Development of meadow voles is influenced postnatally by maternal photoperiodic history

1993 ◽  
Vol 265 (4) ◽  
pp. R749-R755 ◽  
Author(s):  
T. M. Lee

The importance of maternal photoperiodic history during lactation on the postnatal development of meadow vole pups was tested by cross-fostering pups on the day of birth between photorefractory females (housed for 26 wk in a 10:14-h light-dark cycle before mating) and photosensitive females (housed for 2 wk in a 10:14-h light-dark cycle before mating). Control pups were cross-fostered to females with the same photoperiodic history as the gestational dam. Somatic growth and food intake of cross-fostered pups were influenced by the photoperiod of the postnatal lactating dam. Pre- and postnatal maternal photoperiodic history interacted with the sex of the offspring to influence reproductive development. Pelage development was determined exclusively by the prenatal maternal photoperiodic history. The impact of a postnatal maternal influence on pup development of photoperiod-sensitive traits is discussed.

1975 ◽  
Vol 53 (8) ◽  
pp. 1004-1011 ◽  
Author(s):  
Brian N. Turner ◽  
Michael R. Perrin ◽  
Stuart L. Iverson

Beginning in November 1973, numerous meadow voles (Microtus pennsylvanicus) moved onto a spruce forest grid occupied by red-backed voles (Clethrionomys gapperi). A resident meadow vole population resulted, the two species coexisting until April 1974, when most meadow voles disappeared from the grid during a relatively short period. Interspecific aggression levels, as determined from voles temporarily removed from the populations and tested in paired encounters in a laboratory arena, were low during the winter, but increased when males of both species entered reproductive condition in the spring. Microtus was generally dominant in early breeding period encounters, but this dominance declined concurrently with the meadow voles' disappearance from the forest. It is argued that meadow voles did not leave the forest to breed, or because the snow cover melted, since this species will live and reproduce in forest in the absence of Clethrionomys. The results are interpreted as support for an earlier hypothesis that competitive habitat exclusion varies seasonally with reproduction-related aggression. Thus, these species apparently may coexist in either of their preferred habitats when interspecific aggression is low (the nonbreeding season), but this relationship terminates when interspecific aggression levels increase with the resumption of breeding in the spring.


2009 ◽  
Vol 51 (4) ◽  
pp. 358-366 ◽  
Author(s):  
Mariana Schroeder ◽  
Michal Schechter ◽  
Ester Fride ◽  
Timothy H. Moran ◽  
Aron Weller

Author(s):  
Katherine D Vande Pol ◽  
Austin L Laudwig ◽  
Aaron M Gaines ◽  
Beau A Peterson ◽  
Caleb M Shull ◽  
...  

Abstract Litter sizes in commercial pig production have increased substantially over recent years; however, farrowing pen sizes have generally not changed over the same time period. The objective of this study was to evaluate the effect of farrowing pen size on piglet pre-weaning growth and mortality. Differences in pen size were created by varying the width of pens of the same length, increasing the creep area available to the piglets. The study used a total of 1,786 litters in a randomized complete block design to compare two Farrowing Pen Size treatments (FPS): Standard (pen width 1.52 m) and Increased (pen width 1.68 m). Litter sizes were equalized across treatments (12.9 ± 1.95 piglets) at 24 h after birth using cross-fostering. Litter weights were collected at birth and weaning (21.3 ± 2.08 d); pre-weaning mortality was recorded. The experimental unit was the litter; models included FPS and replicate. Farrowing Pen Size had no effect (P > 0.05) on litter size at birth (12.8 and 13.0 for the Standard and Increased FPS, respectively), after cross-fostering (12.9 for both treatments), or at weaning (11.2 and 11.3, respectively). There was no effect (P > 0.05) of FPS on total litter or average piglet weight at birth, after cross-fostering, and at weaning. These results suggest no benefit in piglet performance from increasing the width of farrowing pens. As litter sizes continue to increase in commercial production, further research is warranted to re-evaluate the impact of farrowing pen size on pre-weaning mortality.


2021 ◽  
Vol 26 (6) ◽  
pp. 1055-1066
Author(s):  
Anna Derdak ◽  
Magdalena Felska ◽  
Joanna Mąkol ◽  
Paula Zajkowska

The impact of temperature and light/dark cycle on morphological traits of Platytrombidium fasciatum was examined in larvae obtained from field-collected females. The eggs laid by 65 females at laboratory conditions were assigned to four experimental groups. Varied thermal conditions affected the values of nine out of 46 (nonparametric MANOVA) and 26 out of 37 (LDA) morphometric traits in larvae. As many as six quantitative traits differed significantly irrespective of the method (MANOVA, LDA) applied. The analysis of the metric traits within the dorsal sclerites revealed that the lower mean temperature over the period of egg incubation, translated into longer duration of development, was associated with an increase in distance between the bases of 3rd pair of non-sensillary setae on scutum at the decrease in distance between the bases of 2nd pair of non-sensillary setae as well as in distance between the level of sensilla and the posterior edge of the sclerite. In the case of 40 measurable traits in larvae of P. fasciatum, the variability going beyond the hitherto knowledge on the species was observed.


1977 ◽  
Vol 53 (2) ◽  
pp. 96-99
Author(s):  
Arthur M. Martell ◽  
Andrew Radvanyi

Poison-bait feeder stations were placed on a hardwood plantation in southern Ontario in 1973 to attempt long-term control of a meadow vole (Microtus pennsylvanicus) population by continuous dispensing of poisoned grain. Baiting by means of feeders successfully reduced the numbers of meadow voles and maintained them at a low density, about 3-6/ha (1.2-2.4/acre), through April 1976. During the same period, the density of meadow voles on surrounding unpoisoned areas declined from a 1973 peak to about the same as that found on the poisoned plot by fall and winter 1975-76. Despite that low density, less than 4/ha (1.6/acre), severe gnawing and girdling of young hardwoods occurred during winter. Poison-bait feeders are efficient at reducing meadow vole populations from high to low density, but it cannot be assumed that even those low-density populations will not damage hardwood plantations.


Author(s):  
B. L Bayne ◽  
D. L. Holland ◽  
M. N. Moore ◽  
D. M. Lowe ◽  
J. Widdows

Mussels (Mytilus edulis L.) were held under five different experimental conditions for 8 weeks during which measurements of physiological condition, and certain cytological and cytochemical observations, were made. The mussels were then induced to spawn and the numbers of eggs released, the weights of these eggs, and their biochemical composition, were determined. During the experiment new gametes were developed by mussels under all conditions, but there was also a simultaneous regression and resorption of previously formed gametes, particularly in mussels under the greatest stress from high temperature and lack of food. The degree of stress experienced by the animals was measured as the scope for growth, or the energy available for somatic growth and the production of gametes. The distribution and activity of lysosomal enzymes within the Leydig tissue of the mantle suggested that autolysis of these cells occurred, coupled to the mobilization of glycogen for gametogenesis. Mussels under stress produced fewer and smaller eggs, in smaller follicles, than mussels not under stress. The biochemical composition of the eggs (as µg of biochemical component per mg of egg) did not vary consistently with adult condition, but eggs from stressed females had less lipid and protein than eggs from normal females. It is suggested that these relationships between the physiological condition of the adult, gametogenesis, fecundity and the biochemical content of the eggs are important for understanding the impact of the environment on ecological fitness.


2020 ◽  
Author(s):  
Daniela Rosado ◽  
Marcos Pérez-Losada ◽  
Ana Pereira ◽  
Ricardo Severino ◽  
Raquel Xavier

Abstract Background: Important changes in microbioal composition related to sexual maturation have been already reported in the gut of several vertebrates including mammals, amphibians and fish. Such changes in fish are linked to reproduction and growth during developmental stages, diet transitions and critical life events. We used amplicon (16S rRNA) high-throughput sequencing to characterize the skin and gill bacterial microbiota of farmed seabass and seabream belonging to three different developmental age groups: early and late juveniles and mature adults. We also assessed the impact of the surrounding estuarine water microbiota in shaping the fish skin and gill microbiota. Results: Microbial diversity, composition and potential metabolic functions varied across fish maturity stages. Alpha-diversity in the seabass microbiota varied significantly between age groups and was higher in older fish. Conversely, in the seabream, no significant differences were found in alpha diversity between age groups. Microbial structure varied significantly across age groups; moreover, high structural variation was also observed within groups. Different bacterial metabolic pathways were predicted to be enriched in the microbiota of both species. Finally, we found that the water microbiota is significantly distinct from all the fish microbiota across the studied age groups, although a high percentage of ASVs is shared with the skin and gill microbiota. Conclusions: We report important microbial differences in composition and potential functionality across the different ages of farmed seabass and seabream. These differences may be related to somatic growth and the onset of sexual maturation. Importantly, some of the inferred metabolic pathways could enhance the host coping mechanisms during stressful conditions. Our results provide new evidence suggesting that growth and sexual maturation have an important role in shaping the external mucosa microbiota of fish and highlight the importance of considering different life stages in microbiota studies.


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