Peatlands are unique ecosystems of global importance for biodiversity, though are severely threatened by human activities. Dragonflies are valuable ecological indicators, but comprehensive studies on ...the species inhabiting peatlands are limited. To fill this knowledge gap, we investigated the determinants of peatland odonate assemblages in the Italian Alps along the bog-poor fen-rich fen series, a vegetation gradient influenced by pH. The ultimate goal was to distil management recommendations to inform peatland dragonfly conservation. Species richness, bog specialist richness, and community composition were assessed at both pristine and human-impacted sites and then related to environmental and antrophogenic drivers. We showed that bog and poor fen assemblages were significantly distinct from those of intermediate and rich fens, which, in turn, displayed the highest species richness, but the lowest number of specialists, whilst being also the most degraded. Excavated sites, compared to non-excavated ones, harboured a higher number of species, although this effect was not significant for bog specialists. Drainage and abandonment of mowing/grazing practices determined reed and shrub/tree invasion, negatively impacting fen species. Water availability and heterogeneous spatial arrangements of water pools within the peatland positively affected most species, with bog specialists only favoured by the latter. Peatland dragonfly conservation should primarily rely on the preservation of pristine sites, as they harbour unique dragonfly assemblages. Impacted sites could benefit from restoration actions; specifically, reed control, and the creation of pools of different sizes and depths within the more terrestrified peatlands are likely the most effective measures to support peatland Odonata communities.
The Odonata are considered among the most endangered freshwater faunal taxa. Their DNA‐based monitoring relies on validated reference data sets that are often lacking or do not cover important ...biogeographical centres of diversification. This study presents the results of a DNA barcoding campaign on Odonata, based on the standard 658‐bp 5′ end region of the mitochondrial COI gene, involving the collection of 812 specimens (409 of which barcoded) from peninsular Italy and its main islands (328 localities), belonging to all the 88 species (31 Zygoptera and 57 Anisoptera) known from the country. Additional BOLD and GenBank data from Holarctic samples expanded the data set to 1,294 DNA barcodes. A multi‐approach species delimitation analysis involving two distance (OT and ABGD) and four tree‐based (PTP, MPTP, GMYC and bGMYC) methods was used to explore these data. Of the 88 investigated morphospecies, 75 (85%) unequivocally corresponded to distinct molecular operational units, whereas the remaining ones were classified as ‘warnings’ (i.e. showing a mismatch between morphospecies assignment and DNA‐based species delimitation). These results are in contrast with other DNA barcoding studies on Odonata showing up to 95% of identification success. The species causing warnings were grouped into three categories depending on if they showed low, high or mixed genetic divergence patterns. The analysis of haplotype networks revealed unexpected intraspecific complexity at the Italian, Palearctic and Holarctic scale, possibly indicating the occurrence of cryptic species. Overall, this study provides new insights into the taxonomy of odonates and a valuable basis for future DNA and eDNA‐based monitoring studies.
Physiological trade-offs mediated by limiting energy, resources or time constrain the simultaneous expression of major functions and can lead to the evolution of temporal separation between demanding ...activities. In birds, plumage renewal is a demanding activity, which accomplishes fundamental functions, such as allowing thermal insulation, aerodynamics and socio-sexual signaling. Feather renewal is a very expensive and disabling process, and molt is often partitioned from breeding and migration. However, trade-offs between feather renewal and breeding have been only sparsely studied. In barn swallows (Hirundo rustica) breeding in Italy and undergoing molt during wintering in sub-Saharan Africa, we studied this trade-off by removing a tail feather from a large sample of individuals and analyzing growth bar width, reflecting feather growth rate, and length of the growing replacement feather in relation to the stage in the breeding cycle at removal and clutch size. Growth bar width of females and length of the growing replacement feather of both sexes were smaller when the original feather had been removed after clutch initiation. Importantly, in females both growth bar width and replacement feather length were negatively predicted by clutch size, and more strongly so for large clutches and when feather removal occurred immediately after clutch completion. Hence, we found strong, coherent evidence for a trade-off between reproduction, and laying effort in particular, and the ability to generate new feathers. These results support the hypothesis that the derived condition of molting during wintering in long-distance migrants is maintained by the costs of overlapping breeding and molt.
Birds in seasonal habitats rely on intricate strategies for optimal timing of migrations. This is governed by environmental cues, including photoperiod. Genetic factors affecting intrinsic ...timekeeping mechanisms, such as circadian clock genes, have been explored, yielding inconsistent findings with potential lineage-dependency. To clarify this evidence, a systematic review and phylogenetic reanalysis was done. This descriptor outlines the methodology for sourcing, screening, and processing relevant literature and data. PRISMA guidelines were followed, ultimately including 66 studies, with 34 focusing on candidate genes at the genotype-phenotype interface. Studies were clustered using bibliographic coupling and citation network analysis, alongside scientometric analyses by publication year and location. Data was retrieved for allele data from databases, article supplements, and direct author communications. The dataset, version 1.0.2, encompasses data from 52 species, with 46 species for the Clock gene and 43 for the Adcyap1 gene. This dataset, featuring data from over 8000 birds, constitutes the most extensive cross-species collection for these candidate genes, used in studies investigating gene polymorphisms and seasonal bird migration.
Ticks are obligate haematophagous ectoparasites of vertebrates and frequently parasitize avian species that can carry them across continents during their long-distance migrations. Ticks may have ...detrimental effects on the health state of their avian hosts, which can be either directly caused by blood-draining or mediated by microbial pathogens transmitted during the blood meal. Indeed, ticks host complex microbial communities, including bacterial pathogens and symbionts. Midichloria bacteria (Rickettsiales) are widespread tick endosymbionts that can be transmitted to vertebrate hosts during the tick bite, inducing an antibody response. Their actual role as infectious/pathogenic agents is, however, unclear.
We screened for Midichloria DNA African ticks and blood samples collected from trans-Saharan migratory songbirds at their arrival in Europe during spring migration.
Tick infestation rate was 5.7%, with most ticks belonging to the Hyalomma marginatum species complex. Over 90% of Hyalomma ticks harboured DNA of Midichloria bacteria belonging to the monophylum associated with ticks. Midichloria DNA was detected in 43% of blood samples of avian hosts. Tick-infested adult birds were significantly more likely to test positive to the presence of Midichloria DNA than non-infested adults and second-year individuals, suggesting a long-term persistence of these bacteria within avian hosts. Tick parasitism was associated with a significantly delayed timing of spring migration of avian hosts but had no significant effects on body condition, whereas blood Midichloria DNA presence negatively affected fat deposits of tick-infested avian hosts.
Our results show that ticks effectively transfer Midichloria bacteria to avian hosts, supporting the hypothesis that they are infectious to vertebrates. Bird infection likely enhances the horizontal spread of these bacteria across haematophagous ectoparasite populations. Moreover, we showed that Midichloria and tick parasitism have detrimental non-independent effects on avian host health during migration, highlighting the complexity of interactions involving ticks, their vertebrate hosts, and tick-borne bacteria.
The use of species distribution models (SDMs) to predict local abundance has been often proposed and contested. We tested whether SDMs at different spatiotemporal resolutions may predict the local ...density of 14 bird species of open/semi‐open habitats. SDMs were built at 1 ha and 1 km, and with long‐term versus a mix of current and long‐term climatic variables. The estimated environmental suitability was used to predict local abundance obtained by means of 275 linear transects. We tested SDM ability to predict abundance for all sampled sites versus occurrence sites, using N‐mixture models to account for imperfect detection. Then, we related the R2 of N‐mixture models to SDM traits. Fine‐grain SDMs appeared generally more robust than large‐grain ones. Considering the all‐transects models, for all species environmental suitability displayed a positive and highly significant effect at all the four combinations of spatial and temporal grains. When focusing only on occurrence transects, at the 1 km grain only one species showed a significant and positive effect. At the 1 ha grain, 62% of species models showed (over both climatic sets) a significant or nearly significant positive effect of environmental suitability on abundance. Grain was the only factor significantly affecting the model's explanatory power: 1 km grain led to lower amounts of variation explained by models. Our work re‐opens the debate about predicting abundance using SDM‐derived suitability, emphasizing the importance of grains and of spatiotemporal resolution more in general. The incorporation of local variables into SDMs at fine grains is key to predict local abundance. SDMs worked out at really fine grains, approaching the average size of territory or home range of target species, are needed to predict local abundance effectively. This may result from the fact that each single cell may represent a potential territory/home range, and hence a higher suitability over a given area means that more potential territories occur there.
Traditional livestock systems have supported farmland biodiversity for millennia. However, modern intensive husbandry is challenging wildlife persistence in agroecosystems. We assessed the multiscale ...determinants of the species richness of breeding bird communities, as well as the occurrence of a flagship raptor species, the lesser kestrel Falco naumanni, in an intensive agroecosystem mostly dedicated to the production of the world-renowned Parmigiano Reggiano cheese. We relied on three avian community richness metrics reflecting a gradient of increasing association with farmed landscapes, i.e. the overall breeding bird species richness, the richness of farmland species, and the richness of ground-nesters (i.e. species that mostly breed within crops) and tested their association with the landscape, agricultural, and pedological variables as well as with lesser kestrel occurrence. We showed that environmental variables determining overall richer avian assemblages did not coincide with those shaping farmland and ground-nesting species richness, thus challenging the potential effectiveness of conservation actions. However, such actions could be optimized by taking into account different spatial scales affecting different species groups. Indeed, landscape heterogeneity, semi-natural/marginal habitats, and a moderate cover of build-up areas enhanced overall species richness at a small spatial scale. At a broader scale, landscape heterogeneity enhanced farmland species richness, whereas fragmentation determined by urbanization negatively affected ground-nesters. Avian community richness metrics were maximized at an intermediate cover of three prevailing crops (winter, summer, and hay crops), increasing when they co-occurred, i.e., in the presence of crop rotation. Lesser kestrel occurrence was associated with richer assemblages of ground-nesting species because this raptor and ground-nesters showed analogous ecological requirements. These findings suggest that the lesser kestrel can be regarded as an ideal flagship for market-based conservation initiatives (e.g., tailored to the production of biodiversity-friendly agri-food products) in intensive agroecosystems since actions aimed at improving the foraging habitats of the species are likely to benefit co-occurring farmland birds of conservation interest.
•Lesser kestrels are associated with richer assemblages of ground-nesting birds.•Lesser kestrels and ground-nesters share similar ecological requirements.•The lesser kestrel is an ideal flagship for market-based conservation.•Conservation can be optimized by considering spatial scales affecting species groups.
Kin selection theory predicts that individual progeny members, in species where offspring share depreciable parental care, should increasingly attempt to monopolize resources provided by the parents ...as their relatedness to brood competitors declines. Although the level of relatedness among broodmates is often variable in vertebrates, whether it affects within-brood competition dynamics has seldom been studied. We tested this prediction in nestlings of the lesser kestrel, Falco naumanni, a cavity-nesting colonial raptor that can breed in high-density colonies, where nestlings often move between nearby nests, generating mixed parentage among broodmates. Pairs of nestlings composed of either unrelated, unfamiliar individuals or siblings were experimentally forced to compete for food. Nestlings stole prey more frequently when competing with an unrelated, unfamiliar competitor than when competing with a sibling. This finding adds to the limited evidence that rivalry among broodmates is affected by their relatedness, suggesting that kin recognition and kin selection may play an important role in determining individual competitive strategies and care allocation in multiparous species.
•Coloniality favours the occurrence of mixed kinship broods.•Competition for food should differ between siblings and unrelated offspring.•We tested this prediction in mixed kinship lesser kestrel broods.•Prey thefts were more frequent when competitors were unrelated.•Kin selection affects competitive behaviour in altricial avian offspring.
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