scholarly journals Effect of Population Density on Timing of Oviposition and Brood Size Reduction in the Burying BeetleNicrophorus pustulatusHerschel (Coleoptera: Silphidae)

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Claudia M. Rauter ◽  
Renae L. Rust
Keyword(s):  
Population Density ◽  
High Mortality ◽  
Brood Size ◽  
Physiological Stress ◽  
Reduction Rate ◽  
Brood Reduction ◽  
Burying Beetles ◽  
Physiological Constraints ◽  
Newly Hatched Larvae ◽  
Eggs And Larvae

Burying beetles (Nicrophorusspp.) bury small carcasses to feed their larvae. Carcasses are a limited, high-quality resource and contests over carcasses become more frequent with increasing population density. Successful beetles kill eggs and larvae present on carcass. In response, females should accelerate oviposition, while offspring development should increase to minimize mortality. Both value of a carcass and frequency of contests decrease as larvae develop. If overproduction of offspring is an insurance against high mortality, females should reduce brood size as carcass value declines. Testing our predictions, we reared female burying beetles,Nicrophorus pustulatus, at high and low densities and compared oviposition and brood reduction. High-density females delayed oviposition, suggesting that high population density imposes nutritional and/or physiological stress. Females responded to the physiological constraints and the potentially high mortality rates of eggs and newly hatched larvae by lengthening oviposition period and changing brood reduction rate.

scholarly journals Effect of the product of radiational removal of SO2 and NOx from combustion gases on the population of Globodera rostochiensis nematodes (Woll., Behrens 1975)

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 642-644
Author(s):  
G. Kaup ◽  
K. Janowicz ◽  
K. Paruch
Keyword(s):  
Population Density ◽  
Globodera Rostochiensis ◽  
Combustion Gases ◽  
Growing Seasons ◽  
Second Year ◽  
Lower Population ◽  
Eggs And Larvae ◽  
Lower Population Density

The studies were carried out in a greenhouse of the Agricultural University of Szczecin, during two growing seasons. The aim of this study was determine the effect of the product obtained from radiational SO<sub>2</sub> and NO<sub>x</sub> removal from combustion gases on the populations of Globodera rostochiensis nematodes — one of the most common quarantine organisms. The analysis of the effect of the applied product on the population of nematodes demonstrated their varied character of response. In the combination with the product of radiational purification of combustion gases, also significantly lower population density (number of eggs and larvae in 1 g of soil) and lower fecundity of Globodera rostochiensis females were observed compared to the control combination. And in the second year of the experiment, the number of cysts in the combination with the product of SO<sub>2</sub> and NO<sub>x</sub> removal from combustion gases was significantly lower compared to the control, and was less than half of the quantity of the previous year.

Common Eider (Somateria Mollissima) Body Condition and Parasitic Load during a Mortality Event in the Baltic Proper

2018 ◽  
Vol 11 (3) ◽  
pp. 167-172 ◽  
Author(s):  
Svend-Erik Garbus ◽  
Peter Lyngs ◽  
Jens Peter Christensen ◽  
Kurt Buchmann ◽  
Igor Eulaers ◽  
...  
Keyword(s):  
Body Mass ◽  
High Mortality ◽  
Physiological Stress ◽  
Morphological Changes ◽  
Somateria Mollissima ◽  
Common Eiders ◽  
Baltic Proper ◽  
Average Body Mass ◽  
The Baltic ◽  
Average Body

During late spring of 2007 and 2015, we observed unusually high mortality of Common Eiders (Somateria mollissima) on Christiansø in the Baltic Proper. The number of dead birds (2007: 125; 2015: 110) composed 5–10% of the total colony. In 2015, we collected 15 (12 adult females, three subadult males) of the 110 recently deceased Common Eiders for detailed autopsy. The average body mass of the females was 1,040 g (920–1,160 g) which is ca 60% lower than what can be expected of healthy females during wintertime. Similarly, for the subadult males the average body mass of 1,203 g (1,070–1,300 g) comprised only 45% of what can be expected for healthy subadult males during winter. All 15 birds were thus severely emaciated and cachexic with general atrophy of muscles and internal organs. Hunger oedema, distended gall bladder, empty stomach, empty and dilated intestines and dilated cardiomyopathy were observed as well. In addition, all 15 Common Eiders were infected with high loads of the acanthocephalan parasite Polymorphus minutus. No gross morphological changes suggested toxicological, bacteriological or viral causes to the mortality. Taken together, our autopsy suggested starvation leading to secondary metabolic catabolism and eventually congestive heart failure. Five birds that were examined in 2007 showed the same symptoms. We suspect that the introduction of suboptimal feeding conditions in combination with a high parasite load over the last decade synergistically caused high physiological stress leading to population level effects manifested as high mortality.

scholarly journals Population Density and Killing Capacity by Predators of Eggs and Larvae of the Diamondback Moth in Nicaragua

2011 ◽  
Vol 40 (2) ◽  
pp. 333-341 ◽  
Author(s):  
Freddy Miranda ◽  
Helena Bylund ◽  
Lina Grönberg ◽  
Linda Larsson ◽  
Christer Björkman
Keyword(s):  
Population Density ◽  
Diamondback Moth ◽  
Eggs And Larvae

scholarly journals Increasing adult density compromises anti-bacterial defense in Drosophila melanogaster

2022 ◽  
Author(s):  
Paresh Nath Das ◽  
Aabeer Kumar Basu ◽  
Nagaraj Guru Prasad
Keyword(s):  
Immune Response ◽  
Drosophila Melanogaster ◽  
Immune System ◽  
Population Density ◽  
Post Infection ◽  
Physiological Stress ◽  
Pathogen Transmission ◽  
Adult Density ◽  
Density Dependent ◽  
Adult Drosophila

The density-dependent prophylaxis hypothesis predicts that risk of pathogen transmission increases with increase in population density, and in response to this, organisms mount a prophylactic immune response when exposed to high density. This prophylactic response is expected to help organisms improve their chances of survival when exposed to pathogens. Alternatively, organisms living at high densities can exhibit compromised defense against pathogens due to lack of resources and density associated physiological stress; the density stress hypothesis. We housed adult Drosophila melanogaster flies at different densities and measured the effect this has on their post-infection survival and resistance to starvation. We find that flies housed at higher densities show greater mortality after being infected with bacterial pathogens, while also exhibiting increased resistance to starvation. Our results are more in line with the density-stress hypothesis that postulates a compromised immune system when hosts are subjected to high densities.

Nematode egg-shells

Parasitology ◽  
1980 ◽  
Vol 81 (2) ◽  
pp. 447-463 ◽  
Author(s):  
David Wharton
Keyword(s):  
High Mortality ◽  
Free Living ◽  
Biotic Potential ◽  
Wastage Rate ◽  
Egg Shells ◽  
Nematode Eggs ◽  
Eggs And Larvae

SUMMARYThe transmission of parasites often involves a high mortality of free-living stages in the environment outside the host. This may be offset by a high biotic potential. In addition, adaptations of nematode eggs and larvae that ensure their survival or increase their chances of infecting a host will reduce the potential wastage rate. Increasing transmission will have an effect equivalent to increasing the fecundity of the parasite and, energetically, may be the more favourable strategy.

scholarly journals Selection on personality in a songbird affects maternal hormone levels tuned to its effect on timing of reproduction

2008 ◽  
Vol 4 (5) ◽  
pp. 465-467 ◽  
Author(s):  
Ton G.G Groothuis ◽  
Claudio Carere ◽  
Joe Lipar ◽  
Piet J Drent ◽  
Hubert Schwabl
Keyword(s):  
Brood Size ◽  
Genetic Selection ◽  
Bird Species ◽  
Brood Reduction ◽  
Correlated Response ◽  
Timing Of Reproduction ◽  
Yolk Androgens ◽  
Laying Sequence ◽  
Food Conditions ◽  
Adaptive Tool

The increase or decrease in yolk androgens over the laying sequence of a clutch in birds may mitigate or enhance, respectively, the disadvantage of the last-hatched chicks, providing a potentially adaptive tool to adjust brood size to food conditions. This variation may involve a genetic component on which Darwinian selection can act. We found that two lines of a wild bird species selected for bold and shy personalities show, respectively, increased and decreased androgen concentrations over the laying sequence. The line showing the increase laid earlier in the season, when food conditions are normally sufficient to raise the whole brood. The line showing the decrease laid later, when food is normally scarce, which may facilitate brood reduction. The results indicate a correlated response in maternal hormone transfer to genetic selection on personality, which relates to ecological conditions.

Juvenile dispersal in Gray Jays: dominant brood member expels siblings from natal territory

1991 ◽  
Vol 69 (12) ◽  
pp. 2935-2945 ◽  
Author(s):  
Dan Strickland
Keyword(s):  
Sex Ratio ◽  
Weight Distribution ◽  
Brood Size ◽  
Food Storage ◽  
Brood Reduction ◽  
Juvenile Dispersal ◽  
Storage Season ◽  
Unrelated Pair ◽  
Gray Jays ◽  
Perisoreus Canadensis

Breeding pairs of Gray Jays (Perisoreus canadensis) in Quebec and Ontario were accompanied in the autumn significantly more often by one nonbreeder, and less often by none or two, than expected from initial brood size frequencies. Among the rare cases of two nonbreeders accompanying a pair, there was no evidence that both were from the same brood. These observations, and the fact that 30.6% of single nonbreeders closely associated with autumn pairs of known, same-year breeding history were unrelated to those adults, indicated the division of juvenile Gray Jays into "stayers," which remained with their parents at no more than one per pair, and "leavers," which left their natal territory and sometimes joined an unrelated pair. The weight distribution of 62 stayers indicated that about two-thirds were males. Leavers had a more equal sex ratio and showed a strong tendency to associate with failed breeders. Stayers apparently had much higher first-summer survival than leavers but no significant chance to inherit their natal territory. Gray Jay broods broke up in June, through intrabrood aggression, when the young were 55–65 days old. Stayers were the dominant juveniles that forced out the leavers. Partial June dispersal may function as a type of brood reduction that permits the dominant juvenile to have exclusive access to a parental subsidy of stored food that is reliably adequate for the survival of only one extra bird on the territory. The best models describing the origin and winter acquisition of such a subsidy postulate recovery of stored food by memory and require that the expulsion of subordinate siblings occur at the beginning of the food storage season. The models predict that food stored by Gray Jays in June survives in significant enough quantities to enhance winter survival.

Early development and buccal incubation in the fork-tailed catfish Arius graeffei Kner & Steindachner (Pisces : Ariidae) from the Clarence River, New South Wales

1985 ◽  
Vol 36 (3) ◽  
pp. 405 ◽  
Author(s):  
MA Rimmer
Keyword(s):  
Early Development ◽  
Brood Size ◽  
New South ◽  
New South Wales ◽  
Oral Epithelium ◽  
Average Increase ◽  
Brooding Period ◽  
South Wales ◽  
Eggs And Larvae ◽  
Branchial Region

Fertilized oocytes of A. graeflei ranged from 12.3 to 15.2 mm in diameter (mean 13.3 mm). Eggs and larvae were incubated orally by the male; maximum observed brood size was 83. The branchial region of brooding males became distended to accommodate the eggs and larvae, and the oral epithelium thickened to cover the palatine tooth patches. The brooding period lasted from 6 to 8 weeks, with hatching at 4-5 weeks. Larvae began feeding on plankton soon after hatching, and juveniles were up to 59 mm total length when released. The average increase in weight from fertilization to release was 20%.

scholarly journals The Influence of Biological Factors on Haematological Values in Wild Marsh Harrier (Circus aeruginosus) Nestlings

Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2539
Author(s):  
Urszula Zaremba ◽  
Zbigniew Kasprzykowski ◽  
Elżbieta Kondera
Keyword(s):  
Blood Cell ◽  
Cell Count ◽  
Mixed Models ◽  
Brood Size ◽  
Linear Mixed Models ◽  
Brood Reduction ◽  
Blood Cell Count ◽  
Marsh Harrier ◽  
Circus Aeruginosus ◽  
Nest Initiation

Marsh harrier (Circus aeruginosus) is a species with obligatory cainism, in which hatching asynchrony creates a pronounced size hierarchy in nestlings. The size-related competitive advantage of older nestlings means that they tend to dominate the younger ones, and brood reduction occurs in most nests. The aim of the study was to reference values and carry out a haematological examination in order to evaluate the physiological status and health of nestlings with respect to hatching order, brood size, and nest initiation date. To do so, we examined 19 nests with a total of 58 nestlings from a free-living population of this species located in fishpond complexes in the agricultural landscape of eastern Poland. Repeated blood samples (118 in all) were collected from nestlings. The following parameters were measured using fresh full blood: red blood cell count (RBC), haemoglobin level (Hb), white blood cell count (WBC), and plasma glucose level (Glu). The data were analysed using generalized linear mixed models and linear mixed models ((G)LMM). The study revealed that hatching order, but not brood size or nest initiation date, affected the physical condition of marsh harrier nestlings. Hb levels and RBC counts gradually decreased, whereas Glu levels and WBC counts increased from the first- to the last-hatched nestlings. This result points to the generally poorer condition of the youngest nestlings compared with their older siblings. The poor physiological condition of the youngest nestlings may consequently increase the likelihood of their perishing, and hence, of brood reduction.

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