native plants – Page 2

Pipevine Swallowtails and the case for caterpillar gardening

When you think of gardening for pollinators, you most likely think of beautiful flowering plants which attract bees, butterflies, and other insects by offering copious amounts of nectar or pollen. But flowers cannot give all pollinators the food they need. Butterflies in particular can be very picky when deciding what to eat when first starting out their lives as caterpillars. Most butterfly species have evolved to specialize feeding on one or a handful host plants. In a sense, when it comes to supporting butterfly communities, providing ample host plants for these soon-to-be-butterflies could be just as beneficial as planting nectar flowers for adults!

Pipevine swallowtail eggs are laid in small clusters so that when they emerge, these caterpillars work together eating leaves in small groups

The Pipevine swallowtail Battus philenor is one butterfly that benefits tremendously from the gardening of its favorite plant, Pipevine Aristolochia, after which it is named. Both Pipevine and the butterfly with which it shares its name is native across eastern North America, including Massachusetts. The plant itself is highly toxic and could cause severe kidney problems or even cancer if ingested by humans, but Pipevine swallowtail caterpillars could not care less.

These caterpillars have evolved not only to cope with the toxins in the plants, but to actively seek them out. Pipevine swallowtails, like many other butterflies, including Monarchs and their beloved milkweed, acquire the toxic chemicals present in their host plant and sequester them. As caterpillars they build of reserves of this chemical making them unpalatable to potential predators for the rest of their life. This is part of the reason many butterflies display such bright and captivating scales – it can be a signal to predators that nothing good will come from eating them.

In the right conditions Pipevine can scale great heights clinging to trees or other supports

Though these caterpillars cannot get enough of Pipevine, the adult swallowtails themselves do not nectar on the flowers it produces. Pipevine, like the name suggests, produces curved flowers that resemble a smoking pipe which is not conducive for a butterfly proboscis. Dutchman’s pipe Aristolochia macrophylla, is the most common species in eastern North America, and produces small tubular flowers with a small circular entryway. Into that entryway go flies which are actually attracted to the flower’s fragrance. Upon entering the narrow pipe, the flies get a little stuck, catching some of the flower’s pollen and carrying it with them until they end up in another flower which they help fertilize. After fertilization, the plant produces great seed pods which, when rooted and grown, will provide more food for those hungry caterpillars.

Before you start thinking this toxic, fly-attracting plant might not be the right fit for your garden, consider that Pipevine has been an immensely popular ornamental plant since Victorian times. It is an ideal option for trellises, fences or pergolas, providing plenty of shade when mature! If you are interested in attracting these beautiful butterflies to your home or garden in the future be sure to water your Pipevine as it needs lots of water and give it a place to climb. Be sure, too, to get Aristolochia macrophylla specifically, as some species will not support these caterpillars or might even be invasive – moreover macrophylla will provide the best shade (it is given the Greek name meaning ‘large leaf’) and will attract some marvelous butterflies looking for the right place to lay their eggs.

Adult Pipevine swallowtails have a remarkable coloration, with black and iridescent blue wings that have orange and white spots on the underside (Photo credit: John Flannery)

educate

Five easy ways to support pollinators in 2021

2020 was a rough year for everyone, including pollinators. Asian giant hornets arrived in Washington state, threatening honey bees; western Monarch butterfly numbers were the lowest in the past 30 years; neonicotinoid pesticides continue to be approved for use in the United States; and endangered rusty-patched bumble bees did not receive critical habitat because their biology is too poorly understood. That’s just the start.

Pollinators face a relentless barrage of threats from humans. The main factors driving pollinators declines include habitat loss, pesticides, climate change, light pollution, and the spread of exotic species and disease. Recently, scientists framed pollinator declines as “death by a thousand cuts,” underscoring that no single factor is solely responsible. Rather, the combination of multiple factors working in tandem is the greatest threat.

With this in mind, 2021 is a perfect year to resolve to make a small change in your lifestyle to support pollinators. Inspired by a recent list of actions to conserve insects, TPI proposes five actions you can take in 2021 to make a difference in the lives of urban pollinators:

1. Grow native plants. Native plants are beautiful and adapted to the local environment, meaning they require less water and fewer chemical inputs compared to ornamental plants. Even more, they offer food (pollen, nectar, leaves), nesting sites, and shelter for pollinators. Native plants also provide cultural benefits in the form of reconnecting community members to their local environments. Interested in growing natives? Check out our native planting guides and stay tuned for details regarding TPI’s native plant sale during 2021 national pollinator week.

Plant native goldenrod to assist eastern Monarch butterflies on their fall migration to Mexico.

2. Reduce your pesticide use. Pesticides are nasty chemicals that are widely used to suppress pest insects and weeds, but also cause non-target effects in pollinators. In spite of successful efforts in Europe to increase regulation on these pesticides, as well as ongoing campaigns here in the U.S., many harmful chemicals remain available to consumers worldwide. On average, lawns receive ten times more pesticides than do conventionally grown crops. Use pesticides judiciously and in a targeted way; avoid broad applications and claims by companies to “eradicate mosquitos.” Remember: any product that kills a mosquito also kills a bee.

3. Turn off your lights at night. Artificial light at night (ALAN) is one of most recognizable signatures of humanity from space. Yet, it also spells disaster for nocturnal pollinating insects like moths and beetles. Insects attracted to lights are easily picked off by predators and are worse at finding mates. As a result, insect populations suffer in areas with high ALAN such as cities. To curb declines of nocturnal pollinating insects, install motion-activated lights, replace bright blue-white lights with softer red-orange ones, or plant a moon garden containing night-blooming plants. Let’s keep our skies dark.

4. Shop local and support farmer’s markets. Many growers and vendors in Somerville and Medford near Tufts University (like the Somerville Winter Market and Neighborhood Produce) are committed to supporting pollinators by selling pesticide-free, locally-made products. Shop there as often as possible in order to avoid less insect-friendly alternatives at larger chain stores.

5. Educate others and share this post. Urban pollinator conservation depends on the active participation of the community. Become an advocate for pollinator conservation by writing to your politicians, installing a yard sign, or by simply talking about it—to your kids, your friends, your neighbors, your hairdressers, your bakers, your baristas. Teach them that bees come in all shapes and sizes or challenge them to notice their first monarch butterfly of the year. Simple awareness of pollinators—getting people to notice their environment—is the goal.

Have you made any pollinator resolutions for 2021? Let us know! We’d love to hear from you.

cultivate, educate

Plants and pollinators in our gardens

Over the past few months, TPI members have hard at work sifting through and analyzing the data we collected in summer 2020. Each week, three times per week, we identified the flowering plants in our gardens and counted flower-visiting insects. We’ve summarized the diversity of plants and insects found in our gardens on two new webpages: Plant Diversity and Pollinator Diversity. In short…

Our gardens contain more than 20 species each of native wildflowers. At least one species was blooming in our gardens each week between May and October. Some of the most popular native wildflowers of pollinators and humans alike are wild bergamot (Monarda fistulosa), culver’s root (Veronicastrum virginicum), blazing star (Liatris scariosa), new york ironweed (Vernonia noveboracensis), and new england aster (Symphyotrichum novae-angliae). Do you have any of these plants in your garden?

Our urban garden is attractive to both people and pollinators!

Our gardens attracted over 115 species of insect pollinators. Some of those insects found food in our gardens: six different bumble bee species (Bombus spp.) collected pollen from sunflowers, sand wasps (Bembix americana) hunted flies, and gray hairstreak caterpillars (Strymon melinus) browsed on mountain mint. Other insects made their home in our gardens: furrow bees (Halictus sp.) and leaf-cutter bees (Megachile sp.) nested in the bare soils. Our gardens are just two years old and already they are supporting more insects than we could have imagined! We can’t wait to see what we find during our surveys in 2021.