Habitat Mangement for Native Pollinators

Habitat Management for Native Pollinators

(and Natural Enemies)

Robyn McCallum, Nancy McLean and Chris Cutler November 2015

ACORN

How can we enhance agroecosystems?

Outline• What is habitat management? • How does it work? • What are some benefits of habitat management?

• Native pollinators in Atlantic Canada • Natural enemies • Biology • Their needs • How do we start thinking like them?

What are Native Pollinators?

Wild Bees• ~ 200 different bees in NS • ~ 900 different bees in Canada • ~ 20,000 worldwide

Bumble bees (Bombus)

Halictids

Image from entnemdept.ufl.edu

Image from discoverlife.org

Andrenids

Image from naturespot.org.uk

Image form bee-busy.com

Megachilids

Images from bugguide.net

Apidae

Image from beneficialbugs.org

Managed Pollinators

• Honey Bees • Alfalfa Leafcutter Bees • Bumble bees

Why are native pollinators important?

• conservation

• ‘insurance policy’

• free services- food and plant biodiversity

• challenges facing managed bees

• efficient & effective

• buzz pollination

VS

What are natural enemies?

• beneficial insects, parasitoids, predators

• Involved in pest control • E.g. beetles, wasps • Similar needs as pollinators

Why are natural enemies important?

• Biological control • Dual purpose- pollination • Nature takes care of itself

Image from atlanticpestsolutions.net

Image from ipm.iastate.edu

Native Bee Biology

Solitary vs Social Bees• Most bees are solitary • Cavity nesting, ground nesting

• Some are social - Honey bees ! hives - Bumble bees ! rodent holes

Nesting• Trees, stems, reeds,

under rocks, in old cars, in roof eaves, milk cartons

• Proximity of water

• Parasites- nesting aggregation

• Soil tillage

Food• Typically pollen & nectar from flowers, but also oils

• Specialists vs generalists

How can we manage nesting?

• Tubes for cavity-nesters

• Soil conditions for ground-nesters

How can we manage food?

• Floral plantings along field edge

• Marginal land, ditches, etc have also been used

• Provides habitat in addition to food at valuable times

• Annual and perennial wildflowers • Growing interest in “native flowers” • Important to have diversity of flowers- tongue

length, nectar rewards

• Important to note that bees and other pollinators need food throughout the season- before and after crop bloom

Nutrition

Foraging Range• Depends on body size,

species

• Affects foraging & access to flowers

• Ranges from ~100 m to 5 km

Emergence, Phenology

• Spring vs later in the season

• Varying adult life spans- weeks to months to years

• What happens if required flowers aren’t blooming at the right time? Climate change? Evolution? Tongue length example

Development• Bumble bees vs solitary bees

How do we think like bees?

• What are basic needs? Food, water,

habitat

Habitat Management

• Conservation biology ! improve availability of resources (Landis et al. 2000)

• Connecting habitat mgmt with pollinator abundance and crop yield ?

• Apple & highbush blueberry studies

Habitat ManagementPotential benefits include:

Alternative or complement to managed bees

Increased biodiversity

Increased biological

control

What Drives Conservation Biology?

Economic Factors

Conservation Concerns

What do I plant?

• Annuals & Perennials • Different bloom times • Different flower structures

• Red clover, alfalfa, sweet clover, buckwheat, black eyed susan, vetch, sunflowers

• Wild roses, goldenrod, St. John’s Wort • Phacelia? Wild bergamot? • Spring-flowering trees (willow, etc.)

• Takes time- both plant and bee establishment

Soil Prep• pH ** • Tillage • Habitat disturbance risks- mitigate with perennials

On-Farm Techniques

• Weeds for food- balancing act • Woodpiles for habitat • Setting aside poor land for flowers • Pollinator gardens

Public Concern for Native Pollinators

• Population decline? • Pesticides? • Pathogen spillover from managed hives (or vice

versa??) • Lack of habitat ** • Lack of food (flowers) **

Enhancing Native Pollinators and Natural Enemies in Wild

Blueberry Agroecosystems

• Many crops require pollinators for fruit set • Pollinator services from managed bees = high input

costs • Native pollinators are efficient, effective and already

present (Javorek et al. 2002)

Background

• Native pollinators provide important ‘free’ services

• Populations could be increased to become more economically important

Lowbush Blueberry

• Requires cross pollination • Pollination services can be #1 cost (honey bees, other

managed bees) • Unique cropping system (crop vs sprout) • Opportunity to enhance agroecosystem for pollinators

• Techniques to boost native pollinators & natural enemies

• Focused on habitat and food

Objectives

Habitat

Trap nests Clay lids

Food

Buckwheat Operation Pollinator

Buckwheat

• Can we plant buckwheat around the field to provide food after blueberry bloom?

Buckwheat

• Annual • Can tolerate low pH • Tolerates poor soil fertility • Improves soil structure • Doesn’t spread • Attractive to bees • Long blooming period • Used for honey bees

Buckwheat

Data Collection

Buckwheat results so far

Challenges• Producer inputs !tillage, seed, management (no spray), need to plant each year, perhaps 2x per season

• Drought • Deer

• Economic benefits? • Conservation benefits?

Habitat

Trap nests Clay lids

Food

Buckwheat Operation Pollinator

Operation Pollinator

• Mixture of annuals and perennials • Can we measure nectar content? • What is persistence like, weed invasion, etc?

Habitat

Trap nests Clay lids

Food

Buckwheat Operation Pollinator

• Trap nests for Osmia species (Hymenoptera: Megachilidae)

• Cavity-nesting bee, readily accepts artificial nests

• Known to be good pollinators

Habitat Management for Mason Bees

• Solitary

• 8-9 species involved in blueberry (Stubbs et al. 1997)

• Queen lays eggs on pollen provision, larva ! pupa ! emerges the next year (Torchio 1989; Bosch et al. 2001)

• Linear sequence of ‘cells’

Osmia Biology

• Adult life span! 3- 5 weeks • Can fly @ low temps and emerge early in season • Need mud to ‘cap’ their nests, so water source important

Osmia Biology

www.bugguide.net

• What species are involved? • Does nesting uptake differ from crop field

to sprout field? • When does nesting occur? • Are nests parasitized?

Questions

• 80 trap nests in 4 fields (64 wooden, 16 milk cartons)

• Placed 10 m apart along field edge and facing the sun, supported on stakes

• Set out 22 April in crop fields in northeastern Nova Scotia

Materials & Methods- 2014

Wooden Trap Nests

• Examined different hole diameters, rain cover, burning

• Tubes were 10 cm deep

• 12 tubes/ 2L carton • Tubes = 15 cm long • Varying diameters (7 and 9 mm) • Tubes from rolled white paper + newspaper and placed

through high-density polystyrene foam; spray foam insulation to support tubes (Sheffield et al. 2007)

• Cartons painted white

Milk Cartons

Results 2014Nesting Success

%

Succ

ess

0

18

35

53

70

Nest Typemilk carton wooden

• n =

n = 14

• Focused on milk cartons only • Compared crop and sprout

Materials & Methods- 2015

• Modified design • 16 tubes instead of 12 • All the same diameter (7 mm) • Added plastic straws

Milk Cartons- 2015

• 26/32 milk cartons had capped nests (81%) • 4 milk cartons were removed due to bear

damage

Results & Discussion- 2015

Question: Crop vs Sprout

• No significant difference

• Trade offs for nearby crop/sprout rotations (bees & pests)

Question: Timing

Phenology of Osmia Nesting in 2015

Tota

l # C

appe

d N

ests

0

35

70

105

140

Date12-Jun 26-Jun 1-Jul 10-Jul 17-Jul 22-Jul 31-Jul

• Blueberry Bloom

Question: Timing• Capped nests appeared

after blueberry bloom had finished

• Not all tubes were capped at the ends

• Queens likely nested in more than one tube

• TBD, as well as species of Osmia

Question: Parasitism

• Why are milk cartons attractive? -Longer tubes -Smell? -Pink Styrofoam? White carton?

• Landscape factors- water sources, previous populations, food throughout season

Discussion 2015

Implications for Industry & Science

• Better understanding of Osmia nesting biology & involvement in wild blueberry

• Nests could be moved to crop fields requiring pollinators

• Practical, inexpensive technique

Implications for Industry & Science

• More efficient pollination

• Biodiversity conservation

• Alternative & complement to managed bees

Diversity of pollinators demands a diversity of habitat management techniques

Global Importance• $ for farmers in Europe who implement

bee-friendly practices • Marketing strategy for US farms “bee

friendly farms” • “bee friendly” product labeling

Community Engagement

• Fact sheets for blueberry production • OP seed mix fact sheet • 4H pollinator project development • Grower field days • Industry meetings • Schools • Garden Clubs

Agvocate Challenge• We need more positive ag stories! • First blossom, bees, tractors, people • Use opportunity to share

Resources

• Lawrence Packer Lab, York University

• Sheila Colla- online resources • Nova Scotia Dept of Ag handout

re: bees • Discover Life • Bug Guide

AcknowledgementsCommittee Members

Dr. Paul Hoekstra, Syngenta Blueberry Producers of NS for Field Sites

Snake Patrol

Robyn McCallum [email protected]

@mccallumrobyn

Questions?