Protonemura gevi
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Protonemura gevi , male |
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| Scientific name | ||||||||||||
| Protonemura gevi | ||||||||||||
| Tierno de Figueroa & López-Rodríguez , 2010 |
Protonemura gevi is a stonefly species from the genus Protonemura . So far it is only known from a cave in the south of Spain . The entire life cycle of this stonefly from larval development to maturity takes place in this habitat.
features
Adults
The adults of Protonemura gevi show conspicuous features that are seen as an adaptation to cave life as troglobionts . These include the reduced complex eyes , which are hardly needed in the lightless environment of their living space, and the more than body-length sensors , which with their receptors enable increased tactile perception and transmit olfactory stimuli. A reduction in the wings is also noticeable.
The males are 6.1–8.0 mm long, the females 6.9–8.4 mm. The head is yellowish, with a brown triangle in the area of the ocelles . The antennae are very dark except for the yellowish colored base. The legs are yellow with brown transverse bands on the femures . The abdomen is yellowish, but the posterior segments are brown, from the eighth segment in the males and from the ninth segment in the females. The cerci are cylindrical and narrower at the ends than at the base. They are quite long compared to other species.
Nymphs
The male nymphs are 6 to 7 millimeters long, the female 8 to 10 millimeters. Their body color is yellowish brown, the legs, antennae and cerci are of a similar color but lighter.
On the underside of the first breast segment there are six tracheal gills combined into two triple tufts . The wing sheaths are directed obliquely backwards. The links of the tarsi are darker on the top than on the underside.
Location
The only place where the stonefly species was found is the Cueva del Nacimiento del Arroyo de San Blas , the cave in which the San Blas mountain stream rises, near Siles, a municipality in the province of Jaén , Spain. The cave is 60 meters deep and 1000 meters above sea level. Despite regular examinations, no nymphs or adults were found outside the cave or found in other caves in the area. Protonemura gevi appears to be endemic to this cave.
Way of life
After Leuctra, Protonemura is the most species-rich genus of stonefly in Europe. The larvae of some species of stonefly live in spring streams that arise from caves. Others, such as populations of Brachyptera tristis and Nemoura cinerea , were also found directly in cave waters. Insect species rarely complete their entire life cycle in the caves. According to research so far, Protonemura gevi is one of them.
Protonemura gevi lives in complete darkness with 67% humidity, the water temperature averages 11.65ºC, with very little fluctuations during the year. The mean value of the oxygen saturation is 86.76%. The stony subsoil and the oligotrophic conditions in the water offer few nutrients. The stonefly larvae serve as food near the entrance, where there are also remains of wood, mainly larger organic particles as well as fungal hyphae and spores . At the back of the cave, they feed on debris and animal protein that comes from carcasses such as bats and other animals. The mouthparts of the stone flies do not allow them to prey for prey in order to supplement the nutrient-poor detritus, which comes from roots and occasionally particles carried in by wind and water, with protein-rich animal food.
Due to the small seasonal temperature fluctuations in the stenothermal caves, it was not originally possible to say exactly whether the flight time of the stone flies is limited to the summer months, as is the case with their relatives living outside the caves in Europe. In any case, visits to the cave from July to September found both nymphs and sexually mature animals. In later studies with monthly collections over a year it was found that mating takes place throughout the year, on the rocks protruding out of the water in the back of the cave, where the animals can be found even without light, probably with the help of their antennae can perceive. Rhythmic drumming with the abdomen, as it was observed in some other stonefly species as advertising behavior, could not be determined in Protonemura gevi . In the water there were nymphs in different growth stages all year round, so there is no seasonally induced synchronous development in the cave.
Systematics and taxonomy
The species name gevi is derived from the "Grupo Espeleológico de Villacarillo" (GEV), a group of Spanish speleologists who discovered the species. Manuel Baena and Antonio Pérez Ruiz from the GEV had already drawn attention to the occurrence of stone flies in the cave in 2002. However, the specimens they collected were lost in the mail when they were about to be sent to the scientists at the University of Granada for investigation. It was not until July 2009 that nymphs and adults were collected again, which led to the first description of the species in 2010.
A phylogenetic study from 2014 showed the probability of a peripatric divergence of the cave species from its relatives due to glacial climatic fluctuations around 1.4 million years ago. The species most closely related to Protonemura gevi appears to be Protonemura culmenis from the Pyrenees .
Individual evidence
- ↑ a b c d e f g José Manuel Tierno de Figueroa & Manuel Jesús López-Rodríguez: Protonemura gevi sp. n., a cavernicolous new species of stonefly (Insecta: Plecoptera). Zootaxa, 2365, pp. 48-54, 2010
- ↑ a b c d Manuel Jesús López-Rodríguez & José Manuel Tierno de Figueroa: Life in the dark: on the biology of the cavernicolous stonefly Protonemura gevi (Insecta, Plecoptera). American Nataturalist, 180, 5, pp. 684-691, November 2012 doi : 10.1086 / 667888
- ↑ Francisco J. Ruiz-Ruano, Juan Pedro M. Camacho, Josefa Cabrero, Manuel J. López-Rodríguez & José Manuel Tierno de Figueroa: Peripatric origin of the only cave-restricted stonefly species known (Insecta: Plecoptera). Arthropod Systematics & Phylogeny, 72, 1. pp. 3–10, Senckenberg Society for Natural Research, April 2014 PDF
literature
- José Manuel Tierno de Figueroa & Manuel Jesús López-Rodríguez: Protonemura gevi sp. n., a cavernicolous new species of stonefly (Insecta: Plecoptera). Zootaxa, 2365, pp. 48–54, 2010 (first description)
Web links
- RE DeWalt, MD Maehr, U. Neu-Becker & G. Stueber Protonemura gevi , Plecoptera Species Files Online, Version 5.0, 2016, accessed on January 20, 2016