Function of note strings in Japanese Tit alarm calls to the Common Cuckoo:a playback experiment

Background: Birds produce alarm calls to convey information about threats. Some Passerine alarm calls consist of several note strings, but few studies have examined their function. Previous studies have shown that Japanese Tits(Parus minor) can alter the calling rate and number and combination of notes in response to predators. We previously found the combinations of note types in Japanese Tit alarm calls to be significantly different in response to the Sparrowhawk(Accipiter nisus) and Common Cuckoo(Cuculus canorus).Methods: Through playback experiments, we tested whether the note strings in Japanese Tit alarm calls to the Common Cuckoo have different functions in conveying information. The note strings of selected alarm calls were divided into the categories of C and D, and different calls were then constructed separately based on the two note string categories. Original alarm calls(C–D), C calls and D calls were played back to male Japanese Tits during the incubation period.Results: Male Japanese Tits had a significantly stronger response to C calls than to C–D calls, and they showed a significantly stronger response to both C and C–D calls than to D calls, suggesting that Japanese Tits discriminated between the C and D calls.Conclusions: Our study demonstrated that the C-and D-category note strings of Japanese Tit alarm calls to the Common Cuckoo have different functions, which supports the previous finding that different note strings in an alarm call can provide different information to receivers. However, the exact meanings of these note strings are not yet known, and further investigation is therefore required.

High levels of genetic diversity and an absence of genetic structure among breeding populations of the endangered Rufous-backed Bunting in Inner Mongolia,China:implications for conservation

Background:The Rufous-backed Bunting,Emberiza jankowskii,is an endangered species that is primarily distributed in Inner Mongolia,China.The main threats to the continued persistence of this species are habitat loss and degradation.However,the impact of population loss on genetic diversity remains unclear.To support future conservation and management efforts,we assessed the genetic diversity and population structure of E.jankowskii using mitochondrial DNA and microsatellites.Methods:Blood samples were collected from 7-8-day-old nestlings in Inner Mongolia,China between May and August of 2012 and 2013.Mitochondrial DNA sequences and microsatellite markers were used to assess the genetic diversity,genetic structure and inbreeding of E.jankowskii.The results of genetic diversity and inbreeding were compared to other avian species.Results:We found an unexpectedly high level of genetic diversity in terms of mitochondrial DNA and microsatellite compared to other avian species.However,there were high levels of gene flow and minimal genetic structuring,among the fragmented breeding populations of E.jankowskii in Inner Mongolia.These findings suggest that E.jankowskii in Inner Mongolia is a metapopulation.Despite the high genetic diversity of E.jankowskii,local populations in each small patch remain at risk of extinction due to habitat loss.In addition,the E.jankowskii population has a high risk of inbreeding.Conclusions:To minimize further loss of genetic diversity of this endangered species,we suggest that the E.jankowskii in Inner Mongolia should be considered as a protected species for management purposes.Conservation efforts should concentrate on E.jankowskii habitat management.This may be most effectively achieved by protecting the current breeding habitats and prohibiting over-grazing.

Molecular evidence of introgressive hybridization between related species Jankowski's Bunting(Emberiza jankowskii)and Meadow Bunting(Emberiza cioides)(Aves:Passeriformes)

Natural hybridization,which often occurs between closely related species exhibiting sympatric or parapatric distributions,is an important source of genetic variation within populations.The closely related Jankowski’s Bunting(Emberiza jankowskii)and Meadow Bunting(E.cioides)are similar in morphology and genetics,occupy overlapping niches,and are sympatric in eastern Inner Mongolia.Previous studies have reported trans-species polymorphisms of alleles between the two species,as well as an unexpectedly high genetic diversity of the endangered E.jankowskii.We speculate that introgressive hybridization has occurred between the two species and contributed to the additional unexpected variation to E.jankowskii.We used mitochondrial NADH dehydrogenase subunit 2(ND2)gene and 15 nuclear microsatellite markers to compare the genetic diversity of E.jankowskii and E.cioides,and inferred the origin of trans-species polymorphisms between the two species by phylogenetic reconstruction and Bayesian cluster analysis.The two species could be clearly distinguished by population cluster analysis.Despite the large number of mutational differences,we still detected sharing of major haplotypes and the presence of hybrids between the two species.Our study confirmed that weak introgressive hybridization has occurred between sympatric E.jankowskii and E.cioides,which may be mediated by female E.cioides individuals,and that interspecific introgression has contributed to the maintenance of high genetic diversity in E.jankowskii.While being wary of the potential negative effects of introgressive hybridization,we suggest that expanding the habitat of E.jankowskii remains the most effective conservation strategy at present.

Identification of sympatric bat species by the echolocation calls

One hundred and thirty-eight echolocation calls of 63 free-flying individuals of five bat species(Rhinolophus ferrumequinum,Myotis formosus,Myotis ikonnikovi,Myotis daubentoni and Murina leucogaster)were recorded(by ultrasonic bat detector(D980))in Zhi’an village of Jilin Province,China.According to the frequency-time spectra,these calls were categorized into two types:FM/CF(constant frequency)/FM(R.ferrumequinum)and FM(frequency modulated)(M.formosus,M.ikonnikovi,M.daubentoni and M.leucogaster).Sonograms of the calls of R.ferrumequinum could easily be distinguished from those of the other four species.For the calls of the remaining four species,six echolocation call parameters,including starting frequency,ending frequency,peak frequency duration,longest inter-pulse interval and shortest inter-pulse interval,were examined by stepwise discriminant analysis.The results show that 84.1%of calls were correctly classified,which indicates that these parameters of echolocation calls play an important role in identifying bat species.These parameters can be used to test the accuracy of general predictions based on bats’morphology in the same forest and can provide essential information for assessing patterns of bat habitat use.