Envenomation by brown spiders of the genus Loxosceles Heinecken and Lowe, 1832 of North America, the Middle East, South Africa and South America commonly results in impressive local necrotic skin lesion and more rarely causes systemic effects, including profound intravascular haemolysis (Gerstch, 1967; Newlands et al., 1982, Gerstch and Ennik, 1983; Barreto et al., 1985; Futrell, 1992; Sezerino et al., 1998).
Loxosceles sp. are the most poisonous spiders in Brazil. Children who develop the more severe systemic effects after envenomation nearly always die. At least three different synanthropic species of Loxosceles of medical importance are known in Brazil: L. intermedia (Mello-Leitão, 1934), L. laeta (Nicolet, 1849) and L. gaucho (Gertsch, 1967). More than 3,000 cases of envenomation by L. intermedia alone are reported each year. Because of a lack of understanding of the mechanism of action of the venom, an effective treatment is not available.
Studies on the effect of venom from synanthropic species of Loxosceles have been extensively reported. However were rare analyses of the venom from those living in natural environment.
Loxosceles spiders are present in several different habitats. In the anthropic ambience they live in dark, dry places in houses, such as doorsteps, wall cracks, spaces behind pictures, furniture or even curtains, as well as in household rubbish and buildings (Gertsch, 1967; Gertsch and Ennik, 1983). They are found in different altitudes and diverse ecosystems. In the natural environment its natural biotope is tree hollows, dry leaves, ravine cracks, rocky walls and caves.
According to Trajano (1987) these spiders are among the members of the Brazilian hypogea fauna and are the most common throglophile arachnid.
To date, two species of Loxosceles spiders were registered as belonging
to troglophile fauna in caves of Brazil Loxosceles adelaida (Brignoli,
1972, Eickstead, 1975) and L. similis (Gonçalves-de-Andrade et
al., 2001). The venom of both species was characterized and its toxicity
was analyzed (Pretel et al., 2 005; Silvestre et al., 2005).
The results revealed that the venom of L. adelaida and L. similis
are potentially able to cause envenomation with the same severity of those produced
by synanthropic species.
The outstanding presence of those spiders in the Brazilian karst and the fact that Brazil is a country with large number of caves - 3,990 described and registered in Cadastro Nacional de Cavernas- CNC (Sociedade Brasileira de Espeleologia, 1990) - added to increase of tourism in caves in Brazil in the last years justify the study of the distribution of Loxosceles spiders in this ecosystem.
Thus the justification for the mapping of L. adelaida in karstics areas of Petar, a major most touristic area in Brazil that hosts thousands tourists each year, lies in the association of tropical forest and the extensive cave system.
Materials and Methods
The Parque Estadual Turístico do Alto Ribeira (Petar) is located
in the Southwestern part of São Paulo State, in the Iporanga and Apiaí
counties, Ribeira Valley. It is a natural reserve with an area of 35,712 ha
on the left margin of the upper reaches of the Ribeira River. The altitude of
the hilly terrain of the park varies from about 100 to 1000 m above the sea
level. Most of its 35712 ha is situated on the Paranapiacaba Mountain Ridge.
Together with the other neighbour reserves-Fazenda Intervales State Park, Serra
do Mar Environmental Protection Area, Xitue Ecological Station and Carlos Botelho
State Park-it constitutes one of the most protected areas of the state of São
Paulo. Those five areas represent more than 400,000 ha of protected Atlantic
Geology of Petar region is mainly characterized by carbonate rocks of the Açungui Group, Lajeado Subgroup. This group is a thick sequence of metasedimentary and metavolcanic rocks with ages ranging from the Middle to the Upper Proterozoic. The environmental importance of the area is due to the association between usually well preserved tropical forest and cave systems whose unique underground scenery combines a wide variety of speleothem forms and Quaternary palaeontological sites (Karmann and Ferrari, 2000).
The twenty studied caves are located in Iporanga county, São Paulo State and present calcareous litology. The data of the register number, register name, latitude and longitude of the visited caves have been obtained from the CNC and are listed below: SP-09 Casa de Pedra cave: 24°28'46''S-48°35'23''W; SP-012 Alambari de Baixo cave: 24°33'15"S - 48°39'5500"W; SP-020 Morro do Couto cave: 24°31'14"S - 48°41'43"W; SP-021 Morro Preto cave: 24°31'19"S - 48°41'54"W; SP-025 Agua Suja cave: 24°31'25"S-48°42'27"W; SP-026 Corrego Grande I cave (Synonym Cafezal cave): 24°31'03''S-48°42'47''W; SP-030 Laje Branca cave: 24°32'57''S- 48°43'15''W; SP-041 Santana cave: 24° 3151S-48°4206W; SP-044 Abismo da Pacoca, 24°33'57''S-48°43'0000''W; SP-46 Grilo cave: 24°32'0100''S-48°42'5000''W; SP 49 Corrego Seco cave: 24°33' 05''S-48°40'58''W; SP-054 Ouro Grosso cave: 24°32'32''S-48°40'37''W; SP-58 Pérolas cave: 24°33' 51''S-48°44'33''W and SP-466 Pascoa cave: 24°34' 03''S-48°43'01''W.
The undescribed and uncatalogued (in CNC SBE) caves Laboratorio I, Laboratorio II, JJ 27, Abismo do Bráulio, Sete Portas and Macuco have been included for their insertion in the studied area.
Methodology of Capture of Spiders and Identification
The spiders were captured manually within and outside the caves from the
caves of Petar (capture licenses numbers: 40320/2002 from Instituto Florestal,
SP, Brazil and 20/2002 from IBAMA, Brazil).
The taxonomic studies were performed by morphological analysis using a stereomicroscope with micrometric ocular (Leica®) and an image analysis program (Leica® QWin, Cambridge, UK).
Results and Discussion
Loxosceles adelaida was found inside nineteen the twenty surveyed caves.
This is the first report of this species of brown spider in the following caves:
Casa de Pedra, Alambari de Baixo, Morro do Couto, Morro Preto, Agua Suja, Corrego
Grande I, Laje Branca, Abismo da Pacoca, Grilo, Corrego Seco, Ouro Grosso,
Perolas, Pascoa and in the uncatalogued caves Laboratorio I, Laboratorio
II, JJ27, Abismo do Braulio, Sete Portas and Macuco.
Reports of Loxosceles adelaida in Santana cave were previously made by Eickstedt (1975). Dessen et al. (1980) observed L. adelaida in Santana and Morro Preto caves. Such study however presents no registered observations of these spiders in the adjacencies of these caves, a fact reported in the present study. Dessen et al. (1980) referred the presence of Loxosceles sp. in Agua Suja cave. That spider was also verified in this cave and it was identified as L. adelaida in the present study.
It is noteworthy that Loxosceles spiders are ubiquitous and can be found anywhere in the cave as observed in this study. Such finding is consistent with the significant adaptive capacity of this spider and can be in contradiction with the common belief that Loxosceles is a sedentary spider and that is present only in the mouth cave area.
The presence of L. adelaida was noted not only in the interior of caves, but also in the adjacent forests of the caves Morro Preto, Couto, Santana and Ouro Grosso.
Its is also important to highlight the observed pervasive capacity of the brown
spider. Its presence was marked not only inside the visited caves but also in
the forest areas presenting rock and earth walls as verified in the way to the
caves Corrego Grande I, Agua Suja, Couto, Morro Preto, Ouro Grosso,
Pascoa, Pacoca, Casa de Pedra and Abismo do Braulio.
It is also relevant that even in the presence of natural shelters such as caves
the Loxosceles spiders invade natural areas with anthropic activity that
mimetic the natural shelters. This behavior could be proven as of the actual
finding of the L. adelaida population in an abandoned man made lead mine
on the way to Grilo cave and in the abandoned constructions of the infrastructure
of this mine. Equally occupied by L. adelaida spiders are the areas of
the forest in the vicinities of the trail to Alambari de Baixo, Pacoca and Pascoa
caves where the presence of the human occupation vestiges such tiles, break
piles and debris were also noted.
The geographic d istribution of L. adelaida has been, therefore, updated, adding the analysed areas in this study to those data published by Gerstch (1967), Brignoli (1972), Eicksted (1975), Trajano (1987), Pinto-da- Rocha (1995) and Zeppelini-Filho et al. (2003): Grajau, RJ, Brazil (Gerstch, 1967); SP-178 Olho de Cabra cave, Altinopolis, SP, Brazil (Zeppelini-Filho et al., 2003); SP-183 Fradinhos Cave, Altinopolis, SP, Brazil (Zeppelini-Filho et al., 2003); SP-184 Cinco Bocas cave Altinopolis, SP, Brazil (Zeppelini-Filho et al., 2003); Prata cave Altinopolis, SP, Brazil (uncatalogued in CNC) (Zeppelini-Filho et al., 2003); SP-09 Casa de Pedra cave, Iporanga, SP, Brazil; SP-012 Alambari de Baixo cave, Iporanga, SP, Brazil; SP-020 Morro do Couto cave, Iporanga, SP, Brazil; SP-021 Morro Preto cave, Iporanga, SP, Brazil; SP-025 Agua Suja cave, Iporanga, SP, Brazil; SP-026 Corrego Grande I cave (Synonym Cafezal cave), Iporanga, SP, Brazil; SP-030 Laje Branca cave, Iporanga, SP, Brazil; SP-041 Santana cave, Iporanga, SP, Brazil (Eickstedt, 1975); SP-044 Abismo da Pacoca, Iporanga, SP, Brazil; SP-46 Grilo cave, Iporanga, SP, Brazil; SP 49 Corrego Seco cave, Iporanga, SP, Brazil; SP-054 Ouro Grosso cave, Iporanga, SP, Brazil; SP-58 Pérolas cave, Iporanga, SP, Brazil; SP-466 Pascoa cave, Iporanga, SP, Brazil; Laboratorio I (uncatalogued in CNC), Iporanga, SP, Brazil; Laboratorio II (uncatalogued in CNC), Iporanga, SP, Brazil; JJ 27 (uncatalogued in CNC), Iporanga, SP, Brazil; Abismo do Bráulio (uncatalogued in CNC), Iporanga, SP, Brazil; Sete Portas (uncatalogued in CNC), Iporanga, SP, Brazil; Macuco (uncatalogued in CNC), Iporanga, SP, Brazil; SP-18 Areias de Cima (Areias I) cave, Iporanga, SP, Brazil (Brignoli, 1972; Trajano, 1987); SP- 274 Tigre cave, Ribeira, SP, Brazil (Pinto-da-Rocha, 1995); SP-275 Tocão cave, Ribeira, SP, Brazil (Pinto-da-Rocha, 1995); PR-106 Rocha cave, Adrianopolis PR, Brazil (Pinto-da-Rocha, 1995); PR-108 Ermida Paiol do Alto cave, Adrianopolis, PR, Brazil (Pinto-da-Rocha, 1995); PR-118 Bom Sucesso cave, Cerro Azul, PR, Brazil (Pinto-da-Rocha, 1995); PR-123 Ermida do Paiol de Capim cave, Cerro Azul, PR, Brazil (Pinto-da-Rocha, 1995); PR-128 Buraco dos Seiscentos cave, Adrianopolis, PR, Brazil (Pinto-da-Rocha, 1995); PR-131 Taborda cave, Adrianopolis, PR, Brazil (Pinto-da-Rocha, 1995); PR-137 Ermida do Maciel cave, Adrianopolis, PR, Brazil (Pinto-da-Rocha, 1995); PR-138 Mina do Paqueiro cave, Adrianopolis, PR, Brazil (Pinto-da-Rocha, 1995).
The fact that Loxosceles spiders reside not only in the interior of caves but also in the rocky environment outside the cave and in areas modified by man that provide them shelters, added to the increasing touristic potential of the karstic environment in Brazil demonstrate the need for careful investigation of Loxosceles spiders, the etiologic agent of the severe human accident, in this biotope.
We would like to thank Jurandir Aguiar dos Santos and Benedito Ursulino dos Santos the guides from Petar, for his dedication while guiding us through the caves and helping us in the capture of the spider and the technician José Cassiano Borba for his dedication in caring for the spiders kept in captivity.