Friend or Foe? Insect? Bug? Beneficial? Pest? Insect Relative? Pollinator? Other?
All these terms, and the creatures/animals they represent, can fall into, “What's Bugging Me”. I'd like to introduce you to some common thoughts and definitions about these creatures as well as a little scientific information. Some people use the terms insect, bug, or pest to mean pretty much the same thing, an organism that gets into and/or onto things they shouldn't and cause damage.
What is a pest? A pest can generally be defined as any animal, plant, or other organism whose biology, behavior, or location places it in direct conflict with humans. Because some insects threaten human health, destroy food, damage structures or landscapes, or cause general annoyance or anxiety, they are considered pests. Insect pests can cause serious crop damage; they also carry viral, bacterial, and fungal diseases which they can transmit to crop plants, livestock, and humans.
According to the California Master Gardener Handbook, 2nd Edition, page 176, insects are the most abundant animals on the earth - there are well over one million species of insect. The vast majority are considered neutral or have a beneficial effect.
Entomology is the study of insects. You can find insects just about anywhere on this planet except perhaps in the open ocean. Insects live in or on animals; plants; soil; wood structures; buildings; carpet, furniture, and fabric; water bodies like streams, lakes, ocean shores; and stored food products.
Thinking back to your early school days you might remember learning about taxonomy, a way of categorizing or naming living organisms in an ordered system intended to indicate natural relationships. We learned (well, maybe some of us learned, I always had to look it up) the terms Kingdom, Phylum, Class, Order, Family, Genus, Species. Each level is more specific or defining.
Let's look at the classification of insects:
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: there are over 30 different Orders
Family: each order can have 90 or more Families
Genus: each family has many Genera
Species: each Genera has several Species
As you can see from the taxonomic classification above, insects belong to a group of animals called Arthropods, this includes beetles, butterflies, grasshoppers, dragonflies, ants, and flies to name a few. Arthropods are cold blooded, have an exterior skeleton (exoskeleton) and their adult form must have the following features:
- Three distinct body areas – head, thorax, and abdomen. The legs and wings attach to the thorax.
- Jointed legs, three pairs. The six legs attach to the thorax and can be used for jumping, grasping, or walking
- Antennae, one pair, attached to the head. Antennae are sensory organs. They can be short, long, smooth, serrated, or feathery.
- Wings (none, one, or two pairs). Wings can be colored or clear, ornamental and the vein pattern play an important role in identifying the species.
Some of the more common and frequently encountered Arthropods are:
Order | Common Name | Distinguishing Characteristics |
Coleoptera “hard or sheath wing”
| Beetles | Pair of hardened wings meet in the middle in a straight line down back |
Lepidoptera “scaly wing” | Butterflies and moths | Two pair of wings covered in small powdery scales. Curly mouthparts called a proboscis
|
Hymenoptera “membrane wings” | Bees, wasps, ants | Two pairs of wings, the forewings are generally larger than the hind wings. Generally, have a constricted waist
|
Diptera “two wings”
| Flies, gnats, midges, mosquitos | One pair of wings; second pair is reduced in size and often not seen |
Hemiptera “half wings” or “different wings”
| True bugs*, leaf or treehoppers, aphids, scale | Two pairs of wings, a thick outer part and a membranous wing that folds up and look like a triangle |
Orthoptera “straight wings” | Grasshoppers, crickets, katydids | Four wings, front ones thickened: jumping hind legs. Stout mouthparts.
|
* Definition of bug: any in the order(Hemiptera and especially its suborder Heteroptera) of insects (such as an assassin bug or chinch bug) that have sucking mouthparts, forewings thickened at the base, and incomplete metamorphosis and are often economic/agricultural pests.
Several other creatures in the Arthropod phylum are often called insects or bugs but their characteristics and taxonomy are different so they aren't really insects, and some can be considered pests. Think of them as insect relatives. Common insect relatives in the garden and home include spiders (Class = arachnoid), scorpions (Class = Scorpiones), fleas (Class = Siphonaptera), centipedes (Class = Chilopoda), and pillbug (Class = Isopoda).
Some of the creatures we call bugs/insects/pests are not arthropods at all but are in a different taxonomic phylum and class. Snails and slugs fall into this category. They are in the Phylum = Mollusca and Class = Gastopoda, and they are the bane of many a gardener.
For the most part, insects are identified by genus and species and of course their common name which can be one thing on the west coast, another in the mid-west, another on the east coast and another in other parts of the world. Common names can get us in trouble, take for example the common name, pillbug, roly-poly bug, doodle bug, sow bug (not in the same family), wood louse, potato bug, slater and armadillo bug have all been used to identify the same creature. Using the scientific name, Armadillidium vulgare, helps us talk to each other about the same organism which is why taxonomy is important.
You can see that all this bug, insect, and pest stuff can be quite complicated and interesting. Future What's Bugging Me columns will focus on land dwelling arthropods and perhaps a few other phylum/classes of creatures that we find in our garden, landscapes and home be they bug, insect, or pest, friend or foe. We'll look at what they are, what they do, what they look like, ways to control them, ways to encourage them and more. Here's one to get us started:
- They are not insects or true bugs
- They are soil dwelling crustaceans in the class Crustacea, order Isopoda, family Armadillididae
- Description:
o Small heads with antennae, six small abdominal parts, seven large thoracic segments each with a pair of legs attached.
o Hard, shell like covering made up of segmented plates which allows them to roll up into balls when disturbed. They have an “armored” appearance.
o Coloring & Size:
- Immatures are pale yellow to whitish and about 1/12th of an inch long (1 – 2 mm.)
- Older pillbugs are brown to dark gray and about 1/3 to ¾ inch long (8mm - 1 cm long). If they have recently molted, they can appear blue.
- Life cycle:
o Adults can live 2 – 5 years
o Pillbugs are prolific, giving birth to 30 – 80 young per brood. Producing 2 to 3 generations a year.
o Eggs are kept in a brood sac on the underside of the females
o Eggs hatch about one month after being produced and stay in the brood sac until they emerge about 2 weeks later.
o For the next 4 to 5 months, the young will molt every 1 – 2 weeks as they grow into adults.
- They live under organic litter and other debris on the ground beneath low-growing plant parts. They prefer moist areas over dry ones.
- They can be considered beneficial because they feed primarily on decaying plant material and are important decomposers of organic matter.
- They can also be considered pests as they also like to chew on fruit, succulent plant parts, seedlings and vegetables that touch damp soil. And sometimes they come into the house.
If you have placed them in the pest category here are some solutions:
- Clean-up debris around your plants. Eliminate unnecessary piles of leaves, grass clippings and mulch.
- Flowerpots, planters, dog houses, firewood, bricks or other objects that sit directly on the ground should be elevated to allow airflow and drying underneath. This decreases their hiding and breeding spots.
- Minimize wetness on the soil surface, water in the early morning.
- If they are coming indoors, seal or screen gaps around openings in buildings.
- They are harmless and can be removed by hand or vacuumed. Due to decreased moisture indoors, they rarely survive more than a day or two.
See you next time on What's Bugging Me?
Resources:
California Master Gardener Handbook, Second Edition
How to Manage Pests, Pests in Gardens and Landscapes, Pillbugs and sowbugs http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/PESTS/sowbugs.html
Michael Merchant, Ph.D. Texas A&M AgriLife Extension, Insects in the City, Pillbugs https://citybugs.tamu.edu/factsheets/landscape/veggie/ent-1006/
Whitney Cranshaw, Colorado State University, High Plains Integrated Pest Management, Pillbug, https://wiki.bugwood.org/HPIPM:Pillbug
University of Florida, IFAS, Institute of Food and Agricultural Sciences https://blogs.ifas.ufl.edu/entnemdept/2014/05/06/difference-between-insect-and-a-bug/
Webster Dictionary https://www.merriam-webster.com/dictionary/bug
Image: Insect illustrations | ala.org | CC BY SA 3.0 https://www.mylearning.org/resources/hand-drawn-illustrations-of-insects
Image: Adult Pillbugs http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/PESTS/sowbugs.html
Image: Defensive Pillbug https://wiki.bugwood.org/File:PillbugF4.jpg
