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  • Author: Piotr Tryjanowski x
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Abstract

Age of male is an important cue in mate selection, including extra-pair copulations; different phenotypic and behavioural traits are known to be age related. Paternity studies show that older males predominate as fathers of extra-pair young. It remains unclear if females actively choose older males because they possess high quality traits or because older males are more successful in coercing fertile females. We experimentally provided mounted males of different age (yearling vs. adult) of great grey shrike Lanius excubitor with nuptial gifts of different quality (vole vs. cricket) and observed reactions of females and their social partners. Females strongly preferred older males with energy-rich nuptial gifts. The reactions of females’ social partner to the extra-pair male did not differ significantly amongst experimental groups. However, males responded to the reaction of their mates and male aggressive behaviour increased when their mate showed an interest in an intruder.

Abstract

Antagonistic interactions between insects and amphibians are the subject of many scientific articles, mostly concerning amphibian predation on insect, but many fewer examples exist of the opposite situation. In this article we review available information from the literature and add our own observations collected during amphibian pitfall trap monitoring in 2012–2016 in Western Poland, as well as discuss potential conservation implications of observed behavior. We identified a total of 29 cases involving 94 individual ants attacking four species of Anura, Rana temporaria, Pelophylax esculentus complex, Bufo bufo, and Pelobates fuscus, and biting their back, cloaca, armpits, or hind legs. Bites were inflicted by three ant species: Myrmica rubra, Lasius fuliginosus, and Formica polyctena. The number of ants found on an amphibian was positively and significantly correlated with its body length. To date, direct damage by ants on amphibians was reported mainly from the tropics in general predation accident. However, as we document here, it is probably a more common phenomenon, especially in some ecological traps or during pitfall trapping, which is a common method to mitigate road mortality of frogs and toads.

Abstract

The red mason bee Osmia bicornis L. (Hymenoptera: Megachilidae) is a solitary gregarious species that is known to be a good pollinator of pear, apple, and several other Rosaceae fruit plants. Mainly females are active in plant pollination, and therefore they are of strong interest to farmers. As natural populations are usually male biased, here we studied the possibility of rearing a female-biased population of Osmia bicornis by examining the effects of sex ratio changes on female survival, insemination rate, and sperm count in the spermatheca. Using bees that had completed their winter diapause and were maintained in flying cages, we created three groups with different male:female sex ratios: 1:1, 1:2, and 1:3. The 1:3 sex-ratio group exhibited the best survival of females, but the lowest spermathecae sperm count. The insemination rate did not differ between groups. Our results indicate that-at least among bees housed in isolator cages for plant breeding- skewing the sex ratio towards more females does not affect bee survival, and efficient insemination can be expected with twice as many females as males.

Abstract

Bee-eaters (Meropidae) are considered agricultural pests and their presence provokes conflicts with beekeepers and farmers who rely on the pollination services of honey bees. This problem is often deal with through the mass killing of the birds, even though the quantitative evidence on the impact of bee-eaters on honey bee colonies is scarce. The current paper reports the performance of honey bee colonies protected with mist nets from migrating flocks of European bee-eaters Merops apiaster in Israel. In the study the weight gains of bee hives surrounded by mist nets were 6.44 times higher than that of unprotected hives (26.4 kg vs. 4.1 kg). The results confirmed that bee-eaters locally pose a problem to apiaries and potentially to the crops that require pollination. Mist- netting appeared to be an effective mitigation method for alleviating conflicts between beekeepers and bee-eaters. However, the study also showed that bees were able to differentiate between their main predator and other avian species trapped in mist nets and stung only bee-eaters. Moreover, the bees were targeting the most vulnerable body parts of birds which resulted in some bird fatalities. Therefore, due to accidental mortal- ity of birds, mist-netting is recommended only on the migratory routes in cases when bee hives cannot be moved to other areas.

Abstract

Farmland landscapes are recognized as important ecosystems, not only for their rich biodiversity but equally so for the human beings who live and work in these places. However, biodiversity varies among sites (spatial change) and among seasons (temporal change). In this work, we tested the hypothesis that bird diversity hotspots distribution for breeding is congruent with bird diversity hotspots for wintering season, focusing also the representation of protected areas for the conservation of local hotspots. We proposed a framework based on the use of species richness, functional diversity, and evolutionary distinctiveness to characterize avian communities.

Although our findings show that the spatial distribution of local bird hotspots differed slightly between seasons, the protected areas’ representation was similar in both seasons. Protected areas covered 65% of the most important zones for breeding and 71% for the wintering season in the farmland studied. Functional diversity showed similar patterns as did bird species richness, but this measure can be most effective for highlighting differences on bird community composition. Evolutionary distinctiveness was less congruent with species richness and functional diversity, among seasons.

Our findings suggest that inter-seasonal spatial congruence of local hotspots can be considered as suitable areas upon which to concentrate greater conservation efforts. However, even considering the relative congruence of avian diversity metrics at a local spatial scale, simultaneous analysis of protected areas while inter-seasonally considering hotspots, can provide a more complete representation of ecosystems for assessing the conservation status and designating priority areas.

Abstract

To study the seasonal changes in avian communities, we collected data in an extensively used farmland in Western Poland during 2006-2013. Generalized additive mixed models were used in order to study the effects of seasonality and protected areas on the overall bird species richness. A similarity percentage analysis was also conducted in order to identify the species that contribute most strongly to dissimilarity among each bird according to the phenological season. Furthermore, the differences in bird communities were investigated applying the decomposition of the species richness in season, trend, and remainder components. Each season showed significant differences in bird species richness (seasonality effect). The effect of the protected areas was slightly positive on the overall species richness for all seasons. However, an overall negative trend was detected for the entire period of eight years. The bird community composition was different among seasons, showing differences in terms of dominant species. Greater differences were found between breeding and wintering seasons, in particular, the spatial pattern of sites with higher bird richness (hotspots) were different between breeding and wintering seasons. Our findings showed a negative trend in bird species richness verified in the Polish farmlands from 2006. This result mirrors the same negative trend already highlighted for Western Europe. The role of protected areas, even if slightly positive, was not enough to mitigate this decline process. Therefore, to effectively protect farmland birds, it is necessary to also consider inter-seasons variation, and for this, we suggest the use of medium-term temporal studies on bird communities’ trends.