The role of volatile organic compounds, morphology and pigments of globeflowers in the attraction of their specific pollinating flies.

• Floral scents and visual cues of the globeflower Trollius europaeus may play a key role in the attraction of Chiastocheta flies, involved in a highly specific nursery pollination mutualism. • Here, headspace collection and GC-MS were used to identify and quantify the volatile organic compounds emitted by the globeflower. • Scents are produced in three different floral parts by four structures: secretory glands and flat epidermis cells in the abaxial sepal epidermis, conical cells in the adaxial sepal epidermis, and pollen.

How sympatric is speciation in the Howea palms of Lord Howe Island?

The two species of the palm genus Howea (Arecaceae) from Lord Howe Island, a minute volcanic island in the Tasman Sea, are now regarded as one of the most compelling examples of sympatric speciation, although this view is still disputed by some authors. Population genetic and ecological data are necessary to provide a more coherent and comprehensive understanding of this emerging model system. Here, we analyse data on abundance, juvenile recruitment, pollination mode and genetic variation and structure in both species.

A comparative analysis of pollinator type and pollen ornamentation in the Araceae and the Arecaceae, two unrelated families of the monocots.

Background: The high diversity of ornamentation type in pollen grains of angiosperms has often been suggested to be linked to diversity in pollination systems. It is commonly stated that smooth pollen grains are associated with wind or water pollination while sculptured pollen grains are associated with biotic pollination. We tested the statistical significance of an association between pollen ornamentation and pollination system in two families of the monocotyledons, the Araceae and the Arecaceae, taking into account the phylogenetic framework.

Sympatric speciation in palms on an oceanic island.

The origin of species diversity has challenged biologists for over two centuries. Allopatric speciation, the divergence of species resulting from geographical isolation, is well documented. However, sympatric speciation, divergence without geographical isolation, is highly controversial.

Localization of production and emission of pollinator attractant on whole leaves of Chamaerops humilis (Arecaceae).

Volatile compounds, which frequently play important roles in plant-insect interaction, can be produced either by flowers to attract pollinators or by leaves to deter herbivores. The specialized structures associated with odor production differ in these two organs. The European dwarf palm Chamaerops humilis represents a unique intermediate between these two.

Temporal and sexual variation of leaf-produced pollinator-attracting odours in the dwarf palm.

Information on intra-specific variation in pollinator-attracting floral traits provides clues to selective pressures imposed by pollinators. However, these traits also reflect constraints related to floral phenology or morphology. The specific weevil pollinator Derelomus chamaeropsis of the dioecious Mediterranean dwarf palm Chamaerops humilis is attracted by volatile compounds that leaves, and not flowers, release during anthesis.

Olfactive detection of fig wasps as prey by the ant Crematogaster scutellaris (Formicidae; Myrmicinae).

In the species-specific and obligate mutualism between the fig (Ficus carica) and its pollinator (the fig wasps Blastophaga psenes), a third participant, the ant Crematogaster scutellaris, is a predator of the wasps. Here, we ask how ant workers can rapidly localise such prey, whose availability is limited in time and space. Using a Y-tube olfactometer, we tested ant response to odours emitted by different types of figs (receptive female, ripe female or male figs) and by fig wasps (pollinators or non-pollinators).

A weevil pollinating the Canary Islands date palm: between parasitism and mutualism.

Palm pollination systems are highly diverse, including by wind and by several different groups of insects. Many palm species are associated with more or less specific pollinating weevils that are also floral herbivores. For many such palms, the importance of these "palm flower weevils" as pollinators has not been examined.

Emerging Issues in Population Viability Analysis.

Population viability analysis ( PVA) has become a commonly used tool in endangered species management. There is no single process that constitutes PVA, but all approaches have in common an assessment of a population's risk of extinction (or quasi extinction) or its projected population growth either under current conditions or expected from proposed management. As model sophistication increases, and software programs that facilitate PVA without the need for modeling expertise become more available, there is greater potential for the misuse of models and increased confusion over interpreting their results.

Variation in the effectiveness of biotic defence: the case of an opportunistic ant-plant protection mutualism.

Benefits to plants in facultative ant protection mutualisms are highly variable. This allows examination of the sources of this variation and the mechanisms by which ants protect plants. We studied opportunistic interactions between ants and an extrafloral nectary-bearing vine, Dioscorea praehensilis, during 3 different years.

Benefits conferred by "timid" ants: active anti-herbivore protection of the rainforest tree Leonardoxa africana by the minute ant Petalomyrmex phylax.

In this study, we demonstrate that an important benefit provided by the small host-specific ant Petalomyrmex phylax to its host plant Leonardoxa africana is efficient protection against herbivores. We estimate that in the absence of ants, insect herbivory would reduce the leaf area by about one-third. This contributes considerably to the fitness of the plant.

Critical population size for fig/wasp mutualism in a seasonal environment: effect and evolution of the duration of female receptivity.

Fig trees and their pollinating wasps form ca. 750 pairs of obligate mutualists, mainly in the tropics. Survival of each partner depends on that of its associated species.