Exponential distribution of velocities and power distribution of quiescent periods in the spontaneous movement patterns of three hunting spiders

2021 ◽  
Author(s):  
Erik Baatrup ◽  
Anders O Rasmussen ◽  
Hans Malte ◽  
Søren Toft
Keyword(s):  
Power Distribution ◽  
Single Cells ◽  
Logarithmic Scale ◽  
Spontaneous Movement ◽  
Decay Function ◽  
Spider Species ◽  
Hunting Strategies ◽  
General Rules ◽  
Locomotor Patterns ◽  
Hunting Strategy

Abstract Here, we investigate the spontaneous locomotor patterns in three spiders with different hunting strategies. The locomotor activity of adult wolf spiders Pardosa amentata, with a sit-and-move hunting strategy, has previously been demonstrated to follow strictly mathematical rules, with most time spent at lower velocities and exponentially decreasing time spent at increasing velocities. Likewise, they have an abundance of short quiescent (resting) periods following a power decay function towards longer quiescent periods. In the present study, we explored whether similar distributions were expressed in juveniles of P. amentata and in two other spider species with different hunting strategies: the sit-and-wait spider Xysticus cristatus and the actively searching sac spider Clubiona phragmitis. We found that all three spider species followed the same two general rules of movement. However, there were differences among the three species. On a logarithmic scale of exponential velocities and a double-logarithmic scale of the rest power decay function, the slopes of the lines for the three species differed. We propose that these differences reflect the behavioural and locomotor differences of the three hunting strategies. Furthermore, we compare our results with similar movement distributions in single cells, fruit flies, mice and even humans.

scholarly journals Small-molecule mimicry hunting strategy in the imperial cone snail, Conus imperialis

2021 ◽  
Vol 7 (11) ◽  
pp. eabf2704
Author(s):  
Joshua P. Torres ◽  
Zhenjian Lin ◽  
Maren Watkins ◽  
Paula Flórez Salcedo ◽  
Robert P. Baskin ◽  
...  
Keyword(s):  
Small Molecules ◽  
Bioactive Peptides ◽  
Cone Snail ◽  
Fake News ◽  
Specialized Metabolites ◽  
Hunting Strategies ◽  
Venomous Animals ◽  
Platynereis Dumerilii ◽  
Species Specific ◽  
Hunting Strategy

Venomous animals hunt using bioactive peptides, but relatively little is known about venom small molecules and the resulting complex hunting behaviors. Here, we explored the specialized metabolites from the venom of the worm-hunting cone snail, Conus imperialis. Using the model polychaete worm Platynereis dumerilii, we demonstrate that C. imperialis venom contains small molecules that mimic natural polychaete mating pheromones, evoking the mating phenotype in worms. The specialized metabolites from different cone snails are species-specific and structurally diverse, suggesting that the cones may adopt many different prey-hunting strategies enabled by small molecules. Predators sometimes attract prey using the prey’s own pheromones, in a strategy known as aggressive mimicry. Instead, C. imperialis uses metabolically stable mimics of those pheromones, indicating that, in biological mimicry, even the molecules themselves may be disguised, providing a twist on fake news in chemical ecology.

Pronghorn Dental Age Profiles and Holocene Hunting Strategies at Hogup Cave, Utah

2009 ◽  
Vol 74 (2) ◽  
pp. 299-321 ◽  
Author(s):  
David A. Byers ◽  
Brenda L. Hill
Keyword(s):  
Late Holocene ◽  
Large Scale ◽  
Small Scale ◽  
Western North America ◽  
Dental Age ◽  
Temporal Shift ◽  
Hunting Strategies ◽  
Communal Hunting ◽  
Hunting Strategy ◽  
Middle And Late Holocene

In this article, we use pronghorn dental age data to document pronghorn hunting strategies at Hogup Cave, Utah, and explore their relationship with a widespread late Holocene trend in increasing large-game abundances noted in archaeofaunal contexts throughout western North America. Specifically, we test the hypothesis that at Hogup Cave, pronghorn hunting methods changed from a middle Holocene strategy dominated by encounter hunting of individual animals to a late Holocene strategy emphasizing large-scale communal hunting. Our analysis suggests that ancient hunters visiting Hogup Cave most likely employed small-scale encounter hunting during the fall and winter months and that this subsistence pattern varied little between the middle and late Holocene. Moreover, while hunting strategies appear to have remained generally similar throughout the 8,800-year occupational record at Hogup Cave, artiodactyl abundances show a dramatic increase relative to smaller, lower-ranked prey in late Holocene strata, suggesting that a temporal shift in the favored hunting strategy, by itself, cannot explain this trend in every context.

Importance of body size and hunting strategy during interactions between the Mexican red-rump tarantula (Brachypelma vagans) and the wolf spider Lycosa subfusca

2013 ◽  
Vol 91 (8) ◽  
pp. 545-553 ◽  
Author(s):  
A. Dor ◽  
Y. Hénaut
Keyword(s):  
Life History ◽  
Wolf Spider ◽  
Life Stages ◽  
Wolf Spiders ◽  
Predatory Behaviour ◽  
Spider Species ◽  
Behavioural Adaptation ◽  
Brachypelma Vagans ◽  
The Relationship ◽  
Hunting Strategy

Behavioural adaptation helps animals to maximize their ability to obtain food and to avoid being eaten, increasing fitness. To achieve this, they must assess predation risk and evaluate foraging needs simultaneously. In two sympatric spider species, the wandering wolf spider Lycosa subfusca F.O.P. Cambridge, 1902 and the sit-and-wait Mexican red-rump tarantula (Brachypelma vagans Ausserer, 1875), we studied the relationship between predatory behaviour and antipredatory behaviour at different life stages. In the laboratory, encounters were organized between one wolf spider (small, medium-sized, or large) and one tarantula (spiderling, small, medium-sized, or large). Attack latencies and behaviours were recorded. The results showed that wolf spiders attacked and successfully captured younger tarantulas, while they avoided or retreated from older ones. Tarantulas preferentially attacked and captured older wolf spiders. On other hand, younger wolf spiders were more cautious than older ones, which waited until for the tarantulas to attack before retreating. Younger tarantulas were also more cautious than adults, which never retreated from attack and increased their success in attacks with age. Finally, we discuss the relationship between the predatory strategies of both spiders with their perception abilities and life history.

scholarly journals Variation in the sacroiliac joint in Felidae

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11116
Author(s):  
Jean-Pierre Pallandre ◽  
Franck Lavenne ◽  
Eric Pellé ◽  
Grégory Breton ◽  
Mélina Ribaud ◽  
...  
Keyword(s):  
Body Size ◽  
High Speed ◽  
Large Prey ◽  
Lynx Canadensis ◽  
Acinonyx Jubatus ◽  
Hunting Strategies ◽  
Articular Surfaces ◽  
Behavior Of Cats ◽  
Hunting Strategy ◽  
Iliac Angle

Felidae species show a great diversity in their diet, foraging and hunting strategies, from small to large prey. Whether they belong to solitary or group hunters, the behavior of cats to subdue resisting small or large prey presents crucial differences. It is assumed that pack hunting reduces the per capita risk of each individual. We hypothesize that the sacroiliac articulation plays a key role in stabilizing the predator while subduing and killing prey. Using CT-scan from 59 felid coxal bones, we calculated the angle between both iliac articular surfaces. Correlation of this inter-iliac angle with body size was calculated and ecological stressors were evaluated on inter-iliac angle. Body size significantly influences inter-iliac angle with small cats having a wider angle than big cats. Arboreal species have a significantly larger angle compared to cursorial felids with the smallest value, and to scansorial and terrestrial species with intermediate angles. Felids hunting large prey have a smaller angle than felids hunting small and mixed prey. Within the Panthera lineage, pack hunters (lions) have a larger angle than all other species using solitary hunting strategy. According to the inter-iliac angle, two main groups of felids are determined: (i) predators with an angle of around 40° include small cats (i.e., Felis silvestris, Leopardus wiedii, Leptailurus serval, Lynx Canadensis, L. rufus; median = 43.45°), the only pack-hunting species (i.e., Panthera leo; median = 37.90°), and arboreal cats (i.e., L. wiedii, Neofelis nebulosa; median = 49.05°), (ii) predators with an angle of around 30° include solitary-hunting big cats (i.e., Acinonyx jubatus, P. onca, P. pardus, P. tigris, P. uncia; median = 31.80°). We suggest different pressures of selection to interpret these results. The tightening of the iliac wings around the sacrum probably enhances big cats’ ability for high speed and large prey control. In contrast, pack hunting in lions reduced the selective pressure for large prey.

Effects of Electrical Discharges in Low Pressure Gases on the Morphology of Polyethylene Crystals

1974 ◽  
Vol 32 ◽  
pp. 544-545
Author(s):  
L.H. Bolz ◽  
D.H. Reneker
Keyword(s):  
Power Distribution ◽  
Electrical Discharge ◽  
Dielectric Breakdown ◽  
Ionic Species ◽  
Low Pressure ◽  
Polymer Surfaces ◽  
Electrical Discharges ◽  
Adhesive Bonds ◽  
Power Distribution Lines ◽  
Modification Of The Surface

The attack, on the surface of a polymer, by the atomic, molecular and ionic species that are created in a low pressure electrical discharge in a gas is interesting because: 1) significant interior morphological features may be revealed, 2) dielectric breakdown of polymeric insulation on high voltage power distribution lines involves the attack on the polymer of such species created in a corona discharge, 3) adhesive bonds formed between polymer surfaces subjected to such SDecies are much stronger than bonds between untreated surfaces, 4) the chemical modification of the surface creates a reactive surface to which a thin layer of another polymer may be bonded by glow discharge polymerization.

Effects of carbamylcholine on chick embryo aggregate retina cell cultures

1988 ◽  
Vol 46 ◽  
pp. 350-351
Author(s):  
Glenn M. Cohen ◽  
Radharaman Ray
Keyword(s):  
Cell Cultures ◽  
Single Cells ◽  
Retinal Cell ◽  
Cell Aggregates ◽  
High Concentration ◽  
In Ovo ◽  
Sterile Culture ◽  
Retinal Tissue ◽  
Synaptic Junctions ◽  
And Control

Retinal,cell aggregates develop in culture in a pattern similar to the in ovo retina, forming neurites first and then synapses. In the present study, we continuously exposed chick retinal cell aggregates to a high concentration (1 mM) of carbamylcholine (carbachol), an acetylcholine (ACh) analog that resists hydrolysis by acetylcholinesterase (AChE). This situation is similar to organophosphorus anticholinesterase poisoning in which the ACh level is elevated at synaptic junctions due to inhibition of AChE, Our objective was to determine whether continuous carbachol exposure either damaged cholino- ceptive neurites, cell bodies, and synaptic elements of the aggregates or influenced (hastened or retarded) their development.The retinal tissue was isolated aseptically from 11 day embryonic White Leghorn chicks and then enzymatically (trypsin) and mechanically (trituration) dissociated into single cells. After washing the cells by repeated suspension and low (about 200 x G) centrifugation twice, aggregate cell cultures (about l0 cells/culture) were initiated in 1.5 ml medium (BME, GIBCO) in 35 mm sterile culture dishes and maintained as experimental (containing 10-3 M carbachol) and control specimens.

Selective Staining of Acid Mucopolysaccharides By Ruthenium Red

1968 ◽  
Vol 26 ◽  
pp. 38-39
Author(s):  
J. H. Luft
Keyword(s):  
Electron Microscope ◽  
Light Microscopy ◽  
Light Microscope ◽  
Osmium Tetroxide ◽  
Single Cells ◽  
Ruthenium Red ◽  
Collagen Fibers ◽  
Selective Staining ◽  
Pectic Substances ◽  
Solid Tissues

Ruthenium red is one of the few completely inorganic dyes used to stain tissues for light microscopy. This novelty is enhanced by ignorance regarding its staining mechanism. However, its continued usefulness in botany for demonstrating pectic substances attests to selectivity of some sort. Whether understood or not, histochemists continue to be grateful for small favors.Ruthenium red can also be used with the electron microscope. If single cells are exposed to ruthenium red solution, sufficient mass can be bound to produce observable density in the electron microscope. Generally, this effect is not useful with solid tissues because the contrast is wasted on the damaged cells at the block surface, with little dye diffusing more than 25-50 μ into the interior. Although these traces of ruthenium red which penetrate between and around cells are visible in the light microscope, they produce negligible contrast in the electron microscope. However, its presence can be amplified by a reaction with osmium tetroxide, probably catalytically, to be easily visible by EM. Now the density is clearly seen to be extracellular and closely associated with collagen fibers (Fig. 1).

Fluorescent potentiometric dyes for membrane-potential imaging

1994 ◽  
Vol 52 ◽  
pp. 166-167
Author(s):  
Leslie M. Loew
Keyword(s):  
Membrane Potential ◽  
Single Cells ◽  
Quantitative Imaging ◽  
Optical Recording ◽  
Biological Processes ◽  
Major Focus ◽  
The Past ◽  
Excitable Systems ◽  
Major Application ◽  
The Impact

A major application of potentiometric dyes has been the multisite optical recording of electrical activity in excitable systems. After being championed by L.B. Cohen and his colleagues for the past 20 years, the impact of this technology is rapidly being felt and is spreading to an increasing number of neuroscience laboratories. A second class of experiments involves using dyes to image membrane potential distributions in single cells by digital imaging microscopy - a major focus of this lab. These studies usually do not require the temporal resolution of multisite optical recording, being primarily focussed on slow cell biological processes, and therefore can achieve much higher spatial resolution. We have developed 2 methods for quantitative imaging of membrane potential. One method uses dual wavelength imaging of membrane-staining dyes and the other uses quantitative 3D imaging of a fluorescent lipophilic cation; the dyes used in each case were synthesized for this purpose in this laboratory.

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