Do parasitoids explain differential abundance of two syntopic orb-weaver spiders (Araneae: Araneidae)?

Autor(es)

Gonzaga, Marcelo O. ^[1] ; Cardoso, Joao C. F. ^[2] ; Vasconcellos-Neto, Joao ^[3]

Afiliação do(s) autor(es)

^[1] Univ Fed Uberlandia, Inst Biol, Uberlandia, MG - Brazil

^[2] Univ Fed Uberlandia, Inst Biol, Posgrad Ecol & Conservacao Recursos Nat, Uberlandia, MG - Brazil

^[3] Univ Estadual Campinas, Dept Biol Anim, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY; v. 69, p. 113-120, NOV 2015.
• Citações Web of Science: 3

Resumo

In this study, we examined the relative abundance of two congeneric species of orb-weaver spiders, Cyclosa fililineata and Cyclosa morretes, in an area of Atlantic forest in southeastern Brazil, and the relationship of this variable with fecundity and attacks by parasitoids. We also investigated responses to vibrational stimuli that simulated the approach of a wasp and described architectural changes in webs of parasitized individuals of C. fililineata. C fililineata was more abundant throughout the year, although this species produced a lower number of egg sacs and a lower number of eggs per egg sac when compared with C. morretes. Both species showed similar types of behavioral responses to vibrational stimuli, but C. fililineata remained motionless more often. The frequency of parasitism by the wasp Polysphincta janzeni on adults and juveniles was low and similar for C. fililineata and C. morretes in both dry and wet seasons. The parasitoid caused alterations in the web design of C. fililineata similar of those observed in other orb-weavers attacked by ichneumonid wasps. Webs constructed by spiders parasitized by larvae in their last instar had a lower number of radii and sticky spirals were completely absent. An egg parasitoid, Baeus cyclosae, attacked C. morretes more often than C. fililineata, possibly as a consequence of its greater clutch size and/or larger eggs. These results indicate that egg mortality caused by B. cyclosae, but not subadult and adult mortality promoted by P. janzeni, may be an important factor determining the relative abundance of these two Cyclosa species. (C) 2015 Elsevier Masson SAS. All rights reserved. (AU)

• Processo FAPESP: 99/06089-4 - Funções e variabilidade estrutural dos stabilimenta construídos por Cyclosa spp. (Araneae: Araneidae)
• Beneficiário: Marcelo de Oliveira Gonzaga
• Modalidade de apoio: Bolsas no Brasil - Doutorado