July 2022 – Discover-Nature

Butterfly Defense

Eastern Tiger Swallowtail on Buttonbush by DonArnold, 2020)

The life cycle of a butterfly includes four stages: the egg, the larva or caterpillar, the pupa or chrysalis, and the adult butterfly. Butterflies are eaten by many predators including birds, frogs, toads, ants, wasps, snakes, rodents, and mammals. They are vulnerable during any of the life cycle stages, but mostly as caterpillars or adults. Butterflies have developed several strategies to avoid predation including flight, camouflage, poison, and mimicry.

Four life cycle stages….egg laying, larva, pupa with adult emerging

Butterflies in flight are hard to follow. Large, flexible wings brought together in a clapping motion forcefully expels the air caught between the wings. Butterflies have control over which way the wings are aligned and the direction the air is expelled, pushing the butterfly where it wants to go. They use this ability to direct their flight in sudden changes of direction to avoid flying predators.

White cabbage butterfly flight by DonArnold, 2022

Camouflage is another highly effective defense strategy. Dark, round spots located farther back on the wings appear to an observer as eyes on a much larger face. Deimatic behavior involves sudden movement in combination with this type of pattern that causes potential predators to hesitate or stop from attacking.

Butterflies often have many splendid colors on the backs of their wings. The underside of the wings of many species are quite drab. In this way, the insect can sit still with wings folded together and draw very little attention to itself. Patterns and colors may also blend in with their surroundings making them appear as sticks, leaves, tree bark, or bird droppings.

Adonis Blue, Lysandra bellargus, by Tom Lee, May 2017

Male has bright colors while female can hide easier with duller colors

Bright colors, such as the oranges seen on Monarch butterflies, are a warning display to potential predators that this butterfly is bad tasting or toxic. Several plants, such as milkweed, have developed chemical toxins as a defense against herbivores eating them. Monarchs and other species can eat these plants, separate out the toxin, and store it for their own use. After becoming sick from eating one or more of these butterflies, predators learn to avoid them.

Notice closely related top and side colorations between Monarch (toxic) and Vicery (mimic)

Some species have developed bright colorful patterns that are quite similar to toxic species. The viceroy butterfly can be difficult to distinguish from a monarch, especially given only a quick look. Advertising their bright colors, viceroy butterflies fool predators into thinking they are also toxic. This is referred to as mimicry.

Butterflies are out in large numbers throughout the high summer, and you can observe many of these strategies in backyards, public areas, or open fields.

Coneflowers

Purples, yellows, and pinks to brighten your garden

Coneflowers are one of the summer’s many showy spectacles in the garden. There are nine species native to the central and eastern United States, four of which can be found growing in the wild in our area. Additional hybrids, available for sale in local garden centers, have been developed for their appearance and variety of colors.

Purple coneflower, pale purple coneflower, yellow coneflower in backyard garden by DonArnold, 2022

Coneflowers are perennials, growing from two to four feet in height. Blooming from midsummer to the first frost, they like full sun and well-drained soils. They are drought tolerant and do particularly well in poor soil conditions provided they get a small amount of water every few days.

Purple coneflower, Echinacea purpurea by DonArnold, 2021

Purple coneflower, Echinacea purpurea, is rare in naturally occurring habitat in northeastern Illinois: yet it is one of the most popular species in backyard gardens. Pale purple coneflower, Echinacea pallida, is another favorite in backyard gardens and is commonly used in local prairie restorations.

Pale purple coneflower, Echinacea pallida, by DonArnold, 2021

Yellow coneflower, Ratibida pinnata, by DonArnold, 2021

Yellow coneflower, Ratibida pinnata, also called gray-headed coneflower, has flowers on slim, tall spikes that can be seen waving in any slight breeze. It is heavily used in prairie restorations due to its tendency to germinate the first year after seeds are planted. Rough coneflower, Rudbeckia grandiflora, is very rare and found only in a few patches in northeastern Illinois, all in DuPage County.

Purple coneflower, Echinacea purpurea disc and ray florets by DonArnold, 2021

Coneflowers have a composite flowerhead with 200-300 rose-colored florets surrounded by eight to twenty-one ray florets in colors ranging from dark purple to pale pink to yellow or white. Leaves are hairy with a rough texture. Coneflowers spread by self-seeding, dropping seeds within a few feet of each plant as they bend and sway in the wind. The mother plant is a perennial and will continue to return each year.

Several dozen species of butterflies, bees, wasps, beetles, and flies feed off the nectar. Soldier beetles appear late in the season, feeding on insect eggs and larvae deposited on the plants by other insects. Seeds are also a favorite food item for goldfinch, cardinal, and blue jay. Seed heads left through the winter will continue to feed the area birds until spring.

Black Swallowtail on Purple coneflower by DonArnold, 2022

Consider adding some coneflowers to your backyard gardens and watch for the butterflies and birds that will soon visit.

Succulents

Plants that save water!

Succulents are a group of plants able to store water in their leaves, stems, and roots. This group includes between 8,000 and 10,000 species across several plant families, equal to 3%-5% of all plant species. They are found on every continent except Antarctica.

Backyard succulent garden by DonArnold, 2022

Succulents are largely perennial species storing water for use in drought periods. They have features that limit the amount of water loss from evaporation. Most species have thick cuticles, the outer skin, and fewer stomata, the cells on the underside of leaves used for exchanging gases, including carbon dioxide and oxygen, with the outside environment. Many plants exchange gases during non-daylight hours only.

By storing water, succulents are able to survive in habitats with limited water availability, including habitats that receive only dew or mist versus measurable rainfall. Limited water availability may also refer to habitats where infrequent rainfall occurs with lengthy intervening dry periods.

Aloe vera crosscut leaf by Evelyn Chu, Dec 2010

Additional water-saving features include round versus flat leaves and stems exposing less surface area to the air and thus reducing water loss through evaporation. Plant surfaces may be waxy, hairy, or spiny creating micro-habitats to further reduce air movement across the surface. Plants are able to seal and heal wounds quickly. Roots are shallow allowing the plant to absorb minute amounts of moisture reaching the soil.

Hydrangea leaf, flat leaf structure with large surface area, by DonArnold, 2022

Plants retaining large amounts of water must have robust support to handle the extra weight. In smaller plants, additional fiber strengthens stems and leaves. In larger plants, such as trees and shrubs, stems contain thicker wood walls to maintain their upright stature. This provides additional protection against wind damage. In most species, if any part of the plant is broken off, fragments are capable of taking root and growing a new plant.

Since water temperature does not fluctuate as rapidly as air temperature, succulents are able to stay warmer due to the large amount of retained water. Succulents are still vulnerable to damage at very low freezing temperatures, but only over a prolonged period of several hours.

Succulents are often found in homes and backyard gardens and are well-liked because of their low maintenance and unusual appearance. Popular varieties that may come to mind include aloe vera, Christmas cactus, jade plant, sedum, and yucca. Consider starting a small pot on your windowsill or planting some in your backyard. Note: Be sure to pay close attention to the labels identifying which can be grown outdoors in your area.

Aloe vera by Forest & Kim Starr, Dec 2015

Jade plant, Crassula argentea by Hornbeam Arts, Nov 2012

Common Milkweed Pollinators

Observe dozens of pollinator species on one plant

Butterfly weed, Asclepias incarnata, with bee, genus Andrena, by DonArnold 2020

Swamp milkweed, Asclepias incarnata, and monarch butterfly, Danaus plexippus by NatureNerd 2015

There are 15 species of milkweeds in the Chicago area. The genus name, Asclepias is named after the physician Aesculapius, the son of Apollo, who studied medicine under Chiron, a centaur in Greek mythology of great wisdom and knowledge of medicine. The common milkweed, Asclepias syriaca is found in several different habitats that all have plenty of sun and disturbed soils. These areas include old fields, pastures, remnant prairies, fens and along roadsides and railroads. This species and several other milkweed species are favorite plants in backyard gardens.

Common milkweed, Asclepias syriaca by DonArnold 2022

Common milkweed supports many insects and pollinator species. All parts of the plant are used for food including nectar, pollen, foliage and stems. Several species also breed on common milkweed, laying eggs in flowers where larva can feed on nectar and later move to feed on foliage.

Common milkweed foliage, Asclepias syriaca, by DonArnold 2022

Nectar provides food for 14 species of butterflies, four beetles, one weevil, six plant bugs, eight ants, 41 bees, six wasps, and six flies. The bees, wasps and flies also eat the pollen as do an additional ten beetles, three weevils and two ant species.

Black Swallowtail Butterfly, Eastern Tiger Swallowtail Butterfly, Monarch Butterfly, bees in the Andrena genus, and Hummingbird Moths are some of the more common insects that you can observe on milkweeds.

Eastern black swallowtail, Papilio polyxenes, by DonArnold 2020

Monarch butterfly,Danaus plexippus, by DonArnold 2020

All of the bees, wasps, and flies mentioned above plus ten beetle species, three weevils, and two ant species gather pollen from the flowers.

Bee, genus Andrena, on common milkweed by DonArnold 2022

Hummingbird moth, Hemaris thysbe, by DonArnold 2022

Milkweed foliage is food for three beetle species, one earwig, one leaf miner, and one weevil. The foliage also supports seven species of aphids and their symbiotic partners, ten ant species. The aphids feed on the common milkweed stem and leaves, then produce a sweet substance that the ants use for food. In return, the ants provide protection from predators for the aphids.

Ants & aphids on milkweed stem by Linda Tanner, 2012

Observing the many species of insects using this one plant throughout the day is fun and interesting. Many other milkweed species and insect groups are also found in our area. Take along a camera or hand lens on your next walk and watch closely to see all of the activity!

Milkweed beetle on common milkweed by DonArnold 2022

Honey bee, beetle and bumble bee on common milkweed by DonArnold 2022

Long-legged fly on common milkweed by DonArnold 2022

American Goldfinch

As I sit on the backyard deck, watching the thistle feeder hanging within the protection of our Austrian pines, American goldfinches, Spinus tristis, keep this feeder busy most of the day. Finches have the most vegetarian diet of any North American songbird. Their favorite feeder foods include thistle and hulled black-oil sunflower seeds.

American goldfinch, Spinus tristis, female on feeder by DonArnold, 2021

In the wild, they prefer tree and shrub seeds, and other soft plant parts including buds, berries, and sap. All parts provide fiber, nutrients, and a good source of water. During summer, they may incorporate small insects where insect species are abundant, but depend upon seeds for the majority of their nutritional requirements.

American goldfinch, Spinus tristis, female & male coloring by DonArnold 2021

American goldfinches are sexually dimorphic, with different coloration between males and females. In late spring, preceding their breeding season, they have a unique pre-alternate molt that brightens the colors for both males and females. During the breeding season, males are bright lemon yellow with black caps, black wings, and white wing bars. Breeding females are an overall olive green with black wings and white wing bars. They molt again before winter and colors for both sexes become more cinnamon and duller in appearance.

American goldfinch nestlings by Brian Henderson, 2012

Nest sites are selected by the female, who also builds the nest in a crotch of branches well protected by overhanging leaves. Two to seven pale blue eggs are laid and incubated by the female for 12 to 14 days. Males bring food back for the female every one to two hours during incubation and for another two to three weeks after the nestlings hatch. Four to five days after hatching, the male will also begin to feed the nestlings, who are now able to create their own body heat, allowing the female to leave the nest for short periods. Parents continue to feed the young for another month before the young leave the nest.

American goldfinches are rarely troubled by cowbirds, a brood parasite that lays its eggs in other species’ nests. Goldfinch nestlings are fed a sticky, regurgitated mass of seeds with a few insects. This food mixture does not contain enough protein for the young cowbirds to survive.

American goldfinches are gregarious singers, vocalizing a variety of unique songs while feeding, eating, and in flight. Monogamous pairs, males and females will sing identical songs to each other while in flight. This strengthens the pair bonding and helps them identify each other. Males defend the territory around the female rather than around the nest. Squabbling males are an indication that one has gotten too close to the other’s mate.

American goldfinch on goldenrod at Cuba Marsh by JanetandPhil, 2009

Goldfinch eating seed from sunny-day coreopsis by John Brandauer, 2011

A group of finches is known as a “charm,” from the Middle English word “cherm” referring to a blended singing of birds or children. Some plants to include in your gardens to attract these fun, musical companions include coneflower, coreopsis, catmint, sunflowers, black-eyed Susan, and goldenrod. Grasses, cattails, and spider silk are readily used to line their nests for comfort.