scholarly journals Individual, Temporal, and Seasonal Variation in Sperm Concentration in Tree Swallows

The Condor ◽  
2002 ◽  
Vol 104 (4) ◽  
pp. 803-810
Author(s):  
Michael P. Lombardo ◽  
Armetris N. Forman ◽  
Matthew R. Czarnowski ◽  
Patrick A. Thorpe
Keyword(s):  
Sperm Concentration ◽  
Egg Laying ◽  
Tachycineta Bicolor ◽  
Tree Swallows ◽  
Sperm Production ◽  
Period 2 ◽  
Incubation Periods ◽  
Nestling Period ◽  
Sperm Depletion ◽  
Fertility Insurance

Abstract We determined sperm concentrations in Tree Swallows (Tachycineta bicolor) by manually expressing semen samples from males during prelaying, egg-laying, incubation, and nestling periods. Sperm concentrations varied by orders of magnitude (0–109 sperm mL−1) among males. Sperm concentrations were highest during the incubation period and lowest during the prelaying period. None of the samples collected during the prelaying, egg-laying, and incubation periods were devoid of sperm. In contrast, 45% of samples collected during the nestling period lacked sperm. Sperm concentrations (1) did not vary over the course of the morning during prelaying, egg-laying, and incubation periods but significantly increased during the nestling period; (2) did not vary with the date that samples were collected during prelaying, egg laying, and incubation but significantly decreased with date during the nestling period; and (3) did not vary with the number of fertile females at the study site during any part of the breeding season. We hypothesize that the variations in sperm concentration arose from a combination of factors including intrinsic differences among males, daily patterns of sperm depletion associated with copulation, and an end-of-season decline in sperm production. If males vary in sperm availability then female Tree Swallows may benefit from pursuing extra-pair copulations as fertility insurance. Variación Individual, Temporal y Estacional en la Concentración de Esperma en Tachycineta bicolor Resumen. Determinamos la concentración de esperma en Tachycineta bicolor tomando manualmente muestras de semen de machos durante los periodos de pre-puesta, puesta de huevos, incubación y con pichones. La concentración de esperma varió en órdenes de magnitud (0–109 esperma por mL) entre machos. Las concentraciones de esperma fueron mayores durante el periodo de incubación y menores durante el periodo de pre-puesta. Todas las muestras colectadas durante los periodos de pre-puesta, puesta e incubación contuvieron esperma. En contraste, el 45% de las muestras colectadas durante el período con pichones no contuvieron esperma. Las concentraciones de esperma (1) no variaron durante el curso de la mañana en los periodos de pre-puesta, puesta e incubación, pero aumentaron significativamente durante el periodo con pichones; (2) no variaron con la fecha en la que las muestras fueron colectadas durante los periodos de pre-puesta, puesta e incubación, pero disminuyeron significativamente con la fecha durante el periodo con pichones; y (3) no variaron durante toda la estación reproductiva con el número de hembras fértiles en el sitio de estudio. Hipotetizamos que esta variación en la concentración de esperma se originó de una combinación de factores incluyendo diferencias intrínsecas entre machos, patrones diarios de vaciamiento de esperma asociados con la cópula, y una disminución al final de la estación en la producción de esperma. Si los machos varían en la disponibilidad de esperma, entonces las hembras de T. bicolor se beneficiarían de obtener copulaciones extra-pareja para asegurar la fertilidad.

scholarly journals Effects of Food Abundance, Weather, and Female Condition on Reproduction in Tree Swallows (Tachycineta Bicolor)

The Auk ◽  
2005 ◽  
Vol 122 (4) ◽  
pp. 1225-1238 ◽  
Author(s):  
Jacqueline K. Nooker ◽  
Peter O. Dunn ◽  
Linda A. Whittingham
Keyword(s):  
Body Condition ◽  
Egg Laying ◽  
Food Abundance ◽  
Tachycineta Bicolor ◽  
Laying Date ◽  
Foraging Efficiency ◽  
Tree Swallows ◽  
Female Condition ◽  
Incubation Periods ◽  
Feather Clipping

AbstractFood abundance, weather, and female body condition are believed to influence the timing of breeding and reproductive performance of birds. We simultaneously studied the effects of weather and food abundance on reproduction in Tree Swallows (Tachycineta bicolor) while experimentally reducing female condition and foraging efficiency by clipping some flight feathers prior to egg laying. Control females laid larger clutches earlier in the season, had longer incubation periods, and raised heavier nestlings than experimental females. Fledging success did not differ after controlling for laying date and brood size. Greater insect abundance was associated with laying earlier in the season, heavier eggs, and shorter incubation periods. Most likely, feather-clipping affected clutch size through reduced foraging efficiency, which delayed the date of laying, rather than through loss of body condition. This outcome is consistent with the idea that Tree Swallows are “income” breeders that base their timing of reproduction on short-term rates of food intake near the time of breeding. Contrary to studies of other species, Tree Swallows do not appear to time their laying so that hatching will coincide with seasonal peaks in food supply. Rather, they appear to breed when temperature and food abundance are sufficient to allow females of a given body condition to initiate egg laying.Efectos de la Abundancia de Alimento, del Clima y de la Condición de las Hembras sobre la Reproducción en Tachycineta bicolor

Transgenerational effects of maternal immune challenge in tree swallows (Tachycineta bicolor)

2002 ◽  
Vol 80 (5) ◽  
pp. 918-925 ◽  
Author(s):  
G A Lozano ◽  
R C Ydenberg
Keyword(s):  
Egg Laying ◽  
Tachycineta Bicolor ◽  
Cell Mediated Immunity ◽  
Immune Challenge ◽  
Ecological Context ◽  
Allocation Of Resources ◽  
Tree Swallows ◽  
Immune Development ◽  
Nestling Growth ◽  
Better Than

The fact that avian eggs contain antibody of maternal origin is well documented, but only recently has this phenomenon been considered in an ecological context. We used tree swallows (Tachycineta bicolor) to examine the possibility of transgenerational immunity and its effect on nestling growth and immune development. We measured cell-mediated immunity with a delayed-hypersensitivity assay and antibody-mediated immunity with a hemagglutination test with sheep red blood cells (SRBCs). We tested for differences in immunocompetence and growth between nestlings from females who had been exposed to a novel antigen prior to egg laying and nestlings from unexposed females. To determine whether the effect, if any, resulted from something transferred to the eggs prior to egg laying or from subsequent changes in parental behaviour, nestlings were exchanged so that at each nest half the nestlings were from females who had been injected with SRBCs and half were from females who had not been exposed to SRBCs. Finally, brood sizes were independently manipulated to either 4 or 6 nestlings. We failed to detect maternal antibodies in any nestlings, and whether a female was exposed to SRBCs or not had no effect on the growth or cell-mediated immunity of her brood. However, nestlings in smaller broods grew better than nestlings in larger broods, though we did not find the expected differences in cell-mediated immunity. Furthermore, within each nest, nestlings whose mothers had been exposed to SRBCs grew better than nestlings whose mothers had not been exposed. These results are contrary to the idea of a simple trade-off in the allocation of resources between parasite protection and reproduction; however, they support the idea that exposure of females to parasites prior to egg laying leads to better nestling growth, and are congruous with the possibility of mithridatic parental care.

Sources of Variation in Growth of Tree Swallows

The Auk ◽  
1986 ◽  
Vol 103 (2) ◽  
pp. 389-400 ◽  
Author(s):  
Terry E. Quinney ◽  
David J. T. Hussell ◽  
C. Davison Ankney
Keyword(s):  
Foster Parents ◽  
Field Experiments ◽  
Egg Laying ◽  
Population Variation ◽  
Tree Swallows ◽  
Factors Affecting ◽  
Nestling Period ◽  
Sources Of Variation ◽  
Insect Biomass ◽  
Two Populations

Abstract We studied two populations of Tree Swallows (Tachycineta bicolor) that differed primarily in the amount of food available to the breeding birds. We obtained an index of food abundance and performed field experiments to distinguish factors affecting variability in growth of nestlings. The experiments were designed to detect the influence of the location of egg laying, incubation, and nestling rearing, type of parent (natural or foster), and year of breeding on nestling growth. Some broods were transferred between nests and raised by foster parents, and some clutches and broods were transferred between populations. Variables were analyzed in two- and three-way factorial analyses of variance. The insect biomass index during the nestling period differed about 7-fold between locations, regardless of year of breeding. Nestlings with more food grew and survived better. Type of parent (i.e. natural or foster) or prehatch factors such as location of incubation did not influence growth. The location where nestlings were raised, however, explained as much as 51% of the variation in growth, and genetic variation in offspring and variation in provisioning abilities of parents may have been important components of within-population variation in growth regardless of where parents nested.

The costs of reproduction in tree swallows (Tachycineta bicolor)

1991 ◽  
Vol 69 (10) ◽  
pp. 2540-2547 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Joanna Leary ◽  
Caragh Fitzgerald
Keyword(s):  
Life History ◽  
Clutch Size ◽  
Brood Size ◽  
Life History Theory ◽  
Tachycineta Bicolor ◽  
Laying Date ◽  
Tree Swallows ◽  
Costs Of Reproduction ◽  
Return Rates ◽  
Trade Offs

We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.

scholarly journals REPRODUCING QUALITIES OF RAMS OF THE MOLDOVAN TYPE KARAKUL BREED

2020 ◽  
Vol 59 ◽  
pp. 92-96
Author(s):  
D. Rotari
Keyword(s):  
Sperm Count ◽  
Sperm Concentration ◽  
Animal Husbandry ◽  
Sperm Production ◽  
Livestock Farming ◽  
High Quality ◽  
Average Percentage ◽  
Reproductive Ability ◽  
First Time

Issues related to the reproduction of animals have been and remain one of the most complex and relevant problems of biology and are constantly finding a direct and effective way out into livestock farming practice. The rational use of breeding sheep as producers is limited by the lack of standard, objective methods and methods for the timely assessment of their reproductive ability. The article presents the results of evaluating the sperm production of rams-producers. For the first time, the freshly obtained sperm of rams of Moldavian type producers of the Karakul breed was evaluated using the macroscopic method - ejaculate volume, color and smell, as well as the microscopic method - motility, sperm concentration in the ejaculate, total sperm count in the ejaculate sperm movements (VAP; VSL and VCL) as well as the percentage of abnormal forms of sperm. The experiments were carried out on sheep producers grown on a pedigree farm of the experimental farm of the Moldavian Scientific and Practical Institute of Biotechnology in Animal Husbandry and Veterinary Medicine. As a result of the studies, it was found that the ejaculate volume on average was 0.99 ± 0.04 ml, motility was 0.95 ± 0.02 and sperm concentration 1.51 ± 0.14 billion/ml. The percentage of pathological forms in sperm averaged 13.72 ± 0.61, an indicator that characterizes the high quality of sperm. The average quality indicator of ejaculates obtained from ram-producers of the Moldavian type of the Karakul breed corresponds to physiological standards for the Karakul breed. The average percentage of pathological forms of sperm found in ejaculates indicates that the rams were in good conditions of feeding and keeping. According to research, we can say that the Moldovan type of Karakul rams can be successfully used to obtain high quality ejaculates suitable for freezing sperm at 196°C.

scholarly journals Semen quality and diversity of morphological sperm abnormalities in bulls: breed and strain effects

2019 ◽  
Vol 22 (8) ◽  
pp. 931-938
Author(s):  
M. A. Kleshchev ◽  
V. L. Petukhov ◽  
L. V. Osadchuk
Keyword(s):  
Sperm Motility ◽  
Environmental Conditions ◽  
Western Siberia ◽  
Semen Quality ◽  
Sperm Count ◽  
Sperm Concentration ◽  
Sperm Head ◽  
Sperm Dna Fragmentation ◽  
Sperm Production ◽  
Sperm Abnormalities

At present great attention is paid to studying genetic regulation of farm animal adaptations to environmental conditions. This problem is very important due to a wide expansion of highly productive cattle breeds created in Europe and North America. However, until the present no investigation of changing semen quality in bulls of imported breeds during their adaptations to environmental conditions of Western Siberia has been conducted. The aim of this study was to investigate semen quality peculiarities and the diversity of morphological sperm abnormalities in bulls of imported and local breeds kept in the environmental conditions of the southern part of Western Siberia. We determined sperm concentration, sperm count, and rate of sperm with progressive motility and percentage of morphologically normal spermatozoa. The rate of sperm abnormalities according to Blome’s classifcation was determined too. It was found that the mean values of sperm concentration, sperm motility and percentage of morphologically normal spermatozoa in the bulls investigated were similar to those in bulls kept in European countries. Inter­breed differences in these parameters were not found. However, bulls of the Red Danish, Angler, and Simmental breeds had a higher percentage of misshapen sperm head and pyriform sperm head than bulls of the Black­White breed. An inter­strain difference in sperm motility in bulls of the Black­White breed was observed. It was found that bulls of Reflection Sovereign 198998 strain had lover sperm motility than bulls of Wis Burke Ideal 1013415 strain. No inter­strain differences in sperm production, percentage of morphologically normal spermatozoa and rate of main sperm abnormalities were found. Thus, it has been found that the environmental conditions of the southern part of Western Siberia do not seriously affect the sperm production, sperm motility or percentage of morphologically normal spermatozoa in bulls. However, the increased rate of misshapen and pyriform sperm heads in the bulls of the foreign breeds points to a need to study sperm DNA fragmentation.

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