Related Experiment Video
Updated: Jun 10, 2026
04:10
Visually Sexing Loggerhead Shrike (Lanius Ludovicianus) Using Plumage Coloration and Pattern
Published on: March 8, 2020
Sexual dimorphism in immune function changes during the annual cycle in house sparrows
Péter László Pap1, Gábor Arpád Czirják, Csongor István Vágási
1Behavioural Ecology Research Group, Department of Evolutionary Zoology, University of Debrecen, 4032, Debrecen, Egyetem tér 1, Hungary. peterlpap@gmail.com
Die Naturwissenschaften
|August 14, 2010
Summary
Bird immune responses vary significantly by sex and life cycle stage. Females showed stronger immunity during mating, while other stages had less pronounced sex differences, indicating immune system fine-tuning.
Area of Science:
- * Avian immunoecology and behavioral ecology.
- * Comparative immunology and host-parasite interactions.
Background:
- * Sex differences in parasitism are common in birds, potentially linked to immune investment or parasite exposure.
- * Life-history strategies and annual cycles can drive sexually dimorphic immune responses.
- * Previous studies often overlook seasonal and sex effects on the complex immune system.
Purpose of the Study:
- * To investigate seasonal and sex-specific variations in house sparrows' immune system components.
- * To assess how different life-history stages (mating, breeding, moulting, winter) influence immune function in males and females.
- * To determine if specific arms of the immune system (innate, acquired, cellular, humoral) respond differently to life cycle stages and sex.
Main Methods:
- * Measurement of major immune system components (innate, acquired, cellular, humoral) in male and female house sparrows (Passer domesticus).
- * Sampling across four distinct life-history stages: mating, breeding, moulting, and winter (including aviary conditions).
- * Statistical analysis to detect interactions between life cycle stage and sex on immune variables.
Main Results:
- * Three out of eight immune variables exhibited a significant interaction between life cycle stage and sex.
- * Females displayed consistently stronger immune function than males during the mating stage across five immune variables.
- * Sex-based differences in immune variables were generally non-significant during breeding, moulting, and winter stages.
Conclusions:
- * The house sparrow immune system demonstrates significant variability across life cycle stages and between sexes.
- * Immune responses appear to be finely tuned to specific physiological states and environmental conditions, particularly during the mating period.
- * Understanding these sex- and stage-specific immune dynamics is crucial for avian immunoecology research.
Related Concept Videos
02:27Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
01:20Mate Choice
Mate choice—the decision about whom to mate with—is a type of natural selection, since animals must reproduce to pass down their genes. Mate choice is also called intersexual selection because the behavior occurs between the sexes.
02:45The Ratio of X Chromosome to Autosomes
In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
01:21Frequency-dependent Selection
When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.Positive Frequency-Dependent SelectionIn positive...
01:46Types of Selection
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
02:45Biological Clocks and Seasonal Responses
The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.