Cannibalism in common kestrel (Falco tinnunculus)

acta ethologica - We report two separate observations of adult male common kestrel (Falco tinnunculus) killing and feeding upon second-year (SY) conspecifics in Israel. On 22 January 2022, while...     

Isolation, characterization and cross-amplification of polymorphic microsatellite loci in Laelia speciosa (Orchidaceae)

Laelia speciosa is an endangered epiphytic orchid endemic to central Mexico. Here, we report on the development of 14 perfect and imperfect microsatellite repeat loci for this species. Numbers of alleles ranged from two to 16 and levels of observed heterozygosities among the 14 loci ranged from 0.28 to 1.00 across two widely divergent populations. All loci were also tested for cross-amplification in four other Laelia species and other selected genera of the subtribe Laeliinae.     

Correlates of oxidative stress in wild kestrel nestlings (Falco tinnunculus)

The fitness of an organism can be affected by conditions experienced during early development. In light of the impact that oxidative stress can have on the health and ageing of a bird species, this study evaluated factors accounting for the variation in oxidative stress levels in nestlings of the Eurasian kestrel (Falco tinnunculus) by measuring the serum concentration of reactive oxygen metabolites and the serum antioxidant barrier against hypochlorite-induced oxidation. The ratio between these two variables was considered as an index of oxidative stress, with higher values meaning higher oxidative damage. Six-chick broods showed the highest level of oxidative stress, while no effect of sex was found. Age showed an inverse relationship with the oxidants and the levels of oxidative stress, with younger birds having higher levels. Hatching date, body condition, body mass and carotenoid concentration did not show any relationship with oxidants, antioxidants or degree of oxidative stress. These findings suggest that intrabrood sibling competition could play a role in determining oxidative stress, and that in carnivorous birds other antioxidant molecules could be more important than carotenoids to reduce oxidative stress.     

Isolation, characterization, and cross-amplification of polymorphic microsatellite loci in Guaiacum coulteri (Zygophyllaceae)

Guaiacum coulteri is a dry forest hardwood species of conservation concern endemic to the Pacific coast of Mexico. Fifteen microsatellite markers were developed which show high levels of polymorphism across two populations with the number of alleles ranging from four to 21. Most loci additionally exhibited consistent multiple banding patterns, indicating the likely polyploidy of this species. All loci were tested for cross-amplification with most found to amplify well across the genus Guaiacum, although amplification in other related genera of the Zygophyllaceae was limited.     

Evidence of prey depletion around lesser kestrel Falco naumanni colonies and its short term negative consequences

Predation may reduce prey numbers in such extent that prey may be depleted, which has negative effects on predator populations. Prey depletion would be more likely when the number of predators increase and/or concentrate their activity in a certain area, as is the case of colonial birds. As a matter of fact, food depletion due to intraspecific competition is considered a major cost of coloniality, and several studies have shown indirect evidence of this. However, no direct measures of food depletion have been provided along with its consequences for the fitness of the colony inhabitants. We carried out a field study with the lesser kestrel Falco naumanni, a raptor that breeds in colonies ranging from two to dozens of pairs. During the nestling period we sampled the main prey of the kestrels around different sized colonies at increasing distances. At the same time, we recorded hunting distances and prey delivery rates to the nest. In addition, we monitored the reproductive success in colonies of different sizes. Lesser kestrels feed their nestlings mainly with grasshoppers and these prey became depleted through the season in the surroundings of the large colonies. Prey depletion made kestrels fly longer distances to forage and prey delivery rates to the nest decreased. Lower feeding rates were not compensated by bringing larger prey, hence, the net amount of energy provided to the chicks decreased with the date in large colonies. By contrast, none of this occurred around small colonies, where both prey abundance and hunting distance remained constant throughout the season. As a consequence, the seasonal decline in the reproductive success (number of fledglings and fledgling body condition) was greater the larger the colony. Thus, these results evidence that food depletion and its fitness costs are related to colony size, as they are suffered by the kestrels breeding in large colonies but not by those settled at small ones. Finally, the consequences of prey depletion on the demographic dynamics and the regulation of colony size are discussed.     

Characteristics of loci and individuals are associated with germline microsatellite mutation rates in lesser kestrels (Falco naumanni)

Although microsatellites are one of the most popular tools in genetic studies, their mutational dynamics and evolution remain unclear. Here, we apply extensive pedigree genotyping to identify and analyze the patterns and factors associated with de novo germline mutations across nine microsatellite loci in a wild population of lesser kestrels (Falco naumanni). A total of 10 germline mutations events were unambiguously identified in four loci, yielding an average mutation rate of 2.96x10(-3). Across loci, mutation rate was positively correlated with locus variability and average allele size. Mutations were primarily compatible with a stepwise mutation model, although not exclusively involved single-step changes. Unexpectedly, we found an excess of maternally transmitted mutations (male-to-female ratio of 0.1). One of the analyzed loci (Fn2.14) resulted hypermutable (mutation rate=0.87%). This locus showed a size-dependent mutation bias, with longer alleles displaying deletions or additions of a small number of repeat than shorter alleles. Mutation probability at Fn2.14 was higher for females and increased with parental (maternal) age but was not associated with individual physical condition, multilocus heterozygosity, allele length or allele span. Overall, our results do not support the male-biased mutation rate described in other organisms and suggest that mutation dynamics at microsatellite loci are a complex process which requires further research.     

Environmental and genetic components of oxidative stress in wild kestrel nestlings (Falco tinnunculus)

In this study, we estimated the environmental and genetic components of two variables related to avian oxidative stress using wild nestlings of the Eurasian kestrel (Falco tinnunculus). The study was carried out during two breeding seasons. In the first season, we assessed the between- and within-nest resemblance in serum reactive oxygen metabolites (ROMs) and total serum antioxidant barrier (OXY). In the second season, we carried out a cross-fostering experiment to determine the importance of environmental and genetic factors on ROMs and OXY. The 23.5% of ROMs variance was explained by the nest of origin, indicating a main genetic component. In contrast, the 52.8% of OXY variance was explained by the nest of rearing, indicating that this variable was more influenced by environmental components. These findings suggest that variations in ROMs and OXY could reflect, respectively, the expression of different genetic polymorphisms and differences in dietary uptake of antioxidants.     

Extensive polymorphism and geographical variation at a positively selected MHC class II B gene of the lesser kestrel (Falco naumanni)

Understanding the selective forces that shape genetic variation in natural populations remains a high priority in evolutionary biology. Genes at the major histocompatibility complex (MHC) have become excellent models for the investigation of adaptive variation and natural selection because of their crucial role in fighting off pathogens. Here we present one of the first data sets examining patterns of MHC variation in wild populations of a bird of prey, the lesser kestrel, Falco naumanni . We report extensive polymorphism at the second exon of a putatively functional MHC class II gene, Fana- DAB*1. Overall, 103 alleles were isolated from 121 individuals sampled from Spain to Kazakhstan. Bayesian inference of diversifying selection suggests that several amino acid sites may have experienced strong positive selection (ω = 4.02 per codon). The analysis also suggests a prominent role of recombination in generating and maintaining MHC diversity (ρ = 4 Nc  = 0.389 per codon, θ = 0.017 per codon). Both the Fana -DAB*1 locus and a set of eight polymorphic microsatellite markers revealed an isolation-by-distance pattern across the Western Palaearctic ( r  = 0.67; P  = 0.01 and r  = 0.50; P  = 0.04, respectively). Nonetheless, geographical variation at the MHC contrasts with relatively uniform distributions in the frequencies of microsatellite alleles. In addition, we found lower fixation rates in the MHC than those predicted by genetic drift after controlling for neutral mitochondrial sequences. Our results therefore underscore the role of balancing selection as well as spatial variations in parasite-mediated selection regimes in shaping MHC diversity when gene flow is limited.     

Isolation and characterization of polymorphic microsatellite markers from Primula nutans (Primulaceae)

Seven polymorphic microsatellite loci were developed for a perennial seashore plant, Primula nutans. Degenerate oligonucleotide‐primed (DOP)–polymerase chain reaction (PCR)‐amplified DNA was ligated to TOPO TA vector and screened with radioactively labelled dinucleotide repeat probes. A sample of 378 individuals from Finland, Norway and Russia were used to characterize those loci, which exhibited two to four alleles per locus with observed heterozygosity of 0.003–0.229 and expected heterozygosity of 0.016–0.527. No linkage disequilibrium was found between these seven loci. These are the first microsatellite markers reported for P. nutans.     

Isolation and characterization of 36 polymorphic microsatellite markers in Schima superba (Theaceae)

? Premise of the study: Our objective was to develop microsatellite markers to investigate the level of genetic diversity within and among populations in a dominant evergreen broad-leaved tree, Schima superba, in southern China. ? Methods and Results: Thirty-six microsatellite markers were developed and showed polymorphism in three populations. The number of alleles per locus ranged from six to 34, with an average of 19. The observed and expected heterozygosities ranged from 0.242 to 1.000 and from 0.504 to 0.945, respectively. ? Conclusions: The developed microsatellites will be useful for studying genetic diversity and population structure in S. superba.     

Isolation, characterization and cross-amplification of polymorphic microsatellite loci in the threatened endemic Mammillaria crucigera (Cactaceae)

The cactus Mammillaria crucigera is a threatened species endemic to central Mexico. As a means of assessing population genetic status of these species, eight microsatellite markers were developed. These primers were tested in 40 individual from two wild populations. The results showed that these primers will be useful to describe population structure and aid to the conservation of species. The eight primers were tested in other Mammillaria species and most of them showed successful amplification.     

基于454测序技术的青藏高原黄绿蜜环菌微卫星引物的开发

【目的】本研究利用454焦磷酸测序技术,对青藏高原黄绿蜜环菌(Armillaria luteo-virens)转录组进行测序,从获得的Expressed sequence tags(EST)序列中开发EST-SSR引物。【方法】利用高通量测序获得的EST序列设计微卫星引物,通过PCR扩增、琼脂糖凝胶电泳和毛细管电泳检测筛选出合格的微卫星引物。【结果】共得到了1997121条reads,总数据量超过80Mb,序列平均长度为449bp。对于所获得的reads进行拼接后得到了22236条非冗余的EST序列,其中含有2024条contigs(平均读长974bp)和20212条singletons(平均读长404bp)。在所有序列中共找到321条符合条件的含有SSR的序列,从中随机选择98对,成功开发出27对具有多态性条带的微卫星引物。利用采集自3个不同居群的66个个体对上述27对引物进行验证,有17对引物符合Hardy-Weinberg平衡且没有连锁不平衡现象。【结论】首次成功利用高通量测序技术开发的EST-SSR引物将会对今后黄绿蜜环菌遗传多样性的研究以及种质资源鉴定、遗传图谱构建等打下了坚实基础。     

Isolation and characterization of highly polymorphic microsatellite markers in Hypochaeris radicata (Asteraceae)

We developed five highly polymorphic dinucleotide microsatellite loci for the grassland species Hypochaeris radicata (Asteraceae). Polymorphism of these markers was examined in six populations in the Netherlands. All loci were polymorphic in all populations. The number of alleles per locus varied between 18 and 43. Expected heterozygosity was between 0.86 and 0.91. Cross‐species amplification was tested in six Hypochaeris species and was successful for three different loci in four species. These microsatellites are a useful tool in population genetic, dispersal and metapopulation studies or in testing levels of inbreeding.     

Daytime variation in T-cell-mediated immunity of Eurasian kestrel Falco tinnunculus nestlings

Host-parasite interactions are central in evolutionary and behavioural ecology. In the last few years, skin injections of the mitogen Phytohaemagglutinin (PHA) have become one of the most important and widely used in-vivo assays of immune function in birds. However, there are no studies of the circadian variation suggesting that care should be taken interpreting results when using this technique. This 3-year study assessed PHA responses as a function of daylight time in 310 Eurasian kestrel Falco tinnunculus nestlings at 24 days of age in Central Spain. I found that T-cell-mediated immunity was positively related to nestling mass and varied among years. Controlling for these variables, I also found that T-cell-mediated immunity decreased with the hour of sampling, and that this pattern was consistent between years. In addition, I found that at the end of the day only, T-cell-mediated immunity decreased with brood size. Parasites seem not to be behind this pattern, but I suggest that the cumulative effect of sibling competition during the day might explain the decrease of cellular immunity with the hour of sampling. Thus, I strongly recommend that future studies of cellular immunity should control for this potential source of variation when nestling self-maintenance is evaluated by the PHA-induced skin-swelling response.     

Isolation and characterization of polymorphic microsatellite markers in Anthyllis vulneraria

To study the reproductive system of the putative autogamous species Anthyllis vulneraria in Belgian calcareous grasslands, eight polymorphic microsatellite loci were developed using the sequence‐tagged microsatellite profiling technique and 35 plants were typed for all loci. No linkage disequilibrium was found between any pair of loci. Over the loci, the number of alleles ranged from two to five. Observed and expected heterozygosities ranged from 0.053 to 0.688 and from 0.053 to 0.631, respectively. The estimated F_IS values (F_IS = 0.031 and 0.122) are not in accordance with a predominantly selfing reproductive system.     

Photoperiodic control of reproduction and molt in the kestrel, Falco tinnunculus

An adaptive decline in average clutch size with progressive date of laying is characteristic of most bird species with a single clutch of variable size per year. The effect of photoperiod on timing of laying, clutch size, and subsequent molt was investigated in kestrel pairs breeding and raising their young in captivity. In natural daylight (nLD), clutch size, under ad libitum feeding, showed the same decline with date as in nature. Birds breeding later also started molt later and molted faster (more feathers simultaneously), so that all birds completed molt more or less at the same time. Constant long days (LD 17.5:6.5 and LD 13:11) from December 1 onward advanced both reproduction and molt. The LD 17.5:6.5 group developed the reproductive system faster, had a shorter courtship period, and laid eggs earlier than the LD 13:11 group. In both photoperiods there was a decrease in clutch size with progressive laying date, similar to that in nLD. Molt started in both groups at about the end of the laying period and slowed down in the longer photoperiod, especially in males. Plasma luteinizing hormone (LH) changes in the two photoperiods were different for males and females. Males showed the expected slower LH response in the shorter photoperiod, but the initial LH response by females was the same in both photoperiods. Data on LH, reproductive behavior, and body mass suggest that females have a wider annual reproductive window than males. Data on time of laying and number of eggs suggest that clutch size in the kestrel is determined by laying date itself, following an endogenous rhythm that is phase-locked to the reproductive cycle.