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Flower infestation by pathogens may influence pollination effectiveness. At the same time, by sharing infested flowers, pollinators increase transmission of pathogens. In the presented study we identified fungi that colonised flowers of the invasive alien Himalayan balsam Impatiens glandulifera, one of the most nectar rewarding plants in Europe, as well as its pollinators. We determined factors (e.g., plant size, length of flower lower sepal and the width of its entry, air temperature and sun illuminance) that affect pathogen species presence and pollinators numbers. The study was conducted in three regions in Poland differing in time from the I. glandulifera invasion onset. It allowed embedding our results in the context of the evolution of increased competitive ability (EICA) hypothesis. With reference to this hypothesis we tested whether I. glandulifera from the two younger populations are more frequently pollinated than individuals from the old one, which may be a result of the higher infection prevalence in the flowers of individuals from the latter population. Harmful primary pathogens of I. glandulifera (e.g., Botrytis cinerea and Fusarium graminearum) were identified from its flowers. Although the knowledge of the impact of the recorded pathogen species on the pollinators that transmit them is still limited, these pathogens are known to cause devastating diseases of native plant species and to incur significant economic losses in crops. Therefore, the facilitation of their transmission by I. glandulifera in the invaded communities may pose a serious threat both to native biodiversity and nearby crop production. We did not find support for the EICA hypothesis that flower release from pathogens may increase the pollinator’s activity. Bombus hortorum was the most frequent visitor in the youngest surveyed population, while B. pascuorum was most frequent in the two others. So far the dominance of B. hortorum as a pollinator of I. glandulifera has not been recorded. A possible explanation is that flowers in the youngest population, with significantly wider entries than in the two older ones, were more accessible for this large bumblebee. We suggest that the shifts in flower dimensions may result from the evolutionary processes and/or phenotypic plasticity; however, this suggestion needs to be confirmed in further studies. At the same time, it can be expected that exceptionally frequent visits of B. hortorum in flowers of I. glandulifera in the youngest population may contribute to increasing transmission rate of pathogen species to the new native host plants that are particularly associated with this pollinator.

The fungal grass endophyte Epichloë typhina (Pers.) Tul. & C. Tul. (Ascomycota: Clavicipitaceae) grows intercellulary in aerial plant parts and reproduces asexually by invading host seeds. In this phase, it enhances seed production and germination, which accelerates its vertical spread. This relationship may be distorted by other seed-born fungi, whose spread is not so directly dependent on the success of the grass. Recently, the fungus Clonostachys epichloë Schroers has been observed on Puccinellia distans (Jacq.) Parl seeds originating from grass clumps infested with stromata, sexual structures of Epichloë typhina that are formed in spring on some host culms, preventing flower and seed development (‘choke disease’). C. epichloë shows mycoparasitic activity toward Epichloë stromata by reducing the production of ascospores, which are responsible for horizontal transmission of the fungus. The aim of this study was to investigate the effect of seed-borne C. epichloë on seed germination, as well as the size and weight of P. distans seedlings and to examine whether C. epichloë alters the influence of Epichloë in the early developmental stages of P. distans. The results showed that if C. epichloë acts on seeds together with E. typhina endophytes, the seeds were negatively affected due to the elimination of the positive effect of the latter in terms of both seed germination rate and seedling length. At the same time, C. epichloë increased the proportion of E. typhina-untreated germinated seeds. Additionally, only the joint action of the two fungi, E. typhina and C. epichloë, effectively stimulated seedling dry mass; the presence of E. typhina alone was not sufficient to noticeably affect seedling size. Based on the increasing commonality of C. epichloë on Epichloë stromata, as well as its potential to be used in biocontrol of ‘choke disease’, we should take a closer look at this fungus, not only in terms of its mycoparasitic ability, but also in terms of its cumulative impact on the whole Epichloë-grass system.

Abstract Vocal communication of woodpeckers has been relatively little studied so far, mostly because majority of species use drumming to communicate. Our recent study on the Middle Spotted Woodpecker revealed that a call which is specific for floaters is individually distinctive and functions as a vocal signature of unpaired individuals. The aim of the current study is to investigate whether a contact call of paired territory owners of the same species enables discrimination of individuals and their sex. Acoustic analyses revealed that the call is individually distinctive and experimental approach confirmed that woodpeckers are able to distinguish between a contact call of their partner and a stranger. We also found that the contact call shows significant sex differences. Interestingly, the acoustic parameter enabling sex identification is different than the parameters coding individual variability of the call. The design of a call so that its first part would code the identity of an individual and the second part would code its sex presents an effective and fine-tuned communication system. The results of our study also suggest that the contact call of paired Middle Spotted Woodpeckers may be useful for conservation biologists as a tool supporting other census methods.

Presently, there is an intensive search for fungal endophytes to be used in agriculture for the protection and condition improvement of plants and in medicine. We screened for the presence of endophytes in raspberry, which occurs naturally in the Białowieża Forest. The fungal isolates representative of each morphotype were analysed using the molecular markers ITS1 and ITS2. In total, we found 34 taxa of endophytic fungi. The majority were potential pathogens. As many as 27 taxa were found in the leaves of mature plants. No fungi could be isolated from the surface sterilized seeds obtained from these plants. Seedlings were grown from the seeds deposited in the soil seed bank in the Białowieża Geobotanical Station of the University of Warsaw in Białowieża. 8 taxa of endophytic fungi were found in seedlings. It could be due to a possibility of seed infection with these endophytes in soil conditions. [ABSTRACT FROM AUTHOR]