Butterfly Gardening for Babies, Children, and Teenagers

This is a follow-up post to Butterfly Gardening for Adults.

So you’ve planted nectar flowers and attracted lots of adult butterflies to your yard, and now you want to see if you can add species diversity.  Or, perhaps you want to observe these beautiful insects during any or all of their other 3 life stages.  With just a little bit of effort you can rear a butterfly from an egg to an adult, right in your yard.

An adult female butterfly has one main motivation:  find the correct plant and lay her eggs.  What do I mean by “the correct plant”?  It turns out that most species of butterflies are picky about where they’ll lay their eggs.  Monarchs famously lay their eggs on milkweed (Asclepias spp.), but most other species would find milkweed to be just as toxic and unpalatable as  you and I would.  If a monarch female laid her eggs on the foliage of a rose bush, her children would find the leaves inedible and they would starve to death.  Because of this, butterflies (and people who study them!) need to be good botanists.  Lepidopterists (scientists who focus their studies on moths and butterflies) often work with botanists, native plant societies, chemists, and others to try to understand how a butterfly decides where to lay her eggs.  These plants are referred to as host plants, and they are a critical component of the butterfly life cycle.

A Colorado Hairstreak, Hypaurotis crysalus, on its hostplant, Gambel Oak, Quercus gambelii

Why would the Monarch caterpillars starve to death if their mother deposits her eggs on the wrong plant?  Because plants produce chemicals (called phytochemicals) that give them color, produce fragrance, help carry out physiological processes, and defend them against enemies.  Enemies of plants include fungi, bacteria & viruses, and herbivores (animals that eat plants).  Butterfly caterpillars are herbivores.  If they’re present in large enough numbers they can strip the leaves and stems from a plant, weakening or even killing it.  Because of this, many plants have evolved the ability to produce defensive chemicals to reduce the likelihood that they’ll fall victim to herbivores.  But, just like in an arms race, some herbivores have managed to overcome these defenses and exploit the plant in question as a food source.  The milkweed- Monarch example is a great illustration of this.  Milkweeds produce chemicals that are toxic to most herbivores (including humans), but the monarch has evolved the ability to ingest milkweed foliage without incurring damage from those chemicals.  Monarch mothers can lay their eggs where very few other insects can, and her children will thrive.

So how do you decide which host plants to include in your garden?  You can start by researching the host plants used by the adults that come to your garden.  Butterfly field guides almost always include information on the host plant used by each species.    If you want to attract new species to your garden, these same sources can help with that, too.  Look to see which species you can expect in your area, paying close attention to the habitat type (e.g. if you live in a sage desert, you’re not going to get marshland species in your yard!) as well as to the geographic distribution.  eButterfly is a great way to track what shows up in your yard as well as to see what species are showing up nearby.  You can also keep an eye on wildflower gardens and nurseries in your neighborhood to see what other species of butterflies are around.

Once the eggs hatch out, the caterpillars will be very hungry.  While a few species tend to lay

Pipevine Swallowtail larva, Battus philenor, on its host plant Aristolochia

eggs on one host plant but spend their time as caterpillars on another, most  stay on the same species for both life stages.  For this reason you can usually accommodate eggs and caterpillars of a given species with the same plant.  Be aware, though, that caterpillars can have voracious appetites.  Very few butterfly species are considered to be crop pests in the US (a notable exception is the Cabbage White, Pieris rapae), but they can seriously defoliate your plants, nevertheless.  If you have a vegetable garden, be aware that you may lose some things to caterpillars if you don’t find a way to discourage them.  This is mainly true of crucifers and legumes, which serve as host plants to many species of sulphurs and whites.  Anise, citrus trees, alfalfa, blueberry and cranberry plants, gooseberry plants, rice, figs,guava, and cherries are some of the other plants that might unintentionally become host plants in your butterfly garden.  It’s unlikely that a colony of Giant Swallowtails, Papilio cresphontes, are going to seriously damage your lime trees, but a few Cabbage Whites can put a hurting on the mustards in your salad garden.

Caterpillars go through several molts, growing larger each time.  We call these instars– after hatching from the egg, the caterpillar is in its first instar; after the first molt, it is in its second instar; etc.  The number of larval instars varies from species to species but averages ~5.  Once the caterpillar enters its final instar it will prepare for the pupal stage, also called the chrysalis.  The caterpillar will prepare to pupate by crawling to a place that is (hopefully) safe from environmental extremes, predators, parasitoids, and has a good substrate for attachment.  This might be its host plant, but is often a textured vertical rock face, a tree trunk, or, in a garden, a fence post or flower pot.  The caterpillar will attach herself to the surface she’s chosen and build a complex structure around herself.  She’ll then appear to go dormant for several weeks- several months, depending on species.  In reality, though, there’s a complex developmental process going on inside that pupal casing!  But that’s a post for another day.   To make sure you are providing a place for your caterpillars to pupate, include some vertical surfaces like decorative rocks or fenceposts, and experiment with giving them a little shelter- a small overhang or roof can help protect the pupae from the weather.  Once development is complete, the adult butterfly will emerge and the cycle starts anew.

Next time:  Enemies in the Garden

Butterfly Gardening for Adults

Part I- attracting adult butterflies to your yard.

When leading butterfly walks or giving talks about butterfly watching, some of the most common questions that I get pertain to butterfly gardening.  Planting a butterfly garden is a great way to expand your butterfly-watching opportunities, brighten up and add value to your home, and provide essential habitat for butterflies in your corner of the world.  A butterfly garden can be as simple as adding a potted plant to the balcony of your apartment.

Before going into the details of what to plant, it’s important to note a very strict rule if you want your butterfly garden to be successful- no pesticides!  Insecticides don’t discriminate.  They’ll just as easily kill a butterfly as they will cutworms and squash beetles.

A Variegated Fritillary, Euptoieta claudia, nectaring on thistle. Photo taken near Prescott, AZ by Zach Smith

When most people think of butterfly gardening, they think of showy flowering plants that will attract nectaring adult butterflies.  This is, of course, an important component of a butterfly garden, and it may be sufficient for your level of interest, the space you have available, or the resources you have to commit to your garden.  It’s also a great first step- plant some nectar flowers and see who shows up!  You may find after a while, though, that you want to observe butterflies during their other life stages, and this is where some knowledge of natural history comes in handy.

Butterflies have four developmental life stages (they’re holometabolous), so a well-rounded butterfly garden should accommodate eggs, larvae, pupae, and adults.  But one individual species might have completely different needs for each life stage, and the requirements of one species will often differ from the requirements of another.  How to accommodate all of those different needs?

Let’s start with the adult stage.  Many (but not all!) species of butterflies in the US come to flowers to sip nectar for energy.  Unlike hummingbirds and moths, butterflies need to perch in order to drink (which they do by unrolling their long, tongue-like proboscis).  They locate nectar sources visually and by chemical sensing (similar to our sense of smell).  Some colors are more attractive than others but there are no hard and fast rules.  The best strategy is to observe what’s happening in your area and see what flowers are attracting the locals.  Take a walk around your neighborhood, your favorite park for butterfly watching, and a few nurseries.  Try a variety of colors and sizes for the best chance to attract multiple species.  Try to plant so that you maximize the blooming season- rather than lots of flowers that all bloom at once, try to stagger plantings so that things flower in different seasons, ensuring a constant supply of available nectar.

The shape and structure of the flower determines who can pollinate it, and who will come to sip nectar (if the plant produces it- not all flowers make nectar).  In addition to a landing pad, appropriate scent, and attractive color, a butterfly needs to be able to reach the nectar with her proboscis.  This means the throat of a flower can’t be too deep or too shallow.  For example, a small butterfly like a roadside skipper can easily reach the nectar of a small flower like lantana, but would probably have trouble getting nectar out of the long spurs of a golden columbine.

Taxiles Skipper, Poanes taxiles, nectaring on thistle flower. Note the black proboscis extending into the flower.

I always recommend planting native species whenever possible.  Native plants provide habitat for many different animals, reduce the amount of watering and fertilizing you’ll need to do, and help lessen the chance of spreading pests and invasive species.  If you’re lucky there’s a native plant nursery in your area, but if not, there is bound to be a native plant society, nature center, or master gardener group that can give you some pointers on how to acquire native plants for your garden.  The Xerces Society has a lot of great resources to help you with this.

Some flowers, despite being attractive additions to a cut flower garden, are essentially useless to butterflies.  Unfortunately, roses, peonies, and a lot of cultivated showy flowers won’t do much to attract butterflies.  This doesn’t mean a butterfly garden can’t be beautiful and showy, though-  milkweeds, butterfly bush (Buddleja), lantana, coneflower, lavender, (single) zinnias, and Joe-Pye weed are just some of the reliable flowers that butterflies find irresistible.

Some butterfly species are attracted to things that are… less charming than flowers.  Rotten fruit is attractive to species like emperors, admirals, anglewings, and many others.  Try smearing some overripe bananas on trees or fenceposts in your yard and see what happens.  Newly-emereged males of some species are often attracted to damp patches of ground, where they suck minerals out of the moisture with their proboscis.  This activity, called puddling, is apparently so compelling that a butterfly might lose all sense of inhibition and let you catch it by hand!  Puddles, stream edges, and seeps often attract dozens of butterflies at a time, all mesmerized by the intoxicating minerals they’re busy slurping up.  Probably the least winning habit of nutrient-seeking butterflies, at least as far as human sensibilities are concerned, is the tendency to come to scat and carrion, again presumably for the salts and minerals.   Since I doubt very many people want to incorporate either of those particular delicacies into their garden, I’ll refrain from expanding on that particular topic.

Up next: Butterfly Gardening for early life stages

 

Heads or Tails?

Hairstreaks are a group of butterflies in the Family Lycaenidae.  In the US, hairstreaks are widespread but frequently go unnoticed because of their small size and often drab appearance.  When they are noticed, they’re commonly mistaken for moths.  Their fast, erratic flight lends to this confusion.  If you get the opportunity to observe a hairstreak closely, though, it’s worth the effort.

Colorado Hairstreak showing purple dorsal surface. Photo taken outside of Prescott, AZ by Zach Smith

Like all butterflies, hairstreaks are susceptible to predators unless they develop some type of strategy to reduce the likelihood of being noticed, caught, and eaten.  Birds, lizards, and other invertebrates like mantids and spiders are just some of the predators that butterflies have to be able to evade if they are going to survive long enough to pass on their genes.  Many hairstreaks show some degree of crypsis, or coloration that helps them to blend in with their backgrounds.  A few, like the Colorado Hairstreak Hypaurotis crysalus are cyrptic on the ventral surface (underside), but vibrantly colored on the dorsal surface (upperside).  This bright purple hue is most likely an adaptation to distract predators, although colorful signals like this can often be used to signal to other butterflies- potential mates, competitors for mates, or individuals of a different species.

Many hairstreaks, however, have gone beyond the standard cryptic coloration mechanisms to evade predators.  The trailing (back) edge of their hind wings exhibits a “false head“.  Typically this false head consists of some combination of eyespots and “hairs” or tails resembling antennae and/or legs.  The idea is that if a predator notices the hairstreak, its attention will be drawn to the false head and it will aim its attack there, because a successful attack on the head is more likely to incapacitate the butterfly than an attack on another part of the body.  Instead, the predator comes away with a mouthful of flimsy wing, which breaks off while the butterfly makes its escape.  Experimental evidence (link above, reference below) suggests that this adaptive strategy is successful in increasing survival in butterflies that have this trait.

Gray Hairstreak, Strymon melinus, showing beak marks on the hind wing. Photo taken near Jerome, AZ by Zach Smith

Colorado Hairstreak ventral surface showing eyespots and tails

As if that isn’t cool enough, though, many hairstreaks have taken this deception even further.  Hairstreaks have a habit of perching with their wings closed, upside down, and rubbing the trailing edges of their hind wings together.  This subtle movement is enough to further direct the predator’s attention to the false head, and it strongly resembles the movements made by the butterfly’s head while she sips on flower nectar.

Keep your eyes open for hairstreaks the next time you’re outside. If you’re fortunate enough to see one, take the time to observe it while it perches and see if you get tricked by the false head!  Want to learn more about the research on false heads?  There are several great studies out there.  Here’s just one (linked above):

R. K. Robbins 1981.  The “False Head” Hypothesis:  Predation and Wing Pattern Variation of Lycaenid Butterflies. American Naturalist Vol. 118, No. 5 pp770-775