Approximately 300 genera and 1000 species, grouped into 10 subfamilies, are are known from all continents except Antarctica (Rhainids, Davis, and Price, 2009).
Nearctic, Palearctic, Oriental, Ethiopian, Australian, Oceanic Island
Chorion opaque white.
Egg mass pattern:
Winged females use their long ovipositor to lay eggs in crevices, usually some distance from the pupation site. Apterous females with functional legs stay on their bag upon mating and insert their telescopic abdomen into the lower opening of the bag to oviposit in their pupal case. In species with vermiform females that remain inside their pupal case, peristaltic contractions of the abdomen allow females to discharge their eggs intermixed with abdominal setae inside the upper section of their pupal case, progressively shrinking in the process (Rhainids et al, in press).
Description of egg morphology:
Egg of Perisceptis carnivora Davis 0.45-0.5 mm in length, maximum diameter ~ 0.35 mm, superficially similar to that described for Brachycyttarus griseus De Joannis (Davis 1990). Micropyle consisting of an irregularly circular central disk ~ 8-13 �m in diameter with 11-13 low, slender ridges radiating outwards; arms occasionally branching, sometimes joining adjacent ridges to form a few closed cells. Each egg (only for Perisceptis carnivora) enclosed within a firmly woven, golden cocoon spun from long, finely barbed setae derived from seventh abdominal segment of female; length of egg cocoon ~ 1.0 mm, width ~ 0.7 mm (Davis, et al 2008).
Larval head description:
Frontoclypeus extending ca. 0.5 to epicranial notch; ecdysial lines converging at or just dorsad to apex of frontoclypeus. Venter of labrum with 4 pairs of epipharyngeal setae.
Larval body description:
Body usually between 6-50 mm long, with head and thorax well sclerotized and variously pigmented; abdomen usually unicolorous, varying from white to fuscous, or with dark, dorsal plates.
Larval thorax description:
Thoracic legs well developed and directed anteriorly; coxae partially to completely fused at midline; lateral pinacula of T1, bearing 3L setae and spiracle, fused to pronoturn.
Pairs of thoracic legs:
Larval abdomen description:
All prolegs present, moderately short.
Pairs of abdominal legs:
uniserial, arranged in penellipse
Crochet arrangement description:
Crochets of A3-6 uniordinal and arranged in a lateral penellipse; crochets of A10 in a uniordinal semi-ellipse.
Anal comb on A10:
Adult Abdomen Morphology
Female genitalia description:
Highly variable depending upon degree of specialization; segments 8 and 9 + 10 usually long and telescoping, with 2 pairs of apophyses and 1 pair of pseudapophyses (within A10) in more basal genera, to greatly shortened and with only 1-2 pairs of apophyses in most derived, vermiform ?? (Davis 1964). Ostium located on S8 or at caudal margin. Ductus bursae and corpus bursae usually short and membranous; signum absent; ductus seminalis sometimes greatly elongated in most derived genera.
Female pregenital sexual scales:
Female accessory glands:
Female oviduct opening:
Female bursa ostium opening:
on venter 8
Female anterior apophyses originating:
originating from T8
Male pregenital sexual scales:
Male genitalia description:
Uncus completely fused, rounded caudally or represented by short, setose lobes. Tegumen well developed, hoodlike. Vinculum U- to Y -shaped; saccus often elongate. Gnathos absent. Juxta sometimes present and fused with partially sclerotized anellus in lower forms. Subscaphium sometimes sclerotized, usually absent. Valvae relatively slender, elongate, typically with a broad, setose pad at base (often referred to as pulvillus, vallum penis, but probably derived from anellus) as well as an acute or spinose process from ventral margin or apex of sacculus. Transtilla usually present. Seven pairs of genital muscles present (Kuznetsov and Stekol'nikov 1977). Aedoeagus elongate, slender, usually without cornuti.
Sternum 5 gland:
Adult abdomen description:
Paired sternal apodemes of S2 elongate, straight to curved, continuing more than half way into 2S as sternal rods. A pair of short coremata sometimes present on S8 of males in more primitive genera; S8 usually sclerotized with a pair of prominent apodemes directed anteriorly. Female with dense corethrogyne of long piliform scales encircling A7, often concentrated in clusters.
phallotheca and aedeagus (phallus)
Adult Thorax Morphology
Adult thorax description:
Male fully winged, female either fully winged, brachypterous, apterous, or vermiform with all body appendages vestigial or lost. Metafurca with furcal apophyses joined as a bridge to secondary arms; Legs with tibial spur pattern highly variable, ranging from 0-2-4 to 0-0-0; epiphysis present or absent. apterous, or vermiform with all body appendages vestigial or lost.
Number of tibial spurs foreleg:
Number of tibial spurs midleg:
from 0 to 2
Number of tibial spurs hindleg:
from 2 to 4
Forewing length from mid-dorsum to apex (mm):
from 4 to 28mm
Forewing with M present in cell; accessory and intercalary cells usually absent; 1A + 2A either with or without basal fork.
Forewing cell veins:
Forewing basal loop:
present, with frenulum
Forewings slender to broad; index 0.3-0.66, forewings normally with 7-9 veins arising from cell; Rs4 terminating on termen. Male retinaculum varying from a broad fold to a more slender coiled flap from underside of costal membrane immediately anterior to and extending under base of Sc.
Hindwing index 0.33-0.76; male frenulum a single stout seta; alate female with 3-8 frenular setae.
Adult Head Morphology
Number of labial palp segments:
from 0 to 3
Labial palpus modification:
Labial palpi often absent, 1-3 segmented in more primitive genera; lateral bristles absent.
present, absent, minute
Number of maxillary palp segments:
from 0 to 3
Number of chaetosomata:
present, absent, reduced
Proboscis usually absent, present in a few of the most primitive genera.
Head vertex scaling:
Number of flagellomere scale rows:
General antennae description:
Antennae 0.3-0.8 the length of forewing; usually vestigial in vermiform female; scape rough, pecten present but often indistinct; flagellum filiform to strongly bipectinate in male, usually filiform in female(when developed) to rarely serrate; vestiture variable, usually with scales scattered over dorsal half, sometimes with one distinct row per segment.
Adult head description:
Vestiture generally rough, consisting usually of moderately long, slender to piliform scales directed mostly forward. Ocelli present in some primitive genera, usually absent. Eyes small to large; interocular index 0.4-2.3; cornea naked. Pilifers and mandibles absent. Maxillary palpi usually absent, rarely rudimentary to 3-segmented (in Kearfottia, Lamyristis).
Larval labrum with four pairs of epipharyngeal setae. Larval pronotum expanded laterally and fused to the lateral pinnaculum to include the spiracle and all 3 prespiracular setae. Larval abdominal crochets on segments 3-6 arranged in a uniordinal, lateral penellipse
Life History and Behavior
All larvae are case bearers throughout all instars and feed on a broad range of plant hosts, from lichens, grasses, to leaves of evergreen and decidous trees and shrubs; a few have also been reported as insectivorous (Clausen 1940). Structure of larval case highly divergent (Figs. 7.6F-N), from helical (Fig. 7.6 H) to greatly elongated, from less than 6 mm long at maturity to 32.7 cm (Oiketicus aristocosma). Number of instars not well known, at least 4 or more (Jones and Parks 1928; Davis 1964; Kozhanchikov 1956) the male sometimes possessing one more instar than female.
Life History: Immature Stages
The number of eggs laid by female bagworms in different species varies from less than 50 in Apterona helicoidella Vallot and more than 5,000 in Oiketicus kirbyi Guilding, with overall trends of enhanced fecundity with increasing body size, both within and between species. The fecundity is higher for tropical species than temperate species, and for species with vermiform females than those with winged females (Rhainids et al, in press).
Evolution and Systematics
Systematic and taxonomic history
Determining the monophyly of the family based on adult morphology is difficult due to a broad range of morphological variation. One important synapomorphy for Psychidae, the presence of fused metathoracic furcal bridges, is shared with the sister group Arrhenophanidae. The female psychid has evolved a greater array of morphological specializations, especially involving appendage reductions, than any other Lepidoptera family. Assessing the family relationships of psychid species with fully winged females was a consistent problem for early lepidopterists, who often proposed such taxa in Tineidae or Yponomeutoidea (Davis, 1998). Consequently, previous attempts to classify the family have varied from the recognition of as many as 10 families (Tutt 1990)to as few as two subfamilies (Kozhanchikov 1956), or a superficial division in two paraphyletic families: Micropsychidae (= Micropsychiniidae Gomez Bustillo, 1984) to include ??tineid-like?? forms; and the ??true?? Psychidae, or ??bombyx-like?? forms (Gomez Bustillo, 1979). Adults are small to medium size moths, with forewings ranging from 4 to 28 mm in length. Males are always fully winged; the females are either fully winged, brachypterous, apterous, or vermiform (with all body appendages vestigial or lost). The larvae construct portable cases, as do genera in at least 10 other families of Lepidoptera. The morphology of the larval stage is more conservative and exhibits features diagnostic for the family.
The earliest reported fossil records for Psychidae are from the Rupelian stage of the middle Tertiary (Larsson 1978, Rohdendorf 1991). Sobczyk and Kobbert (2009)have recently reviewed psychid remains from Baltic amber and described a new genus and two new species from their larval cases.
Larvae of bagworm moths protect themselves by building spiral-patterned cases out of environmental materials such as twigs, leaves, and silk.
"The bagworm constructs a case around itself soon after hatching from its egg. The bagworm finds twigs or leaves in the tree or shrub where it feeds, and weaves these together in a silken case. As the bagworm grows, it adds to this 'armor.' The animal carries the protective case along with it as it moves around, poking out its head to feed.
"When the bagworm is full-grown, it uses silk to anchor the case to a branch or leaf. Sealing the opening with silk, it spins a silk inner case, or cocoon. There the caterpillar pupates. The adult male develops wings and leaves his cocoon to mate. The adult female never leaves her cocoon and lays her eggs in it. When the eggs hatch, the larvae crawl out of the case and move away, each to make its own tiny new case.
"The remarkable thing about the design of the bagworm twig casing is that it is designed to resist failure by crushing. The bagworm does this by placing the twigs in an ingenious pattern that, in section, forms a spiral configuration. Differing species apply this principle in various effective ways." (Tsui 1999:128)
Learn more about this functional adaptation.
- Tsui, Eugene. 1999. Evolutionary Architecture: Nature as a Basis for Design. Wiley. 360 p.
Molecular Biology and Genetics
Statistics of barcoding coverage
|Specimen Records:||3,092||Public Records:||513|
|Specimens with Sequences:||2,622||Public Species:||149|
|Specimens with Barcodes:||2,310||Public BINs:||153|
|Species With Barcodes:||349|
- "Bagworm" redirects here. This may also refer to two Macrolepidoptera species, the Fall Webworm (Hyphantria cunea) or the Eastern Tent Caterpillar (Malacosoma americanum).
The Psychidae (bagworm moths, also simply bagworms or bagmoths) are a family of the Lepidoptera (butterflies and moths). The bagworm family is fairly small, with about 1350 species described. Bagworm species are found globally, with some, such as the Snailcase Bagworm (Apterona helicoidella), settling continents where they are not native in modern times.
Another common name for the Psychidae is "case moths", but this is just as well used for the case-bearers (Colephoridae). The names refer to the habits of caterpillar of these two families, which build small protective cases in which they can hide. The bagworms belong to the superfamily Tineoidea, which is a basal lineage of the Ditrysia just as the Gelechioidea, in which the case-bearers are placed. This means that the bagworms and case-bearers are only as closely related to each other as either is to butterflies (Rhopalocera).
Most bagworms are inoffensive to humans and not at all conspicuous; some are occasional nuisance pests. However, a few species can become more serious pests, and have caused significant damage e.g. to wattle (Acacia mearnsii) in South Africa and Orange (Citrus ×sinensis) in Florida. If detected early, picking the cases from the trees while in their pupa stage is an effective way to check an infestation; otherwise, insecticides are used. One bagworm species, the Fangalabola (Deborrea malgassa) of Madagascar, is in some places encouraged to breed on wattle trees, because its pupae are collected as a protein-rich food.
The caterpillar larvae of the Psychidae construct cases out of silk and environmental materials such as sand, soil, lichen, or plant materials. These cases are attached to rocks, trees or fences while resting or during their pupa stage, but are otherwise mobile. The larvae of some species eat lichen, while others prefer green leaves. In many species, the adult females lack wings and are therefore difficult to identify accurately. Case-bearer cases are usually much smaller, flimsier, and consist mainly of silk, while bagworm "bags" resemble caddisfly cases in their outward appearance – a mass of (mainly) plant detritus spun together with silk on the inside.
Bagworm cases range in size from less than 1 cm to 15 cm among some tropical species. Each species makes a case particular to its species, making the case more useful to identify the species than the creature itself. Cases among the more primitive species are flat. More specialized species exhibit a greater variety of case size, shape, and composition, usually narrowing on both ends. The attachment substance used to affix the bag to host plant, or structure, can be very strong, and in some case require a great deal of force given the relative size and weight of the actual "bag" structure itself. Body markings are rare. Adult females of many bagworm species have only vestigial wings, legs, and mouthparts. In some species, parthenogenesis is known. The adult males of most species are strong fliers with well-developed wings and feathery antennae but survive only long enough to reproduce due to underdeveloped mouthparts that prevent them from feeding. Their wings have few of the scales characteristic of most moths, instead having a thin covering of hairs.
In the larval stage, bagworms extend their head and thorax from their mobile case to devour the leaves of host plants, often leading to the death of their hosts. Trees infested with bagworms exhibit increasingly damaged foliage as the infestation increases until the leaves are stripped bare. Some bagworms are specialized in their host plants (monophagous), while others can feed on a variety of plant species (polyphagous). A few species also consume small arthropods (such as the Camphor Scale Pseudaonidia duplex, a scale insect).
Since bagworm cases are composed of silk and the materials from their habitat, they are naturally camouflaged from predators. Predators include birds and other insects. Birds often eat the egg-laden bodies of female bagworms after they have died. Since the eggs are very hard-shelled, they can pass through the bird's digestive system unharmed, promoting the spread of the species over wide areas.
A bagworm begins to build its case as soon as it hatches. Once the case is built, only adult males ever leave the case, never to return, when they take flight to find a mate. Bagworms add material to the front of the case as they grow, excreting waste materials through the opening in the back of the case. When satiated with leaves, a bagworm caterpillar secures its case and pupates. The adult female either emerges from the case long enough for breeding or remains in the case while the male extends his abdomen into the female's case to breed. Females lay their eggs in their case and die. The female Evergreen Bagworm (Thyridopteryx ephemeraeformis) dies without laying eggs, and the larval bagworm offspring emerge from the parent's body. Some bagworm species are parthenogenetic, meaning their eggs develop without male fertilization. Each bagworm generation lives just long enough as adults to mate and reproduce in their annual cycle.
The subfamilies of Psychidae, with some notable genera and species also listed, are:
- Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness - Lepidoptera
- Sobczyk, T. 2011. Psychidae. World Catalogue of Insects 10. Apollo Books Stenstrup, 467 pp.
- Nieukerken, E. J. van, L. Kaila, I. J. Kitching, N. P. Kristensen, D. C. Lees, J. Minet, C. Mitter, M. Mutanen, J. C. Regier, T. J. Simonsen, N. Wahlberg, S.-H. Yen, R. Zahiri, D. Adamski, J. Baixeras, D. Bartsch, B. Å. Bengtsson, J. W. Brown, S. R. Bicheli, D. R. Davis, J. de Prins, W. de Prins, M. E. Epstein, P. Gentili-Poole, C. Gielis, P. Hättenschwiler, A. Hausmann, J. D. Holloway, A. Kallies, O. Karsholt, A. Y. Kawahara, S. (J.C.) Koster, M. V. Kozlov, J. D. Lafontaine, G. Lanas, J.-F. Landry, S. Lee, M. Nuss, K.-T. Park, C. Penz, J. Rota, A. Schintlmeister, B. C. Schmidt, J.-C. Sohn, M. A. Solis, G. M. Tarmann, A. D. Warren, S. Weller, R. V. Yakovlec, V. V. Zolotuhin, A. Zwick. 2011. Order Lepidoptera Linnaeus, 1758. In: Zhang, Z.-Q. (Ed.) Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness. – Zootaxa 3148: 1–237.
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