July 2021 – Discover-Nature

Field Guides

Field guides are special books. Lots of them fit in your pocket and can be used out in the field to identify particular plants or animals. Field guides come in several formats, and address aspects of nature using differing methods. Let’s take a look at a selection of these and how we might use them.

Traditional field guides contain a list of all the species within a class such as mammals, birds, or insects. If the class is very large, a guide may only contain species from one or more orders. There are thousands of species of insects, but this class can be broken down into many manageable orders such as bees, dragonflies, beetles, and more. Guides provide information on names, field marks, range maps, habitat, food, reproduction, predation and impacts from/to humans. The arrangement of information within a field guide can be based on one or more identifying characteristics such as color, field marks, taxonomy, habitat, or a unique feature, i.e. number of petals. Many guides use a dichotomous key, an identification method that asks a series of questions and offers two choices for each answer, eventually leading to a single organism.

Guides by Geographic Region, by DonArnold

Several traditional field guides are issued as parts of series intended to cover a wide variety of life in specific geographic areas. General guides include Peterson’s Field Guides series; The Audubon Society series, and North Woods Naturalist series. Pocket-size field guides are limited to only a select group of species within a class or order, usually the most common ones that are likely to be found. Some that may be of interest include Birds of Illinois by Stan Tekiela; Kaufman Field Guide to Birds of North America, and the Golden Nature Guides. Other series take several books to cover only one class of animal. Examples of these guides include The Sibley Guides, Stokes Field Guides, and The Crossley Guides, all of which include multiple volumes about birds.

Nontraditional field guides teach us about nature by using a descriptive element applied to a group of species. Consider some of the following:

Guides by habitat – Peterson’s Eastern Forests; The Book of Field and Roadside by John Eastman; Discover Nature in Water & Wetlands by Elizabeth P. Lawlor
Guides by characteristic – Peterson’s Eastern Birds’ Nests; Pollinators of Native Plants by Heather Holm; Tracks & Signs of Insects and Other Invertebrates by Charley Eiseman and Noah Charney
Guides by geographic region – INHS Field Guide to Reptiles & Amphibians of Illinois; North Woods Naturalis Series; Trees of Illinois by Linda Kershaw; Flora of the Chicago Region by Gerould Wilhelm and Laura Rericha

The latest technology in field guides is to have information and search capabilities using an app on your phone or tablet that you can carry with you. Three of my favorites include Seek by iNaturalist for plant and animal identification; Merlin Bird ID by Cornell Lab of Ornithology for bird identification; and SkyView by Terminal Eleven for stargazing at night. All of these let you use the camera on your device to take a picture to identify the object or view. Follow-up questions are included to help refine your ID and provide you with additional information.

For those of you who like to keep it simple, consider making your own field guide. Start with a nature coloring book or a blank sketchpad. Do your own drawings, colorings, and field notes. This type of field guide accumulates extensive information over the years and becomes a treasured source for descriptions and notes on your own personal interaction with nature. Any way you choose to learn, get out and have fun today!

Grasshoppers

Grasshoppers, familiar insects of summer, are found all over the world with about 550 species native to North America. Grasshoppers, crickets, and katydids make up the insect order Orthoptera, characterized by hard, external skeletons, three pairs of jointed legs, three-part bodies, compound eyes and two antennae. Their mouths are used to shear vegetation and the palps on either side of the mouth are used for feeling and tasting. Tympanal organs are holes under the wings, at the base and sides of the abdomen and perform the same function as human ears. They have a leathery upper pair of wings that folds over to cover and protect a lower pair of wings. The back legs are large and muscular for jumping.

Differential Grasshopper, Melanoplus differentialis by Phil Myers, Museum of Zoology, UMAA

Grasshoppers are one of the many insects that use singing to attract a mate. The hind legs are used as a “bow”. A set of peg-like protrusions on the inside of the leg are drawn across a raised vein on the forewing making a rasping sound. This is called stridulation. Other species may use crepitation, the ability to make loud snapping noises with their wings while in flight. Although both males and females are capable singers, singing is all about staking territory and finding a mate, and males tend to be more vociferous. Grasshoppers are strictly daytime singers and get more vocal as daytime temperatures soar.

Mischievous Bird Grasshopper, Schistocerca damnifica by Judy Gallagher

In all singing insects, females will begin searching for a place to lay eggs immediately after mating. Breeding sites require undisturbed soil found in empty lots, roadsides and open fields. A female will push her ovipositor into the soil and secrete a frothy substance within which the eggs are suspended. This dries into an inch long plug containing two to a hundred eggs. Eggs remain underground over winter and hatch in spring. Nymphs are simply miniature adults, molting through five instar stages while they grow. Wings and sexual organs develop during this period. A large number of eggs are lost each year to soil disturbance and weather, especially flood conditions.

Red-legged Grasshopper, Melanoplus femurrubrum by Phil Myers, Museum of Zoology, UMAA

Spur-throated Grasshopper, Melanoplus ponderosus by Alfred Crabtree

Grasshoppers are a type of locust, a group of insects found in swarms that may be harmful to crop production, although this behavior is rare in Illinois. They are well adapted to urban environments, feeding mostly on a variety of grasses, but they may also eat leafy vegetables, beans, corn and ragweed. In agricultural fields their favorite foods include alfalfa, corn, barley, and wheat. A heavy infestation of 16-17 grasshoppers per square yard will consume one ton of leaves per day in a 40 acre field. Grasshoppers are particularly hard to control because of their great mobility, but, there are natural controls from predators including poultry, birds of prey, spiders and rodents to diseases caused by fungi, protozoa and nematodes.

Two-striped Grasshopper, Melanoplus bivittatus by Phil Myers, Museum of Zoology, UMAA

Observe a grasshopper while it is eating and notice the ragged, serrated edge left along the chewed area versus the smooth-edge cut from a caterpillar. When molting, they hang upside down from grass or twigs. The skin splits open along the back and the insect pushes outward to clear its wings and antenna first from the old casing. When moving through wet soil, hopping leaves two deep impressions from the rear legs with four much lighter impressions from the front toes and sometimes a line down the center where the abdomen may drag. Nymphs are able to move long distances by walking, while adults can fly miles at elevations of several hundred feet. Have some fun watching these interesting insects and their behaviors in your own backyard.

Fireflies

Lightning bugs are fireflies, but fireflies are not flies and lightning bugs are not true bugs. Fireflies are winged beetles in the Lampyridae family. The family is known for their ability to produce light from chemical reactions. There are about 2000 species worldwide, including almost 200 in North America, but only three species can be found in Illinois.

Photuris pennsylvanica, Pennsylvania firefly by Dann Thombs-2

Fireflies use their lights as signals to find mates. Preferring early summer’s warm and humid evenings, fireflies start to flash as soon as it is dark, and continue for several hours. Males fly a repetitive pattern in one area, flashing and watching for a return flash from a female lying in wait in the grass. Each species has a unique flash pattern determined by interval between flashes, flash color, number, rate, brightness, and how far the firefly travels between flashes.

Photinus pyralis, Big Dipper firefly by Terry Priest

The big dipper firefly, Photinus pyralis, has a black body, wings edged in bright yellow, a black and yellow belly, and the top of the head is yellow with a red patch and a black center dot. Big dipper gets its name from its signature flash, starting bright and dimming as it swoops in an upward “J” arc. The black firefly, Lucidota atra, has completely black wings, and a head topped in yellow with a large black center spot edged in red. Black fireflies can emit light, but unlike other fireflies that flash to find a mate, they use pheromones. The Pennsylvania firefly, Photuris pennsylvanica, is similar in appearance to the big dipper but only the outer edge of the wing is striped in dark orange. They emit a yellow-green glimmer every few seconds, but females may flash the signal of the big dipper to attract a male of that species. The female captures and eats the male to gain a steroid that naturally occurs in his body and makes the female taste bad to her main threat, jumping spiders.

Lucidota atra, Black firefly by Phil Myers, Museum of Zoology, UMAA

Flashes are the result of a chemical reaction in specialized cells, called photocytes, located in the abdomen. Oxygen is taken directly into these cells and combined with the chemical luciferin and an enzyme, luciferase. The light emitted is controlled by limiting the amount of oxygen. Fireflies produce cold light, one of the most energy efficient sources of light in nature. Over 99% of the reaction produces light vs. about 10% from an incandescent light bulb where the rest of the reaction is heat. In human medicine, luciferase, created from genetically engineered chemicals, is used to screen for tumors, blood diseases, and as a fast-acting detector of infection.

Photuris pennsylvanica, Pennsylvania firefly by Dann Thombs

Fireflies live for a little over a year. After mating, females will lay about 500 eggs. Adults will die soon afterwards. In about four weeks, the eggs will hatch and flat, worm-like larvae will spend the summer in moist areas under logs or leaf litter. They are nocturnal and prey on earthworms, caterpillars, and other soft-bodied invertebrates. As winter approaches, they will move to underground burrows and continue feeding until spring. Their sickle-shaped jaws inject a toxin that helps to liquify the insides of their prey, allowing the larvae to suck out the nutrients. Leaving their underground burrows in spring, they search for a mate and begin a new cycle.

Lucidota atra, Black firefly by Katja Schulz

Fireflies have been steadily declining over many years from habitat loss, pesticide use and light pollution. We can help by mowing the lawn less often or leaving the grass taller in places to provide a safe area. Leaving leaf litter or rotting wood in garden beds provides for eggs, larvae and prey. Avoiding pesticides, especially lawn applications, preserves healthy habitat. An essential element to mating is the ability to see each other’s flashes. Reducing our use of outdoor lighting provides darker areas so flashes are more visible and recognized. I hope you enjoy this wonderful summertime phenomena in your own backyard theatre tonight!

Beavers

Beavers, Castor canadensis, members of the order Rodentia, are mammals characterized by a single pair of continuously growing teeth located in each of the upper and lower jaws. Between three and three-and-a-half feet in length, beavers weigh 26 to 60 pounds. Their fur is reddish-brown with an outer layer of long, coarse guard hairs covering an inner layer of fine, short hair. Beavers often groom themselves and comb oil into their fur to make it waterproof, keeping the animal dry and warm. Their tails are covered with leathery scales and a few short hairs.

Castor canadensis, American beaver by Phil Myers, Museum of Zoology, UM-Ann Arbor

A beaver’s body, shaped like a bullet, is made for swimming with a top speed of 6-mph in the water. Their back feet have five toes with flexible webbing in between providing lots of power in the water, but making them rather clumsy and slow on land. Several other adaptations assist in making a beaver an incredible swimmer. Valves in their ears and nose can be closed to prevent water from entering. The eyes have a transparent eyelid that closes, protecting the eye, but allows them to still see underwater. Beavers can remain underwater for up to 15 minutes, covering a half-mile in distance. Upon diving, the heart rate slows by half, and the animal can tolerate a considerable amount of carbon dioxide buildup before requiring clean oxygen. They keep their front paws balled up in fists close to their heads to act as bumpers to push floating debris away, and their tail acts as a rudder.

Castor canadensis, American beaver by Tanya Dewey, American Diversity Web

Beavers live in colonies including a male and female who mate for life, their yearlings and new born kits. Kits mature in one-and-a-half to two years, and are then encouraged to move out on their own. Evidence of beaver activity in an area includes dams, gnawed trunks, paths and mudslides. Beavers make paths about a foot wide with trimmed edges and a brushed surface leading from their dwelling to feeding grounds. As paths become well used, they turn into mudslides when they lead into a pond. Usually roaming no more than a half mile from home, families will leave scent mounds of mud and bark mixed with anal gland secretions to mark their territories. When swimming, tails are used to send a warning by slapping the water. This not only creates a loud sound, but also can be used to generate a wave of water in the face of a potential predator allowing the beaver time to escape.

Path of Castor canadensis, American beaver by Tanya Dewey, American Diversity Web

Beavers are herbivores, and the plants they eat depend on what species are available in their home habitat. Woody species are an important food source during winter months, and are harvested in summer and fall to be cached in their dwelling or at the bottom of ponds near the dwelling entrance. These can then be accessed during winter months even if ponds are frozen over. Beavers are known to eat willow, river birch, maple, cottonwood, black cherry, dogwood, beech, and oak. They also eat roots and rhizomes of aquatic plants including water lilies, duckweed, arrowhead, and cattails, and will consume grasses, sedges, clovers, and corn on land. Beavers eat one-and-a-half to two pounds of food daily.

Bank dwelling of Castor canadensis, American beaver by Tanya Dewey, American Diversity Web

In the mid-to-late 1800s, beavers were extirpated in many localities by trapping for the fur trading industry. Reintroduced from neighboring colonies throughout the first half of the 1900s, beavers continue to fill an important role in the proper functioning of an ecosystem from blocking flowing water to create new wetlands to removing stands of trees and allowing new vegetation to colonize an area. New wetlands attract waterfowl, turtles, snakes, mammals, and insects. After several generations have cleared the surrounding land of trees and shrubs, beavers will move to a new area, allowing the abandoned homesite to slowly drain and fill in with new soils and opportunities for meadow flora and fauna.

Cattails

Cattails are a familiar plant seen growing in wetland habitats throughout the area. Native to many parts of the world, including North America, South America, Africa and Eurasia, they provide food and protection for many species living in wetlands. Cattails are an emergent plant, with roots growing in soil underwater and the remainder of the plant emerging above the surface, into the air. Cattails prefer six to eighteen inches of water, although they can tolerate drought conditions as long as the soil remains moist.

Broad-leaved cattail, Typha latifolia by Tom Benson

Narrow-leaved cattail flowers, Typha angustifolia by Ryan Hodnett

There are two species of cattails common in Illinois. Broad-leaved cattail, Typha latifolia, and narrow-leaved cattail, Typha angustifolia, have many of the same characteristics and hybridize easily, so identification may be difficult. Stems are three feet to nine feet tall and are firmly anchored in the wet soil by a complex system of fine, tentacled roots; they are flanked by slightly shorter, narrow, upright, olive-green leaves. Separate groups of male and female flowers grow at the top of the stem. Yellow male flowers are located at the tip above a thick, velvety cluster of dark brown female flowers. The male flowers of broad-leaved cattails grow immediately above the female flowers, but on narrow-leaved cattails there is a space of several inches between the two groups.

Broad-leaved cattail flowers, Typha latifolia by Kevin Kenny

Both cattail species live in the same habitat and are aggressive spreaders. They utilize two different reproductive strategies. Rhizomes, roots growing horizontally along the soil surface, begin to spread in autumn. They cease growth during the colder temperatures of winter, but become active again in spring. Where the rhizome comes in contact with the soil, a new clone of the original plant is started. Clonal clusters grow in tight masses of up to a hundred stems. A second reproduction strategy is wind pollination. Pollen, a male sex cell, fertilizes female flowers. Seeds are then also spread by the wind. After pollen is dispersed, the male portion of the flower spike withers and falls off. The dark brown cluster of seeds may include up to 200,000 per stem. As seeds pull away from the stem, an attached silk plume billows out behind, allowing the seed to be borne long distances on steady breezes.

a quiet canoe trip on Isobel Lake…a Marsh Wren’s (Cistothorus palustris) desk amongst the reeds…Marsh Wren nest by Murray Foubister

Wetlands provide safe habitat for many species of spiders, insects, fish, turtles, birds and mammals. The denseness of cattail clusters keeps predators out while providing small pockets for homes. The area is a favorite for marsh wren, red-winged blackbird, yellow-headed blackbird, American coot and many species of rails and bitterns. Leaves are used for building nests and muskrat lodges. Young leaves provide food for many insects, mammals and birds. The carbohydrate-rich rhizome is an important food source for muskrat and geese. Seeds are rarely eaten, but seed heads provide over-wintering habitat for several moth larvae which in turn are a spring food source for many birds.

Muskrat with cattails by Michael B Smith

Early native Americans also enjoyed cattails in their meals. Flower spikes were roasted and served like corn cobs. Pollen was mixed with wheat flour to provide a nourishing base for bread. Today, leaves are woven into chair seats, rugs, and mats. Look for stands of cattails in nearby wetland communities, and observe the other species that live among them including ferns, rushes, sedges, grasses and the many animals that call these environments home.