identical with homogenous life-history properties. This assumption is certainly false for most natural systems, raising the question of what role individual variation plays in the dynamics of populations. While there has been an increase of interest regarding the effects of within population variation on the dynamics of single populations, there has been little study of the effects of differences in within population variation on patterns observed across populations. We found that life-history differences (clutch size) among individuals explained the majority of the variation observed in the degree to which population sizes of eastern fence lizards Sceloporus undulatus fluctuated. This finding suggests that differences across populations cannot be understood without an examination of differences at the level of a system rather than at the level of the individual [Current Zoology 58 (2): 358–362, 2012].

A Review of the Literature as to the Present Possibilities and Limitations in Estimating the Time of Death

1976 ◽  
Vol 16 (4) ◽  
pp. 269-276 ◽  
Author(s):  
R. Van Den Oever
Keyword(s):  
Forensic Medicine ◽  
Large Error ◽  
Time Of Death ◽  
Post Mortem ◽  
Review Of The Literature ◽  
Biochemical Tests ◽  
Post Mortem Interval ◽  
Suitable Combination ◽  
Exact Moment ◽  
The Individual

Determining the exact moment of death in medicolegal cases is not possible since post-mortem changes of the human body are variable and often misjudged. The most reliable physical and biochemical methods of estimating the post-mortem interval are reviewed and the author tries to find out why, in spite of all the previous studies, which have often given good results, the individual methods are neither popular nor practical in routine forensic medicine cases. For greater accuracy in estimating the time of death further investigation should be carried out to find a suitable combination of some physical and biochemical tests complementary to the data produced by each method and preventing the rather large error range of each individual test.

scholarly journals A novel experimental approach for studying life-history traits of phytophagous arthropods utilizing an artificial culture medium

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Kamila Karpicka-Ignatowska ◽  
Alicja Laska ◽  
Lechosław Kuczyński ◽  
Brian G. Rector ◽  
Mariusz Lewandowski ◽  
...  
Keyword(s):  
Life History ◽  
Host Plant ◽  
Life History Traits ◽  
Culture Medium ◽  
Interspecific Interactions ◽  
Suitable Condition ◽  
Mite Species ◽  
Artificial Culture ◽  
Wide Range ◽  
Artificial Culture Medium

AbstractExperimental approaches to studying life-history traits in minute herbivorous arthropods are hampered by the need to work with detached host plant material and the difficulty of maintaining that material in a suitable condition to support the animal throughout the duration of the test. In order to address this shortcoming, we developed a customizable agar-based medium modified from an established plant cell-culture medium to nourish detached leaves laid atop it while also preventing arthropods from escaping the experimental arena. The artificial culture medium was tested with two herbivorous mite species: the wheat curl mite (Aceria tosichella; Eriophyidae) and two-spotted spider mite (Tetranychus urticae; Tetranychidae). The proposed approach was a major improvement over a standard protocol for prolonged studies of individual eriophyid mites and also provided some benefits for experiments with spider mites. Moreover, the described method can be easily modified according to the requirements of host plant species and applied to a wide range of microherbivore species. Such applications include investigations of life-history traits and other ecological and evolutionary questions, e.g. mating or competitive behaviours or interspecific interactions, assessing invasiveness potential and predicting possible outbreaks. The approach presented here should have a significant impact on the advancement of evolutionary and ecological research on microscopic herbivores.

scholarly journals Ecological Characteristics of Ventenata dubia in the Intermountain Pacific Northwest

2015 ◽  
Vol 8 (1) ◽  
pp. 57-71 ◽  
Author(s):  
John M. Wallace ◽  
Pamela L. S. Pavek ◽  
Timothy S. Prather
Keyword(s):  
Life History ◽  
Soil Moisture ◽  
Pacific Northwest ◽  
Seed Bank ◽  
Life History Traits ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Integrated Weed Management ◽  
Habitat Types ◽  
Wide Range

AbstractVentenata dubia is an exotic winter annual grass that has invaded Conservation Reserve Program (CRP) lands, improved pastures, intensively managed hay fields, and rangelands within the Intermountain Pacific Northwest (PNW). Currently, producers are attempting to develop V. dubia management strategies with little knowledge of its life history traits. We conducted several studies to characterize V. dubia life history patterns. Preliminary germination trials were completed to describe primary and secondary dormancy characteristics. Field studies were conducted to evaluate (1) seed bank persistence patterns, (2) seedling emergence patterns under V. dubia litter, and (3) seedling emergence and phenological development patterns within timothy hay, CRP, and rangeland habitats. Preliminary germination trials suggest that the after-ripening period required for loss of dormancy does not exceed 30 d and that dormancy breakdown peaks at approximately 90 d, after which germination occurs over a wide range of temperatures (9 to 29 C). A small fraction (< 1%) of the seed bank remained germinable up to 3 yr after burial at 2 cm depth in a grassland habitat. Seedling emergence and survival was significantly greater under high V. dubia litter layers (100% cover) compared with bare surface during the drier study year because of higher soil moisture levels maintained under litter. Across habitat types, mean seedling emergence (50% of total) occurred between 33 and 94 growing degree days (GDD) after soil moisture rose above the permanent wilting point in the fall. Seedling emergence periodicity varied among habitat types in relation to spring seedling emergence, ranging from 0 to 13% of total emergence per year. Phenological development differed across sites and years by up to several hundred GDDs but was closely aligned to Julian days. This collection of studies improves our understanding of V. dubia life history traits and will aid integrated weed management strategies in the Intermountain PNW.

scholarly journals Life History Traits in Two Drosophila Species Differently Affected by Microbiota Diversity under Lead Exposure

Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1122
Author(s):  
Mirjana Beribaka ◽  
Mihailo Jelić ◽  
Marija Tanasković ◽  
Cvijeta Lazić ◽  
Marina Stamenković-Radak
Keyword(s):  
Heavy Metal ◽  
Life History ◽  
Life History Traits ◽  
Developmental Time ◽  
Metal Exposure ◽  
Heavy Metal Exposure ◽  
Variable Regions ◽  
Population Origin ◽  
The Impact ◽  
Microbiota Diversity

Life history traits determine the persistence and reproduction of each species. Factors that can affect life history traits are numerous and can be of different origin. We investigated the influence of population origin and heavy metal exposure on microbiota diversity and two life history traits, egg-to-adult viability and developmental time, in Drosophila melanogaster and Drosophila subobscura, grown in the laboratory on a lead (II) acetate-saturated substrate. We used 24 samples, 8 larval and 16 adult samples (two species × two substrates × two populations × two sexes). The composition of microbiota was determined by sequencing (NGS) of the V3–V4 variable regions of the 16S rRNA gene. The population origin showed a significant influence on life history traits, though each trait in the two species was affected differentially. Reduced viability in D. melanogaster could be a cost of fast development, decrease in Lactobacillus abundance and the presence of Wolbachia. The heavy metal exposure in D. subobscura caused shifts in developmental time but maintained the egg-to-adult viability at a similar level. Microbiota diversity indicated that the Komagataeibacter could be a valuable member of D. subobscura microbiota in overcoming the environmental stress. Research on the impact of microbiota on the adaptive response to heavy metals and consequently the potential tradeoffs among different life history traits is of great importance in evolutionary research.

scholarly journals Detrimental impacts of toxic Microcystis aeruginosa from Vietnam on life history traits of Daphnia magna

2016 ◽  
Vol 8 (1) ◽  
pp. 56-61
Author(s):  
Thi My Chi Vo ◽  
Thanh Luu Pham ◽  
Thanh Son Dao
Keyword(s):  
Life History ◽  
Daphnia Magna ◽  
Microcystis Aeruginosa ◽  
Life History Traits ◽  
Scientific Information ◽  
Reproductive Age ◽  
Viet Nam ◽  
Negative Effects ◽  
The Individual ◽  
Population Rate

In this study, we tested the long-term and negative effects of microcystin-producing cyanobacterium Microcystis aeruginosa from Vietnam on Daphnia magna under the laboratory conditions. The test organisms were fed with mixtures of green alga Scenedesmus armatus and toxic M. aeruginosa at different ratios (10% Microcystis + 90% Scenedesmus, 50% Microcystis + 50% Scenedesmus, 100% Microcystis, and 100% Scenedesmus) for over a period of 21 days. The life history traits of the organisms such as, survival, maturation, fecundity were daily recorded. Besides, the intrinsic population rate of D. magna in each treatment was also calculated based on the survivorship, the reproductive age and the clutch size of the animals. The results showed that survival, maturation and reproduction of the D. magna fed with 10, 50 and 100% M. aeruginosa was impaired. Additionally, the intrinsic population rate of the exposed D. magna was lower than that of the control. This study evidenced the adverse effects of toxic M. aeruginosa on both the individual and intrinsic population levels of D. magna. To our knowledge, this is the first report on the chronically detrimental impacts of toxic M. aeruginosa isolated from Vietnam on D. magna and contributed the scientific information on the severe influences of toxic cyanobacteria world wide. Trong bài viết này, chúng tôi nghiên cứu ảnh hưởng xấu mãn tính của loài vi khuẩn lam Microcystis aeruginosa có khả năng sản sinh độc tố microcysin từ Việt Nam lên Daphnia magna trong điều kiện phòng thí nghiệm. Sinh vật thí nghiệm được cho ăn với hỗn hợp tảo lục Scenedesmus armatus và M. aeruginosa có độc ở các tỷ lệ khác nhau (10% Microcystis + 90% Scenedesmus, 50% Microcystis + 50% Scenedesmus, 100% Microcystis, và 100% Scenedesmus) trong thời gian 21 ngày. Các đặc điểm vòng đời của sinh vật bao gồm sức sống, sự thành thục, sức sinh sản được theo dõi hàng ngày. Bên cạnh đó, tỷ lệ phát triển quần thể của D. magna trong từng lô thí nghiệm cũng được tính toán dựa vào sức sống, tuổi sinh sản và kích cỡ sinh sản của sinh vật. Kết quả cho thấy, sức sống, tuổi thành thục và sự sinh sản của D. magna cho ăn với 10, 50 và 100% M. aeruginosa bị ảnh hưởng xấu. Bên cạnh đó, tỷ lệ phát triển quần thể của D. magna trong lô phơi nhiễm thấp hơn so với đối chứng. Nghiên cứu này chứng minh ảnh hưởng xấu của M. aeruginosa có độc lên cả hai mức độ cá thể và quần thể của D. magna. Theo hiểu biết của chúng tôi, đây là báo cáo đầu tiên về ảnh hưởng xấu mãn tính của M. aeruginosa có độc phân lập từ Việt Nam lên D. magna and đóng góp thêm thông tin khoa học cho những ảnh hưởng nghiêm trọng của vi khuẩn lam có độc trên khắp thế giới.

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