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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Do Agonistic Interactions Underlie the Segregation and Relative Abundances Between Two Loxosceles Species (Araneae: Sicariidae)?

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Fischer, Marta L. [1] ; Diniz, Suzana [2] ; Vasconcellos-Neto, Joao [2]
Total Authors: 3
[1] Pontificia Univ Catolica Parana, Lab Nucleo Estudos Comportamento Anim, Dept Biol, BR-80215901 Curitiba, PR - Brazil
[2] Univ Estadual Campinas, Dept Biol Anim, BR-13083970 Campinas, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Journal of Medical Entomology; v. 51, n. 3, p. 547-559, MAY 2014.
Web of Science Citations: 3

The medically important spiders Loxosceles intermedia Mello-Leitao and Loxosceles laeta (Nicolet) are segregated in Curitiba, southern Brazil, where L. intermedia is more abundant and widespread than L. laeta. Because they share similar microhabitat preferences and wander in search of web sites, agonistic encounters are likely to occur. The purposes of this study were to describe agonistic interactions and interpret their consequences for the relative abundances and spatial segregation of L. intermedia and L. laeta. Experimental contests were performed between residents and intruders. Asymmetries between contestants included sex, age, species, weight, and residence status. Nine behavioral categories were defined. Through discriminant analyses, it was possible to differentiate spider sex, species, and residence based on their agonistic behaviors. Intruders, juveniles, and L. intermedia individuals were better characterized by exploratory behaviors, whereas L. laeta females were differentiated by aggressiveness. By performing a multiple logistic regression, with winning or defeat as a dependent variable of sex, age, species, size, weight, and residence, it was possible to say that residents and L. intermedia individuals had the highest winning odds in contests, where as juveniles had lower winning odds than adults. Advantages of the prior residence may help to explain the predominance of L. laeta in old colonization sites, whereas the higher winning odds of L. intermedia and less aggressive behavior toward conspecifies may lead to a successful establishment of dense populations in new sites. A better understanding of agonistic interactions as a mechanism of spacing, segregation, and species replacement among spiders may be helpful for control purposes. (AU)

FAPESP's process: 99/05446-8 - Biodiversity of Arachnida and Myriapoda of the State of São Paulo
Grantee:Antonio Domingos Brescovit
Support type: BIOTA-FAPESP Program - Thematic Grants