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KNUDSEN, J. T. & TOLLSTEN, L., Trends in floral scent chemistry in pollination syndromes: floral scent composition in moth‐pollinated taxa. Floral scent from 15 moth‐pollinated species in nine families was collected by head‐space adsorption. The chemical composition was determined by coupled gas chromatography‐mass spectrometry (GC‐MS). The typical floral scent of moth‐pollinated flowers contains some acyclic terpene alcohols, their corresponding hydrocarbons, benzenoid alcohols and esters and small amounts of some nitrogen compounds. The floral scent composition of sphingophilous flowers can be distinguished from that of phalaenophilous flowers by the presence of oxygenated sesquiterpenes. The flowers of three of the studied species had the general appearance and floral scent composition of moth‐pollinated flowers, but contained no nectar reward. These species probably rely on deceptive pollination by naive visitors, which are deceived by the similarity of the flowers' morphological and scent chemistry to that of rewarding moth flowers. The finding of similar or structurally closely related floral scent compounds in both temperate and tropical species from both the Old and New worlds suggests that floral scent composition has been selected by a specific group of pollinators, moths that have similar sensory preferences. The functions of floral scent in moth‐pollinated flowers are discussed in relation to an often observed over‐representation of male moth visitors.

Foraging range, an important component of bee ecology, is of considerable interest for insect-pollinated plants because it determines the potential for outcrossing among individuals. However, long-distance pollen flow is difficult to assess, especially when the plant also relies on self-pollination. Pollen movement can be estimated indirectly through population genetic data, but complementary data on pollinator flight distances is necessary to validate such estimates. By using radio-tracking of cowpea pollinator return flights, we found that carpenter bees visiting cowpea flowers can forage up to 6 km from their nest. Foraging distances were found to be shorter than the maximum flight range, especially under adverse weather conditions or poor reward levels. From complete flight records in which bees visited wild and domesticated populations, we conclude that bees can mediate gene flow and, in some instances, allow transgene (genetically engineered material) escape over several kilometers. However, most between-flower flights occur within plant patches, while very few occur between plant patches. cowpea ͉ radio-tracking ͉ Vigna unguiculata ͉ Xylocopa flavorufa B oth solitary and social bees provision their broods by centralplace foraging from their nest. Nesting females return several times to the nest during a given day after foraging bouts. Therefore, the investigation of bee flights is essential to understand their ecology and mobility. Foraging success is determined by habitat size and the amount and variety of forage that a bee utilizes. As the flight range of bees will determine the minimum resource density that can sustain a nest, knowledge of flight range is important for designing strategies for bee conservation when their plant resources are threatened or fragmented (1, 2). Likewise, knowledge of bee flight range is important for beepollinated plants, because flight range governs the distance over which pollen can be transported. Additionally, precise measurement of pollinator flight range has recently become imperative because of concern over the spread of engineered genes through pollen-mediated gene flow from genetically modified crops into conventional agriculture and wild relatives (3).In insect-pollinated plants, pollen movement, rather than movement of seeds,

Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta-analysis to characterize patterns of covariation in CCDs and identified functional or biosynthetically constrained modules. Poorly integrated plant CCDs (i.e. low covariation between scent compounds) support the notion that plants often utilize one or few key compounds to repel antagonists or to attract pollinators and enemies of herbivores. Animal CCDs (mostly insect pheromones) were usually more integrated than those of plants (i.e. stronger covariation), suggesting that animals communicate via fixed proportions among compounds. Both plant and animal CCDs were composed of modules, which are groups of strongly covarying compounds. Biosynthetic similarity of compounds revealed biosynthetic constraints in the covariation patterns of plant CCDs. We provide a novel perspective on chemical communication and a basis for future investigations on structural properties of CCDs. This will facilitate identifying modules and biosynthetic constraints that may affect the outcome of selection and thus provide a predictive framework for evolutionary trajectories of CCDs in plants and animals.