Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Influence of Photoperiod and Temperature on the Larval Behavioral Diapause of Amblyomma cajennense (Acari: Ixodidae)

Full text
Author(s):
Cabrera, Ricardo R. [1, 2, 3] ; Labruna, Marcelo B. [1]
Total Authors: 2
Affiliation:
[1] Univ Sao Paulo, Dept Med Vet Prevent & Saude Anim, Fac Med Vet & Zootecnia, BR-05508270 Sao Paulo - Brazil
[2] Univ Santo Amaro, Sao Paulo - Brazil
[3] Ctr Univ Metropolitana Sao Paulo, Sao Paulo, Guarulhos - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Journal of Medical Entomology; v. 46, n. 6, p. 1303-1309, NOV 2009.
Web of Science Citations: 14
Abstract

Larval behavioral diapause was shown to be the major factor controlling the 1-yr generation pattern of Amblyomma cajennense (F.) (Acari: Ixodidae) in Brazil. During fieldwork, this behavior was shown to coincide with long daylength (>12 h) and high mean ground temperature (approximate to 25 degrees C), which prevail during spring-summer in Brazil. The current study evaluated biological parameters of engorged females, their eggs, and the resultant larvae inside plastic pots planted with the grass Brachiaria decumbens Stapf. held in incubators set with different combinations of temperature and photoperiod. Both the long daylength (photoperiod 14:10 {[}L:D]h) and high temperature (25 degrees C) during larval hatching induced larval behavioral diapause, characterized by the confinement of hatched larvae on the ground below the vegetation for many weeks. When long daylength was present during hatching, but temperature was low (15 degrees C), larvae did not enter diapause. Similarly, when short daylength (10:14 or 12:12) was present during larval hatching, larvae did not enter diapause regardless whether temperature was high (25 degrees C). Termination of diapause was induced by shifting photoperiod from 14:10 to 12:12 or the temperature from 25 to 15 degrees C. When applied to field conditions, the present results indicate that both high ground mean temperature (approximate to 25 degrees C) and long daylength (>12 h) during spring-summer (October-March) are responsible for the induction and maintenance of A. cajennense larval behavioral diapause in the field. Furthermore, both the low ground mean temperature (-20 degrees C) and the short daylength (<12h) during autumn (April-May) are responsible for termination of larval behavioral diapause in the field. (AU)