The high abundance of the recluse spider Loxosceles intermedia Mello-Leitão, 1934 inside buildings in Curitiba, Southern Brazil, suggests that the encounters between males and females are not random, but instead mediated by chemical cues. An analysis of the male and female cuticular extracts revealed that females release two exclusive cuticular compounds: geranyl acetate and geranyl acetone. Bioassays were conducted using female body extracts and male-and female-specific compounds at short distances, and with live males and females as well as female-specific compounds at long distances. Males interacted significantly more with female body extract and female-specific compounds at short distances and were more attracted to female-specific compounds at long distances. However, when live spiders were used as stimuli, females attracted both males and females but responded more intensely to males. This suggests that females, upon detecting the presence of males, display a motor identification pattern signaling their presence, facilitating the approach of the males. These results support the hypothesis that the reproductive behavior of L. intermedia involves multiple signals, primarily vibration and chemoreception.

Abstract The Environmental enrichment technique, although scientifically recognized for raising the level of animal welfare, has led to the questioning of its influence on the results of experimental research. Thus, the goal is to promote reflection about the need for standardization of these procedures. For that, documents and experimental analysis were done, in order to quantify and characterize the types of environmental enrichment used and to evaluate the effect of that in the social behavior of Rattus norvegicus. Data from the document review confirmed the hypothesis that the researchers have used a variety of methods, not demonstrating a concern for standardization and prior assessment of its effects on the search results. Demand was corroborated in the experimental study in which, although there was available a simple object acting as refuge promotes behavioral improvements, the presence of the co-specific, as well as characteristics of the micro and macro environment can compromise the homogeneity of the sample. The data from this study endorse the need for validation procedures of environmental enrichment for specific proposals, to investigative data comparison, are possible and contribute to the refinement of the search to reduce the number of animals targeted for this purpose.

Os grupos de radiação evolutiva de Loxosceles Heinecken & Lowe, 1835 além de compartilharem caracteres morfológicos aparentemente também apresentam comportamentos semelhantes. Assim, o presente estudo objetivou descrever o comportamento agonístico dos machos das espécies do grupo spadicea - Loxosceles intermedia Mello-Leitão, 1934 e Loxosceles hirsuta Mello-Leitão, 1931 - e laeta -Loxosceles laeta (Nicolet 1849) - ocorrentes no estado do Paraná. Para tal, os machos foram pareados, sendo o invasor colocado nas teias do residente, descritos e quantificados os padrões motores exibidos. O comportamento agonístico de machos de L. laeta, L. intermedia e L. hirsuta foi caracterizado pelo afrontamento, defesa e combate, sendo apenas o último ritualizado e relacionado com peculiaridades de cada espécie, tendo em comum a sinalização de tamanho e força. Além dos padrões motores exibidos durante o comportamento agonístico serem semelhantes com aqueles utilizados no comportamento sexual, os padrões motores de L. intermedia e L. hirsuta foram mais semelhantes entre si e diferentes de L. laeta, sugerindo relação com o grupo de radiação evolutiva.

The evolutionary groups of species of Loxosceles Heinecken & Lowe, 1835, besides having morphological characters in common, may also show similar behaviors. The present study describes the agonistic behavior of males of members of the spadicea group - Loxosceles intermedia Mello-Leitão, 1934 and L hirsuta Mello-Leitão, 1931 - and the laeta-group - L. laeta (Nicolet, 1849) - that occur in the state of Paraná. In experiments with paired males, an intruder male was placed in the web of a resident male web, and the motor patterns displayed were described and quantified. Males of all three species showed confrontation, defense and combat behaviors. The combat was ritualized and related to peculiarities of each species, while sharing the signaling of strength and size. The motor patterns shown during agonistic behavior were similar to those used in sexual behavior. The motor patterns of L. intermedia and L. hirsuta were more similar to each other and different from L. laeta, suggesting a relationship to the evolutionary group radiation.

Loxosceles laeta (NICOLET, 1849) é uma espécie cosmopolita que possui grande resistência e longevidade o que favoreceu a sua distribuição passiva por diferentes países, porém no município de Curitiba representa 10% das ocorrências. Tendo em vista a importância médica e a necessidade de compreensão dos padrões envolvidos na distribuição e colonização dos ambientes antrópicos pelas espécies do gênero Loxosceles, o presente estudo teve como objetivo caracterizar o comportamento sexual de L. laeta. Analisou-se 60 cópulas com fêmeas virgens velhas e novas diante de machos virgens. O comportamento sexual de L. laeta foi caracterizado pela intensa utilização da teia e pela exibição de padrões motores relacionados com a sua maior agressividade quando comparada com outras espécies do gênero. Os padrões motores predominantes em fêmeas velhas estiveram ligados com uma maior receptividade, porém as interações foram mais longas, aparentemente este padrão esteve relacionado com uma maior quantidade de teias no recipiente. O comportamento sexual exibido por L. laeta caracterizou o sedentarismo e agressividade da espécie.

Loxosceles laeta (NICOLET, 1849) is a cosmopolitan species with great resistance and longevity which favors its passive distribution for different countries. In the municipal district of Curitiba, south Brazil, this species represents 10% of the occurrences. In view of the medical importance and the need for understanding distribution and colonization patterns of antropic environments by species of the genus Loxosceles, the objective of the present study was to characterize the sexual behavior of L. laeta. A number of 60 couples represented by old and young virgin females with virgin males were analyzed. The sexual behavior of L. laeta was characterized by the intense use of the web and for the exhibition of motor patterns related to higher levels of aggressivity when compared with other species of the genus. In old females the predominant motor patterns were linked to a larger receptivity. However, the interactions were longer which seems that this pattern may be related to the larger amount of webs found in the container. The sexual behavior exhibited by L. laeta characterizes his sedentary habit and aggressiveness.

A co-ocorrência de Pholcus phalangioides (Fuesslin, 1775) e de Loxosceles intermedia Mello-Leitão, 1934 no intra e no peridomicílio somada à natureza araneofágica e invasora de teias de P.phalangioides sugere que ambas as espécies tenham desenvolvido algum padrão de interação interespecífica. Assim, objetivou-se caracterizar essa interação e avaliar a eficiência de P.phalangioides como predador de L.intermedia. Foram realizados cinco experimentos laboratoriais visando quantificar os padrões motores utilizados na captura de diferentes presas, preferência alimentar, influência do regime alimentar no desenvolvimento pós-embrionário e aspectos de colonização pelas duas espécies. A predação de L.intermedia foi maior apesar de P.phalangioides ser até cinco vezes mais leve. Além de nem todas as espécies do gênero Loxosceles serem predadas em igual proporção, diante de diferentes presas P.phalangioidespreferiu os insetos em detrimento de L.intermedia, sugerindo ser a araneofagia um item complementar na sua dieta. Provavelmente apenas a presença de P.phalangioides no ambiente antrópico não seja o suficiente para a manutenção das populações de Loxosceles em níveis que não causem riscos a saúde humana, porém a co-existência já confere a necessidade de uma partilha de recursos e deve ser considerada em ações de manejo.

The co-occurrence of Pholcus phalangioides (Fuesslin, 1775) and Loxosceles intermedia Mello-Leitão, 1934 outdoor and indoor added to the P.phalangioides araneophagic nature and web invader habit suggest that both species have developed some pattern of interspecific interaction. Thus, we had as objective to characterize this interaction and to evaluate the efficiency of P.phalangioides as predator of L.intermedia.We made five experiments with objective of quantifying the motor patterns used in the capture of different preys, alimentary preference, influence of the diet in the post-embryonic development and colonization for the two species.The predation on L.intermedia was greater despite P.phalangioides be until five times lighter. In the presence of different prey P.phalangioides preferred the insects instead L.intermedia, suggesting being the araneophagy a complementary item in their diet. Probably only the presence of P.phalangioides in the antropic environment is not enough for the maintenance of the Loxosceles populations in levels that do not cause risks to the human health, however the co-existence already takes the need of a resources partitionship and should be considered in management actions.