A Comparative Cytogenetic Analysis of 2 Bothriuridae Species and Overview of the Chromosome Data of Scorpiones

The order Scorpiones is one of the most cytogenetically interesting groups within Arachnida by virtue of the combination of chromosome singularities found in the 59 species analyzed so far. In this work, mitotic and meiotic chromosomes of 2 species of the family Bothriuridae were detailed. This family occupies a basal position within the superfamily Scorpionoidea. Furthermore, review of the cytogenetic data of all previously studied scorpions is presented. Light microscopy chromosome analysis showed that Bothriurus araguayae and Bothriurus rochensis possess low diploid numbers compared with those of species belonging to closely related families. Gonadal cells examined under light and in transmission electron microscopy revealed, for the first time, that the Bothriuridae species possess typical monocentric chromosomes, and male meiosis presented chromosomes with synaptic and achiasmatic behavior. Moreover, in the sample of B. araguayae studied, heterozygous translocations were verified. The use of techniques to highlight specific chromosomal regions also revealed additional differences between the 2 Bothriurus species. The results herein recorded and the overview elaborated using the available cytogenetic information of Scorpiones elucidated current understanding regarding the processes of chromosome evolution that have occurred in Bothriuridae and in Scorpiones as a whole.

The genus Ananteris Thorell, 1891 (Scorpiones, Buthidae) in southeast Brazil, with the description of three new species

A new synthesis of the geographical distribution of the genus Ananteris Thorell, 1891 (Scorpiones, Buthidae) in Brazil is proposed. Three new species, Ananteris chagasi sp. n., Ananteris kuryi sp. n., and Ananteris bernabei sp. n. are described from the States of Bahia, Espirito Santo and Minas Gerais. Only isolated records of Ananteris species where known up to now, for the States of Minas Gerais and Bahia. The record of an Ananteris species from the State of Espirito Santo is new. The total number of Ananteris species is now raised to 67 and from this, 16 species are found in Brazil. The geographical distribution of the genus is considerably enlarged in the country.

LOSS OF HEMISPERMATOPHORES AND SEXUAL-BEHAVIOR OF TITYUS-BAHIENSIS (PERTY, 1834) (SCORPIONES, BUTHIDAE)

Male scorpions (Tityus bahiensis) that have been deprived of their hemispermatophores and hemispermatophore sheaths retain their ability to court females despite their inability to mate successfully. Although hemispermatophores usually regenerate rapidly in nature, no such regeneration occurred after experimental amputation.

A Comparative Cytogenetic Analysis of 2 Bothriuridae Species and Overview of the Chromosome Data of Scorpiones

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Programa de controle de surto de escorpião Tityus serrulatus, Lutz e Mello 1922, no município de Aparecida, SP (Scorpiones, Buthidae).

A scorpion control program was proposed for the town of Aparecida (SP), an endemic region of Tityus serrulatus. Clusters of scorpions in urban and rural areas, environmental degradation of the town's outskirts and new scorpion procreation and dispersal habitats were studied. In addition, infrastructure problems such as the disposal and collection of residential and municipal refuse, sanitation (sewage and storm sewer), condition of vacant lots and constructions in the urban area were evaluated. After an epidemiological study, educational measures such as the distribution of pamphlets, cleaning group work, visits to residences and cooperation from High School teachers and students were also suggested. Chemical control was indicated in high-risk sites, especially those of near-school buildings. Furthermore, the use of natural predators was also mentioned within the present sanitation regulations for urban areas. The authors assert that these procedures must be integrated and continued uninterruptedly for several years. They also suggest a collaborative work with those responsible for the dengue eradication program, as well as the institution of the scorpion study week, which would greatly contribute to the education of the population, to preventive programs and to scorpion control.

Selection of environmental temperature by the yellow scorpion Tityus serrulatus Lutz & Mello, 1922 (Scorpiones, Buthidae)

The preferred temperature of the yellow scorpion Tityus serrulatus was investigated since its dispersion is a matter of concern. Adult T. serrulatus, weighing 1.24 ± 0.20 g (mean + sd) and with a standard length of 59.3 ± 2.5 mm, were used. A metallic corridor (120 cm long, 5 cm large and 10 cm high) with thermal gradient ranging from 0°C to 40°C was used. Tityus serrulatus chose and stayed in temperatures ranging from 14° C to 38°C when safe conditions were offered (dark and thigmotactic stimuli). The number of animals that remained in the 11°C-20°C, 21°C-30°C, and 31°C-40°C temperature zones were 8, 8, and 9, respectively. The chi-square test (degree of freedom = 2) showed that differences were not significant (p>0.05). Some animals moved to lower temperature areas (less than 8°C) when the corridor was completely illuminated and thigmotactic stimuli were absent, which led the animals to present a torpor state. It is concluded that T. serrulatus does not select a specific environmental temperature. Associated with the capacity of temporally surviving at low temperatures, this species seems to be highly adaptable to different thermal zones.

Agressividade relacionada ao contexto alimentar em escorpião-amarelo Tityus Serrulatus (Lutz & Mello, 1922)(Scorpiones, Buthidae)

Scorpions are among the oldest living groups of animals, and are present in almost every continent. Although many studies are made about the toxins present in their venom, little is known about their behavior. The aim of this paper is to investigate the expression of agressiveness in the brazilian yellow scorpion Tityus serrulatus, specifically the relation between agressiveness, motor activity and feeding condition. The study was divided in two parts. First, we used 16 adult individuals, placed in two terrarium, to establish an ethogram. Each group was observed for 36h, and the behaviors displayed were described and categorized as agonistic or non-agonistic. In the second part of the experiment, we used 32 adult animals in three different nutritional states: Feeding (still ingesting food), Sated (1 to 4 days since last meal) and Deprived (14 to 25 days since last meal). The individuals were paired, each pair placed in a terrarium and observed for 30min. Behaviors displayed were timed in seconds. Our results show that only Feeding individuals displayed agonism towards others, and no relation was observed between motor activity and feeding conditions

Mitotic and meiotic chromosomes of Tityus mattogrossensis and Tityus silvestris (Scorpiones, Buthidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Orobothriurus (Scorpiones: Bothriuridae) phylogeny, Andean biogeography, and the relative importance of genitalic and somatic characters

The genus Orobothriurus Maury, 1976 (Bothriuridae Simon, 1880) displays an Andean pattern of distribution, most of its species occurring at high altitudes (over 2000-2500 m to a maximum altitude record of 4910 m) from central Peru to Argentina. The recent discovery of several new species and the uncertain phylogenetic position of Orobothriurus lourencoi Ojanguren Affilastro, 2003, required a reanalysis of Orobothriurus phylogeny. Thirty bothriurid taxa, including all species of Orobothriurus and Pachakutej Ochoa, 2004, were scored for 65 morphological characters and analysed with parsimony under equal and implied weighting. The resulting topology justifies the establishment of a new genus, Rumikiru Ojanguren Affilastro et al., in press, for O. lourencoi and a closely related, new species, Rumikiru atacama Ojanguren Affilastro et al., in press. It also offers new insights about the phylogeny and biogeography of Orobothriurus and related genera. Characters from the male genitalia (i.e. hemispermatophore), comprising approximately 26% of the morphological matrix, were found to be less homoplastic than those from somatic morphology, contradicting suggestions that genitalia are uninformative or potentially misleading in phylogenetic studies.

On the taxonomic status of Chactas camposi Mello-Leitao, 1939 (Scorpiones, Chactidae)

The true taxonomic status of the chactid scorpion Chactas camposi Mello-Leitao, 1939 from Ecuador is established based in the recently discovered holotype female, until now considered lost, at the Museu Nacional do Rio de Janeiro. In base on the analysis of the external morphology, we transfer this species to the genus Teuthraustes Simon, 1878. A detailed redescription and diagnosis according to modern standards are provided. Teuthraustes camposi comb. n. is closely related with Teuthraustes whymperi (Pocock, 1893) from Ecuadorian provinces Pichincha and Cotopaxi.

A double role of sperm in scorpions: the mating plug of Euscorpius italicus (Scorpiones: Euscorpiidae) consists of sperm

Mating plugs occluding the female gonopore after mating are a widespread phenomenon. In scorpions, two main types of mating plugs are found: sclerotized mating plugs being parts of the spermatophore that break off during mating, and gel-like mating plugs being gelatinous fluids that harden in the female genital tract. In this study, the gel-like mating plug of Euscorpius italicus was investigated with respect to its composition, fine structure, and changes over time. Sperm forms the major component of the mating plug, a phenomenon previously unknown in arachnids. Three parts of the mating plug can be distinguished. The part facing the outside of the female (outer part) contains sperm packages containing inactive spermatozoa. In this state, sperm is transferred. In the median part, the sperm packages get uncoiled to single spermatozoa. In the inner part, free sperm is embedded in a large amount of secretions. Fresh mating plugs are soft gelatinous, later they harden from outside toward inside. This process is completed after 3-5 days. Sperm from artificially triggered spermatophores could be activated by immersion in insect Ringer's solution indicating that the fluid condition in the females' genital tract or females' secretions causes sperm activation. Because of the male origin of the mating plug, it has likely evolved under sperm competition or sexual conflict. As females refused to remate irrespective of the presence or absence of a mating plug, females may have changed their mating behavior in the course of evolution from polyandry to monandry.

Complex meiotic configuration of the holocentric chromosomes: the intriguing case of the scorpion Tityus bahiensis

Mitotic and meiotic chromosomes of Tityus bahiensis were investigated using light (LM) and transmission electron microscopy (TEM) to determine the chromosomal characteristics and disclose the mechanisms responsible for intraspecific variability in chromosome number and for the presence of complex chromosome association during meiosis. This species is endemic to Brazilian fauna and belongs to the family Buthidae, which is considered phylogenetically basal within the order Scorpiones. In the sample examined, four sympatric and distinct diploid numbers were observed: 2n = 5, 2n = 6, 2n = 9, and 2 = 10. The origin of this remarkable chromosome variability was attributed to chromosome fissions and/or fusions, considering that the decrease in chromosome number was concomitant with the increase in chromosome size and vice versa. The LM and TEM analyses showed the presence of chromosomes without localised centromere, the lack of chiasmata and recombination nodules in male meiosis, and two nucleolar organiser regions carrier chromosomes. Furthermore, male prophase I cells revealed multivalent chromosome associations and/or unsynapsed or distinctly associated chromosome regions (gaps, less-condensed chromatin, or loop-like structure) that were continuous with synapsed chromosome segments. All these data permitted us to suggest that the chromosomal rearrangements of T. bahiensis occurred in a heterozygous state. A combination of various factors, such as correct disjunction and balanced segregation of the chromosomes involved in complex meiotic pairing, system of achiasmate meiosis, holocentric nature of the chromosomes, population structure, and species dispersion patterns, could have contributed to the high level of chromosome rearrangements present in T. bahiensis.

Complex meiotic configuration of the holocentric chromosomes: the intriguing case of the scorpion Tityus bahiensis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Karyotype Conservation in 2 Populations of the Parthenogenetic Scorpion Tityus serrulatus (Buthidae): rDNA and Its Associated Heterochromatin Are Concentrated on Only One Chromosome

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)