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Floral Resources (floral + resource)
Selected AbstractsFloral resources impact longevity and oviposition rate of a parasitoid in the fieldJOURNAL OF ANIMAL ECOLOGY, Issue 3 2008Jana C. Lee Summary 1The use of floral resource subsidies to improve herbivore suppression by parasitoids requires certain trophic interactions and physiological changes to occur. While the longevity and fecundity of parasitoids are positively affected by nectar subsidies in laboratory studies, the impacts of floral subsidies on the fecundity and longevity of freely foraging parasitoids have not been studied. 2We studied the longevity and per capita fecundity of naturally occurring Diadegma insulare foraging in cabbage plots with and without borders of flowering buckwheat, Fagopyrum esculentum, as well as relationships between longevity, fecundity, sugar feeding and parasitism rates on larvae of the diamondback moth, Plutella xylostella. 3Relative longevity was estimated by counting broken setae on the fringe of the forewing. Floral borders increased the longevity of males and females in adjacent cabbage plots. 4The egg maturation rate of D. insulare was estimated by comparing egg loads of females collected early in the day with egg loads of females held without hosts in field cages throughout the day. Females in buckwheat cages matured 2·7 eggs per hour while females in control cages resorbed 0·27 eggs over the same time period. 5The fecundity of females collected in the afternoon was estimated by comparing their actual egg load to the estimated egg load in the absence of oviposition for females in a given plot. Females foraging in buckwheat plots had marginally fewer eggs remaining in their ovaries, and laid marginally more eggs than females in control plots. Females from both treatments carried 30,60 eggs by the afternoon and therefore were time-limited rather than egg-limited. 6Plots where a greater proportion of females had fed on sugar had longer-lived females. This suggests that feeding enhanced longevity of D. insulare. However, plots with longer-lived and more fecund females did not exhibit higher parasitism rates, although the power of these tests were low. [source] Pollination biology of the sclerophyllous shrub Pultenaea villosa Willd. (Fabaceae) in southeast Queensland, AustraliaPLANT SPECIES BIOLOGY, Issue 1 2009JANE E. OGILVIE Abstract The pollination biology of the common shrub Pultenaea villosa Willd. was examined in a subtropical dry sclerophyll forest in eastern Australia. We determined floral phenology and morphology, the timing of stigma receptivity and anther dehiscence, nectar availability, the plant breeding system, and flower visitors. The shrub's flowers are typical zygomorphic pea flowers with hidden floral rewards and reproductive structures. These flowers require special manipulation for insect access. A range of insects visited the flowers, although bees are predicted to be the principle pollinators based on their frequency on the flowers and their exclusive ability to operate the wing and keel petals to access the reproductive structures. Nectar and pollen are offered as rewards and were actively collected by bees. Nectar is offered to visitors in minute amounts at the base of the corolla. In Toohey Forest, P. villosa flowers in spring and is the most abundant floral resource in the understory of the forest at this time. The breeding system experiment revealed that P. villosa requires outcrossing for high levels of seed set and that the overlap of stigma receptivity and pollen dehiscence within the flower suggests the potential for self-incompatibility. [source] Beyond biomass: measuring the effects of community-level nitrogen enrichment on floral traits, pollinator visitation and plant reproductionJOURNAL OF ECOLOGY, Issue 3 2010Laura A. Burkle Summary 1.,Nitrogen (N) limits primary productivity in many systems and can have dramatic effects on plant,herbivore interactions, but its effects on mutualistic interactions at the community level are not well-understood. The reproduction of many plants depends on both soil N and pollination, and N may affect floral traits, such as flower number or size, which are important for pollinator attraction to plant individuals and communities. 2.,Thus, N may influence plant biomass and reproduction directly as well as indirectly via changes in pollination. The degree to which the effects of N enrichment scale from plant individuals to assemblages through emerging community-level changes in species interactions, like pollination, is relatively unknown. 3.,For 4 years, we tested how N addition to subalpine plant assemblages in Colorado, USA, affected primary productivity and species diversity, floral traits and plant,pollinator interactions, and components of female and male plant reproduction. 4.,At the community level, we found that high-N addition favoured the biomass and seed production of grasses, whereas low-N addition promoted forb growth, flower production and pollinator visitation. However, using a pollen supplementation experiment, we found no evidence that N addition altered patterns of pollen limitation of seed production. Pollinators distributed themselves evenly across floral resources such that per-flower visitation rate did not differ among N treatments. Thus, individual plants did not incur any extra benefit or cost from community-level changes in plant,pollinator interactions that resulted from N enrichment, and the effects of N on forb reproduction were direct. 5.,Synthesis. Understanding how mutualistic and antagonistic species interactions influence individual and community responses to abiotic resources may provide insight to the dominant forces structuring communities and is especially important in the context of predicting the effects of environmental change. In this case, the direct effects of N addition on plants were stronger than the indirect effects mediated through plant,pollinator interactions, thus supporting the concept of bottom-up resource limitation controlling plant response. [source] The effects of neighbouring tree islands on pollinator density and diversity, and on pollination of a wet prairie species, Asclepias lanceolata (Apocynaceae)JOURNAL OF ECOLOGY, Issue 3 2006DEREK R. ARTZ Summary 1The Everglades (Florida, USA) is a mosaic of different habitats. Tropical and temperate trees grow on patches of high ground (tree islands) surrounded by lower elevation wetland communities (marl prairie). 2Tree islands of various sizes provide nesting substrate, larval host plants and floral resources for insect pollinators. Herbaceous plants in the open surrounding wetlands may also depend on these pollinators. 3We investigated pollinator diversity and abundances in both tree island and marl prairie habitats using transect sampling methods and estimated pollination success of the milkweed Asclepias lanceolata, an insect-pollinated marl prairie species, in relation to distance from and size of the closest tree island. 4On a total of 11 bayhead tree islands, we found that insect diversity and abundance were greater on the edge of larger tree islands (20,30 m2) than on smaller tree islands (5,10 m2). Pollinator diversity and abundance in the marl prairie decreased with increasing distance from tree islands. 5Pairs of potted A. lanceolata plants were placed in the marl prairie at distances up to 1000 m from small and large tree islands. Fruit and seed production were highest for plants placed less than 25 m from tree islands and decreased with increasing distance. 6Our results suggest that tree islands are an important source of pollinators for the plants in the tree island and surrounding wetland habitats. 7This landscape-based study illustrates how overall landscape structure affects important biotic interactions, particularly plant,pollinator relationships. Our findings have far-reaching ecological implications for the reproductive success of plants in small, isolated populations that may depend on insect vectors for pollination. [source] Comparing different floral resources on the longevity of a parasitic waspAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 1 2008Livy Williams III Abstract 1,The effects of floral resources of several important non-crop host plants of Lygus lineolaris on the longevity of Anaphes iole, one of its natural enemies, was studied. 2,Median longevity of A. iole wasps provisioned with floral resources (Erigeron annuus, Oenothera speciosa, Lamium amplexicaule, and Capsella bursa-pastoris) was in the range 1.27,3.24 days, and did not differ from wasps in the distilled water only control (1.46,2.81 days), but was less than median longevity of wasps provisioned with distilled water + sucrose (5.30,12.46 days). No difference in longevity was observed between gender, although females usually lived slightly longer than males. 3,High-performance anion-exchange chromatography analyses of O. speciosa floral nectar revealed that the major carbohydrate components were sucrose, glucose, and fructose. 4,The results indicate that the floral resources of some non-crop plants that serve as important reproductive hosts for L. lineolaris offer little or no benefit to A. iole. [source] Evaluation of several strategies to increase the residence time of Episyrphus balteatus (Diptera, Syrphidae) releases in sweet pepper greenhousesANNALS OF APPLIED BIOLOGY, Issue 3 2008A. Pineda Abstract We have investigated several factors affecting the augmentation of the aphidophagous syrphid Episyrphus balteatus in Mediterranean sweet pepper greenhouses. First, the effectiveness of releases has been assessed by recording the larva and pupa number. The abundance of E. balteatus varied between greenhouses, which was not observed to be a release effect. Second, two experiments were performed to assess the effect of three biological control management strategies on the release residence time. In the first experiment, the greenhouse ventilation was shown to have a significant influence on the adult population residence time, which was higher when the side walls were closed rather than open. The introduction of additional floral resources (sweet alyssum and coriander) did not have a significant effect on the release residence time. In the second experiment, the age of the released adults was assessed, and 2-day-old adults stayed longer in the greenhouse than 7-day-old adults, but the 7-day-old adults had more time to lay eggs. Although syrphids are effective aphid natural enemies, the release methodology of introducing pupae appears not to be effective in Mediterranean greenhouses. In this paper, we propose changing the methodology of releasing E. balteatus. [source] Impacts of hive honeybees on Tasmanian leatherwood Eucryphia lucida Labill. (Eucryphiaceae)AUSTRAL ECOLOGY, Issue 2 2009STEPHEN A. MALLICK Abstract Despite honeybees (Apis mellifera L.) occurring as a feral and commercially managed species in many parts of Australia, the effects of honeybees on native Australian ecosystems are poorly understood. We examined the impacts of honeybee apiaries on Tasmanian Leatherwood Eucryphia lucida Labill. (Eucryphiaceae) by comparing commercial apiary sites with control sites >2 km from the nearest apiary. Feral honeybees were common at control sites (73% of honeybees feral) but were scarce at apiary sites (2%), and hive honeybees appeared to be competitively displacing feral honeybees near apiaries. Visit rates by native insects appeared to be un-affected by the increased numbers of hive honeybees near apiaries. Standing crops of nectar sugar were significantly depressed at apiary sites. Pollen was rapidly removed from flowers at apiary sites resulting in full separation of the male and female flower-phases (flowers completely dichogamous). In contrast, at control sites, pollen tended to remain in flowers into the female phase (flowers partially dichogamous). There was no difference in the total number of pollen grains deposited on stigmas or in percentage seed set among apiary and control sites. However, fruit set was elevated at apiary sites, possibly owing to reduced autonomous (within-flower) selfing. Our study indicated that honeybees significantly reduce floral resources (nectar and pollen) around apiaries, although any competitive effects on native insects may have been obscured by large variation in the abundance of native insects among experimental sites. [source] Behavioural environments and niche construction: the evolution of dim-light foraging in beesBIOLOGICAL REVIEWS, Issue 1 2009William T. Wcislo Abstract Most bees forage for floral resources during the day, but temporal patterns of foraging activity vary extensively, and foraging in dim-light environments has evolved repeatedly. Facultative dim-light foraging behaviour is known in five of nine families of bees, while obligate behaviour is known in four families and evolved independently at least 19 times. The light intensity under which bees forage varies by a factor of 108, and therefore the evolution of dim-light foraging represents the invasion of a new, extreme niche. The repeated evolution of dim-light foraging behaviour in bees allows tests of the hypothesis that behaviour acts as an evolutionary pacemaker. With the exception of one species of Apis, facultative dim-light foragers show no external structural traits that are thought to enable visually mediated flight behaviour in low-light environments. By contrast, most obligate dim-light foragers show a suite of convergent optical traits such as enlarged ocelli and compound eyes. In one intensively studied species (Megalopta genalis) these optical changes are associated with neurobiological changes to enhance photon capture. The available ecological evidence suggests that an escape from competition for pollen and nectar resources and avoidance of natural enemies are driving factors in the evolution of obligate dim-light foraging. [source] Survival of Flower-visiting Chrysomelids during Non General-flowering Periods in Bornean Dipterocarp ForestsBIOTROPICA, Issue 5 2008Keiko Kishimoto-Yamada ABSTRACT In SE Asian rain forests, general flowering, a community-wide synchronous flowering, occurs at irregular and supra-annual intervals. During general flowering periods (GFP), most Dipterocarpaceae and many other trees flower profusely, while flowering plants are scant between GFP. During flowerless periods, anthophilous animals that depend on floral resources for food may suffer food shortages and subsequently decrease in abundance. Flower-visiting chrysomelid adults are major pollinators for some canopy tree species that flower during GFP. Although such chrysomelids feed on flower petals, the means by which they survive flowerless periods remains unknown. We determined the abundance of flower-visiting chrysomelids in GFP and non-GFP through light trap samples and examined the effects of the presence of young leaves and flowers of dipterocarps on local abundance, and feeding preferences of flower-visiting chrysomelids. We found no clear tendency that the chrysomelid species number and the abundance during GFP were consistently higher than those during non-GFP. Chrysomelid adults were more abundant on trees with many young leaves or flowers than on trees lacking young leaves and flowers. At least a few flower-visiting chrysomelids were observed feeding on young dipterocarp leaves and visiting young leaves and flowers of non-dipterocarps in the canopy during non-GFP. All results consistently suggest that chrysomelids are able to survive flowerless periods by feeding on the young leaves of dipterocarps and on the young leaves and flowers of non-dipterocarps; through this alternate feeding, chrysomelid populations are maintained at sufficient levels to function as effective pollinators of trees that flower during GFP. [source] | ||||||||||