Browsing by Author "Weissmann, Julie A."
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- Bees of the Azores : an annotated checklist (Apidae, Hymenoptera)Publication . Weissmann, Julie A.; Picanço, Ana; Borges, Paulo A. V.; Schaefer, HannoWe report 18 species of wild bees plus the domesticated honeybee from the Azores, which adds nine species to earlier lists. One species, Hylaeus azorae, seems to be a single island endemic, and three species are possibly native (Colletes eous, Halictus villosulus, and Hylaeus pictipes). All the remaining bee species are most likely accidental introductions that arrived after human colonization of the archipelago in the 15th century. Bee diversity in the Azores is similar to bee diversity of Madeira and Cape Verde but nearly ten times lower than it is in the Canary Islands.
- Honeybees (Apis mellifera) collect latex of Azores bellflowers (Azorina vidalii, Campanulaceae)Publication . Weissmann, Julie A.; Schaefer, HannoThe Azores bellflower (Azorina vidalii (H.C.Wats.) Feer, synonym: Campanula vidalii H.C.Wats.) is a small shrub in the bellflower family, Campanulaceae, which is endemic to the Azores archipelago. Its habitats are coastal rocks and cliffs, often with elevated nitrogen levels (sewage water, rubbish) and close to settlements. Azorina is found on all nine islands of the Azores archipelago but is most common on the western islands of Flores and Corvo (Schaefer 2003). The pollination biology of Azorina is still a bit of a mystery: while flower morphology would fit best to bird pollination, birds have never been observed visiting its flowers and today’s avifauna of the archipelago does not include any obvious candidate species. The first author therefore performed an extensive field study in the summer of 2015, mainly on Corvo but also on Flores and Pico islands, in order to identify the pollinators of this enigmatic endemic. […].
- The importance of generalist pollinator complexes for endangered island endemic plantsPublication . Weissmann, Julie A.; Schaefer, HannoTo investigate whether endangered endemic plants of the Azores are threatened by pollinator limitation, we studied the insect pollinator communities of Azorina vidalii, Euphrasia azorica, Myosotis azorica and Solidago azorica on Corvo Island. We found no evidence for dependence on a specialised pollinator. Instead, we found five to 21 mostly generalist insect pollinators per plant species, six of them probably introduced species. Diptera, with at least 12 species, and Hymenoptera, with at least nine species, are the most important insect orders and also most important in visitation frequency. The relatively high pollinator diversity for each of the studied plants and the high proportion of generalists indicate that the pollination networks of the four study plant species are rather resilient, i.e. the loss of a species would not constitute an immediate threat. Seed counts and numbers of juvenile plants indicate that reproductive success of all four species is stable. Altogether, our results suggest that there is no pollinator limitation in the four study species. Conservation measures should therefore focus on other threats, on Corvo mainly on grazing pressure.