Aerial Insects
Ephemeroptera
The Mayflies
Mayflies are among the most ancient of insects, evolving in the Carboniferous period some 350-280 million years ago. The ordinal name Ephemeroptera is derived from the Greek word "ephemeros", which means "lasting a day". As many people know, adult mayflies live only a few days at most. However, this brief stage occurs after the mayfly has spent much time as an aquatic larva - as long as 3 years in some species. It has been said that this adult, sexual form is merely a vehicle which the larvae use to create more larvae! Mayflies are predominantly associated with freshwater but a few have adapted to live in brackish water; one species has terrestrial larvae. Adults emerge solely to mate and die. They do not eat, filling their guts with air instead, adding to their delicate nature. Unique among insects, mayflies first pass through a temporary phase called a "subimago", a non-sexual adult. Lacking the colors of the true adult into which it will soon molt, this is the smoky-winged “dun” used by fly fishermen. In fact, mayflies constitute the primary basis for both the sport and the technique of fly fishing, not to mention fly tying. In English vernacular, mayflies are known by many other names; willowflies, shadflies, drakes, and spinners, to name but a few. In the temperate parts of Earth they emerge in summer but in the tropics, they may emerge year round. This wide range of species (about 2,500 known so far) feeds on everything from algae to other invertebrates. Some are filter feeders, using long setae on specially adapted forelegs and mouthparts to collect floating food particles. Many mayfly larvae are highly sensitive to toxins in their water supply, particularly those from acid rain. As such, they are excellent indicators of a stream’s health. Mayflies have been exterminated from many bodies of water in both the U.S.A. and Europe, to the loss of much potential fish stock. This is a sad story for an insect so vital to the quality of freshwater ecosystems. Fly fisherman, unite!
Mecoptera
The Scorpionflies
The scorpionflies evolved early on, perhaps about 280 million years ago during the Permian period where they account for 40% of the insect fossil record. Related to seemingly many and yet none of the other insect orders, scorpionflies are strange insects, defined by what they are not. Their ordinal name, Mecoptera, is derived from Greek words meaning, "long wing", of which they have two pairs. They are small insects, with a wingspan of no more than 5cm (2"), and generally much less. They have primitive biting mouthparts that project downward to form a unique, beak-like rostrum. Males of the family Panorpidae have enlarged, upturned abdominal tips, giving rise to their common name, scorpionfly. However, they do not sting and these forceps serve only to grasp the female during mating. Most scorpionflies are associated with shady places and thickets, frequently found at rest on foliage with their wings folded back on their bodies, but the Snow Scorpionflies (Boreidae) are nearly wingless and found in association with cold-weather zones in Europe and North America. Female scorpionflies lay their eggs in soil and the eruciform (caterpillar-like) larvae spend their lives burrowing. Full grow larvae pupate in cells dug out beneath the soil, emerging a few weeks later. Adults and larvae feed on other insects. There are less than 400 known species in 8 families, five of those families occurring almost exclusively in the Southern Hemisphere: Choristidae, Nannochoristidae, Notiothaumidae, Austromeropeidae, and Meropeidae. The geographically-limited family Boreidae seems to contain only about 40 species while Panorpidae and Bittacidae, contain almost half of all known Mecopterans.
Megaloptera
The Dobsonflies, Fishflies and Alderflies
Megaloptera is the order that contains the dobsonflies, fishflies and alderflies. Some scientists consider them a suborder of the Neuroptera but we will treat them as a separate order. Large wings characterize these insects, a trait which earned them the ordinal name "Megaloptera", derived (with no surprise) from the Greek words for “large-wing”. Indeed, adult dobsonflies can reach very great proportions, with wingspans of up to 15cm (6”). The Megalopterans can all be found near fresh water where their aquatic larvae dwell. The female lays her eggs in large masses close to water, often on vegetation. All Megalopteran larvae feed carnivorously, capturing other aquatic insects with their powerful jaws. Larvae may grow slowly, taking several years to reach the last larval instar. When maturity is reached, the larvae crawl out onto land to pupate, hiding themselves in soil or under logs. The short-lived adults emerge later to mate, often eating no food. Some, like male dobsonflies with their tusk-like mandibles, are formidable in appearance yet relatively harmless. The larvae of dobsonflies, called "hellgrammites", may be familiar to some, as fishermen often use them for bait. There are about 300 known species of Megalopterans.
Neuroptera (=Planipennia)
The Lacewings, Mantisflies, Owlflies and Antlions
A diverse and interesting order, Neuroptera contains some well-known species (like the beneficial green lacewings) but is otherwise almost totally unheard of by the layman. Perhaps best “know”, but totally misunderstood, are the doodlebugs. Doodlebugs really do exist; they are not just made-up insects that decorate childrens’ clothing and toys. While the name “doodlebug” has been given to German WWII era flying bombs as well as to self-propelled train coaches, the name really refers to the larval stage of a very interesting insect called an "antlion". Antlions have become very well known for these larvae, dubbed doodlebugs, which build conical pits in sand and dry soil. These larvae lie in wait, buried just beneath the bottom of their pit, and feed on the insects (mainly ants) which fall in. When they have reached maturity, they spin cocoons and pupate into winged adults. All Neuropterans have a larval stage that is predatory and all these larvae eventually transform into winged adults which are mostly predatory. Neuroptera is an order that still remains to be worked on by scientists. Some consider the orders Megaloptera and Raphidioptera to be a part of the Neuroptera; others consider each one a separate order. We treat them as the latter since they are a very diverse group, containing mantisflies, owlflies, spongeflies, antlions, and many kinds of lacewings. The ordinal name "Neuroptera" is derived from the Greek words for “nerve-wing” and references the extensive veining in the wings of most Neuropterans. It does not mean that they have nerves in their wings. The earliest Neuroptera fossils date back to the Permian period (225-280 million years ago) and mark Neuropterans as being the first insects to exhibit complete metamorphosis. At current, there are about 4,500 known species.
Odonata
The Dragonflies and Damselflies
Odonata is the order that contains the dragonflies and damselflies. First appearing in the Carboniferous period some 350-280 million years ago, the Odonates represent some of the most ancient insect forms. Fossil dragonflies dating from the subsequent Permian period (225 million years ago) are almost identical to modern forms. All Odonates are predatory throughout their entire life cycles (the name "Odonata" means "toothed-ones" in Latin). Dragonflies and damselflies are different in structure but similar in general habits. Damselflies have wings that are more teardrop-shaped than those of dragonflies and heads that are more barbell-shaped, with eyes comparatively smaller than those of dragonflies. They are weaker fliers and seem to flutter, a sharp contrast to the agile dragonflies who, with their strong wings and large heads (comprised mainly of two huge eyes), are masters of the sky. Superb fliers, dragonflies are incredibly skilled aerialists and can hover, fly backwards and perform maneuvers so fast that they are difficult to even follow. It is in the air that they hunt and in the air that mating often takes place. The females then deposit fertilized eggs in bodies of water (sometimes on or in plants) where they soon hatch into solitary larvae. All dragonflies and damselflies have an aquatic stage; a wingless, predatory larva called a naiad. When the last larval instar is reached, full-grown naiads climb up out of their aquatic homes and shed their larval skins to emerge as winged adults. Adults spend most of the day on the wing and rest at night. Until birds evolved, dragonflies ruled the air. This ancient lineage, their bright colors and the magnificence of their aerial abilities make them one of the most admired of all the insects. In closing, it is worth noting that some people fear dragonflies. Let it be known: DRAGONFLIES CANNOT STING!! They will not bite you, attack you or sew your mouth shut if you lie or swear. The name “Darning Needle” is simply an archaic namesake that still survives to this day. It is based on the myth that Odonates are in league with the Devil, which is quite silly really. At any rate, they have accrued well over a hundred other slanderous names, including adderbolt, water witch and goblin-fly. In Australia, they are still called “Horse-stingers”. There are about 6,000 described species of Odonates.
Plecoptera
The Stoneflies
The stoneflies are an ancient order, evolving in the Permian period (280-225 million years ago) and perhaps sharing an ancestry with the primitive cockroaches. Today’s stoneflies differ little from their prehistoric ancestors. The word "Plecoptera" is derived from the ancient Greek words for "plait-wing", making reference to the large hind wings which are folded in plaits and lie upon the abdomen, covered by the forewings, when the insect is at rest. The common name "stonefly" comes from the flattened larvae, which are most frequently found beneath the stones of swift-flowing streams where they form an important part of the food chain. Because of their need for clean, well-oxygenated water, their presence is considered a good indicator of a stream’s health. Confined to freshwater habitats, which includes large lakes with serious wave activity, they are always found on or in the substrate. Depending on the species, larva can be carnivores, herbivores, omnivores or detrivores. This aquatic larval stage may last from 1-4 years, depending on the species. Adults live only about 2-3 weeks and eat little or nothing. The adults, usually colored some shade of brown or yellow, can most commonly be found resting on vegetation close to the body of water where they spent their “childhood”. They are weak flyers and seldom fly far from the waters from which they emerge. After mating, females disperse eggs (of which there can be up to 1000) by flying over a chosen body of water, dipping the abdomen beneath the surface of the water and ejecting eggs a few at a time. Having been around so long, some species have evolved to have the adult forms emerge and mate in winter (a tactic devised to avoid predation). The adults of these species can be found walking about on the snow that borders their streams and rivers. As long as the ambient air temperature around this water is above freezing, they are able to successfully complete their lifecycles. Because of the fact that they emerge almost year-round, many tied flies used by fly fisherman imitate them. In fact, the first artificial fly (made over 450 years ago) was based on a British stonefly. There about 3,000 known species.
Raphidioptera
The Snakeflies AKA Camel-neck Flies
Considered by some scientists to be a suborder (Raphidioidea) within Neuroptera, snake flies (also called camel-neck flies) are amongst the most primitive of insects, probably arising as early as 300 million years ago. They get their common name from their long prothorax, at the end of which sits the head. They are small insects with a wingspan of 1-4cm (0.4-1.6") and generally dark in coloration. Adults and larvae are both predatory. Females use their long ovipositor to lay eggs beneath bark, usually in masses of 40-50. Larvae are free-living and hunt on the bark of trees, devouring all sorts of tiny arthropods by day, while hiding away at night and in bad weather. They pupate inside small chambers that they superficially gnaw out in rotten wood or under bark. They are found on all the continents except Australia and Antarctica. There are about 80 known species.
Trichoptera
The Caddisflies
Caddisflies are complex insects that few people have heard of. Perhaps one of the most interesting of the insects, caddisflies are considered the ancestors of all moths and butterflies. Fossil records go back to the Triassic period (225-190 million years ago) and some primitive moths retain features similar to those found in modern caddisflies. Caddisflies are found all over the world (except Antarctica) and are associated with well-oxygenated fresh-water ecosystems. They have an aquatic larval stage, which frequently make "cases" that act as portable homes. Fashioned from the detritus of the stream and pond bottoms where they generally live, these cases can be made from sand, tiny pebbles, or bits of wood, even empty snail shells! The idea is to build a home that mimics the substrate, allowing them to feed undetected. Larva can be carnivorous, with some using silk to spin nets with which they catch tiny aquatic organisms. The majority, however, are herbivores or omnivores. They will live as larva for about a year, pupating within a modified form of their larval retreat. Adults are most vulnerable to fish predation upon emergence as they swim or crawl to land. The adults are winged and can live for a month or two, sometimes much more or less. They have an interesting array of mouthparts which they use to consume herbivorous liquids. The ordinal name "Trichoptera" is derived from the Greek words for "hair wing" because of the hairy forewings of the adult. It is these hairs which were, perhaps, modified into the scales which cover the wings of Lepidopterans. Another interesting (and quite mind-blowing) fact is the existence of a species of caddisfly (Philanisus plebeius) whose larvae are found only in tide pools in New Zealand and southeastern Australia. Although the larvae cannot survive long in 100% seawater, the females deposit their eggs inside the coelomic cavity of starfish - the larvae later migrate to tide pools after they hatch! There are about 7,000 described species of caddisflies.
