Evolution of insect-mediated pollination indicated by Palaeogene flowers and insects from Central Europe
Zusammenfassung der Projektergebnisse
Interactions among species are one of the most important drivers of the ecology and evolution of species. Given the fact that insect pollination is the dominant method of reproduction of flowering plants, which themselves comprise the bulk of the Paleogene and modern flora, the role of insects in shaping major ecosystems cannot be underestimated. In this project, we combined for the first time quantitative studies of Paleogene antagonistic and mutualistic associations between insects and their consumed/visited flowers from temperate ecosystems (mainly represented by Messel lake and Eckfeld lake). Data from this study support three major conclusions. These conclusions warrant further verification from investigations of additional insect and plant clades to further document patterns of specific mutualistic relationships particularly for Northern Hemisphere ecosystems, shortly after the intensification of greenhouse conditions at the Early Eocene Climatic Optimum (EECO), where major biogeographic and taxic transformation of the biota ensued, such as major latitudinal shifts of floras, penecontemporaneous diversification social insect clades that persist to the present day. 1. Migrations of European honey bee lineages into Africa, Asia, and North America. After examining the morphological disparity and affinities of the full living and fossil diversity of honey bees ranging from their earliest origins to the present day, the analysis indicates that honey bees exhibited a greater morphological disparity during the Oligocene and Miocene epochs, a time when the principal lineages were established, and that Apis apparently originated in Europe, spreading from there into Asia, Africa, and North America, with subsequent diversification in the former two regions and extinction in the latter. During the human migrations and colonization honey bees were once again introduced multiple times into the Americas, as well as into Australia and Asia. 2. Bee systematics, morphology and morphometry. In bee systematics, morphology and morphometry of the wing usefully discriminate taxon at different levels: specimens, populations, subspecies, species, and tribes. Until now, variation in bee wing nervation is still considered as neutral character that is not under strong adaptative pressure. The specimen from the Randeck geometric morphometric analysis along with a diversity of other bumble bee species representing most major extant lineages, and particularly the subgenus Bombus s.s. The morphometric analysis supports the placement of the Randeck Maar species within Bombus s.s., as a species distinct from all others in the subgenus. It shows that extant subgenera of bumblebees were already derived in the early/middle Miocene. 3. Patterns of insect pollination and angiosperm radiation and angiosperm success. Pollinators play an important functional role in most terrestrial ecosystems and particularly bees, are the primary pollinators of most wild plants. In terms of the range of specialization or generalization in pollinators behavior during the Paleogene period the microscopical analysis of female pollen loads revealed that Messel bee specimens harvesting pollen from up to 4 plant families, and Eckfeld specimens from up to 16 families. Among the polylectic members of the Electrapini, several intriguing patterns of host plant use were found, suggesting that host plant choice of these bees is constrained to different degrees of flower morphology, pollen and nectar availability. Thus, our data indicate that polylecty appears to be the ancestral state.
Projektbezogene Publikationen (Auswahl)
- 2011. Apis armbrusteri Zeuner, 1931 (Insecta, Hymenoptera): proposed conservation by designation of a neotype. Bull Zool Nomencl 68, 117-121
Engel, M.S., Kotthoff, U., Wappler, T.
- 2011. Miocene honey bees from the Randeck Maar of southwestern Germany (Hymenoptera, Apidae). ZooKeys 96, 11-37
Kotthoff, U., Wappler, T., Engel, M.S.
- 2012. Geometric morphometric analysis of a new Miocene bumble bee from the Randeck Maar of southwestern Germany (Hymenoptera: Apidae). Syst Entomol 37, 784-792
Wappler, T., De Meulemeester, T., Murat Aytekin, A., Michez, D., Engel, M.S.
(Siehe online unter https://doi.org/10.1111/j.1365-3113.2012.00642.x) - 2013. Greater past disparity and diversity hints at ancient migrations of European honey bee lineages into Africa and Asia. J Biogeogr 40, 1832-1838
Kotthoff, U., Wappler, T., Engel, M.S.
(Siehe online unter https://doi.org/10.1111/jbi.12151)
