scholarly journals Past thermal conditions affect hunting behaviour in larval antlions

2021 ◽  
Vol 8 (6) ◽  
pp. 210163
Author(s):  
Krzysztof Miler ◽  
Marcin Czarnoleski
Keyword(s):  
Elevated Temperatures ◽  
Prey Capture ◽  
Thermal Conditions ◽  
Thermal Exposure ◽  
Hunting Behaviour ◽  
Abiotic And Biotic Factors ◽  
Trap Size ◽  
Harsh Conditions ◽  
Antlion Larvae ◽  
Past Conditions

Some sit-and-wait predators, such as antlion larvae, construct traps to capture passing prey. The location of these traps depends on many abiotic and biotic factors, including temperature and the presence of conspecifics, which probably stimulate behaviours that minimize the costs and maximize the benefits of trap building. Here, we exposed second instar antlion larvae to elevated temperatures of 25°C (mild treatment) or 31°C (harsh treatment) for one month and then transferred them to common conditions (20°C) to examine the effects of previous thermal treatment on aggregation tendency and trap size. We predicted that antlions that experienced harsh conditions would subsequently increase the neighbouring distance and trap diameter to reduce competition with conspecifics and improve prey capture success, compensating for past conditions. In contrast with these predictions, antlions exposed to harsh conditions displayed a trend in the opposite direction, towards the decreased neighbouring distance. Furthermore, some of these antlions also built smaller traps. We discuss possible reasons for our results. The effects of previous thermal exposure have rarely been considered in terms of trap construction in antlions. Described effects may possibly apply to other sit-and-wait predators and are significant considering that many of these predators are long-lived.

Linking the Wrangellia Flood Basalts to the Galápagos Hotspot

2021 ◽  
Author(s):  
J. Gregory Shellnutt ◽  
Jaroslav Dostal ◽  
Tung-Yi Lee
Keyword(s):  
Mantle Plume ◽  
Elevated Temperatures ◽  
Volcanic Rocks ◽  
Thermal Conditions ◽  
Internal Variability ◽  
Eastern Pacific ◽  
Unique Region ◽  
Elemental Ratios ◽  
Trace Elemental ◽  
The Caribbean

Abstract The Triassic volcanic rocks of Wrangellia erupted at an equatorial to tropical latitude that was within 3000 km of western North America. The mafic and ultramafic volcanic rocks are compositionally and isotopically similar to those of oceanic plateaux that were generated from a Pacific mantle plume-type source. The thermal conditions, estimated from the primitive rocks, indicate that it was a high temperature regime (T P > 1550°C) consistent with elevated temperatures expected for a mantle plume. The only active hotspot currently located near the equator of the eastern Pacific Ocean that was active during the Mesozoic and produced ultramafic volcanic rocks is the Galápagos hotspot. The calculated mantle potential temperatures, trace elemental ratios, and Sr-Nd-Pb isotopes of the Wrangellia volcanic rocks are within the range of those from the Caribbean Plateau and Galápagos Islands, and collectively have similar internal variability as the Hawaii-Emperor island chain. The paleogeographic constraints, thermal estimates, and geochemistry suggests that it is possible that the Galápagos hotspot generated the volcanic rocks of Wrangellia and the Caribbean plateau or, more broadly, that the eastern Pacific (Panthalassa) Ocean was a unique region where anomalously high thermal conditions either periodically or continually existed from ~230 Ma to the present day.

Disadvantages of living in a populous neighborhood for sit‐and‐wait predators: Competition for space reduces pit‐trap size in antlion larvae

Ethology ◽  
2020 ◽  
Vol 126 (11) ◽  
pp. 1031-1037
Author(s):  
Alejandro G. Farji‐Brener ◽  
Agostina S. Juncosa‐Polzella ◽  
Daniela Madrigal Tejada ◽  
Diego Centeno‐Alvarado ◽  
Mariana Hernández‐Soto ◽  
...  
Keyword(s):  
Competition For Space ◽  
Trap Size ◽  
Antlion Larvae

scholarly journals Flexural Properties of PVC/Bamboo Composites under Static and Dynamic-Thermal Conditions: Effects of Composition and Water Absorption

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Shahril Anuar Bahari ◽  
Warren J. Grigsby ◽  
Andreas Krause
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Dynamic Mechanical Thermal Analysis ◽  
Elevated Temperatures ◽  
Flexural Modulus ◽  
Thermal Conditions ◽  
Flexural Properties ◽  
Particle Sizes ◽  
Flexural Performance

Polyvinyl chloride (PVC)/bamboo composites have been prepared and assessed for their use in interior and exterior load-bearing applications. PVC composites were formed by compounding PVC with different bamboo particle sizes and loadings. The mechanical properties of these composites were determined at both ambient and elevated temperatures and after long-term water soaking. Analysis revealed that bamboo incorporation improved the PVC composite flexural modulus which was also observed with dynamic mechanical-thermal analysis on heating composites toca.70°C. Addition of 25% and 50% bamboo particles increases flexural modulus by 80% with dependency on whether fine (<75 μm) or coarse (<1 mm) particles were used. On water soaking to saturation, composites had water weight uptakes of 10%, with reduced flexural properties obtained for all water-soaked composites. Nonetheless, the results of this study show that PVC/bamboo composites achieve the minimum flexural performance of ASTM D 6662, indicating potential for their use in exterior applications.

Microstructure and Mechanical Properties of a New Ni-Cr-Fe-W-Al Alloy for Advanced Ultra-Supercritical Power Plants

2015 ◽  
Vol 816 ◽  
pp. 586-593 ◽  
Author(s):  
Xian Chao Hao ◽  
Long Zhang ◽  
Xiu Juan Zhao ◽  
Tian Liang ◽  
Ying Che Ma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermodynamic Calculation ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Prolonged Exposure ◽  
Thermal Exposure ◽  
Average Diameter ◽  
Al Alloy ◽  
Microstructural Stability

Optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermodynamic calculation were used to study the phase stability and precipitation in a Ni-Cr-Fe-W-Al alloy. Mechanical properties were also studied. The major precipitates after standard heat treatment or prolonged aging at 725 oC and 800 oC were M23C6 and γ′. M23C6 precipitated intergranularly. P-phase was not detected after thermal exposure, which was different from the results of thermodynamic calculation. The average diameter of γ′ increased with the increasing exposure temperature and time, and could be depicted by the LSW theory. Specimens in solution-annealed condition exhibited excellent ductility. During the prolonged exposure at 725 oC, tensile strength and ductility at room and elevated temperatures kept well, which means this alloy possessed good microstructural stability after a long time exposure.

scholarly journals Speciation through the lens of biomechanics: locomotion, prey capture and reproductive isolation

2016 ◽  
Vol 283 (1838) ◽  
pp. 20161294 ◽  
Author(s):  
Timothy E. Higham ◽  
Sean M. Rogers ◽  
R. Brian Langerhans ◽  
Heather A. Jamniczky ◽  
George V. Lauder ◽  
...  
Keyword(s):  
Biological Sciences ◽  
Reproductive Isolation ◽  
Prey Capture ◽  
Dynamic Interactions ◽  
Fish Predator ◽  
Local Conditions ◽  
Predator Prey ◽  
Primary Driver ◽  
Abiotic And Biotic Factors ◽  
Specific Species

Speciation is a multifaceted process that involves numerous aspects of the biological sciences and occurs for multiple reasons. Ecology plays a major role, including both abiotic and biotic factors. Whether populations experience similar or divergent ecological environments, they often adapt to local conditions through divergence in biomechanical traits. We investigate the role of biomechanics in speciation using fish predator–prey interactions, a primary driver of fitness for both predators and prey. We highlight specific groups of fishes, or specific species, that have been particularly valuable for understanding these dynamic interactions and offer the best opportunities for future studies that link genetic architecture to biomechanics and reproductive isolation (RI). In addition to emphasizing the key biomechanical techniques that will be instrumental, we also propose that the movement towards linking biomechanics and speciation will include (i) establishing the genetic basis of biomechanical traits, (ii) testing whether similar and divergent selection lead to biomechanical divergence, and (iii) testing whether/how biomechanical traits affect RI. Future investigations that examine speciation through the lens of biomechanics will propel our understanding of this key process.

scholarly journals Thermal sensitivity and seasonal change in the gut microbiome of a desert ant, Cephalotes rohweri

2021 ◽  
Author(s):  
Marshall S McMunn ◽  
Asher I Hudson ◽  
Ash Zemenick ◽  
Monika Egerer ◽  
Stacy M Philpott ◽  
...  
Keyword(s):  
Climate Change ◽  
Elevated Temperatures ◽  
Variable Temperature ◽  
Thermal Sensitivity ◽  
Thermal Exposure ◽  
Seasonal Temperature ◽  
Microbiome Composition ◽  
Desert Ant ◽  
Temperature Regimes ◽  
Response To Temperature

Microorganisms within ectotherms must withstand the variable body temperatures of their hosts. Shifts in host body temperature resulting from climate change have the potential to shape ectotherm microbiome composition. Microbiome compositional changes occurring in response to temperature in nature have not been frequently examined, restricting our ability to predict microbe-mediated ectotherm responses to climate change. In a set of field-based observations, we characterized gut bacterial communities and thermal exposure across a population of desert arboreal ants (Cephalotes rohweri). In a paired growth chamber experiment, we exposed ant colonies to variable temperature regimes differing by 5 C for three months. We found that the abundance and composition of ant-associated bacteria were sensitive to elevated temperatures in both field and laboratory experiments. We observed a subset of taxa that responded similarly to temperature in the experimental and observational study, suggesting a role of seasonal temperature and local temperature differences amongst nests in shaping microbiomes within the ant population. Bacterial mutualists in the genus Cephalotococcus (Opitutales: Opitutaceae) were especially sensitive to change in temperature - decreasing in abundance in naturally warm summer nests and warm growth chambers. We also report the discovery of a member of the Candidate Phlya Radiation (Phylum: Gracilibacteria), a suspected epibiont, found in low abundance within the guts of this ant species.

scholarly journals Parallel channels for motion feature extraction in the pretectum and tectum of larval zebrafish

2019 ◽  
Author(s):  
Kun Wang ◽  
Julian Hinz ◽  
Yue Zhang ◽  
Tod R. Thiele ◽  
Aristides B Arrenberg
Keyword(s):  
Feature Extraction ◽  
Visual Field ◽  
Prey Capture ◽  
Receptive Fields ◽  
Lower Visual Field ◽  
Motion Feature ◽  
Hunting Behaviour ◽  
Sensorimotor Transformations ◽  
Visual Areas ◽  
Tectal Neurons

AbstractNon-cortical visual areas in vertebrate brains extract different stimulus features, such as motion, object size and location, to support behavioural tasks. The optic tectum and pretectum, two primary visual areas, are thought to fulfil complementary biological functions in zebrafish to support prey capture and optomotor stabilisation behaviour. However, the adaptations of these brain areas to behaviourally relevant stimulus statistics are unknown. Here, we used calcium imaging to characterize the receptive fields of 1,926 motion-sensitive neurons in diencephalon and midbrain. We show that many caudal pretectal neurons have large receptive fields (RFs), whereas RFs of tectal neurons are smaller and mostly size-selective. RF centres of large-size RF neurons in the pretectum are predominantly located in the lower visual field, while tectal neurons sample the upper-nasal visual field more densely. This tectal visual field sampling matches the expected prey item locations, suggesting that the tectal magnification of the upper-nasal visual field might be an adaptation to hunting behaviour. Finally, we probed optomotor responsiveness and found that even relatively small stimuli drive optomotor swimming, if presented in the lower-temporal visual field, suggesting that the pretectum preferably samples information from this region on the ground to inform optomotor behaviour. Our characterization of the parallel processing channels for non-cortical motion feature extraction provides a basis for further investigation into the sensorimotor transformations of the zebrafish brain and its adaptations to habitat and lifestyle.

scholarly journals Comparative Prey Spectra Analyses on the Endangered Aquatic Carnivorous Waterwheel Plant (Aldrovanda vesiculosa, Droseraceae) at Several Naturalized Microsites in the Czech Republic and Germany

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
M Horstmann ◽  
L Heier ◽  
S Kruppert ◽  
L C Weiss ◽  
R Tollrian ◽  
...  
Keyword(s):  
Prey Species ◽  
Prey Capture ◽  
Trapping Efficiency ◽  
The Czech Republic ◽  
Prey Specificity ◽  
Different Populations ◽  
Trap Size ◽  
Taxonomic Groups ◽  
Prey Mobility ◽  
Successful Capture

Synopsis The critically endangered carnivorous waterwheel plant (Aldrovanda vesiculosa, Droseraceae) possesses underwater snap traps for capturing small aquatic animals, but knowledge on the exact prey species is limited. Such information would be essential for continuing ecological research, drawing conclusions regarding trapping efficiency and trap evolution, and eventually, for conservation. Therefore, we performed comparative trap size measurements and snapshot prey analyses at seven Czech and one German naturalized microsites on plants originating from at least two different populations. One Czech site was sampled twice during 2017. We recorded seven main prey taxonomic groups, that is, Cladocera, Copepoda, Ostracoda, Ephemeroptera, Nematocera, Hydrachnidia, and Pulmonata. In total, we recorded 43 different prey taxa in 445 prey-filled traps, containing in sum 461 prey items. With one exception, prey spectra did not correlate with site conditions (e.g. water depth) or trap size. Our data indicate that A. vesiculosa shows no prey specificity but catches opportunistically, independent of prey species, prey mobility mode (swimming or substrate-bound), and speed of movement. Even in cases where the prey size exceeded trap size, successful capture was accomplished by clamping the animal between the traps’ lobes. As we found a wide prey range that was attracted, it appears unlikely that the capture is enhanced by specialized chemical- or mimicry-based attraction mechanisms. However, for animals seeking shelter, a place to rest, or a substrate to graze on, A. vesiculosa may indirectly attract prey organisms in the vicinity, whereas other prey capture events (like that of comparably large notonectids) may also be purely coincidental.

FE Simulation and Experimental Study of Tube Hydroforming Process for AA1050 Alloy at Various Temperatures

2011 ◽  
Vol 264-265 ◽  
pp. 96-101
Author(s):  
Hassan Moslemi Naeini ◽  
Golam Hosein Liaghat ◽  
S.J. Hashemi Ghiri ◽  
S.M.H. Seyedkashi
Keyword(s):  
Elevated Temperatures ◽  
New Technologies ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Thermal Conditions ◽  
High Strength ◽  
Different Temperatures ◽  
Hydroforming Process ◽  
Production Technologies ◽  
Advanced Production

Considering the necessity of using light weight, high strength and corrosion resistant materials, automotive and aerospace industries need to use advanced production technologies. Hydroforming has been regarded as one of the new technologies in forming of aluminium and magnesium alloys. These alloys have very low formability at room temperature which will be improved at elevated temperatures. In this paper, AA1050 aluminium alloy tube is numerically and experimentally investigated at different temperatures. Thickness distribution in forming zone is studied under different thermal conditions. Numerical results have been verified by experiments and there is a good agreement.

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