Haematological health state indices of reproducing Great Tits: a response to brood size manipulation

Hõrak, Peeter; Ots, I.; Murumägi, Astrid

doi:10.1046/j.1365-2435.1998.00244.x

Cited by 145 publications

(106 citation statements)

References 27 publications

(33 reference statements)

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“…For example, haematocrit was not influenced by the presence of Haemoproteus parasites in great tits but increased in response to brood enlargement [57]. This last result was interpreted as the response to the requirement of elevated oxygen-carrying capacity owing to increased work load [57]. The negative relationship between parasitaemia and haematocrit in the present study suggests that Plasmodium parasites are more virulent than Haemoproteus and destroy a larger amount of erythrocytes (98% of Plasmodium sp.…”

Section: (C) Prevalence and Parasitaemiasupporting

confidence: 42%

“…An increase in heterophil : lymphocyte ratio, a signal of stress, among birds making an intense parental effort further suggests a trade-off between reproductive effort and health state in great tits [57,59]. A study carried out by Horák et al [57] in great tits tried to evaluate the effects of reproductive effort on health status by brood manipulation. The authors observed that the number of lymphocytes in the peripheral blood decreased with the increase of parental effort and suggested that reproductive effort could lead to suppression of the immune response.…”

Section: (C) Prevalence and Parasitaemiamentioning

confidence: 99%

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Twofold cost of reproduction: an increase in parental effort leads to higher malarial parasitaemia and to a decrease in resistance to oxidative stress

et al. 2011

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Parental effort is usually associated with high metabolism that could lead to an increase in the production of reactive oxidative species giving rise to oxidative stress. Since many antioxidants involved in the resistance to oxidative stress can also enhance immune function, an increase in parental effort may diminish the level of antioxidants otherwise involved in parasite resistance. In the present study, we performed brood size manipulation in a population of great tits (Parus major) to create different levels of parental effort. We measured resistance to oxidative stress and used a newly developed quantitative PCR assay to quantify malarial parasitaemia. We found that males with an enlarged brood had significantly higher level of malarial parasites and lower red blood cell resistance to free radicals than males rearing control and reduced broods. Brood size manipulation did not affect female parasitaemia, although females with an enlarged brood had lower red blood cell resistance than females with control and reduced broods. However, for both sexes, there was no relationship between the level of parasitaemia and resistance to oxidative stress, suggesting a twofold cost of reproduction. Our results thus suggest the presence of two proximate and independent mechanisms for the well-documented trade-off between current reproductive effort and parental survival.

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Section: (C) Prevalence and Parasitaemiasupporting

confidence: 42%

Section: (C) Prevalence and Parasitaemiamentioning

confidence: 99%

Twofold cost of reproduction: an increase in parental effort leads to higher malarial parasitaemia and to a decrease in resistance to oxidative stress

et al. 2011

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“…This probably occurs because there is an increase in energy demand during the reproductive period (oviposition, incubation and parental care energy costs) and consequently an increase of oxygen consumption and the need for hemoglobin and CHGM to transport it. OTS & HÕRAK (1996), HÕRAK et al (1998) and KILGAS et al (2006) also noticed that in the breeding season the extra efforts result in an health aggravation.…”

Section: Discussionmentioning

confidence: 99%

Hematological and parasitological health conditions of the Pale-breasted Thrush (Turdus leucomelas) (Passeriformes: Turdidae) in southeastern Brazil

Lobato¹,

Braga²,

Belo³

et al. 2011

Zoologia (Curitiba)

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From an ecological point of view, parasites are considered important selective forces that influence all aspects of a host's life. The purpose of this study was to assess the health state of Turdus leucomelas Vieillot, 1818 (Turdidae: Passeriformes) inhabiting a Brazilian Cerrado in the breeding and molting seasons through a hematological parameter analysis and an evaluation of infection by blood parasites. The birds were collected with mist-nets, ringed and blood sampled to assess hematological parameters (hematocrit, hemoglobin concentration and white blood cells) and blood parasites. We detected blood parasites through optical microscopy and subsequently used PCR (amplification of the 18sRNA gene) to verify the presence of Plasmodium spp. (avian malaria). During the breeding season, the hemoglobin level and CHGM percentage were greater. Global leukocyte count was positively related to hemoglobin level, CHGM percentage and body weight. Of the total 31 T. leucomelas individuals examined, 18 presented Plasmodium parasites (58% of prevalence). There was a significant relationship between the presence of Plasmodium spp. and decreased CHGM. These results suggest a connection between the health parameters of wild birds and the physiological stress associated with the breeding season

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“…Small increases in CORT are likely to drive these individuals to forage more and expend more energy, and this could explain their relatively high haematocrit concentrations (mean > 60). High haematocrit concentrations in birds are often attributed to extreme dehydration or increases in energy demands, such as cold stress and increased activity during breeding or migration (Carpenter 1975;Breuer et al 1995;Horak et al 1998;Box et al 2002;Fair et al 2007). However, all finch species showed no significant seasonal differences in haematocrit, and without obvious changes in haematocrit above or below mean concentrations, interpretation of the reason for relatively high haematocrit values is not possible (Fair et al 2007).…”

Section: Correlations Between Stress and Condition Indicesmentioning

confidence: 99%

Seasonal stress physiology and body condition differ among co-occurring tropical finch species

et al. 2013

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Seasonal changes in avian hormonal stress responses and condition are well known for common species found at temperate and arctic latitudes, but declining and tropical species are poorly studied. This study compares stress and condition measures of co-occurring declining and non-declining tropical grass finch species in Australia. We monitored declining Gouldian finches (Erythrura gouldiae) and non-declining long-tailed and masked finches (Poepila acuticauda and P. personata) during two seasons that are potentially stressful: peak breeding (early dry season when food is plentiful) and moult (late dry to early wet season when food may be scarce). We measured body condition (muscle and fat), haematocrit, and stress response to capture using plasma corticosterone and binding globulin concentrations. All species had higher muscle and lower fat indices during breeding than moult. Haematocrit did not consistently differ between seasons. Long-tailed finches had higher stress responses during breeding than moult, similar to other passerines studied. Masked finches showed no seasonal changes in stress response. Gouldian finches had stress response patterns opposite to those of long-tailed finches, with higher stress responses during moult. However, seasonal trends in Gouldian and long-tailed finch stress responses sometimes differed between years or sites. The differences in stress response patterns between species suggest that the declining Gouldian finch is more sensitive to recent environmental changes which are thought to further reduce grass seed food resources during the late dry to early wet season. Retention of stress responsiveness during a protracted moult could increase the survival potential of Gouldian finches. This study highlights the utility of stress and condition indices to determine the sensitivity of co-occurring species to environmental conditions. This study compares stress and condition measures of co-occurring declining and non-declining tropical grass-finch species in Australia. We monitored declining Gouldian finches (Erythrura gouldiae) and non-declining long-tailed and masked finches (Poepila acuticauda and P. personata) during two seasons that are potentially stressful: peak breeding (early dry season when food is plentiful) and moult (late dry to early wet season when food may be scarce). We measured body condition (muscle and fat), haematocrit, and stress response to capture using plasma corticosterone and binding globulin concentrations. All species had higher muscle and lower fat indices during breeding than moult. Haematocrit did not consistently differ between seasons. Long-tailed finches had higher stress responses during breeding than moult, similar to other passerines studied. Masked finches showed no seasonal changes in stress response. Gouldian finches had stress response patterns opposite to those of long-tailed finches, with higher stress responses during moult.However, seasonal trends in Gouldian and long-tailed finch stress responses sometimes differed between years or ...

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Haematological health state indices of reproducing Great Tits: a response to brood size manipulation

Cited by 145 publications

References 27 publications

Twofold cost of reproduction: an increase in parental effort leads to higher malarial parasitaemia and to a decrease in resistance to oxidative stress

Twofold cost of reproduction: an increase in parental effort leads to higher malarial parasitaemia and to a decrease in resistance to oxidative stress

Hematological and parasitological health conditions of the Pale-breasted Thrush (Turdus leucomelas) (Passeriformes: Turdidae) in southeastern Brazil

Seasonal stress physiology and body condition differ among co-occurring tropical finch species

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