Dilaridae is a family under the order Neuroptera, which are also known as Pleasing lacewings or Dusty lacewings because of their appearance. But earlier, according to the phylogenetic studies of Neuroptera reveals that the family of Dilaridae belonged to the superfamily Hemerobioidea. There are also studies which shows that Dilaridae may belong to the Mantispoidea, as well. This is mainly because they resemble the Mantidflies, and allies to them establishing an apomorphic relationship.
Classification of the Dilaridae family : Kingdom Animalia; Phylum Arthropoda; Subphylum Hexapoda; Class Insecta; Order Neuroptera (Antlions, Owlflies, Lacewings, Mantidflies and Allies); Suborder Hemerobiiformia (Lacewings, Mantidflies and Allies); Family Dilaridae (Pleasing Lacewings)
There are about 9 genera in this family and about 100 valid described species all over the world, which belongs to Dilaridae.The existence of Dilaridae was first established as DilarRambur, 1838. The genus of the same was described after the Dilar region of Spain. It was again re-described by Newman in 1853 and later sorted out in five respective genera of two subfamilies again, namely, Dilarinae and Nallachinae. The genus DilarRambur is till now the best species rich genus of Dilaridae which again forms the part of the family Dilarinae with about 67 described species alone.
The distribution of Dilaridae specifically ranges from North Africa to Europe and Asiatic regions divided in these countries : Afghanistan, Algeria, Andorra, Bulgaria, China, France, Greece, India, Iran, Italy, Japan, Korea, Kyrgyzstan, Lebanon, Malaysia, Nepal, Pakistan, Portugal, Russia, Spain, Sri Lanka, Tajikistan, Thailand, Turkey, Turkmenistan, Vietnam and Yugoslavia.
The species is reportedly found in Asia, Africa, Europe and the Americas. The Dilaridae are found in a geographically widespread variation with about only 20 species reported from the Western Hemisphere, belonging to the genus NallachiusNavasand from the family Nallachinae.
Members of the family Dilaridae, especially the adult ones are very small in size and somewhat are similar like the Neuropteran hemerobiids which are more delicate in nature. Different specimen examinations showed that the forewing length of the Dilarid males vary between 3-16mm and that of females between 5-22mm. The Dilarids are differentiated from the other species in exhibition of different characteristics such as they possess ocelli, exerted ovipositor in females and pectinate antennae in males. They are also characterized by the presence of three prominent tubercles on the vertex.
The Dilarids(Nallachus) are found to be occurring around dead wood logs where they can safely oviposit in the crevices of the same, or just under the surface of the bark. The larvae of the Nallachus inhabit mostly insect pools in decaying area beneath the tightly adhering bark of dead trees. Whereas, the larvae of the Dilaridae were reportedly found in the soil with little known biology and related importance. The dilaridae eggs are elongated and detached from the stalks generally. The occurrence of metamorphosis is quite difficult in them, because they supranumerary in nature.
The phylogeny of Dilaridae shows, that according to Aspock 1992, the physical characteristics which points mainly towards the presence of a flat larval head and band-like broadly inserting cardo+stipes, they have fallen under the heads, Mantispidae, Berothidae and Rhaciberothidae, forming closely related sister groups. The same family have been hypothesized by Schluter in 1986, that they might have arisen from the Upper Jurassic period, when Dilaridae was not even been reported to exist. This hypothesis laid a base for the belief and a presumed phylogenetic relationship of the families, Mantispidae and Berothidae behind its existence. Whereas Rhaciberothidae, showed by Whalley in 1980, represented that they might have been arisen in the Lower cretaceous fauna period by the two genera.
The discovery of Cretanallachiusmagnificus, a Dilaridae which is closely related and resembles to the modern subfamily of Nallachiinae with some plesiomorphic features of the Dilarinae, the study showed that this fossil taxon constitutes the sister group of the modern genusNallachius, and that the family Dilaridae is indeed very ancient, probably present during the Early Cretaceous period. This result also supported the previous studies of an early Mesozoic presence of this clade of organisms.
The emergence of the Dilaridae seems to be during the summer, and in the southern hemisphere, the all records were made between October and January except for one each in September and March (Adams 1970). Very little information is available about their predatory nature, but there are reports of Nallachius larvae feeding upon larvae of CucujusclavipesFabricius,1775 (Coleoptera, Curculionidae), Elaphidion sp. (Coleoptera, Cerambycidae), and Camponotuscastaneus(Latreille,1802) (Hymenoptera, Formicidae) (MacLeod and Spiegler 1961, Kuhar 1995). On the other hand similar studies shows,Penny (1981) indicated that Dilarids appear to be predators that successful thrive on soft-bodied insect, larvae and eggs.
While the larvae of Nallachius have not been reported of their feeding habit, there are observations that they attack other insects, as helpedby the piercing and sucking jaws and their presence within the galleries of wood-inhabiting insects. However they are not equipped to bore in wood, rather with the heavy claws, particularly those are present on the front legs, they are presumably well adapted for locomotion in galleries of insects with the indication for the presence of enemy-insects. The integument of most of the larval body is pale and weakly sclerotized, and apparently they have an adaptation to the exposure of minimum light and open air, needed for survival. Mostly the adults emerge during spring and early summer seasons. And undergo single generations with a life cycle of one and ahalf year.
