Sunday, June 7, 2015

(Most) Butterflies are Not Pollinators

I hate to burst your bubble, but most butterflies are not pollinators. They are eye candy. Butterflies are best described as "flower visitors" that are there seeking nectar, a carbohydrate, to fuel their flight. They could generally care less about pollen. It may actually be a nuisance that builds up on their bodies and has to be groomed off to maintain the insect's keen senses of smell (antennae), and vision (eyes). They pollinate by accident, thanks to pollen getting trapped in body hairs. Pollen grains probably clog the proboscis, too, as that "tongue" is a complex assemblage of several tubular and sheath-like mouthparts that actively pump nectar from the flower into the butterfly's digestive tract.

Painted Lady Butterfly

To be fair, there is one class of butterflies that actually eats pollen: The Heliconiinae subfamily of the brush-footed butterflies (family Nymphalidae). These are the "longwings" that are favorites in the tropical butterfly house industry. Longwings fly rather slowly, often at eye level or lower, and have a great diversity in species. There is even strong diversity in color pattern within a single species. They make near perfect display animals in captivity. They also have greater longevity as adults because they have the capacity to ingest protein in the form of pollen.

Heliconius erato longwing butterfly
Heliconius sapho longwing butterfly

When contemplating planting a "pollinator garden," prime consideration should be given to bees, hummingbirds, moths and flies. Butterflies will be attracted regardless, but the real pollinators need to be your target. Planting native species should take priority over gaudy ornamentals that too often become invasive in the natural landscape, and/or are too demanding in terms of fertilizers, pesticides, and other artificial life-support chemistry.

Sweat bee, Lasioglossum sp., on a composite flower

Tolerate "weeds!" One man's weed is another species' wildflower. Wild composites, that is, flowers in the aster family, are greatly preferred by most insects because they can visit more than one flower at one stop, reducing energy expenditures from flying blossom to far-flung blossom; and the flat surface of composites affords them a greater field of vision to watch for approaching predators. Few insects want to literally dive head-first into tubular flowers, though many bees do so all the time, and I have seen sulphur and swallowtail butterflies do so.

Black Swallowtail caterpillars do eat fennel, dill, anise, and parsley

Tolerate caterpillars! Many people fail to see the link between the butterflies (and colorful moths) they love, and the larvae they loathe. You cannot have one without the other! Planting host plants for caterpillars will arguably do more to attract butterflies to your garden than planting nectar-rich flowers. Remember, too, that plants have their own built-in chemical defenses to protect themselves; and even if defoliated, they can recover. A complete garden ecosystem with all its checks and balances in the form of herbivores, predators, parasites, fungi, soil fauna, and other organisms, is far less expensive to maintain than one that is micro-managed with pesticides and herbicides. Save time and money by choosing the right plants initially, and learning from reputable, unbiased sources what insect species are truly harmful and which are ones you can live with, if not encourage.

Leafcutter bees (Megachile spp.) will nest in holes drilled in wood blocks

Think native bees. The apiculture (honey bee) industry is a powerful lobby, and has largely convinced the general population that honey bees are the *only* bees. The overwhelming majority of bee species are native, and solitary or semi-social in their habits. Agriculture needs honey bees, no question. Your garden, and wild habitats, do not. Consider putting up bee boxes for housing our native, solitary bees. Their traditional nesting sites are being plowed under, paved over, and cut down at such a rate that they can use artificial homes.

Bundles of hollow twigs attract solitary bees that nest inside them

Lastly, I will say this for the Monarch butterfly. They are large insects, powerful enough to effectively pollinate milkweeds. Milkweeds package their pollen in sticky bags that are not easily dislodged from the flower. You can usually find bees, flies, and other insects that have become mortally stuck to milkweed flowers, unable to extricate themselves. Large wasps, large bees, and large butterflies are among the few insects able to effect the pollination of milkweeds. Learning which insects effectively pollinate which plants is also key to making your own garden or yard a "pollinator paradise."

Monarch Butterfly

1 comment:

  1. Several great points. I REALLY appreciate your speaking for the native bees. SO many people (and as you say industries) talk about how important bees are, and it's always a photo of a European honey bee. My husband wanted to have a hive & I said "You can if you want to, but you're on your own. I don't want to subsidize non-native bees." So, he's not done it. =) Turns out he wasn't that motivated.

    I LOVE seeing ALL the different types of native bees in my garden, and their spectacular size range. From BIG B-1 bomber bumblebees to bees SO tiny, I only figure out they're bees by zooming WAY in via a digital photo. Also, if a plant is cool-looking but doesn't attract insects (even if it's edible), it will only be planted in my garden ONE time, e.g. a burgundy amaranth. Really was spurned by bugs, so even tho' I could appreciate its color from 25 yards, it's no longer in my garden. I heart bugs! =) Gotta have 'em. =)


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