Skip to content

Garden Tip #430

The pollinators need our help. Not just because humanity’s food supply relies on pollinators, but because invertebrates are the backbone of a healthy ecosystem. Concerned gardeners will find guidance and an action plan in The Pollinator victory garden: win the war on pollinator decline with ecological gardening: how to attract and support bees, beetles, butterflies, bats, and other pollinators by Kim Eierman (2020).

Eierman’s Tips for a Pollinator Victory Garden

  • Don’t use pesticides of any kind, including organic; and avoid buying nursery plants treated with “neonics.” A quality nursery should be able to tell you whether their plants have been treated with this systemic pesticide.
  • Create over-wintering habitat by leaving some fallen leaf litter on the ground. Soil organisms will also appreciate the leaf litter.
  • Create growing season habitat for solitary, ground-nesting native bees by leaving a sunny, sandy patch of soil free of mulch. Then watch out for little mounds with a hole in the center, kind of like a tiny volcano, for evidence of a bee making a nest for her larvae.
  • Native pollinators prefer native plants, and some rely exclusively on native plants. Eierman compiled a list of plants for the Pacific Northwest on her website, Ecobeneficial.com.

Eierman makes the case for pollinators

Grass-carrying wasps

Who has moved into the tubes in my mason bee house? There are these strange bundles that seem to have dead crickets entombed in them. Do I need to remove them?

 

Your description and photos convince me that these bundles were made by grass-carrying wasps (Isodontia species) who store food (such as crickets!) with their cocoons to nourish the larvae when they emerge. Your mason bee house was a convenient location to nest. They look for any hollow cavities (such as stems, trees, or even window tracks), and the mason bee tubes were a perfect spot.

They would have built the nest in early summer, emerging later (late July through September) to visit flowers for pollen and nectar.

Grass-carrying wasps are beneficial insects just like mason bees, and serve as pollinators, too. This article from Heather Holm’s Restoring the Landscape with Native Plants (author of Bees: An Identification and Native Plant Forage Guide, 2017) mentions them visiting Solidago, Eupatorium, and Plantago.

As far as removing the grass-shrouded crickets or katydids, I would follow your normal mason bee housecleaning schedule. Usually, cleaning the tubes would be done between October and December. This page from David Suzuki’s web page describes the process.

If you are curious to see a grass-carrying wasp in action, entomologist Michael Raupp’s Bug of the Week page includes a video of a wasp creating its nest.

, ,

Washington Bumble Bees in Home Yards and Gardens

“To better conserve and protect bumble bees in home landscapes in the Pacific Northwest, this publication aims to develop public awareness and appreciation of bumble bees and their role in pollination. It will also help readers recognize bumble bees, understand their general life cycle, and suggest things homeowners and the general public can do to encourage these fascinating and beneficial insects.”

Pollinator Partnership

This organization is focused on promoting pollinator health through “conservation, education, and research. Signature initiatives include the NAPPC (North American Pollinator Protection Campaign), National Pollinator Week, and the Ecoregional Planting Guides.” The Resources section includes a learning center and webinars on issues such as habitat restoration.

Effects of nectar-nicotine on bees

I am about to plant Nicotiana mutabilis seeds, and I wonder: if neonicotinoid insecticides are harmful to bees, is the pollen in Nicotiana also harmful? Also, is it a bad idea to plant Nicotiana near my tomatoes (could it spread tobacco mosaic virus)?

Although neonicotinoids are not currently implicated as a direct cause of Colony Collapse Disorder, the Xerces Society for Invertebrate Conservation’s “Are Neonicotinoids Killing Bees?” says that “recent research suggests that neonicotinoids may make honey bees more susceptible to parasites and pathogens, including the intestinal parasite Nosema, which has been implicated as one causative factor in CCD.” The brief summary of the full report on this issue is well worth reading.

I doubt whether the pollen or nectar of the ornamental plant Nicotiana has the same properties as a formulated systemic pesticide which contains a synthetic form of nicotine. For an example of the ingredients in a neonicotinoid pesticide, see this fact sheet for Imidacloprid from the National Pesticide Information Center. I found a scientific article (“The effects of nectar-nicotine on colony fitness of caged honeybees” by N. Singaravelan et al., in Journal of Chemical Ecology, January 2006) which says that the floral nectar of Nicotiana species and of Tilia cordata contains trace amounts of nicotine. The authors concluded that “results indicate that honeybees can cope with naturally occurring concentrations of nicotine, without notable mortality, even when consumed in large quantities for more than 3 weeks.”

As for your other question, Nicotiana does sometimes get tobacco mosaic virus, though the National Garden Bureau (in a link no longer available online) says the plant seldom has much trouble from it. Still, it is probably a good idea to keep some distance between your Nicotiana and your tomatoes (and any other solanaceous plants, like potato, eggplant, pepper) just to be on the safe side, or at least be sure to change gloves and clean tools after handling the plants. The main method of transmission of tobacco mosaic virus is “mechanical,” that is, by handling a plant with the virus and then handling plants that are susceptible to it.

, ,

Bee Basics: An Introduction to Our Native Bees

A 48 page booklet by By Beatriz Moisset, and
Stephen Buchmann. Published by the USDA Forest Service and Pollinator Partnership Publication. Topics include biology, species guide, life cycles, foraging habits, and conservation.

bumble bee nest removal

I am taking a large, overgrown fern out of our backyard, to make room for more lawn (we are doing the opposite in other parts of our outdoor space). While I was cutting off the fronds, to get to the root, bees started to hang out near the cuttings. There seems to be a bumblebee nest at the base of our fern. I know that honeybees have been dying. Should I leave the bees’ nest? They are not aggressive, but I would like to take out the plant. Is there some way to move the nest?

 

Bumblebees are bees native to North America, and they are above all important
pollinators, so if you can leave them, that would be ideal. Fortunately, bumble
bees nest for only one year, so if you don’t mind waiting until fall to remove
your plant that might be the best solution for you and them. This
information, and more, is in Garden Insects of North America, by Whitney Cranshaw
(Princeton: Princeton University Press, 2004). Like honeybees, bumblebees are currently experiencing
a decline, so it’s a good time to protect them. The Xerces Society has useful information on this and other bee-related topics.

Bees choose their nests in the spring, when a queen bumblebee comes out from hibernation. They often choose an old rodent or bird’s nest, or something else with lots
of good insulation, and establish a colony. Find more about the life cycle of bumblebees here. In fact, you can encourage bumblebees to nest in spring by building them a
nesting site! The Xerces Society describes nest plans, if you would like to encourage bumblebees elsewhere.

If you do decide you need to move the plant before fall, you might be able to
get information on moving the next by contacting the Puget Sound Beekeepers
Association
or a Seattle-area stinging-insect enthusiast, Jerry the Bee Guy. Another local stinging insect removal expert is Dan the Bee Man.

hummingbirds and plants’ supply of nectar

I would like to know how the hummingbird’s 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.

 

There has been some research which suggests that a plant’s production of nectar is regulated by hormones. Sometimes the hormone attracts one creature in order to repel another. The article excerpted below suggests that rapeseed plants produce nectar to attract ants that will defend them against caterpillars. Source: Max Planck Society for the Advancement of Science (March 29,2010):
“Jasmonic acid and related molecules are constituents of molecular signal transduction chains in plant tissues. These compounds – generally referred to as jasmonates – are synthesized when caterpillars feed on plants; they are signalling substances and belong to the group of plant hormones. By producing jasmonates the plant regulates its defence against herbivores e.g. by stimulating the synthesis of toxins. Moreover, previous studies have shown that jasmonates regulate the production of “extrafloral nectar”. This particular nectar, which is produced by special glands called “extrafloral nectaries”, has nothing to do with pollination, but attracts ants to the herbivore-attacked plants as defenders against their pests. The sugars in the nectar reward the ants for defending the plant. The same principle applies to floral nectar: nectar production in the flowers attracts and rewards pollinators which in turn contribute substantially to the seed yield. However, up to now, it has not been clear how nectar production is regulated in the flowers.”

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.

varroa mites and grooming behavior in honeybees

Apparently there has been some mystery about struggling honeybees lately, and today I saw what appeared to be a honeybee frantically grooming herself on a strip-upholstered lawn chair. I didn’t know what to do for the creature, who eventually blew or flew away. What should I do if I see this in the future? Also, does the grooming behavior inform the mystery in any way?

 

You may want to talk directly with someone at the Puget Sound Beekeepers Association. They meet at 6:30p.m. every fourth Tuesday of each month except July and December at the Washington Park Arboretum 2200 Arboretum Drive East, Seattle.

The following sites discuss varroa mites and bee behaviors, including grooming:

  • USDA
    Excerpt:
    “We’re not the only ones to brush off an annoying mosquito or other buggy pest.
    Honey bees, when plagued by tiny tracheal mites, will use their legs like a fine-tooth comb to rid themselves of the life-threatening parasites. But, as entomologists with the Agricultural Research Service recently confirmed, some honey bees groom themselves more fastidiously than others.”
  • Dave Cushman’s bee site
  • Wikipedia page on varroa mites

 

The Sustainable Agriculture Research and Education website has information on honeybees and varroa mites, including breeding bees for grooming behavior. Here is an excerpt:
“Bees bred for hygienic behavior are able to detect and physically remove disease-infected brood from the colony before it becomes infectious. Hygienic bees are able to detect and remove diseased brood before the human eye can detect any sign of disease symptoms. When bees remove the disease in the non-infectious stage, it prevents the disease from spreading throughout the colony.”

Studies of colony collapse disorder are underway at Washington State University:
WSU Research news

What you observed in your garden could actually be a sign of a bee fighting off the mites. The best thing you can do is to grow a wide range of bee-attracting plants in your garden, avoid the use of pesticides, and encourage your neighbors to do the same. Below are links to information on bee gardening:
UC Berkeley Urban Bee Lab’s Gardening for Bees
Puget Sound Beekeepers Association list of honey bee-friendly plants for the Puget Sound area
University of Illinois, Champaign-Urbana
Xerces Society (now archived) list of Pacific Northwest Plants for Native Bees