Owlflies are
dragonflyA dragonfly is a type of insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera. It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...
-like insects with large bulging eyes and long knobbed
antennaeAntennae in biology have historically been paired appendages used for sensing in arthropods and crustaceans. More recently, the term has also been applied to cilium structures present in many cell types of eukaryotes....
. They are not true flies, but rather
neuropteransThe insect order Neuroptera, or net-winged insects, includes the lacewings, mantidflies, antlions, and their relatives. The order contains some 4,000 species...
in the family
Ascalaphidae, and as such are not closely related to the true flies at all; to the dragonflies and damselflies, they are even more distantly related.
Owlflies are readily distinguished from dragonflies because the latter have short bristle-like antennae. The closely related ant-lions, family Myrmeleontidae, have short, clubbed antennae, smaller eyes, and very different wing venation. The sole living member of the subfamily Albardiinae, the Brazilian
Albardia furcata, also has short, clubbed antennae, but its typical reticulate ascalaphid wing venation demonstrates its actual relationships.
Ecology
Adult owlflies are aerial predators feeding on other insects. When disturbed, some owlflies will release a strong, musk-like, chemical to deter an enemy. Adults of many New World species are most active at sunset and dawn and can often be collected around lights. During the day, such adults rest on stems and twigs with the body, legs, and antennae pressed to the stem. The abdomen in a few species is held up, projecting into the air, to look like a broken twig. Many Old World species, however, are most active during the day, and are brightly colored – many even hold their wings spread at rest like dragonflies; perhaps this is a form of mimicry to benefit from the fact that dragonflies are aggressive predators which smaller predatory insects (for which the average
neuropteraThe insect order Neuroptera, or net-winged insects, includes the lacewings, mantidflies, antlions, and their relatives. The order contains some 4,000 species...
n would be prey) would better avoid. Most owlflies average about 2 inches in length. Adult
AscalaphinaeThe Ascalaphinae are the namesake subfamily of the owlfly family , winged insects of the order Neuroptera. Most are found in the tropics. Their characteristic apomorphy is the ridge which divides each of their huge compound eyes; they are thus known as split-eyed owlflies.Like the other owlflies,...
such as
Ululodes have large divided eyes, which is where the common name "Owlfly" came from, in addition to their
crepuscularCrepuscular is a term used to describe some animals that are primarily active during twilight, that is at dawn and at dusk. The word is derived from the Latin word crepusculum, meaning "twilight." Crepuscular is thus in contrast with diurnal and nocturnal behavior. Crepuscular animals may also be...
habits. Owlflies are worldwide in distribution, though in North America they are primarily southerly.
Eggs are laid on twigs or under stones.
LarvaA larva is a young form of animal with indirect development, going through or undergoing metamorphosis ....
e are predatory, and lie on the ground or in vegetation, covered with debris, waiting for prey. Larvae resemble those of ant-lions, but have a "finger-like appendage" on the side of each segment. Some genera actively cement sand and debris onto their bodies as
camouflageCamouflage is a method of crypsis that allows an otherwise visible organism or object to remain indiscernible from the surrounding environment through deception. Examples include a tiger's stripes and the battledress of a modern soldier...
. Pupation occurs in a spheroidal silk cocoon in leaf litter.
Systematics
The owlflies are most closely related to the
antlionAntlions are a family of insects in the order Neuroptera with the scientific name Myrmeleontidae ; the most well-known genus is Myrmeleo. There are about 2,000 species...
s (Myrmeleontidae) and the prehistoric Babinskaiidae, and these three make up the most advanced group of Neuroptera. In addition to the three subfamilies, the genus
Cordulecerus is of undetermined placement. The Albardiinae may well be the basalmost living lineage of owlflies, and arguably
Albardia furcata might be placed in the Ascalaphidae without a subfamily to denote this.
On the other hand, the owlflies are an ancient group, dating back to the mid-
MesozoicThe Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino, in the 18th century, although his original name for the era now called the "Mesozoic" was "Secondary" The Mesozoic Era is one of three geologic eras of the...
at least. A number of
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
owlflies and owlfly larvae have been found, often encased in
amberAmber is fossilized tree resin , which has been appreciated for its color and natural beauty since neolithic times. Good quality amber is used for the manufacture of ornamental objects and jewelry...
. Most of these also cannot be placed in a particular subfamily. Most are known from the
OligoceneThe Oligocene is a geologic epoch of the Paleogene period and extends from about 33.9 million to 23 million years before the present. As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
; the
Late JurassicThe Late Jurassic epoch of the Jurassic Period is the unit of geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago, which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name Malm indicates rocks of Late Jurassic age...
Mesascalaphus may be an entirely more basal member of the family. Fossil owlfly genera
incertae sedisIncertae sedis , abbreviated "inc. sed.", is a term used to define a taxonomic group where its broader relationships are unknown or undefined.-Examples:The taxonomy for humans is usually recognized as follows:...
include:
- Ascaloptynx
- Borgia
- Mesascalaphus
- Neadelphus
- Prosuhpalacsa
- Ricartus
Cratopteryx is probably a member of the Myrmeleontoidea and being of
Early CretaceousThe Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
age would possibly belong in some named family of these. Sometimes assigned to the Ascalaphidae, it is better considered
incertae sedis however.
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