The Annonaceae show a broader flower biological radiation than originally thought, with flowers being pollinated not only by beetles, but also by thrips, flies and even bees. The majority of species have hermaphroditic protogynous flowers. Species with white or yellowish‐white, small, delicate, day‐active flowers, may be pollinated either solely by thrips, or by thrips and small beetles (e.g., species of Bocageopsis, Oxandra, Xylopia). Several of these thrips‐pollinated species have stamens with an elongated, tongue‐like connective. Pollination by flies is not well documented for American species, notwithstanding it appears to be more common in Old World species, e.g., in the genus Pseuduvaria. The mitriform flowers exhale an unpleasant smell, produce nectar in purple‐colored petal glands and have a sapromyiophilous syndrome. Flies enter the flower center through large openings between the inner petals. Beetle‐pollinated Annonaceae have flowers with comparatively thick and, often, fleshy petals, which, during anthesis frequently form a pollination chamber with the petals inclining over the flower center. The stamens usually have peltate connective shields, probably a device for protection against voracious beetles. Some cantharophilous species have flowers which are day‐active while others are night‐active. When they are in their pistillate phase, the beetles are attracted by characteristic odor components. They enter the pollination chamber and usually remain in the interior of the flower until the flower has changed to its staminate phase, when pollen is shed and afterwards petals and stamens detach. Two lines of cantharophilous Annonaceae are recognizable on the basis of present knowledge. Species with smaller and more delicate flowers are pollinated by small beetles (Nitidulidae, Curculionidae, Chrysomelidae and Staphylinidae), whereas species with large, more robust flowers in the Neotropics are pollinated by large beetles of the family Scarabaeidae, subfamily Dynastinae. Some species of the cantharophilous Annonaceae, especially the large‐flowered ones, but also some species with smaller flowers, produce heat during anthesis (thermogenesis). Food bodies, developed on the adaxial surfaces or sides of the petals, provide unique nourishment possibilities for beetles when they stay inside the flowers during the pistillate phase. In the staminate stage of the flower, after pollen is shed, beetles also feed on pollen. Apparently, no dynastid‐flower relationship has evolved in Asia and Australia. Pollination by bees was discovered recently in Unonopsis guatterioides in Amazonia and Uvaria concava in North Queensland: the first by scent‐collecting euglossine males and the second by pollen‐collecting Meliponinae. The general trends in morphological/functional floral characteristics in the family are discussed in a presumptive phylogenetic context.

RESUMO -O presente estudo compara a biologia floral e polinização de espécies de palmeiras e anonáceas que apresentam termogênese. Nos arredores de Manaus (AM) foram estudadas onze espécies de palmeiras pertencentes aos gêneros Astrocaryum, Attalea, Bactris e Oenocarpus e nove espécies de anonáceas dos gêneros Anaxagorea, Duguetia e Xylopia. As palmeiras que apresentam termogênese são monóicas e a antese das inflorescências ocorre em períodos que variam de dois dias até cinco semanas, sempre no período noturno. As flores das espécies de anonáceas são protogínicas com a antese ocorrendo entre dois dias, podendo ser diurna ou noturna. Nos representantes das duas famílias os insetos visitantes são atraídos pelo odor emitido pelas flores que é intensificado através da termogênese. Os odores podem ser agradáveis semelhante ao de frutos maduros ou desagradáveis e pungentes. Os insetos visitantes em sua maioria são coleópteros das famílias Scarabaeidae, Nitidulidae, Staphylinidae, Curculionidae e Chrysomelidae, trips e moscas Drosophilidae. Além desses, as flores das palmeiras são visitadas por abelhas, vespas, formigas e moscas. Na área estudada, a polinização por coleópteros foi o modo mais freqüente das espécies de palmeiras e anonáceas com termogênese. É notável que algumas espécies das duas famílias são visitadas pelas mesmas famílias, e inclusive espécies de coleópteros. Supõe-se que adaptações morfológicas e fisiológicas similares na biologia floral das duas famílias, inclusive dos componentes odoríferos sejam responsáveis por essa atração. Palavras-chave:Arecaceae, Annonaceae, biologia floral, polinização, coleópteros, termogênese. Pollination and its Relationship to Thermogenesis in Species of Arecaceae and Annonaceae ofABSTRACT -The present study is a comparison of the flower biology and pollination of some thermogenic species of palms and Annonaceae. In the palms eleven representatives of the genera Astrocaryum, Attalea, Bactris, and Oenocarpus, and in the Annonaceae nine Manaus (AM). All the studied palm species are monoecious and the anthesis of their ants, and other fly groups. However, palms and Annonaceae with thermogenic flowers most frequently showed beetle pollination. It is notable that flowers of some species of both families were visited by the same families and even species of beetles, which might be due to similar morphological and

Many plants attract their pollinators with floral scents, and these olfactory signals are especially important at night, when visual signals become inefficient. Dynastid scarab beetles are a speciose group of night-active pollinators, and several plants pollinated by these insects have methoxylated aromatic compounds in their scents. However, there is a large gap in our knowledge regarding the compounds responsible for beetle attraction. We used chemical analytical analyses to determine temporal patterns of scent emission and the composition of scent released from inflorescences of Philodendron selloum. The attractiveness of the main components in the scent to the dynastid scarab beetle Erioscelis emarginata, the exclusive pollinator of this plant, was assessed in field biotests. The amount of scent increased rapidly in the evening, and large amounts of scent were released during the activity time of the beetle pollinators. Inflorescences emitted a high number of compounds of different biosynthetic origin, among them both uncommon and also widespread flower scents. Methoxylated aromatic compounds dominated the scent, and 4-methoxystyrene, the most abundant compound, attracted E. emarginata beetles. Other compounds, such as (Z)-jasmone and possibly also the methoxylated aromatic compound 3,4-dimethoxystyrene increased the attractiveness of 4-methoxystyrene. Methoxylated aromatics, which are known from other dynastid pollinated plants as well, are important signals in many scarab beetles in a different context (e.g., pheromones), thus suggesting that these plants exploit pre-existing preferences of the beetles for attracting this group of insects as pollinators.

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