Capsule: Sympatric Marsh Warblers Acrocephalus palustris and Blyth's Reed Warblers Acrocephalus dumetorum differ significantly in their life history traits.
Aims: To provide a direct comparison of ...demographic parameters among two sympatric populations of the closely related Marsh Warbler and Blyth's Reed Warbler.
Methods: We examined breeding phenology and reproductive traits at a 25 ha study plot. We use program MARK to estimate daily nest survival and adult apparent survival rates.
Results: On average, Marsh Warblers laid the first eggs 3 days later than Blyth's Reed Warblers. Mean clutch size in the Marsh Warbler was significantly lower than in the Blyth's Reed Warbler. There are no significant differences between the two species for nest daily survival, duration of incubation and nestling periods. Apparent survival of adults was slightly higher in Marsh Warblers than in Blyth's Reed Warblers.
Conclusion: Our findings suggest that two ecologically similar sympatric species differ significantly in terms of life history traits. We assume that observed differences could be the result of adaptations to environmental factors in the central parts of the species' ranges or due to differences in mortality on migratory pathways or wintering grounds.
In this study, blood samples of 259
Acrocephalus
sp. warblers were molecularly analysed for Anaplasmataceae and Rhodospirillaceae based on PCR amplification of 16S rRNA gene fragments. One bird blood ...sample (from Reed Warbler,
Acrocephalus scirpaceus
) yielded a sequence with 99.8% identity to
Haematospirillum jordaniae
. This is the first molecular evidence for the occurrence of this species in the blood of any vertebrate other than human. Another bird blood sample (from Marsh Warbler:
Acrocephalus palustris
) yielded a
Wolbachia
sequence, closely related to a moth endosymbiont with 99.8% identity. A nematode origin of
Wolbachia
DNA detected here in avian blood can be excluded, because results of phylogenetic analysis showed its closest alignment with insect wolbachiae. This is the first finding of insect
Wolbachia
DNA in the circulatory system of birds, which can be explained either by the inoculation of wolbachiae by blood-sucking vectors, or passing of
Wolbachia
DNA from the gut into the blood of this insectivorous bird species.
The brood parasitic common cuckoo Cuculus canorus consists of gentes, which typically parasitize only a single host species whose eggs they often mimic. Where multiple cuckoo gentes co-exist in ...sympatry, we may expect variable but generally poorer mimicry because of host switches or inter-gens gene flow via males if these also contribute to egg phenotypes. Here, we investigated egg trait differentiation and mimicry in three cuckoo gentes parasitizing great reed warblers Acrocephalus arundinaceus, marsh warblers Acrocephalus palustris and corn buntings Miliaria calandra breeding in close sympatry in partially overlapping habitat types. The three cuckoo gentes showed a remarkable degree of mimicry to their three host species in some but not all egg features, including egg size, a hitherto largely ignored feature of egg mimicry. Egg phenotype matching for both background and spot colours as well as for egg size has been maintained in close sympatry despite the possibility for gene flow.
Avian brood parasites and their hosts are involved in complex offence-defense coevolutionary arms races. The most common pair of reciprocal adaptations in these systems is egg discrimination by hosts ...and egg mimicry by parasites. As mimicry improves, more advanced host adaptations evolve such as decreased intra- and increased interclutch variation in egg appearance to facilitate detection of parasitic eggs. As interclutch variation increases, parasites able to choose hosts matching best their own egg phenotype should be selected, but this requires that parasites know their own egg phenotype and select host nests correspondingly.
We compared egg mimicry of common cuckoo Cuculus canorus eggs in naturally parasitized marsh warbler Acrocephalus palustris nests and their nearest unparasitized conspecific neighbors having similar laying dates and nest-site characteristics. Modeling of avian vision and image analyses revealed no evidence that cuckoos parasitize nests where their eggs better match the host eggs. Cuckoo eggs were as good mimics, in terms of background and spot color, background luminance, spotting pattern and egg size, of host eggs in the nests actually exploited as those in the neighboring unparasitized nests.
We reviewed the evidence for brood parasites selecting better-matching host egg phenotypes from several relevant studies and argue that such selection probably cannot exist in host-parasite systems where host interclutch variation is continuous and overall low or moderate. To date there is also no evidence that parasites prefer certain egg phenotypes in systems where it should be most advantageous, i.e., when both hosts and parasites lay polymorphic eggs. Hence, the existence of an ability to select host nests to maximize mimicry by brood parasites appears unlikely, but this possibility should be further explored in cuckoo-host systems where the host has evolved discrete egg phenotypes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Non-kin infanticide is the killing of unrelated young by a conspecific adult, and occurs infrequently in some bird species. We observed a case of non-kin infanticide committed by a male Japanese ...Marsh Warbler (Locustella pryeri) in 2008. The sudden disappearance of a nesting male from his territory made the neighboring male expand his original territory to the vacant area where the unrelated nestlings were being reared by a female in the nest. The male found the nest and attacked the unrelated nestlings. We inferred that the infanticide sequence was done as food resource competition and/or sexually selected infanticide.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The phylogeography and evolutionary history of the long‐distance migratory Eurasian Reed Warbler Acrocephalus scirpaceus were analysed using sequence data from the mitochondrial DNA COI gene of 405 ...individuals and cyt b sequences from a subset of those individuals from 20 breeding, migrating and wintering populations over its wide geographical range. Median‐joining network and Bayesian phylogenetic analyses recovered three lineages corresponding to three subspecies of A. scirpaceus that started to diverge approximately 480 000 years ago: one spanning Asia (Acrocephalus scirpaceus fuscus), one encompassing Europe and Northern Africa (Acrocephalus scirpaceus scirpaceus) and a third that included Eastern Africa and Southwestern Asia (Acrocephalus scirpaceus avicenniae). Phylogenetic analyses suggest that the third clade is basal and diverged from its sister species, the African Reed Warbler Acrocephalus baeticatus, around 700 000 years ago. This earliest subspecies (avicenniae) may have survived the Last Glacial Maximum in one of the African refugia, probably the low forest refugium of the Ethiopian Highlands. Sequences of 348 samples from Germany, which were captured for ringing, showed that one bird was genetically assigned to the subspecies fuscus, the first genetic evidence of this Asian subspecies in Central Europe. According to our DNA sequences, 6.8% of Eurasian Reed Warblers were misidentified at the species level, Marsh Warbler Acrocephalus palustris accounting for most of these misidentified specimens. At the subspecies level, of 22 fuscus identified by genetic analyses, only six had been correctly named by the ringers.
Ecological conditions in wintering quarters strongly influence the survival of long-distance migrant species, moreover food abundance and quality in moulting areas determine feather growth rate and ...wing length too. These circumstances via net primary production can be well characterized by the Normalized Difference Vegetation Indices (NDVI) of the respective areas. In this paper we approach this subject from the opposite direction: supposing this strong relationship between vegetation indices and survival, respectively moult, we try to identify putative wintering and moulting areas of Marsh Warblers (Acrocephalus palustris) with the help of Spearman's rank correlations between annual survival indices, wing lengths and NDVI from entire Africa. We have chosen this species because its movements, stop-over sites and wintering areas are relatively well known compared to other trans-Saharan migrants, hence with the help of the literature we can test the validity of our results. In lack of sufficient ringing-recapture data we have applied a new survival index which is based on the ratio of the abundances of different age classes. Our results are consistent with the available information from literature showing that our survival index, wing lengths and our methods are appropriate to search for putative wintering and/or moulting areas.
In the coevolutionary “arms race” between Common Cuckoos (Cuculus canorus) and their hosts, several adaptations and counter-adaptations have evolved. Here, we investigated natural parasitism and host ...sensitivity to egg rejection in Marsh Warblers (Acrocephalus palustris) in Bulgaria. The level of Common Cuckoo parasitism was high (28%), and average mimicry of Common Cuckoo eggs was good. Experimental parasitism with four egg-types that showed various degrees of mimicry of the host eggs revealed a generally high rejection rate of foreign eggs (37.5–100%). In addition, naturally laid Common Cuckoo eggs were rejected at a moderate rate (50%). The Marsh Warbler's ability to reject foreign eggs was strongly dependent on the degree of mimicry of the parasite egg but apparently not on differences in size between host and foreign eggs. Furthermore, intraclutch variation in host egg appearance was not related to the probability of egg rejection. The Marsh Warbler's highly developed egg-recognition ability and the good mimicry of Common Cuckoo eggs suggests that this poorly known host-parasite arms race has reached an advanced stage. The present study provides new insight into variables that are important for egg rejection in a heavily parasitized host population. Rechazo de Huevos en Nidos de Acrocephalus palustris Fuertemente Parasitados por Cuculus canorus
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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