I am starting with this one because the colloquial term “bug” is typically used for anything creepy and crawly. This includes spiders, ticks, insects, earthworms, centipedes, and millipedes. My heart sank a little bit when I heard someone refer to a frog as a “bug”.
First, let’s go back to 7th grade taxonomy. remember KPCOFGS. Kingdom, Phylum, Class, Order, Family, Genus, Species. – there are multiple sub and super taxa along with tribes, but for the sake of this blog, let’s stick to the basics.
Kingdom: Animalia; Phylum: Arthropoda; (Subphylum: Atelocerata) Class: Hexapoda
So let’s assume you know what an Insect is. 3 pairs of legs, body tagma differentiated into three distinct regions: Head, Thorax, Abdomen. jointed appendages… Multiple types of mouthparts. Most insects are economically important because of their feeding habits. Think locusts or mosquitoes.
All insects are in the Class Hexapoda. But wait Jake… Wikipedia and the internet are telling me insects are in class Insecta? Why are you telling me different. Answer: I, like most other entomologist, use a book called Borror and DeLong’s Introduction to The Study of Insects as my guide to insect taxonomy. It is important to note, I am NOT a taxonomist. They squabble and argue over things like this, but for the sake of this blog, I use B&D’s Introduction to the Study of Insects. Great book for any starting entomologist. Some taxonomists use the term Insecta and Hexapoda interchangeably. I will not, because there are some Hexapods that are NOT insects (Diplurans, Collumbolans, Proturans) and assigning them all to class: Insecta can get confusing.
True bugs are in the order Hemiptera. Most insects are classified taxonomically according to their mouthparts and other external anatomical features. Hemipterans have piercing sucking mouthparts, (think of a long straw like proboscis) or haustellate mouthparts. The best example I use when describing them are stinkbugs. Everyone is familiar with the brown marmorated stink bug that has become the bane of the east coast (I will post about them soon I promise). Other examples would be cicadas, giant water bugs, assassin bugs, and really cool looking fulgorids (google em). A cockroach is NOT a bug. A fly is NOT a bug. A praying mantis is NOT a bug. A butterfly is NOT a bug. All true bugs are insects but not all insects are true bugs. Get it? Good.
Most feed on plants; however, the kissing bug and others in the family Triatominae are obligate blood feeders of humans. They spread Chagas disease.
That being said, in the entomological world, the term “bug” is still used colloquially. I refer to myself as a “bug nerd” on regular basis and the term has become somewhat of a running joke among entomologist.