The relationship between flowers and insect visitors is ancient. There are records of fossil bees and butterflies from the time of the dinosaurs, about 145 - 65 million years ago. Pollinators depend on plants to provide a variety of resources including food, scents, resins, and sometimes shelter. The most common urban garden and farm flower visitors in Hawai'i include bees, flies, wasps, beetles, and moths. Insects seek flowers for the resources they offer, but not all insects seek the same rewards. Local bees for example, often have two very strong reasons to visit plants: nectar and pollen. Nectar, the sugary liquid produced by some plants, provides instant energy for the adult insect, and in some cases is stored in the nest for future use. Honeybees are one of the few insects that collect nectar and transform it into honey, which is then stored in their colonies. Most bees however, do not make honey, but rather it use it as a nutritional component to their diet and their offspring.
Pollen is a reproductive tool for the plant. Pollen grains fertilize female flower parts and are needed in fruit production. Pollen grains have high nutritional value and many pollinators visit flowers to eat the pollen and/or to collect it to feed if to their young.
To offset the "destructive appetite" of these visitors, flowers have been selected to produce either excess pollen, so that some will be attached to the pollinators and accidentally transported to the next flower, or to place pollen in difficult to reach areas of the pollinator's body and offer other rewards instead. For example, some tropical orchids offer scents to bees, while their pollen is packed tightly in a case that is attached to the back of the bee and removed by a receptive flower part at the next visit.
Honeybees depend on pollen to rear their brood and it has been shown that when honeybee colonies prosper when they have access to plentiful and diverse floral resources. Because variety of pollen sources seems to provide a more complete nutrition it is important to consider what is available to bees living in urban or agricultural environments. Large-scale growers tend to simplify their land environment and the diversity of floral resources available for the bees declines. It is possible for growers and gardeners to make simple changes that can improve the habitat for bees, other insect pollinators, and even beneficial insects that consume pests, such as ladybugs and lacewings. These steps involve: 1 - Get to know your farm: examine the landscape of the farm and determining if there are areas not involved in production that could potentially support pollinators. 2 - Once such habitats are identified (including plot edges, ravines, pond and road edges, areas in rotation with cover crops and fallow fields) protect pollinator friendly plants in those areas. 3 - Enhance the habitat by adding flowering plants that are favored by pollinators, taken care to avoid aggressive weedy species. In Hawai'i, micro-habitat improvements need to take into account many aspects of the plants' life history including susceptibility to pest pressure, invasiveness traits of the plant to be added, and cost of introduction and maintenance. Consulting with local nurseries that carry native plants is always a good investment, especially if the nursery staff can provide advice on the plant soil and water requirements. Pollinator friendly guides are being developed for different regions of the US by the Pollinator Partnership (see Pollinator.org for references on Native Hawai'ian plants). However, remember that these are generalized lists and the micro-climate of your property will play a large part in the success of the introduction of bee forage to your farm or garden. For basic information on pollinator issues in Hawai'i and pollinator friendly gardens please check the downloadable handout produced by the UH Honeybee project (on your right) or visit out sister site "here."