51 research outputs found
Yolk androstenedione, but not testosterone, predicts offspring fate and reflects parental quality
Yolk androgen deposition is a widely investigated maternal effect in birds, but its adaptive value is at present unclear. The offspring fitness correlates of natural yolk androgen levels are virtually unknown, whereas manipulations largely focused on testosterone and neglected other androgens. We determined yolk concentrations of the 2 dominant androgens, androstenedione and testosterone, from all eggs in collared flycatcher clutches and followed the fate of individual offspring from these eggs in a crossfostering experiment. Yolk concentration of androstenedione was much higher than that of testosterone. Offspring from eggs with relatively higher androstenedione concentrations within a clutch were relatively large after hatching, grew slower thereafter, and had a higher recruitment rate in subsequent years. The increase of androstenedione with laying order and its within-clutch variance were negatively correlated with a condition-dependent female ornament, perhaps indicating compensatory hormone deposition into later hatching eggs by females in low condition. Yolk testosterone variation within or among clutches was not related to any measured aspect of offspring or parental quality. Our results suggest that in some species, especially those with much more androstenedione than testosterone in the yolk, androstenedione and not testosterone may be the yolk androgen with a long-term function and adaptive deposition pattern.</p
Egy összetett szignalizációs mechanizmus: a madárének lokális, regionális és evolúciós mintázatai = Bird song as a multiple functioning sexual signal: patterns on individual, population and regional levels
Tervezett vizsgálataink cĂ©lja egy komplex, ivarilag szelekctált szignál, a madárĂ©nek funkcionális kapcsolatrendszereinek felderĂtĂ©se volt. KĂĽlönbözĹ‘ szinteken, egyedektĹ‘l a pouláciĂłs szinten keresztĂĽl a fajok közötti kapcsolatokig vizsgáltuk a szignál informáciĂł tartalmát Ă©s annak szerepĂ©t az ivari kiválasztĂłdás Ă©s a termĂ©szetes szelekciĂł folyamatában. Terepi vizsgálataink bizonyĂtották, hogy az Ă©nek kĂĽlönbözĹ‘ paramĂ©terei az egyedi minĹ‘sĂ©g más Ă©s más komponensĂ©t (parazitáltság, kor, stressz-tolerancia, szemĂ©lyisĂ©g) jelzik. Kimutattuk továbbá az Ă©nek szerepĂ©t a hĂm-hĂm versengĂ©sben valamint a hölgyválasz mechanizmusában. PopuláciĂłs szintű vizsgálatainkban szimpatrikusan Ă©s allopatrikusan Ă©lĹ‘ lĂ©gykapĂłk Ă©nekszegregáciĂłját elemeztuk az egyĂĽttĂ©lĂ©s idĹ‘skáláját is figyelembe vĂ©ve. Modern komparatĂv analĂzisekkel interspecifikus kapcsolatot tártunk fel az Ă©nek összetettsĂ©ge Ă©s az agymĂ©ret közötti, mĂg heterospecifikus vokális mimikri evolĂşciĂłját is vizsgáltuk. A kutatás során egy általunk elĹ‘ször alkalmazott repertoármĂ©ret-becslĹ‘ mĂłdszer fejlesztĂ©sĂ©t is folytattuk egy nemzetközi kooperáciĂł keretĂ©n belĂĽl. EredmĂ©nyeinket nemzetközileg elismert folyoĂratokban publikáltiuk. | The aim of the planned research was to investigate the functional relationships of a complex, sexually selected trait, namely bird song. We studied the information content of the signal, and its roles in sexual and natural selection by focusing on three organizational levels, such as individuals, populations and species. Our field research with the collared flycatcher (Ficedula albicollis) proved that different characteristics of the song signal different aspects of male quality (parasite load, age, stress-tolerance and personality). We also found that the song plays role in male-male competition and female choice. Comparisons of sympatric and allopatric populations of flycatchers in Europe revealed evidence for the segregation of song depending on the duration of the evolutionary contact. By using modern comparative methods, we failed to demonstrate an interspecific relationship between bird song and speciation, but discovered that the complexity of songs is evolutionary related to brain dimorphism between sexes. We also demonstrated some evolutionary patterns in association with heterospecific vocal mimicry. During this research, we developed a new method for estimating repertoire size. Our results have been published in the leading journals of the field
Döntési mechanizmusok a madarak viselkedésökológiájában: anyai eredetű biomolekulák környezetfüggő átvitele a petesejtbe = Decision marking in behaviour ecology of birds: maternal preference
Az öröklött tulajdonságok mellett az utĂłdok rátermettsĂ©gĂ©t a korai környezeti (anyai) hatások jelentĹ‘sen mĂłdosĂthatják. Madaraknál vizsgáltuk, hogy a tojĂł által a tojásba juttatott anyagok (ivari hormonok, vitaminok, karotinoidok, immunanyagok) hogyan segĂtik a fiĂłkák fejlĹ‘dĂ©sĂ©t ill. az anyagok allokáciĂłs mintázatát milyen (proximális Ă©s ultimális) változĂłk magyarázhatják. MegállapĂtottuk, hogy az örvös lĂ©gykapĂłnál a tojásmĂ©retet a környezeti tĂ©nyezĹ‘k Ă©s a tojĂł minĹ‘sĂ©ge, a tojás IgG-szintjĂ©t a tojĂł minĹ‘sĂ©ge prediktálta. A karotinoidok, az E- Ă©s A-vitamin, valamint a biliverdin (tojáshĂ©j pigment) deponálása a tojĂł párjának korátĂłl fĂĽggött. KompenzáciĂłs mechanizmusra utal, hogy a tapasztalatlan fiatal hĂmek fĂ©szekaljaiban a tojĂłk növeltĂ©k a tesztoszteront Ă©s az antioxidánsokat. KĂsĂ©rletesen bizonyĂtottuk, hogy a tesztoszteron depozĂciĂłjára hat, a karotinoidok Ă©s az IgG depozĂciĂłjára viszont nem hat a szociális környezet változása. Az örvös lĂ©gykapĂł tojások biopsziás vizsgálataibĂłl Ă©s japánfĂĽrj tojások hormonkoncentráciĂłjának kĂsĂ©rletes megemelĂ©sĂ©bĹ‘l arra következtethetĂĽnk, hogy a tojásokban lĂ©vĹ‘ androgĂ©nek (T, A4, DHT) rövid távon eltĂ©rĹ‘en hatnak az utĂłdok rátermettsĂ©gĂ©re. A kĂ©k cinegĂ©knĂ©l pozitĂv kapcsolatot találtunk a hĂmek egy ivari szignálja (fejtetĹ‘ UV visszaverĂ©se) Ă©s a tojások becsĂĽlt karotinoidmennyisĂ©ge között. VĂ©gĂĽl a szĂ©ncinege többszörös ivari szignalizáciĂłját elemezve rámutattunk a szignalizáciĂł Ă©s az anyai hatások környezetfĂĽggĹ‘sĂ©gĂ©re. | In addition to genetic effects, the fitness of offspring is considerably modified by early environmental (maternal) effects. We examined how egg constituents deposited by the female (sexual hormones, vitamins, carotenoids, immune mediators) help offspring development and what proximate and ultimate factors may explain the allocation pattern of these substances. In the collared flycatcher we found that egg size was predicted by environmental factors and female quality, while IgG level by the quality of the female. The deposition of carotenoids, biliverdin, vitamins A and E depended on the characteristics of the female's mate. Consistent with a compensation mechanism, females increased the concentration of egg testosterone and antioxidants in clutches laid for inexperienced young males. We experimentally demonstrated that changing social environment modifies the deposition of testosterone but not that of carotene metabolites and IgG. By conducting biopsy studies of collared flycatcher eggs and experimentally elevating sex steroid levels in Japanese quail eggs, we found that different androgens in the egg (T, A4, DHT) have different short term effects on offspring fitness. In blue tits, we found a positive relationship between a sexual signal of males (crown UV reflectance) and the estimated carotenoid levels of eggs. Finally, analyses of multiple sexual signals in great tits indicated the environment-dependence of signalization and maternal effects
Sources of variation in haematocrit in the Collared Flycatcher (Ficedula albicollis)
The haematocrit rate of the blood shows the individual physiological state. As the haematocrit grows, the
higher erythrocyte number results in more efficient oxygen uptake capacity which can lead to better performance and
probably a better survival rate of an individual. Hence we assume that the high value of haematocrit reflects good
health state. Altogether 308 blood samples were collected from a wild population of Collared Flycatchers (Ficedula
albicollis) in two breeding stages during a period of 2008–2010. We tried to elucidate the relationship between condition
and haematocrit level of an individual and studied the haematocrit changes of an individual between years.
The haematocrit values differed between years. Females had higher haematocrit values than males in 2010 but not in
2009. At courtship the haematocrit level of males was higher, than during nestling care. The different environmental
effects and energy demands of the individuals may be the driving force behind the observed changes in haematocrit
level. Analysing the changes between two years, there was a positive correlation between changes in condition index
and haematocrit of individuals. The haematocrit values of an individual were repeatable between years. This finding
suggests that haematocrit can be informative about the individual’s general health state
Digit ratio predicts the number of lifetime recruits in female collared flycatchers
The early environment in which an organism grows can have long-lasting
impacts on both its phenotype and fitness. However, assessing this environment
comprehensively is a formidable task. The relative length of the
second to the fourth digit (2D: 4D) is a broadly studied skeletal trait that is
fixed for life during ontogeny. 2D: 4D has been shown to indicate various
early effects including the perinatal steroid milieu in both humans and
non-human animals. However, the fitness relevance of the early effects indicated
by 2D : 4D remains unknown. Here, we investigated hindlimb 2D : 4D
and measures of lifetime performance in wild collared flycatcher (Ficedula
albicollis) females. We found that females with higher 2D: 4D had a greater
number of recruiting offspring to the breeding population. This was the
case despite the fact that such females did not lay more eggs or breed more
frequently during their reproductive life. Our results support the suggestion
that 2D : 4D, known to be a retrospective marker of perinatal development,
positively associates with female quality in the collared flycatcherPeer reviewe
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