Zoraptera
Template:Short description Template:Automatic taxobox
The insect order Zoraptera, commonly known as angel insects, contains small and soft bodied insects with two forms: winged with wings sheddable as in termites, dark and with eyes (compound) and ocelli (simple); or wingless, pale and without eyes or ocelli. They have a characteristic nine-segmented beaded (moniliform) antenna. They have mouthparts adapted for chewing and are mostly found under bark, in dry wood or in leaf litter.<ref name="Rafael2008">Template:Cite journal</ref>
DescriptionEdit
The name Zoraptera, given by Filippo Silvestri in 1913,<ref name="Silvestri1913">Template:Cite journal</ref> is misnamed and potentially misleading: "zor" is Greek for pure and "aptera" means wingless. "Pure wingless" clearly does not fit the winged alate forms, which were discovered several years after the wingless forms had been described.
The members of this order are small insects, Template:Convert or less in length, that resemble termites in appearance and in their gregarious behavior. They are short and swollen in appearance. They belong to the hemimetabolous insects. They possess mandibulated biting mouthparts, short cerci (usually 1 segment only), and short antennae with 9 segments. The abdomen is segmented in 11 sections.<ref name=":0">Template:Cite book</ref> The maxillary palps have five segments, labial palps three, in both the most distal segment is enlarged. They have six Malpighian tubules, and their abdominal ganglia have fused into two separate ganglionic complexes.<ref>Template:Cite journal</ref> Immature nymphs resemble small adults. Each species shows polymorphism. Most individuals are the apterous form or "morph", with no wings, no eyes, and no or little pigmentation. A few females and even fewer males are in the alate form with relatively large membranous wings that can be shed at a basal fracture line. Alates also have compound eyes and ocelli, and more pigmentation. This polymorphism can be observed already as two forms of nymphs. Wingspan can be up to Template:Convert, and the wings can be shed spontaneously. When observed, wings are paddle shaped and have simple venation.<ref name=":0" /> Under good conditions the blind and wingless form predominates, but if their surroundings become too tough, they produce offspring which develop into winged adults with eyes. These winged offspring are then able to disperse and establish new colonies in areas with more resources. Once established, future generations are once again born blind and wingless.<ref>Template:Cite book</ref>
SystematicsEdit
PhylogenyEdit
The phylogenetic relationship of the order remains controversial and elusive. At present the best supported position based on morphological traits recognizes the Zoraptera as polyneopterous insects related to the webspinners of the order Embioptera. However, molecular analysis of 18s ribosomal DNA supports a close relationship with the superorder Dictyoptera.<ref name="Yoshizawa2007">Template:Cite journal</ref><ref name="Yoshizawa2005">Template:Cite journal</ref><ref name="Engel2002">Template:Cite journal</ref><ref name="Ishiwata2011">Template:Cite journal</ref><ref>Template:Cite journal</ref>
The following cladogram, based on the molecular phylogeny of Wipfler et al. 2019, places Zoraptera as the sister group of Dermaptera (earwigs); Zoraptera and Dermaptera together form the sister group of the remaining Polyneoptera:<ref>Template:Cite journal</ref>
ClassificationEdit
The Zoraptera are currently divided into two families, four subfamilies, nine genera and a total of 51 species, some of which have not been yet described.<ref name="Kocarek2020">Template:Cite journal</ref><ref>Zoraptera Species File (Version 5.0/5.0; retrieved 29 May 2021)</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> There are eleven extinct species known as of 2017, many of the fossil species are known from Burmese amber.<ref>Template:Cite journal</ref>
- Family Zorotypidae Template:Au
- Subfamily Zorotypinae Template:Au
- Zorotypus Template:Au — 7 spp.
- Usazoros Template:Au — 1 sp.
- Subfamily Spermozorinae Template:Au
- Spermozoros Template:Au — 6 spp.
- Subfamily Zorotypinae Template:Au
- Family Spiralizoridae Template:Au
- Subfamily Latinozorinae Template:Au
- Latinozoros Template:Au — 3 spp.
- Subfamily Spiralizorinae Template:Au
- Spiralizoros Template:Au — 12 spp.
- Centrozoros Template:Au (=Meridozoros Template:Au; Floridazoros Template:Au) — 8 spp.
- Cordezoros Template:Au — 1 sp.
- Scapulizoros Template:Au — 1 sp.
- Brazilozoros Template:Au — 3 spp.
- Subfamily Latinozorinae Template:Au
Incertae sedisEdit
The following nine species are considered Zoraptera incertae sedis:<ref name="Kocarek2020" />
- Zorotypus congensis Template:Au – Congo (Dem.Rep.)
- Zorotypus javanicus Template:Au – Indonesia (Java)
- Zorotypus juninensis Template:Au (considered a synonym of Centrozoros hamiltoni<ref>Template:Cite journal</ref>) – Peru
- Zorotypus lawrencei New, 1995 – Christmas Island
- Zorotypus leleupi Template:Au – Ecuador (Galapagos Islands)
- Zorotypus longicercatus Template:Au – Jamaica
- Zorotypus newi Template:Au (=Formosozoros newi, is in actuality an immature earwig<ref>Template:Cite journal</ref>) – Taiwan
- Zorotypus sechellensis Template:Au – Seychelles
- Zorotypus swezeyi Template:Au – United States (Hawaii)
Extinct taxaEdit
- Zorotypus Silvestri, 1913
- Subgenus Zorotypus Silvestri, 1913
- Template:ExtinctZorotypus (Zorotypus) absonus Engel, 2008 – Dominican amber, Dominican Republic (Miocene)
- Template:ExtinctZorotypus (Zorotypus) denticulatus Yin, Cai, & Huang, 2018 – Burmese amber, Myanmar (Cretaceous)
- Template:ExtinctZorotypus (Zorotypus) dilaticeps Yin, Cai, Huang, & Engel, 2018 – Kachin amber, Myanmar (Cretaceous)
- Template:ExtinctZorotypus (Zorotypus) goeleti Engel & Grimaldi, 2002 – Dominican amber, Dominican Republic (Miocene)
- Template:ExtinctZorotypus (Zorotypus) mnemosyne Engel, 2008 – Dominican amber, Dominican Republic (Miocene)
- Subgenus Template:ExtinctOctozoros Engel, 2003
- Template:ExtinctZorotypus (Octozoros) acanthothorax Engel & Grimaldi, 2002 – Kachin amber, Myanmar (Cretaceous)
- Template:ExtinctZorotypus (Octozoros) nascimbenei Engel & Grimaldi, 2002 – Kachin amber, Myanmar (Cretaceous)
- Template:ExtinctZorotypus (Octozoros) cenomanianus Yin, Cai, & Huang, 2018 – Kachin amber, Myanmar (Cretaceous)
- Template:ExtinctZorotypus (Octozoros) hudai Kaddumi, 2005 – Jordanian amber, Jordan (Cretaceous)
- Template:ExtinctZorotypus cretatus Engel & Grimaldi, 2002 – Kachin amber, Myanmar (Cretaceous)
- Template:ExtinctZorotypus oligophleps Liu, Zhang, Cai & Li, 2018
- Template:ExtinctZorotypus robustus Liu, Zhang, Cai & Li, 2018
- Subgenus Zorotypus Silvestri, 1913
- Template:ExtinctXenozorotypus Engel & Grimaldi, 2002
- Template:ExtinctXenozorotypus burmiticus Engel & Grimaldi, 2002 – Kachin amber, Myanmar (Cretaceous)
Behavior and ecologyEdit
Zorapterans live in small colonies beneath rotting wood, lacking in mouthparts able to tunnel into wood, but feeding on fungal spores and detritus. These insects can also hunt smaller arthropods like mites and collembolans.<ref name="Choe1997">Template:Cite book</ref> Much of their time is spent grooming themselves or others.<ref>Template:Cite book</ref>
Centrozoros gurneyi lives in colonies which range in size from a few dozen to several hundred individuals, but most often number about 30 individuals. The males are slightly larger than the females, and they fight for dominance.<ref>The Other Insect Societies</ref>
When two colonies of Usazoros hubbardi are brought together experimentally, there is no difference in behavior towards members of the new colony. Therefore, colonies in the wild might merge easily. Winged forms are rare. The males in most colonies establish a linear dominance hierarchy in which age or duration of colony membership is the prime factor determining dominance. Males appearing later in colonies are at the bottom of the hierarchy, regardless of their body size. By continually attacking other males, the dominant male monopolizes a harem of females. The members of this harem stay clumped together. There is a high correlation between rank and reproductive success of the males.<ref name="Choe233-237">Template:Cite journal</ref><ref name="Choe87-93">Template:Cite journal</ref>
Latinozoros barberi lack such a dominance structure but display complex courtship behavior including nuptial feeding. The males possess a cephalic gland that opens in the middle of their head. During courtship they secrete a fluid from this gland and offer it to the female. Acceptance of this droplet by the female acts as behavioral releaser and immediately leads to copulation.<ref name="Choe1997" />
In Spermozoros impolitus, copulation does not occur, but fertilization is accomplished instead by transfer of a spermatophore from the male to the female. This Template:Convert spermatophore contains a single giant sperm cell, which unravels to about the same length as the female herself, Template:Convert. It is thought that this large sperm cell prevents fertilization by other males, by physically blocking the female's genital tract.<ref>Template:Cite journal</ref><ref>Template:Cite magazine</ref>
Effects on ecosystemEdit
Zorapterans are thought to provide some important services to ecosystems. By consuming detritus, such as dead arthropods, they assist in decomposition and nutrient cycling.<ref>Template:Cite journal</ref>
ReferencesEdit
General referencesEdit
- Costa JT 2006 Psocopera and Zoraptera. In: Costa JT The other Insect Societies. The Belknap Press of Harvard University Press, Cambridge, MA and London, UK pp 193–211
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External linksEdit
- Tree of Life Zoraptera
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