scholarly journals Feeding habits of Perlodidae (Plecoptera) in the hyporheic habitats of Alpine streams (Trentino-NE Italy)

2008 ◽  
Vol 19 (3) ◽  
pp. 176-183 ◽  
Author(s):  
Luana Silveri ◽  
José Tierno de Figueroa ◽  
Bruno Maiolini
Keyword(s):  
Life Cycle ◽  
Environmental Conditions ◽  
Feeding Habits ◽  
Life Stages ◽  
Gut Content ◽  
Functional Feeding Group ◽  
Ne Italy ◽  
Refuge Area ◽  
Content Analyses ◽  
Alpine Streams

Toltal of 75 nymphs of Dictyogenus fontium, Perlodes intricatus and Isoperla (cf) rivulorum and 22 juvenile Perlodinae were collected in hyporheic habitats of the Noce Bianco watershed (Trentino, NE Italy). The identification of their life stages allowed considerations regarding their presence in the hyporheos, mainly used as a refuge habitat, particularly during vulnerable phases of their life cycle (neanid stage and pre-imaginal phase). This function is possible, given the more stable environmental conditions and the minor predatory pressures in this habitat. The gut content analyses of the three species assigned them to the engulfers-carnivorous functional feeding group, with slight resource partitions between the two largest species. P. intricatus appears to feed on less mobile and fleshy preys while D. fontium prefers more sclerotized and active preys. The results indicate that the hyporheos acts not only as a refuge area but also as a trophic habitat for some Perlodidae species.

Detailed comparative morphology of the peri-oral structures of the Mysidacea and Euphausiacea (Crustacea): an indication for the food preference

2001 ◽  
Vol 81 (2) ◽  
pp. 235-241 ◽  
Author(s):  
L. De Jong-Moreau ◽  
B. Casanova ◽  
J.-P. Casanova
Keyword(s):  
Food Preference ◽  
Feeding Habits ◽  
Comparative Morphology ◽  
Gut Content ◽  
Scanning Microscope ◽  
Content Analyses ◽  
Carnivorous Species ◽  
Meganyctiphanes Norvegica ◽  
Molar Process

Scanning microscope investigations were carried out on mandibles, labrum and paragnaths of several species of Mysidacea and Euphausiacea. Gut content analyses were in agreement with morphological observations. It appears that the morphology of the peri-oral structures and especially of the mandibles reflect the feeding habits, and that the well known relationships between the size of the molar process and the incisor one, i.e. a large molar process is associated with herbivorous feeding, is not always verified. Bacescomysis abyssalis and Bentheuphausia amblyops are believed to be mostly saprophagous, Boreomysis inermis and Meganyctiphanes norvegica are mostly phytophagous, Hemimysis speluncola is omnivorous, while Siriella armata and Thysanopoda orientalis are carnivorous species.

scholarly journals The Dasypodidae (Mammalia, Xenarthra) from the Urso Fóssil Cave (Quaternary), Parque Nacional de Ubajara, State of Ceará, Brazil: paleoecological and taxonomic aspects

2014 ◽  
Vol 86 (1) ◽  
pp. 147-158 ◽  
Author(s):  
PAULO V. OLIVEIRA ◽  
ANA MARIA RIBEIRO ◽  
ÉDISON V. OLIVEIRA ◽  
MARIA SOMÁLIA S. VIANA
Keyword(s):  
Environmental Conditions ◽  
Feeding Habits ◽  
Early Holocene ◽  
Northeastern Brazil ◽  
Dasypus Novemcinctus ◽  
Sediment Samples ◽  
Wide Geographical Distribution ◽  
Anthropogenic Action ◽  
Euphractus Sexcinctus ◽  
Northwest Region

This paper deals with xenarthrans osteoderms assigned to Dasypus aff. D. novemcinctus, Euphractus sexcinctus and Cabassous sp. The material was collected in subsurface, from 0.10 to 0.60 m in the Urso Fóssil Cave, Parque Nacional de Ubajara, State of Ceará, northeastern Brazil. The ages of sediment samples from levels 4 and 5 (depths of 0.40 and 0.50 m) were determined by thermoluminescence technique, and indicated ages of 8,000 and 8,200 years BP for each layer respectively. The presence in these layers of early Holocene xenarthrans taxa can contribute to the understanding of the biotic evolution of the northwest region of Ceará during the last 10,000 years. Two of the three identified taxa still occur in the region: Dasypus novemcinctus and Euphractus sexcinctus. The Dasypodidae fauna here reported includes animals with generalist feeding habits and current wide geographical distribution. It is suggested, therefore, that the climatic and environmental conditions in the early Holocene were very similar the actual ones, and that the absence of Cabassous may be conditioned to other factors, such as anthropogenic action and loss of habitat by fragmentation of the vegetation.

Autonomy and integration in complex parasite life cycles

Parasitology ◽  
2016 ◽  
Vol 143 (14) ◽  
pp. 1824-1846 ◽  
Author(s):  
DANIEL P. BENESH
Keyword(s):  
Life Cycle ◽  
Holistic Approach ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Functional Specialization ◽  
Life Stages ◽  
Free Living ◽  
New Host ◽  
Complex Life Cycles ◽  
Life Cycle Stages

SUMMARYComplex life cycles are common in free-living and parasitic organisms alike. The adaptive decoupling hypothesis postulates that separate life cycle stages have a degree of developmental and genetic autonomy, allowing them to be independently optimized for dissimilar, competing tasks. That is, complex life cycles evolved to facilitate functional specialization. Here, I review the connections between the different stages in parasite life cycles. I first examine evolutionary connections between life stages, such as the genetic coupling of parasite performance in consecutive hosts, the interspecific correlations between traits expressed in different hosts, and the developmental and functional obstacles to stage loss. Then, I evaluate how environmental factors link life stages through carryover effects, where stressful larval conditions impact parasites even after transmission to a new host. There is evidence for both autonomy and integration across stages, so the relevant question becomes how integrated are parasite life cycles and through what mechanisms? By highlighting how genetics, development, selection and the environment can lead to interdependencies among successive life stages, I wish to promote a holistic approach to studying complex life cycle parasites and emphasize that what happens in one stage is potentially highly relevant for later stages.

scholarly journals 3 Tackling Demolition Waste – An en route to Sustainable Development

2018 ◽  
Vol 8 (1) ◽  
pp. 8
Author(s):  
Nadia Qamar ◽  
Ayesha Alam Khurram
Keyword(s):  
Sustainable Development ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Conditions ◽  
Material Flow ◽  
Flow Analysis ◽  
Material Flow Analysis ◽  
Construction And Demolition Waste ◽  
Water Tank ◽  
Demolition Waste

In Pakistan, construction and demolition waste(CDW) is generated in voluminous amount each year. CDW iswidely ill-handled and ultimately fed to landfills causing harm tothe already alarming environmental conditions. In order tosearch for the solution of this drastic matter, a study was done,which is explained in this paper. This paper presents the studydone at a demolition site near Karachi, in Sindh while thedemolition works were being carried out. At the site there wereold barracks which were being demolished. Before the demolitionworks were commenced, the site was surveyed and structuralcomponents of the barracks were counted and their dimensionswere measured. When the demolition was over, the demolishedwaste was calculated which comprised of concrete and masonryrubble, steel round bars, steel doors, steel windows, steel ceiling,steel girders, steel main gate, and plastic water tank. This studyinterpreted that construction and demolition (C&D) works wereprogressing considering the works’ deadline and the clients’requirements but the ecosystem’s ecology and the environmentalhealth were not taken into account. Recommendations are madeto handle CDW properly throughout its lifecycle. Theserecommendations aim to provide technological and logicalsolutions to grip CDW. The recommendations include wastereduction and reusing waste, life cycle assessment and costing,environmental and economic impact, material flow analysis, andadvanced computerized-tools.

scholarly journals Variación en la abundancia de árboles maderables por efecto de borde en un bosque tropical subcaducifolio

2019 ◽  
Vol 97 (1) ◽  
pp. 35 ◽  
Author(s):  
Víctor Abraham Vargas-Vázquez ◽  
Crystian Sadiel Venegas-Barrera ◽  
Arturo Mora-Olivo ◽  
José Guadalupe Martínez-Ávalos ◽  
Eduardo Alanís-Rodríguez ◽  
...  
Keyword(s):  
Edge Effect ◽  
Environmental Conditions ◽  
Life Stage ◽  
Life Stages ◽  
Cedrela Odorata ◽  
Economic Implications ◽  
Bursera Simaruba ◽  
Environmental Requirements ◽  
Guazuma Ulmifolia ◽  
Favorable Conditions

<p><strong>Background: </strong>The edge effect differentially affects the species in their life stages. We analyzed the environmental conditions associated with the abundance by life stage of four species of timber trees on the edge of a subdeciduous tropical forest.<strong></strong></p><p><strong>Hypothesis:</strong> The edges have higher light incidence and temperature, favorable conditions for the seedlings, so it is expected that the edge will have more abundance of seedlings with respect to the forest interior.</p><p><strong>Species under study:</strong> <em>Bursera simaruba</em> (L.) Sarg.<em>, Cedrela odorata</em> L.<em>, Guazuma ulmifolia </em>Lam.<em>, Lysiloma divaricatum </em>(Jacq.) J.F. Macbr.</p><p><strong>Study site and dates:</strong> Reserva de la Biosfera "El Cielo" (Tamaulipas), Mexico. January-December 2016.</p><p><strong>Methods: </strong>The abundance by life stages and environmental conditions were quantified within the gradient. These variables were correlated, in addition the requirements between stages were contrasted and they were associated with the identified environments.</p><p><strong>Results:</strong> <em>Guazuma ulmifolia</em> showed a negative response to the edge effect, while <em>Cedrela</em> <em>odorata</em> responded positively. The environmental requirements differed between the first life stages and adults. The abundance of the seedlings was associated to conditions of higher light incidence.</p><strong>Conclusions:</strong> Environmental requirements differentially affect each life stage. The abundance of seedlings increases in conditions of higher light incidence, but not in the rest of the stages, except in <em>C. odorata</em>. The loss of cover and the consequent formation of borders can lead to a reduction in the abundance of these species, with economic implications.

scholarly journals Reproductive diapause in Nysius huttoni White (Heteroptera Lygaeidae)

2002 ◽  
Vol 55 ◽  
pp. 308-311
Author(s):  
X.Z. He ◽  
Q. Wang ◽  
A. Carpenter
Keyword(s):  
Life Cycle ◽  
Immature Stages ◽  
Life Stages ◽  
Reproductive Diapause ◽  
Entire Life ◽  
Entire Life Cycle ◽  
Adult Females ◽  
Critical Photoperiod

The induction of reproductive diapause of Nysius huttoni was studied in the laboratory at 20 1C and 60 10 RH under a series of photoperiod regimes 168 h 1410 h 1212 h and 1014 h lightdark Reproductive diapause was considered to have occurred if females failed to lay eggs for 50 days after emergence The sensitivity of different life stages to diapauseinducing photoperiods varied When newly emerged females whose immature stages had been reared at 168 h were transferred to 1014 h and 1212 h 467 and 793 of them entered reproductive diapause respectively However when fifth instar nymphs were transferred from 168 h to 1014 h and 1212 h 100 of adult females entered reproductive diapause If the entire life cycle was maintained at 1014 h and 1212 h 667 and 400 of females entered reproductive diapause respectively The critical photoperiod for reproductive diapause was estimated to lie between 1311 h and 135105 h

scholarly journals Cnidome and Morphological Features of Pelagia noctiluca (Cnidaria: Scyphozoa) Throughout the Different Life Cycle Stages

2021 ◽  
Vol 8 ◽  
Author(s):  
Ainara Ballesteros ◽  
Carina Östman ◽  
Andreu Santín ◽  
Macarena Marambio ◽  
Mridvika Narda ◽  
...  
Keyword(s):  
Life Cycle ◽  
Developmental Stages ◽  
Later Life ◽  
Life Stages ◽  
Accurate Identification ◽  
Early Stages ◽  
Pelagia Noctiluca ◽  
Life Cycle Stages ◽  
Advanced Stages ◽  
Stage 1

Pelagia noctiluca is considered the most important jellyfish in the Mediterranean Sea, due to its abundance and the severity of its stings. Despite its importance in marine ecosystems and the health problems caused by its massive arrival in coastal areas, little is known about its early life stages and its cnidome has never been described. This study of the morphological and anatomical features throughout the life cycle identifies four early stages: two ephyra and two metaephyra stages. Ephyra stage 1, newly developed from a planula, has no velar canals, gastric filaments or nematocyst batteries. Ephyra stage 2, has velar canals, a cruciform-shaped manubrium and gastric filaments. Metaephyra stage 3 has eight tentacle buds and nematocyst clusters for the first time. Lastly, in metaephyra stage 4, the eight primary tentacles grow nearly simultaneously, with no secondary tentacles. Complete nematocyst battery patterns gradually develop throughout the later life stages. Four nematocyst types are identified: a-isorhiza, A-isorhiza, O-isorhiza and eurytele. Of these, a-isorhiza and eurytele are the most important throughout the entire life cycle, while A-isorhiza and O-isorhiza have a more important role in advanced stages. All nematocysts show a positive correlation between increasing capsule volumes and increasing body diameter of the ephyrae, metaephyrae, young medusae and adult medusae. In the early stages, the volumes of euryteles in the gastric filaments are larger than those in the exumbrella, indicating that the capsule volume is critical in the absence of marginal tentacles, specialized for feeding. This study provides updated information, the most extensive description to date, including high-resolution photographs and schematic drawings of all the developmental stages in the life cycle of P. noctiluca. Additionally, the first cnidome characterization is provided for each stage to facilitate accurate identification of this species when collected in the water column, and to raise awareness of the potential for human envenomation.

Sensitivity cycling and its ecological role in seeds with physical dormancy

2009 ◽  
Vol 19 (1) ◽  
pp. 3-13 ◽  
Author(s):  
K.M.G. Gehan Jayasuriya ◽  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Life Cycle ◽  
Environmental Conditions ◽  
Common Phenomenon ◽  
Ecological Role ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Physiological Dormancy ◽  
Seed Coats

AbstractCycling of physically dormant (PY) seeds between states insensitive and sensitive to dormancy-breaking factors in the environment has recently been demonstrated inFabaceaeandConvolvulaceae, and it may be a common phenomenon in seeds with water-impermeable seed coats. In contrast to seeds of many species with physiological dormancy (PD), those with PY cannot cycle between dormancy and non-dormancy (ND). In this paper, we evaluate the role of sensitivity cycling in controlling the timing of germination of seeds with PY in nature, and show that sensitivity cycling in seeds with PY serves the same ecological role as dormancy cycling in seeds with PD. Thus, sensitivity cycling in seeds with PY ensures that germination in nature occurs only at (a) time(s) of the year when environmental conditions for growth are, and are likely to remain, suitable long enough for the plant to complete its life cycle or to form a perennating structure. Further, we describe the experimental procedures necessary to determine whether sensitivity cycling is occurring, and discuss briefly the possible relevance of sensitivity cycling to dormancy classification.

scholarly journals Thermal bottlenecks in the life cycle define climate vulnerability of fish

Science ◽  
2020 ◽  
Vol 369 (6499) ◽  
pp. 65-70 ◽  
Author(s):  
Flemming T. Dahlke ◽  
Sylke Wohlrab ◽  
Martin Butzin ◽  
Hans-Otto Pörtner
Keyword(s):  
Life Cycle ◽  
Fish Species ◽  
Thermal Tolerance ◽  
Thermal Adaptation ◽  
Inverse Correlation ◽  
Climate Projections ◽  
Temperature Sensitive ◽  
Life Stages ◽  
Ontogenetic Changes ◽  
Species Vulnerability

Species’ vulnerability to climate change depends on the most temperature-sensitive life stages, but for major animal groups such as fish, life cycle bottlenecks are often not clearly defined. We used observational, experimental, and phylogenetic data to assess stage-specific thermal tolerance metrics for 694 marine and freshwater fish species from all climate zones. Our analysis shows that spawning adults and embryos consistently have narrower tolerance ranges than larvae and nonreproductive adults and are most vulnerable to climate warming. The sequence of stage-specific thermal tolerance corresponds with the oxygen-limitation hypothesis, suggesting a mechanistic link between ontogenetic changes in cardiorespiratory (aerobic) capacity and tolerance to temperature extremes. A logarithmic inverse correlation between the temperature dependence of physiological rates (development and oxygen consumption) and thermal tolerance range is proposed to reflect a fundamental, energetic trade-off in thermal adaptation. Scenario-based climate projections considering the most critical life stages (spawners and embryos) clearly identify the temperature requirements for reproduction as a critical bottleneck in the life cycle of fish. By 2100, depending on the Shared Socioeconomic Pathway (SSP) scenario followed, the percentages of species potentially affected by water temperatures exceeding their tolerance limit for reproduction range from ~10% (SSP 1–1.9) to ~60% (SSP 5–8.5). Efforts to meet ambitious climate targets (SSP 1–1.9) could therefore benefit many fish species and people who depend on healthy fish stocks.

Sign in / Sign up

Export Citation Format

Share Document