Neobuthus Hirst 1911 (Buthidae) is a genus with very small and rare scorpions distributed in Eastern Africa. Frantisek Kovarik and Greame Low have now published a review of this genus based on a lot of new materials. Some important results:
New species:
Neobuthus awashensis Kovarik & Lowe, 2012
New combination:
Neobuthus ferrugineus (Kraepelin, 1898) (previously in the genus Butheolus)
The paper has many color pictures of species, taxonomical details and habitats. A partial identification key for the genus is presented.
Abstract:
We define key characters distinguishing between the genera Neobuthus Hirst, 1911 and Butheolus Simon, 1882. Butheolus ferrugineus Kraepelin, 1898 is transferred to the genus Neobuthus which includes only African species, in contrast to the genus Butheolus which now includes only species inhabiting the Arabian Peninsula. Neobuthus awashensis sp. n. from Ethiopia is described and compared with two closely related species, Neobuthus ferrugineus (Kraepelin, 1898) comb. n. and Neobuthus berberensis Hirst, 1911. Recent collection of 78 specimens enabled direct comparisons of all three closely related species from their respective localities and discovery of characters hitherto not apparent from discolored specimens preserved for many years in alcohol. We photographically illustrate true coloration and pubescence for these three species, provide first information about their ecology, and present photographs of their habitats and localities. Neobuthus berberensis Hirst, 1911, is lightest colored with pubescence nearly absent, and is adapted to sandy desert conditions in the vicinity of Berbera City (Somaliland). Rocky deserts in Djibouti, Ethiopia (first report), Somaliland and Somalia host the widely distributed Neobuthus ferrugineus (Kraepelin, 1898) comb. n., which varies in color and bears sparse long setae (female) or spiniform setae (male). Neobuthus awashensis sp. n. is the darkest-colored of the three and possesses pubescence similar to N. ferrugineus comb. n., from which it differs in having a longer and narrower pedipalp femur. We document strong sexual dimorphism in all three species, the lack of knowledge of which had caused the female holotype of Neobuthus ferrugineus (Kraepelin, 1898), comb. n. and the male holotype of Neobuthus berberensis Hirst, 1911 to be placed in different genera Butheolus Simon, 1882 and Neobuthus Hirst, 1911.
Reference:
Kovarik F, Lowe G. review of the genus Neobuthus Hirst, 1911 with description of a new species from Ethiopia (Scorpiones: Buthidae). Euscorpius. 2012(138):1-25. [Free fultext]
Family Buthidae
This blog will list news about all aspects of scorpion biology and important taxonomical updates from The scorpion Files. The Scorpion Files is a leading information source about scorpions, and has among others an updated list of all extant families, genera and species.(C) Jan Ove Rein and The Scorpion Files.
31 January, 2012
30 January, 2012
Phylogeography of co-distributed dune scorpions in Central Asia
Matthew Graham, Viktoria Olah-Hemmings and Victor Fet have recently published study of the phylogeography of the rare, psammophilic (sand-adapted) scorpions Anomalobuthus rickmersi Kraepelin, 1900 and Liobuthus kessleri Birula, 1898 (Buthidae) from Central Asia.
Abstract:
Although only distantly related, Anomalobuthus and Liobuthus are monotypic and sympatric scorpion genera with psammophilic phenotypes well-suited to the dune communities of the Karakum and Kyzylkum deserts of Central Asia. We predicted that this unique combination of phenotypic convergence and sympatry should have resulted in shared phylogeographic histories. We tested this hypothesis by using mitochondrial DNA data and molecular dating techniques to reconstruct the matrilineal genealogies of A. rickmersi and L. kessleri. We also developed current and late-glacial species distribution models and landscape interpolations of genetic distances to assess the influence of historical barriers and Pleistocene climates on the phylogeography of each species. Both genera exhibited signals of restricted gene flow across the Amu Darya River, supporting our prediction of mutual histories. Levels of initial genetic differentiation within each genus date to the Late Miocene to late Pliocene. Distribution models indicate that suitable habitat may have fragmented during the Pleistocene, generally in an east-west orientation. Although the observed genetic differentiation at the Amu Darya River could be a coincidental product of lineage sorting, the fact that both species display this pattern suggests that the river has been an important biogeographic element in the development of Central Asian biotas.
Reference:
Graham MR, Olah-Hemmings V, Fet V. Phylogeography of co-distributed dune scorpions identifies the Amu Daraya River as a long-standing component of central Asian biogeography. Zoology of the Middle East. 2012;55:95-110.
Thanks to Victor Fet for sending me this paper!
Abstract:
Although only distantly related, Anomalobuthus and Liobuthus are monotypic and sympatric scorpion genera with psammophilic phenotypes well-suited to the dune communities of the Karakum and Kyzylkum deserts of Central Asia. We predicted that this unique combination of phenotypic convergence and sympatry should have resulted in shared phylogeographic histories. We tested this hypothesis by using mitochondrial DNA data and molecular dating techniques to reconstruct the matrilineal genealogies of A. rickmersi and L. kessleri. We also developed current and late-glacial species distribution models and landscape interpolations of genetic distances to assess the influence of historical barriers and Pleistocene climates on the phylogeography of each species. Both genera exhibited signals of restricted gene flow across the Amu Darya River, supporting our prediction of mutual histories. Levels of initial genetic differentiation within each genus date to the Late Miocene to late Pliocene. Distribution models indicate that suitable habitat may have fragmented during the Pleistocene, generally in an east-west orientation. Although the observed genetic differentiation at the Amu Darya River could be a coincidental product of lineage sorting, the fact that both species display this pattern suggests that the river has been an important biogeographic element in the development of Central Asian biotas.
Reference:
Graham MR, Olah-Hemmings V, Fet V. Phylogeography of co-distributed dune scorpions identifies the Amu Daraya River as a long-standing component of central Asian biogeography. Zoology of the Middle East. 2012;55:95-110.
Thanks to Victor Fet for sending me this paper!
18 January, 2012
A new sub-fossil scorpion species from Malagasy copal
Wilson Lourenco and Hans Henderickx have recently described a new sub-fossil scorpion in the family Buthidae from copal found in Madagascar.
Palaeogrosphus jacquesi Lourenco & Henderickx, 2012
Abstract:
Palaeogrosphus jacquesi sp. n., the third known sub-fossil scorpion from Malagasy copal, is described. This is the fourth record of a sub-fossil scorpion in copal. The copal specimen was collected in the mines of the region of Sambava, Province of Antsiranana in the northeast of Madagascar. It belongs to the genus Palaeogrosphus Lourenço, 2000, described from Madagascar, and now represented by two sub-fossil species.
Reference:
Lourenco WR, Henderickx H. Another new sub-fossil species of scorpion of the genus Palaeogrophus Lourenco, 2000 from Malagasy copal (Scorpiones: Buthidae). Euscorpius. 2012(137):1-4. [Free fulltext]
Please note that this species will not be listed in The Scorpion Files as I only list extant species.
Palaeogrosphus jacquesi Lourenco & Henderickx, 2012
Abstract:
Palaeogrosphus jacquesi sp. n., the third known sub-fossil scorpion from Malagasy copal, is described. This is the fourth record of a sub-fossil scorpion in copal. The copal specimen was collected in the mines of the region of Sambava, Province of Antsiranana in the northeast of Madagascar. It belongs to the genus Palaeogrosphus Lourenço, 2000, described from Madagascar, and now represented by two sub-fossil species.
Reference:
Lourenco WR, Henderickx H. Another new sub-fossil species of scorpion of the genus Palaeogrophus Lourenco, 2000 from Malagasy copal (Scorpiones: Buthidae). Euscorpius. 2012(137):1-4. [Free fulltext]
Please note that this species will not be listed in The Scorpion Files as I only list extant species.
16 January, 2012
A new Tityus from Bolivia
Wilson Lourenco and Elise-Anne Leguin have published a new species of Tityus (Buthidae) from Bolivia.
Tityus horacioi Lourenco & Leguin, 2011
Abstract:
A new species of Tityus Koch (subgenus Tityus) is described from the region of the San Mateo river in the province of Cochabamba, Bolivia. It is the latest member of the ‘Tityus bolivianus’ group of species to be found in this country. The new species seems to be endemic to the region where it was collected. The scorpion fauna of Bolivia remains, however, one of the least studied in South America, and no geographical patterns of distribution have yet been defined.
Reference:
Lourenco WR, Leguin E-A. Une nouvelle espece de Tityus de Bolivie, appartenant au sous-genre Tityus et au groupe d'especes "Tityus bolivanus" (Scorpiones, Buthidae). Boletin de la SEA. 2011(49):103-7.
Family Buthidae
Tityus horacioi Lourenco & Leguin, 2011
Abstract:
A new species of Tityus Koch (subgenus Tityus) is described from the region of the San Mateo river in the province of Cochabamba, Bolivia. It is the latest member of the ‘Tityus bolivianus’ group of species to be found in this country. The new species seems to be endemic to the region where it was collected. The scorpion fauna of Bolivia remains, however, one of the least studied in South America, and no geographical patterns of distribution have yet been defined.
Reference:
Lourenco WR, Leguin E-A. Une nouvelle espece de Tityus de Bolivie, appartenant au sous-genre Tityus et au groupe d'especes "Tityus bolivanus" (Scorpiones, Buthidae). Boletin de la SEA. 2011(49):103-7.
Family Buthidae
A Centruroides sting case on an airport
Ricardo Lobo and co-workers recently reported about a six year old girl being stung by a scorpion when disembarking from an airplane at the Guarulhos International Airport in Brazil. The scorpion was caught and later identified as Centruroides testaceus (DeGeer, 1778) (Buthidae). The girl was returning from a visit in Curacao (Caribbean) where she had visited a park. The scorpion had probably entered her backpack which she carried as hand-luggage on the plane and later climbed out and stung her.
The girl only showed local symptoms and quickly improved, and was given minimal treatment. She was discharged from the hospital after two hours of monitoring.
This is not the first case of scorpion sting happening on a plane or airport and shows that airplanes may be a gateway for the introduction and spread of different species.
Abstract:
Describes the case of a 6-year-old girl who was stung by a Centruroides testaceus, a scorpion native to the Lesser Antilles, in the Guarulhos International Airport, São Paulo, Brazil, as she disembarked from a flight coming from the Caribbean. The patient presented only local symptoms (a small area of erythema and pain at the sting site), which were resolved after a few hours with analgesics, without the need for antivenom. Physicians who treat patients stung by scorpions should be alert to the possibility of such accidents being caused by non native species, especially those cases that occur near airports or ports.
Reference:
Lobo RA, Goldoni PA, Souza CA, Medeiros CR. Accident caused by Centruroides testaceus (DeGeer, 1778) (Scorpiones, Buthidae), native to the Caribbean, in Brazilian airport. Rev Soc Bras Med Trop. 2011;44(6):789-91. [Free fulltext]
The girl only showed local symptoms and quickly improved, and was given minimal treatment. She was discharged from the hospital after two hours of monitoring.
This is not the first case of scorpion sting happening on a plane or airport and shows that airplanes may be a gateway for the introduction and spread of different species.
Abstract:
Describes the case of a 6-year-old girl who was stung by a Centruroides testaceus, a scorpion native to the Lesser Antilles, in the Guarulhos International Airport, São Paulo, Brazil, as she disembarked from a flight coming from the Caribbean. The patient presented only local symptoms (a small area of erythema and pain at the sting site), which were resolved after a few hours with analgesics, without the need for antivenom. Physicians who treat patients stung by scorpions should be alert to the possibility of such accidents being caused by non native species, especially those cases that occur near airports or ports.
Reference:
Lobo RA, Goldoni PA, Souza CA, Medeiros CR. Accident caused by Centruroides testaceus (DeGeer, 1778) (Scorpiones, Buthidae), native to the Caribbean, in Brazilian airport. Rev Soc Bras Med Trop. 2011;44(6):789-91. [Free fulltext]
10 January, 2012
A new species of Hemiscorpius from Egypt
Wilson Lourenco has recently published a paper describing a new species of Hemiscorpius Peters, 1861 (Hemiscorpiidae) from Egypt. This is the first record of Hemiscorpius in Egypt.
Hemiscorpius egyptiensis Lourenco, 2011
Previously, H. somalicus Lourenco, 2o11 and H. novaki Kovarik & Mazuch, 2011 are also described from Africa. Nothing is known about the African species' venom potency and if they are of medical importance like H. lepturus Peters, 1861 in Iran.
Abstract:
A new species, Hemiscorpius egyptiensis sp. n., is described from the Nubia region in the Upper Nile, Egypt. This is the first record of the genus Hemiscorpius Peters for this country. The total number of species in the genus Hemiscorpius is now raised to 14.
Reference:
Lourenco WR. More about the African species of Hemiscorpius Peters, 1861 (Scorpiones: Hemiscorpiidae), and a description of a new species from Egypt. Boletin de la SEA. 2011(49):23-6.
Thanks to professor Lourenco for sending me this paper!
Family Hemiscorpiidae
Hemiscorpius egyptiensis Lourenco, 2011
Previously, H. somalicus Lourenco, 2o11 and H. novaki Kovarik & Mazuch, 2011 are also described from Africa. Nothing is known about the African species' venom potency and if they are of medical importance like H. lepturus Peters, 1861 in Iran.
Abstract:
A new species, Hemiscorpius egyptiensis sp. n., is described from the Nubia region in the Upper Nile, Egypt. This is the first record of the genus Hemiscorpius Peters for this country. The total number of species in the genus Hemiscorpius is now raised to 14.
Reference:
Lourenco WR. More about the African species of Hemiscorpius Peters, 1861 (Scorpiones: Hemiscorpiidae), and a description of a new species from Egypt. Boletin de la SEA. 2011(49):23-6.
Thanks to professor Lourenco for sending me this paper!
Family Hemiscorpiidae
New Lychas from Indonesia
Wilson Lourenco has recently described a new species of Lychas C. L. Koch, 1845 (Buthidae) from West Papua, Indonesia.
Lychas kaimana Lourenco, 2011
The scorpion fauna of West Papua is discussed.
Abstract:
Scorpions collected during the field expedition organized by Dr. Dimitry Telnov in West Papua, Indonesia are studied in the present note. Very few reports are available on the scorpions of the occidental side of the island. Three species were collected during this field expedition: Liocheles australasiae (Fabricius, 1775) and Liocheles karschii (Keyserling, 1885) family Liochelidae Fet & Bechly, 2001 and, Lychas kaimana sp. n., family Buthidae C. L. Koch, 1837, described here.
Reference:
Lourenco WR. Scorpions from West Papua, Indonesia and description of a new species of Lychas C. L. Koch, 1845 (Scorpiones: Buthidae). Entomol Mitt Zool Mus Hamburg. 2011;15(186):317-26.
Thanks to professor Lourenco for sending me this paper!
Family Buthidae
Lychas kaimana Lourenco, 2011
The scorpion fauna of West Papua is discussed.
Abstract:
Scorpions collected during the field expedition organized by Dr. Dimitry Telnov in West Papua, Indonesia are studied in the present note. Very few reports are available on the scorpions of the occidental side of the island. Three species were collected during this field expedition: Liocheles australasiae (Fabricius, 1775) and Liocheles karschii (Keyserling, 1885) family Liochelidae Fet & Bechly, 2001 and, Lychas kaimana sp. n., family Buthidae C. L. Koch, 1837, described here.
Reference:
Lourenco WR. Scorpions from West Papua, Indonesia and description of a new species of Lychas C. L. Koch, 1845 (Scorpiones: Buthidae). Entomol Mitt Zool Mus Hamburg. 2011;15(186):317-26.
Thanks to professor Lourenco for sending me this paper!
Family Buthidae
09 January, 2012
A new troglobitic, cave-dwelling scorpion from Vietnam
Wilson Lourenco and Din-Sac Pham have discovered another fantastic cave-dwelling scorpion from Vietnam belonging to the enigmatic family Pseudochactidae.
Vietbocap thienduongensis Lourenco & Pham, 2012
The new species is a true troglobite (e.g. lacking eyes and pigmentation among other traits) and was collected 2200 meters from the cave entrance of the Thien Duong cave (Vom cave system in the Phong Nha - Ke Bang National Park). This is actually a new distance record from a cave entrance for a scorpion!
Interestingly, this cave is totally isolated from the cave where Vietbocap canhi Lourenço & Pham, 2010 was discovered.
Abstract:
A second species of scorpion belonging to the family Pseudochactidae and to the genus Vietbocap is described from two specimens collected in the Thien Duong cave, which belongs to the Vom cave system, in the Phong Nha - Ke Bang National Park, Quang Binh Province, Vietnam. Like the previously described species of Vietbocap, the new species is also a true troglobitic element, the second known for the family Pseudochactidae. This represents the fourth known record of a pseudochactid, and the second from Vietnam.
Reference:
Lourenço WR, Pham D-S. A second species of Vietbocap Lourenço & Pham, 2010 (Scorpiones: Pseudochactidae) from Vietnam. Comptes Rendus Biologies. 2012;335(1):80-5. [Subscription required for fulltext]
Thanks to Gerard Dupre for informing me about this paper!
Family Pseudochactidae
Vietbocap thienduongensis Lourenco & Pham, 2012
The new species is a true troglobite (e.g. lacking eyes and pigmentation among other traits) and was collected 2200 meters from the cave entrance of the Thien Duong cave (Vom cave system in the Phong Nha - Ke Bang National Park). This is actually a new distance record from a cave entrance for a scorpion!
Interestingly, this cave is totally isolated from the cave where Vietbocap canhi Lourenço & Pham, 2010 was discovered.
Abstract:
A second species of scorpion belonging to the family Pseudochactidae and to the genus Vietbocap is described from two specimens collected in the Thien Duong cave, which belongs to the Vom cave system, in the Phong Nha - Ke Bang National Park, Quang Binh Province, Vietnam. Like the previously described species of Vietbocap, the new species is also a true troglobitic element, the second known for the family Pseudochactidae. This represents the fourth known record of a pseudochactid, and the second from Vietnam.
Reference:
Lourenço WR, Pham D-S. A second species of Vietbocap Lourenço & Pham, 2010 (Scorpiones: Pseudochactidae) from Vietnam. Comptes Rendus Biologies. 2012;335(1):80-5. [Subscription required for fulltext]
Thanks to Gerard Dupre for informing me about this paper!
Family Pseudochactidae
Four new species in family Chactidae from Brazilian Amazonia
Wilson Lourenco and co-workers have published four new species in the family Chactidae from the upper Rio Negro in Brazilian Amazonia.
Broteochactas niemeyerae Lourenco, Ponce de Leao Giupponi & Pedroso, 2011
Brotheas caramaschii Lourenco, Ponce de Leao Giupponi & Pedroso, 2011
Chactopsis yanomami Lourenco, Ponce de Leao Giupponi & Pedroso, 2011
Teuthraustes newaribe Lourenco, Ponce de Leao Giupponi & Pedroso, 2011
The genus Chactopsis Kraepelin, 1912 was transfered from Chactidae to Euscorpiidae by Soleglad & Sissom, 2001, but based on the decisions in Lourenco, 2003 and Lourenco, Ponce de Leao Giupponi & Pedroso, 2011 I have moved this genus back to Chactidae in The Scorpion Files. This until a new family revision is published.
Abstract:
Four new species of chactid scorpions belonging to the genera Broteochactas Pocock, 1893, Brotheas C. L. Koch, 1837, Teuthraustes Simon, 1878 and Chactopsis Kraepelin, 1912 are described from a single location in the upper Rio Negro region, Brazilian Amazonia. These descriptions provide further confirmation of the high biodiversity and the important level of endemicity found in the upper Rio Negro and in the Imeri endemic centre.
References:
Lourenco WR, Ponce de Leao Giupponi A, Pedroso DR. New species of Chactidae (Scorpiones) from the upper Rio Negro in Brazilian Amazonia. Boletin de la SEA. 2011(49):65-73.
Lourenco WR. Le genre Chactopsis Kraepelin ((Scorpiones, Euscorpiidae(ou Chactidae)) en amazonie Bresilienne. Biogeographica. 2003;79(4):167-74.
Soleglad ME, Sissom WD. Phylogeny of the family Euscorpiidae Laurie, 1896: a major revision. In: Fet V, Selden PA, editors. Scorpions 2001 In Memoriam gary A Polis. Burnham Beeches, Bucks: British Arachnological Society; 2001. p. 25-111.
Thanks to Professor Lourenco for sending me this paper!
Family Chactidae
Broteochactas niemeyerae Lourenco, Ponce de Leao Giupponi & Pedroso, 2011
Brotheas caramaschii Lourenco, Ponce de Leao Giupponi & Pedroso, 2011
Chactopsis yanomami Lourenco, Ponce de Leao Giupponi & Pedroso, 2011
Teuthraustes newaribe Lourenco, Ponce de Leao Giupponi & Pedroso, 2011
The genus Chactopsis Kraepelin, 1912 was transfered from Chactidae to Euscorpiidae by Soleglad & Sissom, 2001, but based on the decisions in Lourenco, 2003 and Lourenco, Ponce de Leao Giupponi & Pedroso, 2011 I have moved this genus back to Chactidae in The Scorpion Files. This until a new family revision is published.
Abstract:
Four new species of chactid scorpions belonging to the genera Broteochactas Pocock, 1893, Brotheas C. L. Koch, 1837, Teuthraustes Simon, 1878 and Chactopsis Kraepelin, 1912 are described from a single location in the upper Rio Negro region, Brazilian Amazonia. These descriptions provide further confirmation of the high biodiversity and the important level of endemicity found in the upper Rio Negro and in the Imeri endemic centre.
References:
Lourenco WR, Ponce de Leao Giupponi A, Pedroso DR. New species of Chactidae (Scorpiones) from the upper Rio Negro in Brazilian Amazonia. Boletin de la SEA. 2011(49):65-73.
Lourenco WR. Le genre Chactopsis Kraepelin ((Scorpiones, Euscorpiidae(ou Chactidae)) en amazonie Bresilienne. Biogeographica. 2003;79(4):167-74.
Soleglad ME, Sissom WD. Phylogeny of the family Euscorpiidae Laurie, 1896: a major revision. In: Fet V, Selden PA, editors. Scorpions 2001 In Memoriam gary A Polis. Burnham Beeches, Bucks: British Arachnological Society; 2001. p. 25-111.
Thanks to Professor Lourenco for sending me this paper!
Family Chactidae
05 January, 2012
A new species of Diplocentrus from Guatemala
Armas, Trujillo & Agreda have recently published a new species of Diplocentrus Peters, 1861 (Scorpionidae) from Guatemala.
Diplocentrus lachua Armas, Trujillo & Agreda, 2011
Abstract:
A new species of the scorpion genus Diplocentrus Peters, 1861 is described from the ecological region of Lachuá, Alta Verapaz department, Guatemala. It resembles D. maya Francke, 1977, but differs from it by having a darker pattern of coloration, chelicerae with dark reticulation, a sharper subaculear tubercle, trichobothrium Dt on the fixed finger, and other morphological differences.
Reference:
de Armas LF, Trujillo RE, Agreda EO. Nueva especie de Diplocentrus Peters, 1851 (Scorpionidae: Diplocentrinae) del noroeste de alta Verapaz, Guatemala. Boletin de la SEA. 2011(49):113-7.
Thanks to Rony Trujillo for sending me this paper!
Family Scorpionidae
Diplocentrus lachua Armas, Trujillo & Agreda, 2011
Abstract:
A new species of the scorpion genus Diplocentrus Peters, 1861 is described from the ecological region of Lachuá, Alta Verapaz department, Guatemala. It resembles D. maya Francke, 1977, but differs from it by having a darker pattern of coloration, chelicerae with dark reticulation, a sharper subaculear tubercle, trichobothrium Dt on the fixed finger, and other morphological differences.
Reference:
de Armas LF, Trujillo RE, Agreda EO. Nueva especie de Diplocentrus Peters, 1851 (Scorpionidae: Diplocentrinae) del noroeste de alta Verapaz, Guatemala. Boletin de la SEA. 2011(49):113-7.
Thanks to Rony Trujillo for sending me this paper!
Family Scorpionidae
03 January, 2012
Scorpions - Walking eyes?
Happy New year to you all!
The reason for the cryptic title of this post is a recent paper by Douglas Gaffin and co-workers in Animal Behaviour on the mystery of scorpion fluorescence.
There have been many theories on why scorpions fluorescence when exposed to UV-light. One theory is that this phenomena has no behavioral function and that the fluorescing components are just metabolic byproducts. Alternatively, scorpion fluorescence has a function (e.g. as a prey lure, as an aposematic signal or as an aid in the recognition of conspecifics (mate finding)). Some theories has been tested and rejected, but fluorescence in scorpions is still a mystery.
Gaffin and co-workers have tested scorpion activity under different light wavelengths (including UV-light) with eyes covered or not. The results suggest that scorpion cuticular fluorescence actually may be involved in their perception of light and contributes to orientation and light-avoidance behavior (e.g. helps the decision to stay in their burrow until outside light conditions are optimal for avoiding predators etc.).
This paper says that in addition to medial and lateral eyes, the metasomal elements that are sensitive to green light, the skin of the scorpion actaully works as an extra gigant eye helping in sensing light and detecting shadows. More studies are of course necessary before this theory is confirmed, but this is another proof of how fantastic animals scorpions are.
Abstract:
Scorpions are largely solitary, nocturnal arachnids that glow a bright cyan-green under UV light. The function of this fluorescence is a mystery. Previous studies of four species from three families have shown that scorpion lateral and medial eyes are maximally sensitive to green light (around 500 nm) and secondarily to UV (350e400 nm). Scorpions are negatively phototactic, and we used this behaviour to assay the responses of desert grassland scorpions, Paruroctonus utahensis, to 395 nm UV light, 505 nm cyan-green light, 565 nm green light and no light within small, circular arenas. Based on the eye sensitivity data, we predicted maximal response to 505 nm, followed by lower responses to 395 and 565 nm. In our experiments, however, scorpions responded most intensely (abrupt bouts of locomotory activity) to 395 nm and 505 nm. Next, we ran trials under 395 and 505 nm on scorpions with their eyes blocked. Scorpions with blocked eyes were much less likely to move under 505 nm than under 395 nm and were much less likely to move under 505 nm than were control animals (those without their eyes blocked). These results suggest an active role for fluorescence in scorpion light detection. Other studies indicate that photosensitive elements in scorpion tails are sensitive to green light. We therefore propose that the cuticle may function as a whole-body photon collector, transducing UV light to cyan-green before relaying this information to the central nervous system. Scorpions may use this information to detect shelter, as blocking any part of the cuticle could diminish the signal.
Reference:
Gaffin DD, Bumm LA, Taylor MS, Popokina NV, Mann S. Scorpion fluorescence and reaction to light. Anim Behav. 2012. 83(2):429-436. Doi: 10.1016/j.anbehav.2011.11.014. [Subscription required for fulltext]
An interview with first author Douglas Gaffin about the paper can be found in Wired Magazine.
Thanks to Graeme Lowe for telling me about this paper!
The reason for the cryptic title of this post is a recent paper by Douglas Gaffin and co-workers in Animal Behaviour on the mystery of scorpion fluorescence.
There have been many theories on why scorpions fluorescence when exposed to UV-light. One theory is that this phenomena has no behavioral function and that the fluorescing components are just metabolic byproducts. Alternatively, scorpion fluorescence has a function (e.g. as a prey lure, as an aposematic signal or as an aid in the recognition of conspecifics (mate finding)). Some theories has been tested and rejected, but fluorescence in scorpions is still a mystery.
Gaffin and co-workers have tested scorpion activity under different light wavelengths (including UV-light) with eyes covered or not. The results suggest that scorpion cuticular fluorescence actually may be involved in their perception of light and contributes to orientation and light-avoidance behavior (e.g. helps the decision to stay in their burrow until outside light conditions are optimal for avoiding predators etc.).
This paper says that in addition to medial and lateral eyes, the metasomal elements that are sensitive to green light, the skin of the scorpion actaully works as an extra gigant eye helping in sensing light and detecting shadows. More studies are of course necessary before this theory is confirmed, but this is another proof of how fantastic animals scorpions are.
Abstract:
Scorpions are largely solitary, nocturnal arachnids that glow a bright cyan-green under UV light. The function of this fluorescence is a mystery. Previous studies of four species from three families have shown that scorpion lateral and medial eyes are maximally sensitive to green light (around 500 nm) and secondarily to UV (350e400 nm). Scorpions are negatively phototactic, and we used this behaviour to assay the responses of desert grassland scorpions, Paruroctonus utahensis, to 395 nm UV light, 505 nm cyan-green light, 565 nm green light and no light within small, circular arenas. Based on the eye sensitivity data, we predicted maximal response to 505 nm, followed by lower responses to 395 and 565 nm. In our experiments, however, scorpions responded most intensely (abrupt bouts of locomotory activity) to 395 nm and 505 nm. Next, we ran trials under 395 and 505 nm on scorpions with their eyes blocked. Scorpions with blocked eyes were much less likely to move under 505 nm than under 395 nm and were much less likely to move under 505 nm than were control animals (those without their eyes blocked). These results suggest an active role for fluorescence in scorpion light detection. Other studies indicate that photosensitive elements in scorpion tails are sensitive to green light. We therefore propose that the cuticle may function as a whole-body photon collector, transducing UV light to cyan-green before relaying this information to the central nervous system. Scorpions may use this information to detect shelter, as blocking any part of the cuticle could diminish the signal.
Reference:
Gaffin DD, Bumm LA, Taylor MS, Popokina NV, Mann S. Scorpion fluorescence and reaction to light. Anim Behav. 2012. 83(2):429-436. Doi: 10.1016/j.anbehav.2011.11.014. [Subscription required for fulltext]
An interview with first author Douglas Gaffin about the paper can be found in Wired Magazine.
Thanks to Graeme Lowe for telling me about this paper!