First description of the helminth community in the Whiskered Tern Chlidonias hybrida (Lariforma: Sternidae) in France

First description of the helminth community in the Whiskered Tern Chlidonias hybrida (Lariforma: Sternidae) in France.- The degree of knowledge of the helminth community associated with bird members of the Sternidae family is largely limited and totally absent in some bird species such as the Whiskered Tern Chlidonias hybrida. In the present study, the helminth community is described in this species for the first time from dead chicks collected in France (Lake Grand-Lieu). An analysis of the parasite load in relation to chick age and mortality causes was also performed. The helminth community was composed of five families of which Strigeidae were the most frequent (prevalence: 91.7 %) and abundant (mean intensity: 45.6 ± 10.1 parasites per infested chick). This is the first record of Strigeidae in the Whiskered Tern and also of Capillaridae and Plagiorchiidae in Sternidae. Whatever the chick age, the intensity of parasites in chicks dead from accidental causes (6-12 parasites per chick) was lower than that found in birds (mainly in older chicks, i.e. > 10 days old) whose mortality causes stayed unknown (78 ± 30 parasites per chick, and up to 107 parasites in one chick). Based on these results, we suggest that parasitism is a factor that might affect significantly survival of Whiskered Tern chicks

Using eDNA to detect the distribution and density of invasive crayfish in the Honghe-Hani rice terrace World Heritage site

The Honghe-Hani landscape in China is a UNESCO World Natural Heritage site due to the beauty of its thousands of rice terraces, but these structures are in danger from the invasive crayfish Procambarus clarkii. Crayfish dig nest holes, which collapse terrace walls and destroy rice production. Under the current control strategy, farmers self-report crayfish and are issued pesticide, but this strategy is not expected to eradicate the crayfish nor to prevent their spread since farmers are not able to detect small numbers of crayfish. Thus, we tested whether environmental DNA (eDNA) from paddy-water samples could provide a sensitive detection method. In an aquarium experiment, Real-time Quantitative polymerase chain reaction (qPCR) successfully detected crayfish, even at a simulated density of one crayfish per average-sized paddy (with one false negative). In a field test, we tested eDNA and bottle traps against direct counts of crayfish. eDNA successfully detected crayfish in all 25 paddies where crayfish were observed and in none of the 7 paddies where crayfish were absent. Bottle-trapping was successful in only 68% of the crayfish-present paddies. eDNA concentrations also correlated positively with crayfish counts. In sum, these results suggest that single samples of eDNA are able to detect small crayfish populations, but not perfectly. Thus, we conclude that a program of repeated eDNA sampling is now feasible and likely reliable for measuring crayfish geographic range and for detecting new invasion fronts in the Honghe Hani landscape, which would inform regional control efforts and help to prevent the further spread of this invasive crayfish

Transcription factories in the context of the nuclear and genome organization

In the eukaryotic nucleus, genes are transcribed in transcription factories. In the present review, we re-evaluate the models of transcription factories in the light of recent and older data. Based on this analysis, we propose that transcription factories result from the aggregation of RNA polymerase II-containing pre-initiation complexes assembled next to each other in the nuclear space. Such an aggregation can be triggered by the phosphorylation of the C-terminal domain of RNA polymerase II molecules and their interaction with various transcription factors. Individual transcription factories would thus incorporate tissue-specific, co-regulated as well as housekeeping genes based only on their initial proximity to each other in the nuclear space. Targeting genes to be transcribed to protein-dense factories that contain all factors necessary for transcription initiation and elongation through chromatin templates clearly favors a more economical utilization and better recycling of the transcription machinery

An Unexpected Case of Heterospecific Altruistic Behaviour in a Non-Breeding Migrant Tern (Charadriformes, Sternidae)

Abstract Observations of birds feeding chicks or fledglings of a different species have already been reported in many publications. However, the benefits of the altruistic behaviour are not easy to understand, as benefits and costs of this behaviour have been poorly identified. In May 2013, in a wetland in Central Italy (Piana Fiorentina, Tuscany), some cases of interspecific feeding of an Eurasian Coot Fulica atra chick by an adult non breeding Whiskered Tern Chlidonias hybrida were witnessed. We suggest that the behaviour of the Tern was triggered by the begging of the chick or by its own hormonal status