The Scent Glands of the Neotropical Harvestman Discocyrtus pectnifemur: Morphology, Behavior and Chemistry.
Harvestmen have a pair of scent glands that open through ozopores. The literature suggests a link between the morphology of the ozopore area and the emission of a defensive secretion. A previous study on a species that aggregates in open areas, where individuals are probably more easily spotted by predators, showed that this defensive secretion causes conspecifics to flee. However, it is unknown whether this behavior occurs in species that aggregate in sheltered areas, where prey are harder to find. Herein, we describe the morphology of the ozopore area, the mode of emission of the defensive secretion, and its chemical composition in the harvestman Discocyrtus pectinifemur. We also tested if the defensive secretion is used as an alarm pheromone. We found that D. pectinifemur releases the defensive secretion in different ways, one of them being as a jet. Emission as a jet contrasts with that known for all congeners previously studied, and is in accord with the expected morphology of the ozopore. We found that the defensive secretion of D. pectinifemur does not function as an alarm pheromone. The composition of the defensive secretion, a mixture of quinones, is congruent with those already described for the clade that includes Discocyrtus. Our results support the link between the morphology of the scent glands area and the emission behavior of the defensive secretion, and they suggest that the alarm pheromone function in harvestmen may be dependent on ecological factors.
Programa de Pós Graduação em Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.|Laboratório de Ecologia Sensorial e Comportamento de Artrópodes (LESCA), Universidade de São Paulo, São Paulo, SP, Brazil.
Júlio M G
JM
Segovia
Escola de Artes Ciências e Humanidades, Universidade de São Paulo, Rua Arlindo Béttio, 1000 - Ermelino Matarazzo, 03828-000, São Paulo, SP, Brazil.
Marcos Ryotaro
MR
Hara
Programa de Pós Graduação em Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.|Laboratório de Ecologia Sensorial e Comportamento de Artrópodes (LESCA), Universidade de São Paulo, São Paulo, SP, Brazil.
Guilherme Ferreira
GF
Pagoti
Escola de Artes Ciências e Humanidades, Universidade de São Paulo, Rua Arlindo Béttio, 1000 - Ermelino Matarazzo, 03828-000, São Paulo, SP, Brazil.
Miriam
M
Sannomiya
Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, 05508-090, São Paulo, SP, Brazil.
Deborah Y A C
DY
Santos
Programa de Pós Graduação em Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil. willemart@usp.br.|Laboratório de Ecologia Sensorial e Comportamento de Artrópodes (LESCA), Universidade de São Paulo, São Paulo, SP, Brazil. willemart@usp.br.|Escola de Artes Ciências e Humanidades, Universidade de São Paulo, Rua Arlindo Béttio, 1000 - Ermelino Matarazzo, 03828-000, São Paulo, SP, Brazil. willemart@usp.br.|Programa de Pós Graduação em Ecologia e Evolução, Universidade Federal de São Paulo, São Paulo, Brazil. willemart@usp.br.
Rodrigo Hirata
RH
Willemart
D000818:Animals; D001097:Arachnida / Q000033:anatomy & histology / Q000737:chemistry / Q000502:physiology*; D005260:Female; D008297:Male; D010675:Pheromones / Q000032:analysis; D012543:Scent Glands / Q000033:anatomy & histology / Q000737:chemistry / Q000502:physiology
D010675:Pheromones
Arachnida; Chemical defense; Chemical ecology; Defensive behavior; Defensive secretion; Gonyleptidae; Opiliones; Ozopore