Deviation from an equal sex ratio has been observed in several avian species and there is now descriptive as well as experimental evidence that females are able to modify the sex of their offspring within a brood. Less attention has been paid to consequences of sex ratio manipulation and sex specific differences e.g. in competitive disparities of male and female siblings and parent tactics to compensate for such competitive differences. In this study we examine differences in chick development in relation to sex and hatching order in the socially monogamous bearded tit Panurus biarmicus. Our results revealed that significantly more female than male nestlings were the biggest in the brood. Allometric measurements seem to be a good predictor of age (hatching order). This consequently means that female nestlings frequently hatch earlier and have a higher initial body mass. In contrast male nestlings seem to develop much faster than female nestlings. By modifying the hatching order in favour of female nestlings, mothers seem to promote daughters to compensate for their slower growth.
The Gram-negative, obligate intracellular tick-transmitted pathogen Anaplasma phagocytophilum can cause acute febrile diseases in humans and domestic animals. The expansion of the tick Ixodes ricinus (Linnaeus, 1758) in northern Europe due to climate change is of serious concern for animal and human health. The aim of the present study was to investigate the impact of A. phagocytophilum infection in moose Alces alces (Linnaeus) calves by evaluating the carcass weights of infected and non-infected animals and examining animal tissues samples for co-infections with either species of Babesia Starcovici, 1893 or bacteria of the genus Bartonella. The carcasses of 68 free-ranging moose calves were weighed by hunters during the hunting seasons from 2014 to 2017 in two regions in southern Norway and spleen samples were collected. Anaplasma phagocytophilum was detected in moose sampled from locations infected with ticks with a prevalence of 82% (n = 46). The carcass weights of A. phagocytophilum-infected calves (n = 46) and non-infected (n = 22) calves were compared. Although the average weight of infected calves (45.6 kg) was lower than that of non-infected calves (46.5 kg), the difference was not statistically significant. Three different variants of the bacterium 16S rRNA gene were identified. The average weight of animals infected with variant I was 49.9 kg, whereas that of animals infected with variant III was 42.0 kg, but the difference was not statistically significant (p = 0.077). Co-infections of A. phagocytophilum with Bartonella spp. or with Babesia spp. were found in 20 and two calves, respectively. A triple infection was found in two calves. Sequence analysis of the 18S rRNA gene of Babesia-positive samples revealed the presence of Babesia cf. odocoilei (Emerson et Wright, 1970). Strains of Bartonella closely related to Bartonella bovis (Bermond, Boulouis, Heller, Laere, Monteil, Chomel, Sander, Dehio et Piemont, 2002) were identified based on phylogenetic analysis of the gltA and rpoB genes. The loss of body mass in moose calves in the tick-infected site was probably influenced by multiple factors.
The bleak, Alburnus alburnus, is an invasive fish in the Iberian Peninsula, where this species mainly disturbs the higly endemic fauna via competition and aggression. Despite this impact, information on bleak autecology is scarce in the Iberian Peninsula, with no data on growth and reproduction. The aim of the present study was to compare bleak populations across four Iberian streams: Muga, Fluviá, Cardener and Foix (northeastern Iberian Peninsula).These streams have similar enviromental conditions at the regional scale (e.g. Mediterranean climate, geomorphology). In Muga and Foix streams, bleak showed lower growth rate and back-calculated lenght at age 2. Body condition was lower in Foix streams, whereas lenght at maturity was higher. In Muga stream, the proportiun of females was lower. In Cardener stream, bleak showed higher back-calculated lenght at ages I and 2, growth rate, body condition and reproductive investment. Results showed that bleak populations are able to display wide phenotypic plasticity in small Mediterranean-type rivers. Specifically, bleak population "health" appears to be better in Cardener stream, whereas it is worse in Muga and Foix streams. Present findings suggest that inter-population plasticity allows bleak more successfully to invade Mediterranean fresh waters in the Iberian Peninsula.
The leg bone marrow fat of 11 roe deer (Capreolus capreolus) killed by wolves (Canis lupus) was examined and compared with that of 15 roe deer killed in traffic accidents. Moreover, a sample of 14 red deer (Cervus elaphus) kills was examined. High levels of femur marrow fat (75–100 %) were detected in 45% of the roe deer killed by wolves. The amount of leg bone marrow fat showed a decrease through the winter season, roe deer killed by wolves did not show a significantly lower marrow fat level than those killed in traffic accidents. According to our analyses red deer were in generally poor conditions, and yet such a result cannot be regarded as representative of the average condition of the population.
The aim of this study was to analyze the relation between physical condition, easured as the Kidney Fat Index (KFI), and some reproductive parameters of Lepus granatensis in Navarra province, Spain. Samples were collected between October 2001 and January 2003, totaling 174 hares (87 males and 87 females). All the hares were sexed and classified in three age categories (immature, young and adult). Fertile males and females were present in all monthly samples. Kidney weight was greater in females than in males for all the age classes and kidney weight variation along the year was not significant. Ranges of perirenal fat accumulated were larger in females but mean weight of fat for all hares was similar in males and females. Body weight and kidney fat weight was directly related both for males and females. Global pattern of fat deposition along the year was similar for both sexes. The amount of perirenal fat in adult fertile hares reaches maximum values just before the main reproduction period and reproductive state conditioned kidney fat levels. Pregnancy induces fat deposition in females and factors such as the number of embryos and the stage of gestation influence kidney fat levels.
Host-parasite relationships between the Daubenton's bat, Myotis daubentonii Kuhl, 1817 (Chiroptera: Vespertilionidae), and its haematophagous ectoparasite, the mite Spinturnix andegavinus Kolenati, 1857 (Acari: Spinturnicidae), were subjected to analyses based on data gathered during a six-year study (1999-2004) within a single study area in South Bohemia, Czech Republic. Seven hundred and fifty-one Daubenton's bats were examined by screening wing membranes with an intensive light source, resulting in 4,690 recorded mites. Sex, age, weight and reproductive state were evaluated for each bat. A body condition index was calculated as a ratio of weight to forearm length. The seasonal course of mite infestation displayed distinct dynamics with the peak during the lactation and post-lactation periods coinciding with occurrence of the most numerous colonies of Daubenton's bats in the study area. Infestation rates differed between the two sexes, being higher in adult females than adult males. Juvenile bats of both sexes (with no differences between males and females) were the most infested group of all. Pregnant females had a significantly higher parasite load than non-pregnant ones, while no differences in infestation rates were found between lactating and non-lactating females. The analyses of the relationship between parasite load and body condition of bats revealed no common trends for all sex- and age-related groups. Two possible explanations are suggested and discussed: (1) There is no true relationship between the two tested variables and, thus, the significant results were attained due to a random statistical effect. (2) Different underlying causal mechanisms may exist that influence parasite load and, especially, body condition, with respect to the particular sex and age category of bats. The seasonal roosting dynamics of the Daubenton's bat are suggested to be the result not only of changing energetic demands of resident population members, but also of coevolutionary strategies within host-parasite relationships.