North American Insects & Spiders

Marbled orbweaver female

Spiders are the largest group of arachnids. They are easily recognized by their eight legs, and there are few creatures great or small that elicit such irrational fear in mankind. The vast majority of spiders are completely harmless. Spider Index

Halictidae -Agapostemon splendens on Aster

Hymenoptera: Bees, Wasps, & Ants belong to this large order, which also includes sawflies. Most species are solitary, but some, such as the domestic honeybee, exhibit a complex social structure in which exist sterile female workers and fertile male and female royalty.

Hymenoptera (Latin for “membrane wing”) is a vast assemblage of insects second only to Coleoptera (beetles) in the number of described species. Hymenoptera number some 115,000 species vs. 450,000 in Coleoptera. 18,000 of these species call North America home.

Hymenopterans inhabit a wide variety of habitats, and show an incredible diversity in size, behavior, structure and color. The social colonies formed by bees and ants are among the most complex societies on earth, which may contain millions of individual insects; all programmed with a simple ruleset that describes their every motion through every stage of their lives. Leaderless. Commanded and guided with pheromones and other communicative chemicals generated by her peers and her queen, these little suckers are indeed masters of their environment. They practice sustainable agriculture and only use renewable resources – and have for millions of years. Humans, take note!

Most hymenopterans are happiest (I hope such creatures are capable of feeling well-being) and most active on warm, sunny days, but there are those on the dark side; nocturnal or crepuscular. All adults have chewing mouthparts; bees and some wasps have modified tongue-like structures for drinking liquid nectar. Winged species have four membranous wings which can be hooked together in pairs during flight. This arrangement allows then to fold their wings while at rest, and provides a larger, more efficient wing structure while in the air.

Blister Beetle – Lytta aenea

Coleoptera: Beetles are the dominant form of life on earth: one of every five living species is a beetle. Coleoptera is the largest order in the animal kingdom. There are about 450,000 species of beetles, 30,000 of which live in North America.

Aristotle described beetles as “insects with wing cases” = Coleoptera, from Greek koleon, “sheath”, and pteron, “wing.” Beetles live in nearly every habitat, and for every kind of food, there’s probably a beetle species that eats it. Beetles first appeared during the lower Permian period, about 270 million years ago.

Along with butterflies, bees, flies, moths and some other invertebrates, beetles have the most complex form of metamorphosis, called complete metamorphosis, or holometabolous development, which includes four distinct phases: egg, larva, pupa, and adult. Eggs develop in the female beetle’s ovaries, and are laid in a protected place with conditions suitable for the development of the larvae, including a ready food supply. Eggs are laid singly or in masses; hatching occurs within several days.  Beetles Index

Northern Pearly Eye Butterfly

Lepidoptera: Butterflies are revered for their brightly colored wings and pleasing association with fair weather and flowers. Lepidoptera comprises at least 125,000 known species including 12,000 in America north of Mexico. Learn to identify many of North America’s common species through large format pictures and natural history. -Butterfly Index-

Skipper Butterflies might be one family that come as a surprise to many people. These speedy, feisty creatures will have you cheering for more!

Lepidoptera: Moths. Unlike the butterflies, moths are usually nocturnal. Many moths and their caterpillars are major agricultural pests in large parts of the world, e.g. moths in the family Tineidae are commonly regarded as pests because their larvae eat fabrics, clothes and blankets made from natural fibers such as wool or silk; moths in the genus Farinalis feed on stored grain, flour, corn meal and other milled grain products.  -Moths Index-

Diptera: Flies are prevalent in virtually all habitats, with over 16,000 species in North America. Flies are distinguished from all other insects in that they only have one pair of normal wings.  Mouthparts are adapted for piercing, lapping and sucking fluids (often blood).  Perhaps the world’s most-famous fly, the mosquito, kills more humans than any other invertebrate disease vector. Flies Index

Orthoptera: Grasshoppers, katydids and crickets have long, powerfully muscled hind legs that they use for jumping, large, flat-sided heads with big compound eyes and large chewing mouthparts.  Grasshopper and cricket males are known for their musical sounds made when they rub together roughened portions of their wings or legs. Orthoptera Index

Hemiptera: True Bugs species number almost 5,000 in North America, and 40,000 worldwide. Hemiptera was first recognized by Linnaeus by dint of its possession of distinctive mouthparts, in which the maxillae are modified into a pair of concentric tubes forming salivary and food canals; the mandibles serve a cutting function when introducing the proboscis into the food source, be it flora or fauna.

This feeding method requires liquid food. Saliva may serve a variety of functions including histolysis, paralysis, or anticoagulant, and passes through the salivary canal to the food source. The liquid food is then drawn into the insect gut through the action of pharyngeal and cibarial pumps (the cibarium is the primary sucking organ in mosquitoes). Bugs suck, literally.

It is the introduction of the proboscis and associated chemicals (and sometimes pathogens) into the host that make the bug family so destructive to agriculture and to its animal victims. (See mosaic leaf damage and Chaga’s disease.) -Bugs Index-

Dictyoptera: Mantids and cockroaches. Mantids have triangular heads with huge compound eyes, long, thin bodies, four thin legs, and prominent forelegs held in the characteristic prayerful pose.  The strong mouthparts can cut through even heavily armored heads of insects.  Both genders use their exquisite camouflage and ability to remain motionless to lie in wait and ambush unwary prey.

Neuroptera: Lacewings in this order have many veins and cross veins in their four transparent wings. There are only 338 species in North America. The order includes lacewings, antlions, mantidflies, and spongillaflies.  Green lacewings, one common species, has large, copper-colored compound eyes and long, thin antennae (above).  Their larvae are commonly called aphid lions after their voracious appetite for aphids.

Ephemeroptera: Mayfly adults survive only a few hours or at most a few days. They eat nothing, nor do they crawl or walk. They only fly and mate, sometimes in swarms so large they show up on weather radar.  The chief importance lies in their value as food for fish, dragonfly nymphs and birds. Anglers imitate the adults in dry flies, referred to as “spinners” or “duns,” and pattern wet flies after the nymphs.

Archaeognatha: Bristletails
There are about 22 species of bristletail in 12 genera in 2 families in North America, with 350 species worldwide. In spite of their other-wordly appearance, bristletails are insects with six legs. They prefer grassy or wooded environments; under tree bark, in leaf litter and rock crevices, under rocks.  Often confused with silverfish, bristletails are not found indoors.

Mecoptera – Scorpionflies
Family Panorpidae: Scorpionflies, hangingflies and allies. Scorpionflies do not sting or bite. They spend most of their time in low vegetation, hunting small soft-bodied insects or scavenging on fruit, dead insects and bird droppings. Mecopterans have changed little from fossils 250 million years old, and entomologists consider now-extinct members of this order to be ancestors of modern flies, butterflies, and moths.

Classes Diplopoda (Millipedes) and Chilopoda (Centipedes)
Millipedes do not bite, pinch or sting, but may emit foul-smelling or irritating defensive chemicals. The house centipede can complete its life cycle indoors, as many a terrified homeowner can attest.

The house centipede pictured here is considered harmless to humans or their pets. Size: Body = 25mm, overall = 7cm. Centipedes are some of the oldest terrestrial animals, and some of the very first creatures to crawl from the sea onto the land were probably very similar in appearance to modern centipedes. All centipedes are nocturnal predators which live by actively hunting down insects and other small creatures. They are found mostly in tropical forests, but have also established themselves in temperate forests, deserts, and human habitations. Commonly called “hundred-leggers”, most centipedes have between 15 and 30 pairs of legs, one pair on each body segment.

Tree Encyclopedia
Explore over 3,000 large pictures in more than 450 species, with leaves, bark and form detailed. Trees are the longest-lived and largest organisms on Earth, and have been thriving for more than 370 million years. Today, they can be found almost everywhere from the Arctic Circle to the Sahara Desert. Trees are the climax species nearly everywhere; if arable land is left fallow, it eventually becomes host to trees.  -Trees Index-