Jesús Veiga

In this study we compare the intensity and prevalence of parasites and reproductive parameters across 14 bird populations sampled in two different seasons separated by approximately 10 years apart, in the Western Palearctic, to test for climate-parasite associations. Overall, 9 different bird species and 62 different host-parasite interactions were studied. We found non-significant trends between the two sampling years in terms of reduced clutch and brood size. However, we observed a decrease in population size between the sampling years, while differences in laying date were negatively related to temperature change between the years. Feather parasites and non-dipteran parasites tended to decrease in both prevalence and intensity, while dipteran parasites showed a few changes with time between the two sampling periods. The prevalence of blood parasites showed a non-significant increase between the two years studied. Importantly, the magnitude and even the direction of the temporal changes in parasitism experienced by different host species across populations depended on latitude, with the northernmost populations showing the smallest decrease in parasite intensity. In addition, changes in temperature between the two study periods decreased with latitude. These results, therefore, point to a potential effect of climate change on the incidence of parasitic diseases, but with variable magnitude and direction across a latitudinal gradient in Europe.

Avian malaria parasites and related haemosporidians include a highly diverse group of parasites infecting wild birds worldwide, with variable knowledge depending on bird taxa. Although comparatively less studied than terrestrial species, avian malaria infections in seabirds are generally rare, a pattern attributed to several non-mutually exclusive hypotheses, including limited exposure to vectors and differences in host life history traits. Here, we screened blood parasites by combining molecular detection and observation of blood smears in the highly endangered Bermuda Petrel (Cahow) Pterodroma cahow, sampled during the 2022 breeding season (January–April). In addition, we quantified the blood cell types to provide baseline information on the immunological status of this species. Furthermore, few blood samples of the White-tailed Tropicbird Phaethon lepturus catsbyii breeding in sympatry on the same archipelago were also analyzed for parasite presence. Our results support the absence of blood parasites of the genera Plasmodium , Haemoproteus , and Leucocytozoon as well as filaroid nematodes. The absence of blood parasite infections in both species may reflect low exposure to vectors in offshore marine and terrestrial environments, although other explanations, such as the absence of parasites able to infect these host species, are also possible. We found no significant differences in the relative abundance of monocytes among islets, although differences were observed, and a significantly higher total abundance of leucocytes in female Bermuda Petrels than males. Differential parasite exposure among islets and differential life history traits between sexes could account for these results. Negative records of parasite infections in wild birds, including endangered species, are essential for accurately characterizing global infection patterns and understanding host–parasite associations in avian communities.

Global climate change has intensified extreme weather events, including short‐duration but intense rainfall, which can significantly impact avian reproduction. This study examines the effects of extreme rainfall on the reproductive phenology and performance of the European roller Coracias garrulus , a single‐brooded migratory bird, in a semiarid ecosystem. We analysed breeding parameters during 2023, characterised by exceptionally intense and concentrated rainfall, and compared them with long‐term data (2006–2024). Our results indicate that breeding phenology in 2023 exhibited significant shifts. Rollers initiated egg‐laying approximately five days earlier than the long‐term average in the early breeding season, while late‐season laying was delayed by approximately 11 days. The prolonged breeding season was marked by a high incidence of breeding failures, particularly during incubation. Moreover, we observed an unprecedented surge in apparent replacement breeding attempts, a rare phenomenon in this single‐brooded species. Despite these challenges, overall population productivity remained consistent with long‐term averages because successful breeding was heavily concentrated in resilient nest substrates, nest boxes and sandstone burrows, which buffered the weather's impact and compensated for catastrophic failures in stone cavities. Our findings underscore the European roller's capacity for reproductive flexibility, but also suggest the significant fitness costs and constraints associated with these adaptive responses. These results highlight the need for conservation strategies that consider climate‐induced phenological shifts and the importance of nest box designs optimised to mitigate the interacting adverse effects of extreme rainfall and subsequent heatwaves.

The Asian tiger mosquito (Aedes albopictus) is an invasive mosquito species with a global distribution. This species has populations established in most continents, being considered one of the 100 most dangerous invasive species. Invasions of mosquitoes such as Ae. albopictus could facilitate local transmission of pathogens, impacting the epidemiology of some mosquito-borne diseases. Aedes albopictus is a vector of several pathogens affecting humans, including viruses such as dengue virus, Zika virus and Chikungunya virus, as well as parasites such as Dirofilaria. However, information about its competence for the transmission of parasites affecting wildlife, such as avian malaria parasites, is limited. In this literature review, we aim to explore the current knowledge about the relationships between Ae. albopictus and avian Plasmodium to understand the role of this mosquito species in avian malaria transmission. The prevalence of avian Plasmodium in field-collected Ae. albopictus is generally low, although studies have been conducted in a small proportion of the affected countries. In addition, the competence of Ae. albopictus for the transmission of avian malaria parasites has been only proved for certain Plasmodium morphospecies under laboratory conditions. Therefore, Ae. albopictus may play a minor role in avian Plasmodium transmission in the wild, likely due to its mammal-biased blood-feeding pattern and its reduced competence for the development of different avian Plasmodium. However, further studies considering other avian Plasmodium species and lineages circulating under natural conditions should be carried out to properly assess the vectorial role of Ae. albopictus for the Plasmodium species naturally circulating in its distribution range.

In order to know whether there is a risk of anisakiasis (or anisakidosis) by consumption of fish of the genus Mullus from the western Mediterranean Sea, which are appreciated for their quality, an epidemiological survey was carried out to evaluate the occurrence of zoonotic or potentially zoonotic nematodes in M. barbatus and M. surmuletus. Although the presence of the third larval stage (L3) of anisakids (Anisakis and Contracaecum) has been previously described in these fish, the results showed the absence of anisakids and the presence, never in muscle, of L3 and L4 of raphidascaridids of the genus Hysterothylacium, molecularly identified as H. fabri. Phylogenetic analysis groups them into the Mediterranean Sea clade, far from individuals isolated in the Pacific Ocean. Prevalence was slightly higher, but not significant, in M. barbatus versus M. surmuletus (72.3% vs 60.0%), but mean intensity (MI) and mean abundance (MA) parameters were approximately twice as high in M. barbatus as in M. surmuletus (MI 5.8 vs 2.8, p = .001; MA 4.2 vs 1.7, p < .001). The presence of the parasite seems to have different effects on these two sympatric species. In M. barbatus it seems to affect their growth, as it appreciably reduces the value of allometry coefficient in infected fish (2.78 vs. 2.18). On the other hand, in M. surmuletus the infection significantly (p < .04) affects the Fulton's condition factor, an indicator of the health status of the fish. It can be concluded that the ingestion of these fish by the people poses negligible risk of anisakiasis, but the consumer should continue to be urged to follow the rules of prevention against this illness.

Invasive alien species are one main driver of biodiversity loss and can cause severe economic costs. Effective management of such species requires early detection of colonising individuals, but this is often hampered by biological or economic constraints. Trachymela sloanei (Blackburn, 1896), an Australian Eucalyptus defoliator beetle, is an invasive alien species that has spread to the Americas, Asia and most recently Europe. We analyse the expansion of T. sloanei in the Iberian Peninsula both at regional and local scales, study its phenology and relative abundance, and explore the use of nest boxes for early detection. The species is spreading steadily, and the area potentially affected has increased dramatically in a few years. Both adults and larvae were observed between June and November, suggesting the occurrence of several overlapping generations. More than 300 individuals were found aggregated behind single nest boxes. We conclude that the installation and monitoring of nest boxes or similar structures (e.g., cork boards) can facilitate early detection of this species.

Ascertaining the feeding behavior of vectors is a key for understanding epidemiology of the infections they transmit. For some host–vector–parasite systems, this information is biased towards human and peridomestic habitats, frequently underestimating the likely role of wildlife. In addition, studies on vector interactions often focus on a one‐to‐one host–vector relationship, even though it is crucial to analyze how multiple vector species interact with multiple hosts. These biases particularly affect our knowledge of sandflies, the main vector of Leishmania spp. and various phleboviruses, that are rarely explored in non‐peridomestic habitats and in the context of multiple interactions with various hosts. To reveal the multihost/multivector network involving phlebotomine sandflies in a semiarid and poorly populated area of Spain, we sampled the sandfly community close to avian nests by means of two trapping methods (Centers for Disease Control (CDC) and sticky traps) during 3 years and identified the blood‐meal source of all engorged sandflies. We detected six phlebotomine species with Phlebotomus perniciosus, P. papatasi, and Sergentomyia minuta being the most abundant ones. We identified 13 blood source species, with humans being the most common one, followed by Coracias garrulus (European roller) and Sus scrofa (likely wild boar). Five of the six sandfly species fed largely on wild mammals, although, three also fed on wild birds. Phlebotomus sergenti only fed on birds based on this analysis. Phlebotomus papatasi and P. sergenti were common visitors of bird nests suggesting an endophagic behavior. A network analysis showed a highly‐connected and poorly‐specialized network wherein sandflies shared most of the blood source and showed an opportunistic feeding behavior with marked anthropophilia. Our results obtained close to avian nests show that sandfly populations are maintained by various wild animals, which will greatly complicate the management and control of the pathogens they transmit to humans and domestic animals.

The family Simuliidae includes more than 2000 species of black flies worldwide. Their morphological uniformity creates difficulty for species identification, which limits our knowledge of their ecology and vectorial role. We investigated the systematics of black flies in a semi-arid area of the Iberian Peninsula, an ecologically harsh environment for these organisms. Sampling adult black flies in three different habitats (by means of CDC traps) and in avian nest boxes and collecting immature stages in high-salinity rills provided a representative sample of the component species. A combination of approaches, including morphological, chromosomal, and molecular (based on the mitochondrial cytochrome C oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2) genes) revealed five species: four common species (Simulium intermedium, S. petricolum, S. pseudequinum, and S. rubzovianum) and the first European record for S. mellah. Barcoding gap and phylogenetic analyses revealed that ITS2 is a key marker to identify the species, whereas the COI marker does not provide enough resolution to identify some species or infer their phylogenetic relationships. Morphological and chromosomal features are also provided to identify S. mellah unequivocally. Our study highlights the need for integrated studies of black flies in ecologically extreme habitats to increase our knowledge of their distribution, ecology, and potential risks for public health.

The flavivirus West Nile virus (WNV) naturally circulates between mosquitoes and birds, potentially affecting humans and horses. Different species of mosquitoes play a role as vectors of WNV, with those of the Culex pipiens complex being particularly crucial for its circulation. Different biotic and abiotic factors determine the capacity of mosquitoes for pathogen transmission, with the mosquito gut microbiota being recognized as an important one. Here, we review the published studies on the interactions between the microbiota of the Culex pipiens complex and WNV infections in mosquitoes. Most articles published so far studied the interactions between bacteria of the genus Wolbachia and WNV infections, obtaining variable results regarding the directionality of this relationship. In contrast, only a few studies investigate the role of the whole microbiome or other bacterial taxa in WNV infections. These studies suggest that bacteria of the genera Serratia and Enterobacter may enhance WNV development. Thus, due to the relevance of WNV in human and animal health and the important role of mosquitoes of the Cx. pipiens complex in its transmission, more research is needed to unravel the role of mosquito microbiota and those factors affecting this microbiota on pathogen epidemiology. In this respect, we finally propose future lines of research lines on this topic.