The effect of ground surface rugosity on ant running speed is species-specific rather than size dependent

The locomotory behaviour of 12 ant species belonging to four different genera (Formicinae: Cataglyphis, Formica, Lasius; Myrmicinae: Myrmica) was studied by filming individuals during walking on smoked-glass plates. Subsequent multivariate analyses of walking kinematics and footfall positions showed marked species-specific as well as size-dependent differences in the locomotory behaviour. The geometric properties of the footfall patterns resulting from the alternating tripod gait scale to leg dimensions in a geometric manner. At high speed, footprint distances between succeeding tripods exceed maximum leg extension, indicating that ants are 'trotting' from one tripod to the next one with intermittent aerial phases. In at least one species (Cataglyphis bombycina), there is evidence for quadrupedal locomotion at the highest speed. The functional relationship between stride length (s, the distance between successive footprints of the same foot) and speed (v) was best described by a curvilinear model, s=avb. Exponent b ranges from 0.3 to 0.6 and reveals differences between species. Within species, exponent b is constant, whereas factor a scales to leg length. Females and males show metachronal interleg coordination patterns rather than the alternating tripod coordination pattern seen in workers of the same species.

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Thermal asymmetries influence effects of warming on stage and size-dependent predator-prey interactions

10.1101/2021.12.03.470870 ◽

2021 ◽

Author(s):

Adam Pepi ◽

Tracie Hayes ◽

Kelsey Lyberger

Keyword(s):

Climate Warming ◽

Species Interactions ◽

Vital Rates ◽

Feeding Rates ◽

Temperature Dependent ◽

Predator Prey ◽

Size Dependent ◽

Species Specific ◽

Increasing Temperature ◽

The Impact

AbstractClimate warming directly influences the developmental and feeding rates of organisms. Changes in these rates are likely to have consequences for species interactions, particularly for organisms affected by stage- or size-dependent predation. However, because of differences in species-specific responses to warming, predicting the impact of warming on predator and prey densities can be difficult. We present a general model of stage-dependent predation with temperature-dependent vital rates to explore the effects of warming when predator and prey have different thermal optima. We found that warming generally favored the interactor with the higher thermal optimum. Part of this effect occurred due to the stage-dependent nature of the interaction, and part due to thermal asymmetries. Furthermore, large differences in thermal optima between predators and prey (i.e., a high degree of asymmetry) led to a weaker interaction. Interestingly, below the predator and prey thermal optima, warming caused prey densities to decline, even as increasing temperature improved prey performance. We also parameterize our model using values from a well-studied system, Arctia virginalis and Formica lasioides, in which the predator has a warmer optimum. Overall, our results provide a general framework for understanding stage- and temperature-dependent predator-prey interactions, and illustrate that the thermal niche of both predator and prey are important to consider when predicting the effects of climate warming.

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Spatial patterns of coral survivorship: impacts of adult proximity versus other drivers of localized mortality

PeerJ ◽

10.7717/peerj.1440 ◽

2015 ◽

Vol 3 ◽

pp. e1440 ◽

Cited By ~ 5

Author(s):

David A. Gibbs ◽

Mark E. Hay

Keyword(s):

Hot Spots ◽

Pocillopora Damicornis ◽

Size Dependent ◽

Seriatopora Hystrix ◽

Species Specific ◽

Natural Reefs ◽

Selective Regime ◽

Minimal Evidence ◽

Over Time ◽

Transplant Experiments

Species-specific enemies may promote prey coexistence through negative distance- and density-dependent survival of juveniles near conspecific adults. We tested this mechanism by transplanting juvenile-sized fragments of the brooding coralsPocillopora damicornisandSeriatopora hystrix3, 12, 24 and 182 cm up- and down-current of conspecific adults and monitoring their survival and condition over time. We also characterized the spatial distribution ofP. damicornisandS. hystrixwithin replicate plots on three Fijian reef flats and measured the distribution of small colonies within 2 m of larger colonies of each species. Juvenile-sized transplants exhibited no differences in survivorship as a function of distance from adultP. damicornisorS. hystrix. Additionally, bothP. damicornisandS. hystrixwere aggregated rather than overdispersed on natural reefs. However, a pattern of juveniles being aggregated near adults while larger (and probably older) colonies were not suggests that greater mortality near large adults could occur over longer periods of time or that size-dependent mortality was occurring. While we found minimal evidence of greater mortality of small colonies near adult conspecifics in our transplant experiments, we did document hot-spots of species-specific corallivory. We detected spatially localized and temporally persistent predation onP. damicornisby the territorial triggerfishBalistapus undulatus. This patchy predation did not occur forS. hystrix. This variable selective regime in an otherwise more uniform environment could be one mechanism maintaining diversity of corals on Indo-Pacific reefs.

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Diameter Growth of Juvenile Trees after Gap Formation in a Bolivian Rain Forest: Responses are Strongly Species-specific and Size-dependent

Biotropica ◽

10.1111/j.1744-7429.2011.00803.x ◽

2011 ◽

Vol 44 (3) ◽

pp. 312-320 ◽

Cited By ~ 7

Author(s):

Claudia C. Soliz-Gamboa ◽

Anne Sandbrink ◽

Pieter A. Zuidema

Keyword(s):

Rain Forest ◽

Diameter Growth ◽

Gap Formation ◽

Size Dependent ◽

Species Specific

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Production and STEM examination of controlled-size silver clusters

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075488 ◽

1983 ◽

Vol 41 ◽

pp. 338-339

Author(s):

M. A. Listvan ◽

R. P. Andres

Keyword(s):

Cluster Size ◽

Metal Clusters ◽

Experimental Parameter ◽

Carbon Films ◽

Metal Species ◽

Silver Clusters ◽

Free Jet ◽

Size Dependent ◽

Cluster Properties ◽

Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

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Transfer Technique for Electron Microscopy of Membrance Filter Samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005278x ◽

1974 ◽

Vol 32 ◽

pp. 554-555

Author(s):

Lawrence W. Ortiz ◽

Bonnie L. Isom

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Pore Size ◽

Membrane Filters ◽

Size Dependent

A procedure is described for the quantitative transfer of fibers and particulates collected on membrane filters to electron microscope (EM) grids. Various Millipore MF filters (Millipore AA, HA, GS, and VM; 0.8, 0.45, 0.22 and 0.05 μm mean pore size) have been used with success. Observed particle losses have not been size dependent and have not exceeded 10%. With fibers (glass or asbestos) as the collected media this observed loss is approximately 3%.

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Electron Microscopy in the Study of Natural Phytoplankton Assemblages

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119831 ◽

1985 ◽

Vol 43 ◽

pp. 620-623

Author(s):

Linda Sicko-Goad

Keyword(s):

Electron Microscopy ◽

Aquatic Environment ◽

Size Range ◽

Physical Parameters ◽

Specific Information ◽

Phytoplankton Assemblages ◽

Phytoplankton Productivity ◽

Ecosystem Effects ◽

Time Of Year ◽

Species Specific

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.

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Spindle scaling mechanisms

Essays in Biochemistry ◽

10.1042/ebc20190064 ◽

2020 ◽

Vol 64 (2) ◽

pp. 383-396

Author(s):

Lara K. Krüger ◽

Phong T. Tran

Keyword(s):

Cell Size ◽

Spindle Assembly ◽

Dependent Manner ◽

Post Translational Modification ◽

Size Dependent ◽

A Cell ◽

Chromosome Separation ◽

Spindle Elongation ◽

Protein Gradients ◽

Spindle Structure

Abstract The mitotic spindle robustly scales with cell size in a plethora of different organisms. During development and throughout evolution, the spindle adjusts to cell size in metazoans and yeast in order to ensure faithful chromosome separation. Spindle adjustment to cell size occurs by the scaling of spindle length, spindle shape and the velocity of spindle assembly and elongation. Different mechanisms, depending on spindle structure and organism, account for these scaling relationships. The limited availability of critical spindle components, protein gradients, sequestration of spindle components, or post-translational modification and differential expression levels have been implicated in the regulation of spindle length and the spindle assembly/elongation velocity in a cell size-dependent manner. In this review, we will discuss the phenomenon and mechanisms of spindle length, spindle shape and spindle elongation velocity scaling with cell size.

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