After consistently thinking butterflies - milkweed I was pretty surprised at what actually made the top 5 plants that Lepidoptera had a craving for. 

It’s another one of those situations where you hear something and just take it as truth and forget to do any actual research on it and here we are. Fortunately that paper on Keystone Genera was published and set me straight. 

Yes, Monarchs and milkweed go together like stars and hydrogen. That is one butterfly. 

The checklist on iNaturalist for Ontario, at present, contains 3,248 species of moths alone.

If you could see 10 moths a day, every day of the year, it would take you most of the year to see all of the moths in Ontario. 

But what are the odds of seeing 10 moths a day, every day of the year? Some are in quite rare habitats that must be carefully searched out and you still may not see them the first several times you go look. In reality this could easily be a lifetime’s work. 

And that’s not counting the 5 families of Butterflies found in Ontario. 

So we definitely need more than just milkweed. 

Let’s dive right in. 

Lepidoptera’s top 5 cravings:

Genus: Quercus

Oaks 

• Black Oak (Quercus velutina), 50-60’ tall

• Swamp White Oak (Quercus bicolor), 50-60’ tall 

• Pin Oak (Quercus palustris), 50-70’ tall

• Red Oak (Quercus rubra), 50-75’ tall

• White Oak (Quercus alba), 50-80’ tall

• Bur Oak (Quercus macrocarpa), 60-80’ tall

Genus: Salix

Willows

• Sage-leaved Willow (Salix candida), 1.5-4’ tall

• Heart-leaved Willow (Salix cordata), 3-12’ tall

• Basket Willow (Salix purpurea), 3-15’ tall

• Sandbar Willow (Salix exigua), 4-15’ tall

• Prairie Willow (Salix humilis), 6-10’ tall

• Pussywillow (Salix discolor), 6-15’ tall

• Missouri Willow (Salix eriocephala), 10-12’ tall

• Bebb's Willow (Salix bebbiana), 10-40’ tall

• Shining Willow (Salix lucida), 12-20’ tall

• Peachleaf Willow (Salix amygdaloides), 15-65’ tall

• Laurel Willow (Salix pentandra), 30-50’ tall

• Black Willow (Salix nigra), 30-60’ tall

Genus: Prunus

Cherries, Plums, Peaches etc

• Sandcherry (Prunus pumila), 1-3’ tall

• American Plum (Prunus americana), 15’ tall

• Chokecherry (Prunus virginiana), 20-30’ tall

• Pin cherry (Prunus pensylvanica), 20-30’ tall

• Red Plum, Canada Plum (Prunus nigra), 20-30’ tall

• Black Cherry (Prunus serotina), 50-80’ tall

Genus: Betula

Birch

• Dwarf Birch (Betula borealis, Betula glandulifera, Betula pumila), 12-36’ tall

• Gray Birch (Betula populifolia), 20-40’ tall 

• Cherry Birch (Betula lenta), 50-75’ tall

• Yellow Birch (Betula alleghaniensis), 60-80’ tall

• White Birch (Betula papyrifera), 60-130’ tall

Genus: Populus

Poplars, Aspens, Cottonwoods

• Large-toothed Aspen (Populus grandidentata), 60-80’ tall

• Trembling Aspen (Populus tremuloides), 65-80’ tall  

• Balsam Poplar (Populus balsamifera L.),  75-100’ tall

• Eastren Cottonwood (Populus deltoides Bartr.), 175-190’ tall

These 5 species play a key role in their contribution to the local food webs through the caterpillars munching on them. And the caterpillars being munched on by others. 

They are not butterfly bush, or salvia cultivars or any of the other introduced plants sold as pollinator pals. Who would have thought butterflies, moths and trees go together?

Some interesting statistics that they found in their study:

• 20 woody plants chosen randomly supported  just 38% of Lepidoptera.

  • If, however, 10 of the selected species are keystone plants, 71% of Lepidoptera are supported.

  • That’s 87% better!

• 20 herbaceous plants without keystone species supported just 13% of potential species.

  • With the inclusion of 10 keystone species, 42% of Lepidoptera were supported. 

  • That’s 223% better!

Including these keystone plants achieved the highest diversity with the fewest plants. 

Some statistics for the plant amounts required:

• When 15 woody plants that are keystone species are intentionally included 82% of possible Lepidoptera species and 60% of interactions could be supported. 

  • Whereas, 50 woody plant species were required to reach 80% of the Lepidoptera species and 55% of interactions when plants were chosen randomly. 

• That means you would need 233% more plants and you would still be 2% less in your Lepidoptera count, with 5% less interactions.

If you’re interested in restoration work this really helps to prioritize your plant selection to truly make the most difference on your property. If your plans do not include keystone species you will have far less of a support percentage than you are trying for. 

Richness and diversity in your landscape projects can be achieved by looking past bigbox store availability, aesthetics, and commercial viability and focusing on these species that support energy flow through your local food webs, which in turn affects you, because you also must eat. 

Interestingly the article mentioned “138 native woody genera and 860 native herbaceous genera are currently not known to support any Lepidoptera diversity in the United States at all.” Now in the future some undocumented interactions may be found. 

But if we are planting a pollinator habitat, or a songbird haven, why would we choose any of these plants? Those introduced-species pollinator packs at the bigbox store may not be the best option for your restoration work. Even native plants can be unproductive in terms of the clarity these numbers have defined. 

But does that mean forevermore we must only plant 5 genera of trees to support Lepidoptera? 

See you tomorrow.