Zoraptera
| Zoropterans Temporal range: Cretaceous to Recent
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| File:ZorotypusHubbardi.jpg | |
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| Order: | Zoraptera Silvestri, 1913
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| Family: | Zorotypidae Silvestri, 1913
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| Genus: | Zorotypus Silvestri, 1913
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The insect order Zoraptera contains a single family, the Zorotypidae, which in turn contains one extant genus with 34 species, Zorotypus as well as 9 extinct species [1].
Phylogeny
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 Order Dictyoptera[2][3][4]
Description
The name Zoraptera, given by Filippo Silvestri in 1913[5], 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, 3 millimetres (0.12 in) or less in length, that resemble termites in appearance and in their gregarious behavior. They belong to the hemimetabolous insects. They possess mandibulated biting mouthparts, short cerci (usually 1 segment only), and short antennae with 9 segments. The maxillary palps have five segments, labial palps three, in both the most distal segment is enlarged.
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 7 millimetres (0.28 in), and the wings can be shed spontaneously. 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. The wings are paddle shaped, and have reduced venation.
Behavior and ecology
They live in small colonies beneath rotting wood, eating fungal spores and detritus but also can hunt smaller arthropods like mites and collembola. [6]
Zorotypus gurneyi lives in colonies consisting of up to several hundred of individuals. Most commonly the colonies have a size is around 30 individuals, of which about 30% are nymphs, the remainder adults.
When two colonies of Z. hubbardi are brought together experimentally, there is no difference in behavior towards members of the own or new colony. Therefore colonies in the wild might merge easily. Winged forms are rare. The males in such average 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 hierarchical ladder, 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. [7] [8]
Z. 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. [6]
Species
34 species are found world-wide, mainly in tropical and subtropical regions around the world. Four species occur north of the Tropic of Cancer, two in the USA and two in Tibet.
Currently there are 34 recognized extant and 9 recognized extinct species.[1]
Zorotypus acanthothorax Engel & Grimaldi
Zorotypus amazonensis Rafael & Engel
Zorotypus barberi Gurney
Zorotypus brasiliensis Silvestri
Zorotypus buxtoni Karny
Zorotypus caudelli Karny
Zorotypus ceylonicus Silvestri
Zorotypus congensis Ryn-Tournel
Zorotypus cramptoni Gurney
Zorotypus cretatus Engel & Grimaldi
Zorotypus delamarei Paulian
Zorotypus goeleti Engel & Grimaldi
Zorotypus guineensis Silvestri
Zorotypus gurneyi Choe
Zorotypus hamiltoni New
Zorotypus hubbardi Caudell
Zorotypus huxleyi Bolivar & Coronado
Zorotypus javanicus Silvestri
Zorotypus juninensis Engel
Zorotypus lawrencei New
Zorotypus leleupi Weidner
Zorotypus longicercatus Caudell
Zorotypus manni Caudell
Zorotypus medoensis Hwang
Zorotypus mexicanus Bolivar
Zorotypus nascimbenei Engel & Grimaldi
Zorotypus neotropicus Silvestri
Zorotypus newi (Chao & Chen)
Zorotypus philippinensis Gurney
Zorotypus shannoni Gurney
Zorotypus silvestrii Karny
Zorotypus sinensis Hwang
Zorotypus snyderi Caudell
Zorotypus swezeyi Caudell
Zorotypus weidneri New
Zorotypus vinsoni Paulian
Zorotypus zimmermani Gurney
References
- ^ a b Rafael JA, Godoi FDP, Engel MS, 2008; "A new species of Zorotypus from eastern Amazonia, Brazil (Zoraptera: Zorotypidae)" Transactions of the Kansas Academy of Science 111:193-202
- ^ Yoshizawa K 2007; "The Zoraptera problem: evidence for Zoraptera + Embiodea from the wing base." Systematic Entomology 32: 197-204
- ^ Yoshizawa K & Johnson KP; 2005; "Aligned 18S for Zoraptera (Insecta): Phylogenetic position and molecular evolution." Molecular Phylogenetics and Evolution 37: 572-580
- ^ Engel MS & Grimaldi DA; 2002; "The first mesozoic Zoraptera (Insecta)." American Museum Novitates 3362:1-20
- ^ Silvestri, F. (1913); "Descrizione di un nuovo ordine di insetti." Bol. Lab. Zool. Gen. Agric. Portici 7:193–209.
- ^ a b Choe JC; 1997; "The evolution of mating systems in the Zoraptera: Mating variations and sexual conflicts." Pages 130-145 in Choe JC & Crespi BJ. (Editors), "The Evolution of Mating Systems in Insects and Arachnids." Cambridge Univ. Press, Cambridge, 575 pp.
- ^ Choe JC 1994; "Sexual selection and mating system in Zorotypus gurneyi Choe (Insecta, Zoraptera). II Determinants and dynamics of dominance." Behavioral Ecology and Sociobiology 34: 233-237
- ^ Choe JC 1994; "Sexual selection and mating system in Zorotypus gurneyi Choe (Insecta, Zoraptera ). I Dominance hierarchy and mating success." Behavioral Ecology and Sociobiology 34: 87-93
General References
- 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
- Grimaldi, D. and Engel, M.S. (2005). Evolution of the Insects. Cambridge University Press. ISBN 0-521-82149-5.
{{cite book}}: CS1 maint: multiple names: authors list (link) - Rafael, J.A. & M.S. Engel (2006) A new species of Zorotypus from Central Amazonia, Brazil (Zoraptera: Zorotypidae). American Museum Novitates 3528: 1-11.