Brochosomy (from the ancient Greek. Βρóχoς - cell network and σωμα - body) - microscopic granules with a cellular structure, which are secreted by specialized sections of malpighian vessels of coleoptera insects from the family of tsikadok (Cicadellidae). With the help of the legs, the cycadas transfer brohosomes to different parts of the body surface. Some species also use brohosomes to protect egg clutches. These particles are one of the natural components of atmospheric aerosol .
Content
History of discovery and distribution
Brochosomes were first detected in 1952 with an electron microscope on transparent wings and in water droplets after contact with the surface of insects, including cannons and mosquitoes [2] Later, it was shown that brochosomas are secreted in malpighian vessels of cicadas [3] . Reports on the detection of brochos in other insects are not confirmed and, as a rule, are the result of contamination [4] . Brohosomes are secreted by most of the studied species of tsikadok. In some species, brochosomes are secreted at all ages after hatching from the egg, and in others, only at the adult stage [5] .
Composition and structure
Brochosomes are composed mainly of proteins , probably involving lipids . [6] [7] [8] Most species of tsikadok secrete hollow spherical brohosomes with a honeycomb-like wall. The diameter of such brochosomes is usually 0.2-0.7 micrometers. Often they are based on the shape of a truncated icosahedron , as well as, for example, a soccer ball and a fullerene C 60 . The size and shape of the brochos depends on the type of the cyclone. In some species of the subfamily Cicadellinae, females secrete rod-shaped or tubular brohosomes of various shapes, which are used in egg laying. [9]
Morphogenesis
Brohosomes form inside large secretory cells in the thickened middle part of the malpighian vessels . They originate as secretory vesicles ( vacuoles ) filled with homogeneous material, budding from the Golgi apparatus , and gradually develop into mature particles, which are emitted into large quantities into the vessel lumen. The mechanism of formation of the brohos is not clear. [5] [6] [7]
Integument
Shortly after molting, the insect secretes droplets of brochosome suspension through the intestines, which are either picked up by the legs and transferred to the cuticle, or (in nymphs) are smeared over the body with special abdominal movements. [10] [11] After the suspension dries, the layer of brochosomes is processed and smoothed with quick movements of the legs, equipped with rows of specialized bristles. Some species store dry brohosomes on the elytra in the form of white flat patches of secretion, which were mistaken for the fields of the wax glands.
Functions
The cuticle layer on the cuticle makes it super-hydrophobic . [1] This prevents it from becoming contaminated with liquid, often sugary, excrements of the tsikadok. [12] In some genera of the female Cicadellinae subfamily, after laying eggs, the epidermis of the plant, under which the eggs were laid, is powdered, with a layer of specialized rod-shaped brohos. [9] [13] This layer slows down the process of laying eggs by parasitic hymenoptera chalcides in the cycled egg. [14]
Notes
- 2 1 2 Rakitov R. & Gorb SN (2013) Brochosomal coats turn leafhopper (Insecta, Hemiptera, Cicadellidae) integument to superhydrophobic state. Proceedings of the Royal Society B 7 February 2013 vol. 280 no. 1752 20122391, DOI : 10.1098 / rspb.2012.2391 .
- Ul Tulloch GS, Shapiro JE, Cochran GW The Bulletin of the Brooklyn Entomological Society. - 1952. - Vol. 47. - p. 41-42.
- ↑ Day MF, Briggs M. The Journal of Ultrastructural Research. - 1958. - Vol. 2. - P. 239-244. - PMID 13631751 .
- Con Rakitov RA Contamination as the cause of erroneous records of brochosomes // Psyche. - 2011. - DOI : 10.1155 / 2011/767963 .
- 2 1 2 Rakitov RA Secretory products of the Malpighian tubules of Cicadellidae (Hemiptera, Membracoidea): an ultrastructural study // International Journal of Insect Morphology and Embryology. - 1999. - Vol. 28. - p. 179-192. - DOI : 10.1078 / 0044-5231-00025 .
- 2 1 2 Smith DS & Littau VG (1960) Cellular specializations in the exctory of the insect, Macrosteles fascifrons Stål (Homoptera). Journal of Cell Biology 8: 103–133.
- 2 1 2 Gouranton J. & Maillet PL (1967) Origine et structure des brochosomes. Journal de Microscopie 6: 53-64.
- ↑ Rakitov RA (2009) Brochosomal coatings of leafhoppers (Hemiptera, Cicadellidae). In: SN Gorb (ed.), Functional Surfaces in Biology , Vol. 1, 113-137. ISBN 978-1-4020-6696-2 .
- 2 1 2 Rakitov RA (2004) With leaflets and brochosomes (Insecta, Hemiptera, Cicadellidae). Zoological Journal of the Linnean Society 140: 353-381 DOI : 10.1111 / j.1096-3642.2003.00103.x
- ↑ Rakitov RA (1996) Post-moulting behavior associated with Malpighian tubule secretions in leafhoppers and treehoppers (Auchenorrhyncha: Membracoidea) . European Journal of Entomology 93: 167-184.
- ↑ Rakitov R. & Gorb SN (2013) Brochosomes protect leafhoppers (Insecta, Hemiptera, Cicadellidae) from sticky exudates. Journal of the Royal Society Interface vol. 10: 20130445, DOI : 10.1098 / rsif.2013.0445 .
- ↑ Hix RL (2001) Egg-laying and brochosome sharpshooter. Archived copy from March 3, 2016 at Wayback Machine California Agriculture 50 (4): 19-22.
- ↑ Velema H.-P., Hemerik L., Hoddle MS & Luck RF (2005) Brochosome influence on parasitization efficiency of Homalodisca coagulata (Say) (Hemiptera: Cicadellidae) egg masses by Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae). Ecological Entomology 30: 485-496. DOI : 10.1111 / j.0307-6946.2005.00731.x
Links
- Brochosomes by RA Rakitov, Illinois Natural History Survey
- Leafhopper Egg Brochosomes Image Database by RA Rakitov, Illinois Natural History Survey