Scarlet Rosefinch Carpodacus Erythrinus Research Articles

Male ornamentation and within-pair paternity are not associated with male provisioning rates in scarlet rosefinches Carpodacus erythrinus

As proposed by the ‘good parent model’ for evolution of secondary male ornamentation, secondary ornaments may signal male provisioning rates and, therefore, direct benefit to females. On the other hand, male parental care intensity can potentially be affected by the occurrence of extra-pair offspring in its nest. According to ‘parental investment theory’, males that lose paternity in their nests should reduce their parental care. In this study, we analyse potential relationships between intensity of parental care, male ornamentation, the occurrence of extra-pair paternity and male extra-pair fertilisation success in the scarlet rosefinch Carpodacus erythrinus. Our results based on 50 observed nests indicate no effect of paternity loss on the rate of food provisioning to nestlings in scarlet rosefinches. Simultaneously, we found no evidence for an association between male ornamentation and male provisioning rates. The only male trait associated with provisioning was the ability to sire extra-pair offspring. Our data indicate that direct selection against female promiscuity is weak or absent in rosefinches.

Haemosporidian parasites of a European passerine wintering in South Asia: diversity, mixed infections and effect on host condition

We studied haemosporidian parasites in the scarlet rosefinch Carpodacus erythrinus in a small isolated semicolony during an eight-year period using molecular methods of parasite detection. The scarlet rosefinch is an interesting model of parasite host species. It winters in South Asia which represents a rare exception among European passerines. Males express yellow to red carotenoid-based plumage ornament which is a good predictor of male reproductive success. In 240 blood samples originating from 199 adult individuals, the total parasite prevalence reached 60%. Prevalence varied among years from 36 to 81% in Haemoproteus, 8 to 22% in Plasmodium, and 0 to 14% in Leucocytozoon. Twenty parasite lineages were detected (Haemoproteus: 5 lineages, Plasmodium: 10 lineages, and Leucocytozoon: 5 lineages). Among them, the Haemoproteus ROFI2 lineage, which is a host-specific parasite lineage of the scarlet rosefinch, was the most frequently found. Parasite lineages showed varying degree of lineage specificity. While Haemoproteus lineages detected in the scarlet rosefinch have relatively narrow host breadth restricted mainly to Fringillidae family, Leucocytozoon and Plasmodium lineages generally showed wider host range. The presence of some parasite lineages hitherto detected in sedentary European passerines (SISKIN1, CCF3, BT2) or in Culicoides biting midges at the same locality (ROFI1) suggest local transmission. On the contrary, lineages LK05 and FANTAIL1 that were previously reported exclusively from Asian hosts imply parasite transmission at the scarlet rosefinch wintering sites in South Asia. Mixed infections were found in 17% of infected samples and comprised mainly the most frequent lineages. The pattern of concomitant infections seemed to be rather random and matched expected levels based on lineage frequencies. Between-year comparisons revealed that in a majority of the repeatedly captured individual hosts the infection status remained unchanged (individuals stayed uninfected or possessed the same parasite lineages). However, 16 gains and 8 losses of lineages were also reported. We have not found any effect of haemosporidians on male carotenoid ornament expression or host body mass.

Occurrence of extra‐pair paternity is connected to social male's MHC‐variability in the scarlet rosefinch Carpodacus erythrinus

Genes of the Major Histocompatibility Complex (MHC) represent an essential component of the vertebrate acquired immune system. In the last decades, the role of MHC genes in mate choice has been subject of particular scientific interest. However, results of studies dealing with this topic in different species are equivocal and mechanisms conducting MHC‐based mate choice are still puzzling. We investigated the impact of MHC class I variability on within‐pair and extra‐pair fertilisation success in a wild population of a socially monogamous passerine bird with considerable rates of extra‐pair paternity, the scarlet rosefinch Carpodacus erythrinus. We found some support for the ‘good‐genes‐as‐heterozygosity model’, as social males of high MHC‐heterozygosity were cheated by their females less frequently than less MHC‐heterozygous males. However, cuckolding males were not more MHC‐heterozygous than the cheated social males, nor were extra‐pair young more MHC‐heterozygous than within‐pair young. We did not find any evidence for mating preferences according to the complementarity model.

Extrapair paternity and the opportunity for sexual selection in long-distant migratory passerines

Extrapair fertilizations (EPFs) are frequently documented in songbirds; however, the extent to which this reproductive tactic contributes to variance in male reproductive success and hence the strength of sexual selection on males remains little studied. Using 2 approaches, intraspecific and comparative, we test the hypothesis that the contribution of EPFs to variance in male fitness increases with migration distance in north temperate songbirds. Using data on the genetic mating system of the scarlet rosefinch Carpodacus erythrinus, a long-distance migrant, we show that the number of extrapair mates and within-pair paternity are the most important components of variance in male reproductive success. There was no evidence of a trade-off between extrapair and within-pair success of individual males as males successful in procuring EPFs were less likely to be cuckolded. Comparative data reveal that the opportunity for sexual selection due to EPFs is positively associated with both migration distance and breeding synchrony in north temperate passerines, and we discuss several mechanisms that could extend these relationships. In general, these data suggest that EPFs have a potential to play an important role in the evolution of sexually selected traits in long-distance migratory songbirds such as rosefinches. Key words: comparative analysis, mate choice, parentage assignment, promiscuity, scarlet rosefinch Carpodacus erythrinus, within-pair paternity. [Behav Ecol]

Biometri och könsbestämning av rosenfink Carpodachus erythrinus under häckningsid med hjälp av kloakens utseende

The Scarlet Rosefinch Carpodacus erythrinus was studied in a Swedish west coast area in 1988—1995 in order to evaluate sex-related differences between subadult (2K, 2nd calendar year) males and females (2nd calendar year or older). Biometric examination included weight, wing length, and height, diameter and form of the cloacal protuberance. Subadult "green" males lack the red colour of older males, and are very difficult to separate from females . We found the cloacal protuberance in both "green" and "red" males to differ significantly from that of females of all ages. The cloacal protuberance in both "green" and "red" males was of the "bulbous" type. The size and the form of the cloacal protuberance changed during the breeding cycle. Subadult males had a less well-developed cloacal protuberance than adult males. Subadult males had a smaller protuberance at time of arrival than adult males. The protuberance in both groups of males regressed late in the breeding period. The height of the cloacal protuberance was found to give better sex separation than wing length with nearly no overlap between "green" males and females during the main breeding period. Mean wing length differed significantly between the sexes, but considerable overlap makes this feature unreliable for single individuals. No significant sex- or age-related difference in weight was found.

Nest failures in the Scarlet Rosefinch Carpodacus erythrinus

Over a 4‐year period nest failures in the Scarlet Rosefinch Carpodacus erythrinus averaged 36.9%. Distance of a nest from a habitat edge was the only factor influencing probability of failure. Predation of incubating females is considered the most likely explanation of the failures.