Beetle banks

Beetle banks provide habitat for beneficial insects.

Beetle banks are permanent linear mounds, planted to a mix of perennial grasses and flowering plants, that surround our fields. They provide habitat for beneficial insects, such as predatory beetles and pollinators.

Beetle bank map

The beetle banks were seeded to a Beetle Bank Blend, developed by West Coast Seeds, that contains the following species:

Lewis Flax Linum lewisii
Western Blue-Eyed Grass Sisyrhincium bellum
Nodding Wild Onion Allium cernuum
Butterfly Bush Asclepias tuberosa
Farewell to Spring Clarkia amoena
Blanket Flower Gaillardia pulchella
Black Eyed Susan Rudbeckia hirta
Autumn Sneezeweed Helenium autumnale
Self-Heal Prunella vulgaris
Western Yarrow Achiliea millefolium
Lance-Leaf Coreopsis Coreopsis lanceolata
Russell Hybrid Lupins Lupinus polyphyllus
Douglas Aster Symphyotrichum subspicatum
Globe Gilia Gilia capitata
Sheep Fescue Festuca ovina
Beetle bank by high tunnel
Lupines in beetle bank

The banks also contain self-seeded volunteers endemic to the site. These are encouraged to promote biodiversity. The grasses out-compete most weeds, but routine maintenance involves removal of particularly competitive invasive perennials, such as Canada thistle (Cirsium arvense), Himalayan blackberry (Rubus armeniacus), reed canarygrass (Phalaris arundinacea) and field bindweed (Convolvulus arvensis).

The raised banks provide good overwintering habitat for ground-nesting beetles and pollinators because they do not flood and they are never disturbed by cultivation. These beneficial insects can spread across the crop in spring to keep pest populations in check. Ground beetles are voracious predators that feed on insect eggs, aphids, caterpillars, and many other pests.

Diverse families of ground beetles

Diverse families of predatory BC ground beetles (Coleoptera: Carabidae) from the Spencer Entomological Collection