Fecundity compensation and fecundity reduction among populations of the three-spined stickleback infected by Schistocephalus solidus in Alaska

Parasitology ◽  
2014 ◽  
Vol 141 (8) ◽  
pp. 1088-1096 ◽  
Author(s):  
DAVID C. HEINS ◽  
JOHN A. BAKER
Keyword(s):  
Clutch Size ◽  
Host Response ◽  
South Central ◽  
Schistocephalus Solidus ◽  
Fecundity Compensation ◽  
Two Phases ◽  
Two Populations ◽  
Effect Of Feeding ◽  
Fecundity Reduction ◽  
Host Body Mass

SUMMARYWe surveyed nine populations of the three-spined stickleback infected by the diphyllobothriidean cestode Schistocephalus solidus from south-central Alaska for two apparent forms of tolerance to infection in females capable of producing egg clutches notwithstanding large parasite burdens. Seven populations exhibited fecundity reduction, whereas two populations showed fecundity compensation. Our data suggest that fecundity reduction, a side effect resulting from nutrient theft, occurs in two phases of host response influenced by the parasite : host body mass (BM) ratio. The first is significantly reduced ovum mass without significant reduction in clutch size, and the second one involves significant reductions in both ovum mass and clutch size. Thus, ovum mass of host females who are functionally being starved through nutrient theft seems to be more readily influenced by parasitism and, therefore, decreased before clutch size is reduced. This inference is consistent with expectations based on the biology of and effect of feeding ration on reproduction in stickleback females. Fecundity compensation appears to be uncommon among populations of three-spined stickleback in Alaska and rare among populations throughout the northern hemisphere. Fecundity reduction seems to be common, at least among stickleback populations in Alaska.

Interaction of water with clay surfaces

1984 ◽  
Vol 311 (1517) ◽  
pp. 287-299 ◽  
Keyword(s):  
Surface Force ◽  
Point Of View ◽  
Pure Liquid ◽  
Surface Phase ◽  
Self Diffusion ◽  
Bond Network ◽  
Two Phases ◽  
Clay Suspensions ◽  
Two Populations ◽  
Self Diffusion Coefficient

In clay suspensions and gels water molecules are distributed between two populations in fast exchange. The physical meaning of this distribution is discussed here. From the molecular dynamics point of view it is shown that the surface force fields perturb the rotational motion on a distance z* extending to approximately 10~9m. The product times the surface area available to water defines the volume of a surface phase b. In the bulk phase a the rotational diffusional correlation time is not affected and the pulsed field gradient nuclear magnetic technique shows that the self-diffusion coefficient of water in that phase is the same as in pure liquid. The effects of salt concentration, pressure and temperature on phase b are studied, the main finding being that in the surface phase the well-developed random hydrogen bond network characteristic of liquid water is, at least, partly destroyed. Freezing the the gel suppresses the rapid exchange between the two phases. From the thermodynamic point of view it is not possible with the present data to decide whether phase b has thermodynamic significance or if it constitutes a heterogeneity within the aqueous phase.

scholarly journals Pathogenicity of Meloidogyne Incognita on Sesamum Indicum and the Efficacy of Yield-Based Scheme in Resistance Designation

2008 ◽  
Vol 48 (1) ◽  
pp. 73-80
Author(s):  
Jonathan Atungwu ◽  
Steve Afolami ◽  
Olufunke Egunjobi ◽  
Opeyemi Kadri
Keyword(s):  
Meloidogyne Incognita ◽  
Host Response ◽  
Sesamum Indicum ◽  
Additional Parameter ◽  
Grain Production ◽  
Harvest Time ◽  
Root Knot Nematode ◽  
Population Densities ◽  
Nematode Reproduction ◽  
Two Phases

Pathogenicity ofMeloidogyne IncognitaonSesamum Indicumand the Efficacy of Yield-Based Scheme in Resistance DesignationTwo screenhouse experiments were conducted in 2004 and 2005 rainy season to investigate the reaction of three selectedSesamum indicumcultivars against three population densities of a root knot nematode,Meloidogyne incognita.Seedlings ofS. indicumwere raised in pots arranged in completely randomised design and inoculated with 0, 5 000, and 10 000 eggs ofM. incognita, replicated six times. Root knot disease was evaluated at mid-season and harvest. A new method for evaluating and reporting resistance toMeloidogynespp. that divides the screening procedure into two phases in the same experiment was adapted. The first phase investigated the host response through the traditional standard method that utilises only gall and nematode reproduction indices, while the second considered the effect of root knot disease on grain production of the crop. There was consistency in host designation of E8 and NICRIBEN-01M (syn: 530-1-6) which were classified under the traditional and improved rating schemes as tolerant and resistant, respectively. However,S. indicumbreeding line Pbtil (No. 1) which was considered susceptible under the old system was found to be tolerant using the integrated and improved system. Root galls incited by the nematode degenerated significantly from mid-season to harvest time. Utilising yield as additional parameter for assessing resistance to root knot nematode provides a complete picture ofSesamum-Meloidogyneinteraction, and therefore a more meaningful system for determining host response.

Contender pressure versus resource dispersion as predictors of territory size of coyotes (Canis latrans)

2011 ◽  
Vol 89 (10) ◽  
pp. 960-967 ◽  
Author(s):  
R.R. Wilson ◽  
J.A. Shivik
Keyword(s):  
Canis Latrans ◽  
Alternative Hypothesis ◽  
Territory Size ◽  
Main Determinant ◽  
Movement Rates ◽  
Resource Dispersion ◽  
High Resource ◽  
Movement Data ◽  
South Central ◽  
Two Populations

Many studies have proposed resource dispersion as the main determinant of territory size in coyotes ( Canis latrans Say, 1823), but few have considered contender pressure as an alternative hypothesis. We tested for differences in rates of intra-territorial visitation, movement, and extra-territorial excursions between two populations of coyotes with large differences in territory sizes. We collected fine-scale (15 min) movement data of coyotes in southeastern Texas and south-central Idaho. Both populations were active for similar lengths of each day, but coyotes in Idaho had territories 10× larger, moved 2× faster, traveled 2× farther daily, and made extra-territorial excursions 3× less. Even with increased movement rates, coyotes in Idaho traversed territories slower than coyotes in Texas as predicted by the contender pressure hypothesis. We propose that in regions with high resource abundance, territory size of coyotes is determined by contender pressure and an inability to defend larger areas. Conversely, in low-resource areas, territory sizes are determined more by prey abundance and dispersion because intrusion rates are reduced given the lower density of conspecifics.

Virulence of the cestode Schistocephalus solidus and reproduction in infected threespine stickleback, Gasterosteus aculeatus

1999 ◽  
Vol 77 (12) ◽  
pp. 1967-1974 ◽  
Author(s):  
David C Heins ◽  
Scarlet S Singer ◽  
John A Baker
Keyword(s):  
Gasterosteus Aculeatus ◽  
Parasitic Infection ◽  
Population Level ◽  
Reproductive Period ◽  
Threespine Stickleback ◽  
South Central ◽  
Schistocephalus Solidus ◽  
Chi Squared ◽  
Parasite Relationship ◽  
Host Parasite

We investigated the relationship between reproduction in the threespine stickleback (Gasterosteus aculeatus) and parasitism by plerocercoids of the cestode Schistocephalus solidus in Walby Lake, Alaska, by quantifying stickleback reproduction and parasite infection using 1655 fish from four samples collected in 1990-1996. Stickleback in Walby Lake largely spawned during May and June as 2-year-olds in the second spring-summer after hatching, as was the case with other stickleback populations we studied in south-central Alaska. Contrary to an earlier hypothesis that S. solidus has been selected to delay its deleterious effects on threespine stickleback, i.e., limit its infection levels, until after the stickleback have reproduced, substantial levels of parasitic infection co-occurred with the stickleback reproductive period. Chi-squared analyses of individual samples suggested that in May, infected females were as capable of producing clutches of eggs as uninfected females but in June, S. solidus inhibited clutch production. An overall analysis, however, failed to support the hypothesis that the effect of S. solidus on clutch production differed between early and late periods of the spawning season. We concluded that S. solidus inhibits the ability of female stickleback in Walby Lake to produce a clutch, and that there was no differential effect on clutch production with season. Nonetheless, 77% of all infected females produced clutches. These results contrast with those of one study in which it was found only 9% of infected females became gravid (ripe) and another report that 23% of infected females were able to mature. We offer hypotheses for the co-occurrence of stickleback reproduction and substantial parasitism at the population level and for the ability of a large proportion of infected females to produce clutches. Our results suggest that the host-parasite relationship is more complex than was previously realized.

scholarly journals Determination of the phylogenetic origins of the Árpád Dynasty based on Y chromosome sequencing of Béla the Third

2020 ◽  
Vol 29 (1) ◽  
pp. 164-172
Author(s):  
Péter L. Nagy ◽  
Judit Olasz ◽  
Endre Neparáczki ◽  
Nicholas Rouse ◽  
Karan Kapuria ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Chromosome Analysis ◽  
The Caucasus ◽  
Genome Data ◽  
South Central ◽  
First Millennium ◽  
The Russian Federation ◽  
Two Populations ◽  
Volga Ural Region

AbstractWe set out to identify the origins of the Árpád Dynasty based on genome sequencing of DNA derived from the skeletal remains of Hungarian King Béla III (1172–1196) and eight additional individuals (six males, two females) originally interred at the Royal Basilica of Székesfehérvár. Y-chromosome analysis established that two individuals, Béla III and HU52 assign to haplogroups R-Z2125 whose distribution centres near South Central Asia with subsidiary expansions in the regions of modern Iran, the Volga Ural region and the Caucasus. Out of a cohort of 4340 individuals from these geographic areas, we acquired whole-genome data from 208 individuals derived for the R-Z2123 haplogroup. From these data we have established that the closest living kin of the Árpád Dynasty are R-SUR51 derived modern day Bashkirs predominantly from the Burzyansky and Abzelilovsky districts of Bashkortostan in the Russian Federation. Our analysis also reveals the existence of SNPs defining a novel Árpád Dynasty specific haplogroup R-ARP. Framed within the context of a high resolution R-Z2123 phylogeny, the ancestry of the first Hungarian royal dynasty traces to the region centering near Northern Afghanistan about 4500 years ago and identifies the Bashkirs as their closest kin, with a separation date between the two populations at the beginning of the first millennium CE.

scholarly journals The breeding biology of the Coal Tit Periparus ater in South Central Sweden

Ornis Svecica ◽  
2013 ◽  
Vol 23 (3–4) ◽  
pp. 151-158
Author(s):  
Karl Gustav Schölin ◽  
Hans Källander
Keyword(s):  
Clutch Size ◽  
Egg Laying ◽  
Breeding Biology ◽  
Fledging Success ◽  
South Central ◽  
Coal Tit ◽  
Mean Size

In a nestbox study started in 1948 and still ongoing, the number of breeding Coal Tits Periparus ater was always low. Here we present data on time of egg laying and its advancement during the last three decades, clutch size, fledging success and proportion of second broods. Laying dates varied between 18 April and 10 May, with an overall mean of 5 May, and advanced by 0.36 days per year during the second half of the study. Mean clutch size was 8.55 (first clutches). A mean of 7.25 young fledged (all first broods) or 7.78 (failed first broods excluded). Second broods (12.6%) were often not checked but seven clutches had a mean size of 7.23 eggs and fledged 6.71 young.

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