Contrasting effects of host or local specialization: widespread haemosporidians are host generalist whereas local specialists are locally abundant

Aim: Despite the wide distribution of many parasites around the globe, the range of individual species varies significantly even among phylogenetically related taxa. Since parasites need suitable hosts to complete their development, parasite geographical and environmental ranges should be limited to communities where their hosts are found. Parasites may also suffer from a trade-off between being locally abundant or widely dispersed. We hypothesize that the geographical and environmental ranges of parasites are negatively associated to their host specificity and their local abundance.
Location: Worldwide
Time period: 2009 to 2021
Major taxa studied: Avian haemosporidian parasites
Methods: We tested these hypotheses using a global database which comprises data on avian haemosporidian parasites from across the world. For each parasite lineage, we computed five metrics: phylogenetic host-range, environmental range, geographical range, and their mean local and total number of observations in..., We compiled data on haemosporidian lineages from the MalAvi database (http://130.235.244.92/Malavi/ , Bensch et al. 2009) including all the data available from the “Grand Lineage Summary” representing Plasmodium and Haemoproteus genera from wild birds and that contained information regarding location. After checking for duplicated sequences, this dataset comprised a total of ~6200 sequenced parasites representing 1602 distinct lineages (775 Plasmodium and 827 Haemoproteus) collected from 1139 different host species and 757 localities from all continents except Antarctica (Supplementary figure 1, Supplementary Table 1). The parasite lineages deposited in MalAvi are based on a cyt b fragment of 478 bp. This dataset was used to calculate the parasites’ geographical, environmental and phylogenetic ranges.
Geographical range
            All analyses in this study were performed using R version 4.02. In order to estimate the geographical range of each parasite lineage, we applied the R packag..., , # Contrasting effects of host or local specialization: widespread haemosporidians are host generalist whereas local specialists are locally abundant

[https://doi.org/10.5061/dryad.j3tx95xfb](https://doi.org/10.5061/dryad.j3tx95xfb)

## Description of the data and file structure

This is a global database which comprises data on avian haemosporidian parasites from across the world. For each parasite lineage, we computed five metrics: phylogenetic host-range, environmental range, geographical range, and their mean local and total number of observations in the database.

## Sharing/Access information

The data that support the findings of this study are openly available in MalAvi at [http://130.235.244.92/Malavi/](http://130.235.244.92/Malavi/) (Bensch et al. 2009).