Alien scorpions in the Municipality of São Paulo , Brazil – evidence of successful establishment of Tityus stigmurus ( Thorell , 1876 ) and first records of Broteochactas parvulus Pocock , 1897 , and Jaguajir rochae ( Borelli , 1910 )

We report the successful introduction and invasion of the scorpion species, Tityus stigmurus (Thorell, 1876), in São Paulo municipality, Brazil, more than 1,000 km from its southern-most record. The species has considerable impacts on human health, because of its venomous sting. The first specimen appeared in 2012, and by the end of 2015, three populations were identified, with 86 records so far. They were probably introduced via the fruit trade. Two other alien scorpion species were recorded in São Paulo, including a single specimen of Broteochactas parvulus Pocock, 1897, and two specimens of Jaguajir rochae (Borelli, 1910).


Introduction
Invasive alien species are a constant threat to the local biodiversity, economy, and human health (Elton 1958;Early et al. 2016).Some of these invasive species are venomous animals, such as scorpions (Benton 1991;Toscano-Gadea 1998;Freitas and Vasconcelos 2008).These arachnids are among the primary causes of human envenomation and are mostly distributed in tropical and subtropical regions of the world (Chippaux and Goyffon 2008).They are easily transported to distant countries by human activities (Freitas and Vasconcelos 2008).However, successful introduction of scorpions is rarely recorded.Euscorpius flavicaudis (De Geer, 1778) was introduced into England (Benton 1991) and Uruguay (Toscano-Gadea 1998), and Isometrus maculatus (De Geer, 1778) is now a pan-tropical species (Lourenço 2002).In Brazil, Tityus stigmurus (Thorell, 1876) was introduced in the island of Fernando de Noronha (Freitas and Vasconcelos 2008).The parthenogenetic and medically important Tityus serrulatus (Lutz and Mello, 1922) has expanded considerably from its original geographical distribution to the north and southern parts of Brazil.Single individuals as well as small to large populations of T. serrulatus are found hundreds of kilometers away from its previously known geographic range (Eickstedt et al. 1996;Bortoluzzi et al. 2007;Rosa et al. 2015).Herein, we report the successful introduction of Tityus stigmurus (Figure 1A), a medically important species, originally distributed in the northeastern parts of Brazil (Figure 2A), in three urban areas in the Municipality of São Paulo, state of São Paulo, Brazil (Figure 2B).Records of the alien scorpions Broteochactas parvulus Pocock, 1897, and two specimens of Jaguajir rochae (Borelli, 1910) in São Paulo are also presented here (Figures 1B-C).

Study site
The municipality of São Paulo is one of the most densely populated regions in the world, with approximately 12 million people living within a 1,521 km 2 (IBGE 2016) area.It is a plateau, ca.900 m asl, having originally a mosaic of open fields and Brazilian Atlantic Forest.The region is also crossed by two main rivers.Historically, there were important areas with riparian vegetation and swamps (Usteri 1911;Garcia and Pirani 2005).The areas where T. stigmurus (Figure 1A) specimens were found are highly urbanized (Figure 3).(Laboratory for the Identification of and Research into Synanthropic Fauna), CCZ, São Paulo Municipality, State of São Paulo, Brazil (CFS-SP, Marco Otávio de Matos Júnior).The specimens were identified using the keys and diagnoses based on Lourenço (2002).

Results
Three species of non-indigenous scorpions were recorded for the first time in the São Paulo Municipality: Broteochactas parvulus Pocock, 1897 (Chactidae) (Figure 1B); Jaguajir rochae (Borelli, 1910) (Figure 1C), and Tityus stigmurus (Buthidae) (Figure 1A).A single specimen of Broteochactas parvulus Pocock, 1897 was recorded in a house located in the extreme east of the municipality, close to a milk box which was recently brought from a market, in February 2012 (Figures 1B, 2B, Supplementary material Table S1).Two specimens of J. rochae were found in central-southern São Paulo (Figures 1C,  2B) on November 29, 2010, and on June 3, 2013.Both specimens were found in public schools, one individual was crawling inside the building and the other was coming out of a recently opened box containing melons (Table S1).There were 86 records of T. stigmurus between May 8, 2012 and December 16, 2015, totaling 180 specimens in the three areas (Ts1-3) (Table S2).
The first T. stigmurus specimen was recorded in area Ts1, near a school in May 2012 (Figure 3).A few months later (December 2012), another specimen was recorded inside a school, but 2.5 km away from the first area (Ts2) (Figure 3).We revisited areas Ts1 and Ts2 in 2012 but no additional specimens were found.Other records appeared in the beginning of 2013.In the second semester (late winter to spring and beginning of summer) the records increased considerably (Table S2, Figure 3).In 2014, we had a single record of 3 specimens (Table S2, Figure 3).However, the following year, with a more intense search, we obtained 59 records of 138 specimens, mostly from the pluvial system (Table S2, Figure 3).Recently, in the first semester of 2015, area Ts3 had two additional records.

Discussion
Over the four-year study period, we compiled the records of scorpion species from two areas in the eastern Municipality of São Paulo.The increase in the number of collected specimens during this period and the presence of females carrying young scorpions in their dorsum suggest that T. stigmurus have reproduced, providing evidence that this species is already established in the regions Ts1-2.
Tityus stigmurus is the second species of nonindigenous Tityus to become established in the Municipality of São Paulo (after T. serrulatus Eickstedt et al. 1996).Compared to the indigenous species, Tityus costatus (Karsch, 1879) and Tityus bahiensis (Perty, 1833), T. serrulatus is the most medically important species in Brazil, and has reached the municipality after geographic distribution extension (Eickstedt et al. 1996).However, contrary to this species, the southernmost record of T. stigmurus was ca.1,000 km from São Paulo (Souza et al. 2009;Santos et al. 2014).Therefore, presumably it was introduced passively.Despite the local climate being significantly colder and more humid than that in its original habitat (northeastern parts of Brazil), the species thrived under these modified conditions.The species is known to live in the urban areas in the northeastern parts of Brazil (Albuquerque et al. 2009) and its natural region of origin is not fully resolved.The wide distribution showed by T. stigmurus in northeastern Brazil (Figure 2A) is definitely artificial, reflecting the expansion, introduction, and adaptation that allows the scorpions (for example T. serrulatus) to live and reproduce in the neighboring urban areas (Eickstedt et al. 1996).Their ability to survive harnessing the perturbations of the environment is a critical factor that facilitated the successful introduction of T. stigmurus in São Paulo.Similar to T. serrulatus, T. stigmurus is also parthenogenetic, with a few recorded sexual populations (Ross 2010;Santos et al. 2014).Hence, even a few individuals can successfully establish a new population.
The record of three distinct populations of Tityus stigmurus raises the question as to whether this species was introduced once or in three independent events.The more recent record (Ts3) in central-southern São Paulo suggests that it was an independent event, since the distance to the other records (Ts1 and Ts2) in the eastern region (ca.14 km in straight line) was significant.On the other hand, the two areas in the eastern region were separated by only 2.5 km (shortest distance), which suggests the possibility of a single introductory event.However, we did not find any specimen in the region between the two areas, despite several attempts, reinforcing the hypothesis of distinct introductions.The origin of the specimens is presumably the northeastern part of Brazil, an area known for the presence of this species (Figure 2A).An underlying factor common to all records (except area Ts3, but including J. rochae records) is trade, specifically the routes of fruit trade.The two J. rochae specimens were both found in schools, and one of them was coming out of a box of melons.One of the main areas of melon production in Brazil is the northeastern region, which is inhabited by J. rochae.The same region is also within the native range of T. stigmurus.The two first records in areas Ts1 and Ts2, were inside or close to schools, which normally receive fruits from government programs for student nutrition.The trade of fruits is an important route via which international alien spider transport occurs (Vetter et al. 2014); therefore, it is likely that the same route could be attributed to the introduction of T. stigmurus in São Paulo.
São Paulo Municipality now has three Tityus species (T.bahiensis, T. serrulatus, and T. stigmurus), which pose considerable medical concern.This information must be broadly shared with the local medical care institutions so that they can identify T. stigmurus specimens and treat their envenomation cases.Our findings show that Tityus stigmurus colonizes urban areas with very distinct climate from its indigenous geographical distribution, it can be considered an invasive species, and immediate control actions must be implemented after its first appearance.
Scorpion records were obtained from three sources in the period between May/2012 to December/2015.Either the scorpions were donated spontaneously by the citizens to the CCZ -Centro de Controle de Zoonoses (Center for Zoonosis Control), São Paulo Municipality, state of São Paulo, Brazil, and SUVIS -Supervisão de Vigilância em Saúde (Regionalized Services of Health Surveillance), São Paulo Municipality, State of São Paulo, Brazil, or the scorpions were collected by the municipality agents as a part of a larger anti-scorpion program carried out monthly (CCZ), or as a result of requests by the population for local inspection conducted by SUVIS.Specimens are deposited at the Coleção de Fauna Sinantrópica do Município de São Paulo, Labfauna, -Laboratório de Identificação e Pesquisa em Fauna Sinantrópica

Figure 3 .
Figure 3. Records of Tityus stigmurus (Thorell, 1876) (red dots) for two areas (Ts1 and Ts2) in the eastern region of São Paulo Municipality.The main streets and bridges are shown in yellow; the Metro and railway systems are in orange; the main rivers are in blue; the large empty area with low vegetation coverage and used for high voltage power towers is in green; and the anti-flood area is depicted in brown.