Volume 2, Issue 2

Book and video display: pollinators

Visit the library this month to see and borrow featured resources on pollination. Books range from Eric Grissell's encyclopedic Bees, wasps, and ants: the indispensable role of Hymenoptera in gardens to Luke Dixon's practical Keeping bees in towns & cities. Recent videos include Top-bar beekeeping, a companion to Les Crowder's book of the same name.

Plant Answer Line question:
Can hummingbirds exhaust flowers' nectar supply?

Q: I would like to know how hummingbirds' feeding affects the level of nectar in flowers. I already know about which flowers produce nectar that will attract hummingbirds. My main concern is whether hummingbirds can use up a plant's supply of nectar.

A: In the book The Biology of Nectaries edited by Barbara Bentley and Thomas Elias (Columbia University Press, 1983), there is an essay called "Patterns of nectar production and plant-pollinator co-evolution" (by Robert William Cruden et al.) which states that "flowers pollinated by high-energy requiring animals [this would include hummingbirds] produce significantly more nectar than flowers pollinated by low-energy requiring animals, such as butterflies, bees, and flies."

Similarly, plants whose pollinators are active in the day produce more nectar during the day, and plants pollinated by nocturnal creatures will make more nectar at night. So clearly there is an intricate system of response between the needs of the plants and the needs of the hummingbirds, and the biology of individual plants has evolved to serve the plants' interests which are tied to those of pollinators. In effect, the hummingbird can't exhaust the nectar supply of the flowers, because the plant has adapted to meet its needs. (Read Plant Answer Line Librarian Rebecca Alexander's complete reply in our online Gardening Answers Knowledgebase.)

New and notable books for scholars

Ecology of Plant-Derived Smoke: Its Use in Seed Germination reviews over 1,300 species of plants and the value of smoke from plant sources in improving germination. 

According to Tim Flannery, who wrote the foreword, Biochar for Environmental Management presents a multi-disciplinary discussion of this potential tool to “…address food security, the fuel crisis and the climate problem, and all in an immensely practical manner.”  

New to the Library January 2015