Sisyridae
Encyclopedia
The Sisyridae, commonly known as spongeflies or spongillaflies, is a family
of winged insects
of the order
Neuroptera
. Approximately 60 living species
are known.
In general appearance, the adults resemble some brown lacewings (Hemerobiidae
). The forewings of spongillaflies have a span of 4–10 millimetres. The greyish or brownish wings have few cross veins except in the costa
l field, and most of these are not forked. The subcostal (Sc) and radial (R1) veins are fused near the wingtip.
The larva
e of spongillaflies look rather bizarre. Similar to those of some osmylids (Osmylidae
) at the first glance, they have spindly legs on a bulky thorax
, long antenna
e, and flexible, threadlike mouthpart
s. However, the second and third instar
s carry seven pairs of jointed, movable tracheal
gill
s beneath their plump abdomen. These gills are possessed by no other extant insect family, and readily distinguish them from osmylid larvae.
or nocturnal. They are omnivores, sometimes hunting small invertebrates, but mainly scavenging
on such animals' carcasses, as well as on pollen
and honeydew
.
The females deposit their eggs singly or as small clutch
es on plants that droop over freshwater
lake
s or slow-moving river
s. A protective web is spun to cover the eggs. When the larva
e hatch, they drop down into the water where they develop until pupation. They use their mouthparts to parasitize Spongillidae
freshwater sponges (e.g. of the genus
Spongilla
, hence the name "spongillaflies") and Phylactolaemata
freshwater bryozoa
ns by stinging into the host animals' body and sucking out cell
contents. The antennae are stouter than they look and are used to aid in locomotion. Development to pupation takes between several weeks and one year.
Spongillafly larvae leave the water and go to hidden places nearby to pupate, choosing locations like beneath rocks or behind tree bark
. They spin a cocoon
for pupation, but in temperate
climates they overwinter in the cocoon as larvae, pupating only the following spring.
) and the Nevrorthidae
. This was due to the similar adaptation
s of the larva
e of spongillaflies and osmylids. But this is apparently due to convergent evolution
; actually, the spongillaflies seem to be closer to the brown lacewings (Hemerobiidae
) than to the osmylids, but even more closely related to the dustywings (Coniopterygidae
). And even though they are not often placed in the superfamily
Coniopterygoidea as of yet, they most likely form a clade
with the Coniopterygidae and thus it would seem that the Coniopterygoidea, rather than being an unnecessarily monotypic
taxon
, is expanded to signify that the spongillaflies and the dustywings are each other's closest relatives.
Numerous fossil
genera are known, mainly from the Eocene
like "Sisyra" amissa which may or may not be the first record of the living genus. But the very basal Cratosisyrops proves that the family already existed in the Early Cretaceous
.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of winged insects
Pterygota
Pterygota is a subclass of insects that includes the winged insects. It also includes insect orders that are secondarily wingless ....
of the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Neuroptera
Neuroptera
The insect order Neuroptera, or net-winged insects, includes the lacewings, mantidflies, antlions, and their relatives. The order contains some 6,010 species...
. Approximately 60 living species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
are known.
Description
Hemerobiidae
Hemerobiidae is a family of Neuropteran insects commonly known as brown lacewings. These insects differ from the somewhat similar Chrysopidae not only by the usual colouring but by the wing venation: hemerobiids having numerous long veins lacking in chrysopids. Some of the costal cross veins are...
). The forewings of spongillaflies have a span of 4–10 millimetres. The greyish or brownish wings have few cross veins except in the costa
Costa
Costa may refer to:* Costa , including origin of the name and people sharing the surname* Costa, scientific term, from Latin costa "rib" ** In botany, the central strand of a bryophyte leaf or thallus...
l field, and most of these are not forked. The subcostal (Sc) and radial (R1) veins are fused near the wingtip.
The larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e of spongillaflies look rather bizarre. Similar to those of some osmylids (Osmylidae
Osmylidae
Osmylidae are a small family of winged insects of the net-winged insect order Neuroptera. The osmylids are found all over the world except in North America. A common species through most of Europe is Osmylus fulvicephalus.-Description and ecology:...
) at the first glance, they have spindly legs on a bulky thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
, long antenna
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
e, and flexible, threadlike mouthpart
Insect mouthparts
Insects exhibit a range of mouthparts, adapted to particular modes of feeding. The earliest insects had chewing mouthparts...
s. However, the second and third instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
s carry seven pairs of jointed, movable tracheal
Invertebrate trachea
The invertebrate trachea refers to the open respiratory system composed of spiracles, tracheae, and tracheoles that terrestrial arthropods have to transport metabolic gases to and from tissues....
gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
s beneath their plump abdomen. These gills are possessed by no other extant insect family, and readily distinguish them from osmylid larvae.
Ecology and life cycle
Adult spongillaflies are crepuscularCrepuscular
Crepuscular animals are those that are active primarily during twilight, that is during dawn and 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 active on a bright...
or nocturnal. They are omnivores, sometimes hunting small invertebrates, but mainly scavenging
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...
on such animals' carcasses, as well as on pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
and honeydew
Honeydew (secretion)
Honeydew is a sugar-rich sticky liquid, secreted by aphids and some scale insects as they feed on plant sap. When their mouthpart penetrates the phloem, the sugary, high-pressure liquid is forced out of the gut's terminal opening. Honeydew is particularly common as a secretion in the Hemipteran...
.
The females deposit their eggs singly or as small clutch
Clutch (eggs)
A clutch of eggs refers to all the eggs produced by birds or reptiles, often at a single time, particularly those laid in a nest.In birds, destruction of a clutch by predators, , results in double-clutching...
es on plants that droop over freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
s or slow-moving river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s. A protective web is spun to cover the eggs. When the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e hatch, they drop down into the water where they develop until pupation. They use their mouthparts to parasitize Spongillidae
Spongillidae
The Spongillidae are a family of sponges that live in fresh water lakes. There are 23 genera....
freshwater sponges (e.g. of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Spongilla
Spongilla
Spongilla is a genus of freshwater sponge in the family Spongillidae. They are found in lakes and slow streams. Sponges of the genus Spongilla attach themselves to rocks and logs and filter the water for various small aquatic organisms such as protozoa, bacteria, and other free-floating pond life...
, hence the name "spongillaflies") and Phylactolaemata
Phylactolaemata
Phylactolaemata is a class of the phylum Bryozoa whose members live only in freshwater environments. Like all bryozoans, they filter feed by means of an extensible "crown" of ciliated tentacles called a lophophore. They live in colonies, each of which consists of clones of the founding member...
freshwater bryozoa
Bryozoa
The Bryozoa, also known as Ectoprocta or commonly as moss animals, are a phylum of aquatic invertebrate animals. Typically about long, they are filter feeders that sieve food particles out of the water using a retractable lophophore, a "crown" of tentacles lined with cilia...
ns by stinging into the host animals' body and sucking out cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
contents. The antennae are stouter than they look and are used to aid in locomotion. Development to pupation takes between several weeks and one year.
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
. They spin a cocoon
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
for pupation, but in temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
climates they overwinter in the cocoon as larvae, pupating only the following spring.
Systematics and taxonomy
Spongillaflies were formerly placed in the Osmyloidea, as their closest relatives were held to be the osmylids (OsmylidaeOsmylidae
Osmylidae are a small family of winged insects of the net-winged insect order Neuroptera. The osmylids are found all over the world except in North America. A common species through most of Europe is Osmylus fulvicephalus.-Description and ecology:...
) and the Nevrorthidae
Nevrorthidae
The Nevrorthidae - often incorrectly spelled "Neurorthidae" - are a small family of winged insects of the order Neuroptera. They are a living fossil....
. This was due to the similar adaptation
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
s of the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e of spongillaflies and osmylids. But this is apparently due to convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
; actually, the spongillaflies seem to be closer to the brown lacewings (Hemerobiidae
Hemerobiidae
Hemerobiidae is a family of Neuropteran insects commonly known as brown lacewings. These insects differ from the somewhat similar Chrysopidae not only by the usual colouring but by the wing venation: hemerobiids having numerous long veins lacking in chrysopids. Some of the costal cross veins are...
) than to the osmylids, but even more closely related to the dustywings (Coniopterygidae
Coniopterygidae
The dustywings, Coniopterygidae, are a family of Pterygota of the net-winged insect order . About 460 living species are known...
). And even though they are not often placed in the superfamily
Taxonomic rank
In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...
Coniopterygoidea as of yet, they most likely form a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
with the Coniopterygidae and thus it would seem that the Coniopterygoidea, rather than being an unnecessarily monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
, is expanded to signify that the spongillaflies and the dustywings are each other's closest relatives.
Numerous fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
genera are known, mainly from the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
like "Sisyra" amissa which may or may not be the first record of the living genus. But the very basal Cratosisyrops proves that the family already existed in the Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
.