Ontogenetic Effects on Locomotory Gaits in Nymphs of Baetis tricaudatus Dodds (Ephemeroptera:Baetidae)

1998 ◽  
Vol 17 (4) ◽  
pp. 475-488 ◽  
Author(s):  
Tracy N. Kutash ◽  
Douglas A. Craig
Keyword(s):  
Ontogenetic Effects ◽  
Baetis Tricaudatus

scholarly journals The relative taxonomic value of morphological characters in the genus <i>Nummulites</i> (Foraminiferida)

1992 ◽  
Vol 11 (2) ◽  
pp. 197-209 ◽  
Author(s):  
Andrew Racey
Keyword(s):  
Morphological Character ◽  
Morphological Characters ◽  
Species Discrimination ◽  
Evolutionary Trends ◽  
Ontogenetic Effects

Abstract. The main evolutionary trends in the nummulites are briefly summarised and the value of certain morphological characters in species discrimination are summarised. The degree of interdependence of each morphological character on all other characters is assessed and the characters are weighted in order of importance. Environmental and ontogenetic effects on each character are then reviewed and the characters reweighted in order of importance.

Genetic, Acclimatization, and Ontogenetic Effects on Habitat Selection Behavior in Daphnia pulicaria

Evolution ◽  
1994 ◽  
Vol 48 (4) ◽  
pp. 1324 ◽  
Author(s):  
Mathew A. Leibold ◽  
Alan J. Tessier ◽  
Colin T. West
Keyword(s):  
Habitat Selection ◽  
Daphnia Pulicaria ◽  
Selection Behavior ◽  
Ontogenetic Effects

scholarly journals Variations of Salminus hilarii diet (Ostariophysi, Characidae): seasonal and ontogenetic effects

2015 ◽  
Vol 75 (3) ◽  
pp. 574-580
Author(s):  
GA Villares Junior ◽  
R Goitein
Keyword(s):  
Prey Size ◽  
Pearson Correlation ◽  
Feeding Activity ◽  
Stomach Contents ◽  
Food Composition ◽  
Spearman Correlation ◽  
Statistical Comparison ◽  
Significant Difference ◽  
Ontogenetic Effects ◽  
Size And Morphology

AbstractThis study described the variations seasonal and ontogenetic of Salminus hilarii diet. Samples were collected in the Sorocaba River, São Paulo, Brazil, one of the few rivers where individuals of the species still occur in a higher frequency. The preys consumed were analyzed by Importance Alimentary Index (AIi). To determine similarities between year seasons, the AIi data were analyzed by the Morisita-Horn index and reduced in cluster analysis, along with a statistical comparison made by one-way ANOSIM test (5%). The feeding activity was analyzed according to the stomach repletion index and compared among the year seasons using non parametric variance analysis Kruskal-Wallis test (5%). Comparison of prey consumed between immature and adult individuals was made by Spearman correlation (5%). A Pearson correlation (5%) was applied between the standard length of the fish and prey consumed, as well as between the mouth and prey heights. The analyzes of stomach contents showed that the diet of this species was exclusively piscivorous, with significant difference of prey consumption during the period, the same happening among adult and immature individuals. It was observed that these fishes use to swallow their prey whole and that significant correlations between size of predator and prey size can be observed. There is also correlation between the mouth height and the maximum prey depth. Salminus hilarii feeds on the available prey, and the species food composition and feeding activity depends on prey`s abundance, their size and morphology, as do the water temperatures.

Dynamics of Drift and Microdistribution of Two Mayfly Populations: A Predictive Model

1987 ◽  
Vol 44 (4) ◽  
pp. 832-845 ◽  
Author(s):  
Jan J. H. Ciborowski
Keyword(s):  
Large Scale ◽  
Distribution Patterns ◽  
Flow Conditions ◽  
Transition Matrices ◽  
Permanent Displacement ◽  
Redistribution Mechanism ◽  
Baetis Tricaudatus ◽  
Stable Flow ◽  
Downstream Movement ◽  
Made In

A model is derived to predict changes in larval microdistribution of Ephemerella inermis Eaton and Baetis tricaudatus Dodds (Ephemeroptera) that result from drift. Transport by drift was assumed to be a Markov process. Estimates of departure from the substrate, downstream movement, and lateral transport were combined to produce transition matrices from which changes in microdistribution, magnitude of drift, and mean daily downstream displacement of live and dead animals were determined. Predictions from the model were compared with observations made in a river similar in composition to the area modelled. There were marked differences between expected drift of living versus dead animals; estimates for drift of living animals corresponded most closely to values observed in the field. Predicted drift either corresponded to or was less than observed levels. Observed changes in benthic microdistribution were minimal, but the model predicted large-scale relocation of animals toward river margins. Thus, magnitude and spatial pattern of drift could be adequately modelled but benthic distribution could not. Drift is an important redistribution mechanism but animals must have a complementary ability to actively travel towards the river center to maintain constant benthic distribution patterns. Inhibition of movement during floods should produce increased abundance at margins. During stable flow conditions, drift and benthic activity probably act together to produce and maintain microdistributional patterns among vagile organisms. In contrast, drift of invertebrates possessing poor locomotory ability probably reflects larger-scale, permanent displacement events that are a normal aspect of development, or the outcome of aggressive interactions.

Metamorphosis Affects Metal Concentrations and Isotopic Signatures in a Mayfly (Baetis tricaudatus): Implications for the Aquatic-Terrestrial Transfer of Metals

2017 ◽  
Vol 51 (4) ◽  
pp. 2438-2446 ◽  
Author(s):  
Jeff S. Wesner ◽  
David M. Walters ◽  
Travis S. Schmidt ◽  
Johanna M. Kraus ◽  
Craig A. Stricker ◽  
...  
Keyword(s):  
Metal Concentrations ◽  
Isotopic Signatures ◽  
Baetis Tricaudatus

Ontogenetic scaling of burrowing forces in the earthworm Lumbricus terrestris

2000 ◽  
Vol 203 (18) ◽  
pp. 2757-2770 ◽  
Author(s):  
K.J. Quillin
Keyword(s):  
Body Weight ◽  
Body Mass ◽  
Force Production ◽  
Lumbricus Terrestris ◽  
Axial Forces ◽  
Order Of Magnitude ◽  
Ontogenetic Effects ◽  
Radial Forces ◽  
The Difference ◽  
Earthworm Lumbricus

In hydrostatic skeletons, it is the internal fluid under pressure surrounded by a body wall in tension (rather than a rigid lever) that enables the stiffening of the organism, the antagonism of muscles and the transmission of force from the muscles to the environment. This study examined the ontogenetic effects of body size on force production by an organism supported with a hydrostatic skeleton. The earthworm Lumbricus terrestris burrows by forcefully enlarging crevices in the soil. I built a force-measuring apparatus that measured the radial forces as earthworms of different sizes crawled through and enlarged pre-formed soil burrows. I also built an apparatus that measured the radial and axial forces as earthworms of different sizes attempted to elongate a dead-end burrow. Earthworms ranging in body mass m(b) from hatchlings (0.012 g) to adults (8.9 g) exerted maximum forces (F, in N) during active radial expansion of their burrows (F=0.32 m(b)(0.43)) and comparable forces during axial elongation of the burrow (F=0.26 m(b)(0.47)). Both these forces were almost an order of magnitude greater than the radial anchoring forces during normal peristalsis within burrows (F=0.04 m(b)(0.45)). All radial and axial forces scaled as body mass raised to the 2/5 power rather than to the 2/3 power expected by geometric similarity, indicating that large worms exert greater forces than small worms on an absolute scale, but the difference was less than predicted by scaling considerations. When forces were normalized by body weight, hatchlings could push 500 times their own body weight, while large adults could push only 10 times their own body weight.

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