When hummingbirds are the thieves: visitation effect on the reproduction of Neotropical snowbell Styrax ferrugineus Nees & Mart (Styracaceae)

The spectrum of floral visitors associated with a particular plant is frequently larger than predicted by the traditional concept of floral syndromes and the role that unpredicted visitors play in plant reproduction deserves attention. Hummingbirds are frequently recorded visiting flowers with distinct floral syndromes, especially in some hummingbird flower poor ecosystem such as the Cerrado. In this study we investigated the effect of frequent hummingbird visits on the reproduction of melittophilous Styrax ferrugineus. The flowers were visited by many different insect groups and visits by hummingbirds were frequent, especially early in the morning when nectar availability was higher. Nectar parameters varied considerably during the flower life span, and was probably affected by the temperature variation during the day. Hummingbird exclusion experiments showed no effect in the fruit-set of the plant. The inability of hummingbirds to deplete all of the nectar produced in this mass-flowering plant, and the existence of another resource (pollen) for the primary pollinator (large bees), are possible reasons why there was no perceptible hindrance of plant reproduction by the hummingbirds. Although no effect in the fruit-set was observed, the use of non-ornithophilous flowers must be important for hummingbirds, which are specialized nectar consumers.

Reproductive biology of Monttea aphylla (Scrophulariaceae)

Monttea aphylla is an aphyllus shrub abundant in the Monte Desert, Argentina. This species presents particular floral syndromes including violet, tubular flowers with trichome elaiophores that produce oil. Oil flowers are associated with specialised bees with an oil-collecting apparatus. To better understand the reproductive biology of M. aphylla, the mating system, flowering phenology, the associated pollinator assemblage and foraging behaviour was determined at the southern-most part of its distributional range. Results were compared with those of previous studies and discussed. At this southern location M. aphylla is a self-incompatible species; it relies on pollinators for fruit production and presented a low fruit set. Flowering occurred during the spring, from October to December. M. aphylla was pollinated by three species of bees (Apidae); two generalist species (Centris brethesi and Mesonychium jenseni) and one specialist to M. aphylla (Centris vardyorum). M. jenseni is a cleptoparasite of Centris species. Centris species are oil-collecting bees and showed territorial behaviour (i.e. they always visited a restricted group of plants which they protected from other visitors), they visited several flowers/plants, which enhanced geitonogamous self-pollination and reduced pollination efficiency, and which might explain the low natural fruit set observed in M. aphylla. C. vardyorum was the most important pollinator of M. aphylla in the study area. The reproductive biology of M. aphylla differs along its distributional range. Apparently, southern populations of M. aphylla are more specialised than the northern populations, the former being pollinated by a few related pollinator species whereas at the northern location a variety of visitors were observed.

Flowering of Australia's Rainforests

The Flowering of Australia's Rainforests provides an overview of pollination in Australian rainforests, especially subtropical rainforests. It also examines the plant-pollinator relationships found in rainforests worldwide. The Flowering of Australia's Rainforests progresses through introductory and popular sections that cover pollination in lore and legend; plant and flower evolution and development; and the role and function of colour, fragrance and form. Later chapters deal with breeding systems; mimicry; spatial, temporal and structural influences on plant-pollinator interactions; and a discussion and overview of floral syndromes. The book concludes with a section on conservation and fragmentation, and individual plant pollination case studies. Illustrated with colour photographs of major species, this reference work will be treasured by field naturalists, ecologists, conservation biologists, botanists, ecosystem managers, environmentalists, community groups and individuals involved in habitat restoration, students, and those with a broad interest in natural history.