| 1. |
- Cortazar-Chinarro, Maria, 1985-, et al.
(författare)
-
Latitudinal MHC variation and haplotype associated differential survival in response to experimental infection of two strains of Bd-GPL in common toads
- 2024
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- While both innate and adaptive immune system mechanisms have been implicated in resistance against the chytrid fungusBatrachochytrium dendrobatitis, studies on the role of specific MHC haplotypes onBdinfection are rare. Here, we studied latitudinal variation in MHC Class IIB loci along a latitudinal gradient from southern to northern Sweden in common toads,Bufo bufo. Swedish toad populations had fewer MHC Class IIB haplotypes compared to a previous study of populations in Britain. Furthermore, we found MHC diversity to decline from south to the north within Sweden. The low diversity may compromise the ability of northern populations to fight emerging disease, such as the chytrid fungusBd. In a laboratory experiment, we infected newly metamorphosed toads with two strains of the Global Pandemic Lineage of the fungus (Bd-GPL) and compared survival with sham controls. We foundBd-infected toads had lower survival compared to controls. Survival was dependent onBd-strain and whether experimental toads where collected in the south or the north of Sweden with lower survival in northern individuals. MHC diversity was lower in toads of northern origin, all northern animals being monomorphic for a single MHC haplotype, whereas we found seven different haplotypes in southern animals. Survival of infected animals was dependent on bothBd-strain and MHC haplotype suggesting differential infection dynamics depending on bothBd-strain and host MHC characteristics.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Meurling, Sara, et al.
(författare)
-
Body size mediates latitudinal population differences in response to Bd infection in two amphibian species
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The chytrid fungus Batrachochytrium dendrobatidis (Bd), is a generalist pathogen which has caused amphibian population declines worldwide. In many species Bd infection causes the disease chytridiomycosis, leading to high mortality. However, infection may cause sub-lethal fitness effects even in species that are resistant or tolerant to Bd. Moreover, populations of the same species may differ in their sensitivity to Bd, but the factors behind this variation are poorly understood. Here we exposed two common North European amphibians (moor frog Rana arvalis, common toad Bufo bufo) from two latitudinally divergent regions to two different BdGPL strains in a laboratory experiment. We found that Bd exposure lowered survival in both species, but this effect was much stronger in B. bufo. Moreover, survival was lower in the northern region in both species, this difference again being much stronger in B. bufo. Northern individuals were smaller in both species and the survival difference between regions was size mediated with smaller individuals being more sensitive to Bd. We discuss potential additional factors contributing to this result. Bd exposure also led to sub-lethal effects in terms of reduced growth in both species suggesting that even individuals surviving the infection may have reduced fitness mediated by reduction if body size. However, we did not detect any differences in amphibian responses to the two Bd strains.
|
|
| 10. |
- Rowiński, Piotr, 1982-, et al.
(författare)
-
Thermally induced parental effects influence life history traits and covary with an environmental cline in common frog populations
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Across latitudinal clines, the juvenile developmental rates of ectotherms often covary with the length of the growing season, due to life-history trade-offs imposed by time-constrained environments. However, as the start of the growing season often varies substantially across years, adaptive parental effects on juvenile developmental rates may mediate the costs of a delayed spring. By employing a meta-analysis, we tested whether larval developmental rates across a latitudinal cline of common frogs (Rana temporaria) are affected by fluctuating onsets of breeding, across years. We predicted that larval developmental rate will be inversely related to the onset of breeding, and that northern populations will be more prone to shorten their developmental rate in response to late breeding, as the costs of delayed metamorphosis should be highest in areas with a shorter growing season. We found that the larval period of both northern and southern populations responded to parental environmental conditions to similar degree in absolute terms, but in different directions. In northern populations, a late season start correlated with decreased development time, suggesting that the evolution of parental effects aid population persistence in time-constrained environments. In southern populations, late season start correlated with increased development time, which could potentially be explained as a predator avoidance strategy. Our findings suggest that local ecological variables can induce adaptive parental effects, but responses are complex, and likely trade-off with other ecological factors.
|
|
