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Memórias do Instituto Oswaldo Cruz
Fundação Oswaldo Cruz, Fiocruz
ISSN: 1678-8060 EISSN: 1678-8060
Vol. 102, No. 4, 2007, pp. 449-454
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Bioline Code: oc07071
Full paper language: English
Document type: Research Article
Document available free of charge
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Memórias do Instituto Oswaldo Cruz, Vol. 102, No. 4, 2007, pp. 449-454
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Daily rhythm of aggregation in the haematophagous bug Triatoma infestans (Heteroptera: Reduviidae)
Minoli, SA; Baraballe, S & Figueiras, AN Lorenzo
Abstract
Triatomine bugs show a temporal modulation of many activities. Here, we analyse the daily modulation of
the aggregation behaviour of Triatoma infestans larvae and its chronobiological basis. In the laboratory, groups
of six bugs were released over an experimental arena during six consecutive days, where their aggregation
behaviour was quantified every hour. When submitted to a 12/12 h photoperiod (L/D), the larvae of T. infestans
exhibited a cyclic pattern of aggregation with a 24 h period, evincing the existence of a daily rhythm of aggregation
in this species. Bugs exhibited the maximum aggregation tendency at the end of the scotophase (7:00 h),
moment in which they naturally search for refuges. The minimum aggregation (i.e. maximal dispersion) was
observed during the last part of the photophase and beginning of the scotophase (15:00 to 1:00 h). This cyclic
pattern disappeared when constant conditions of illumination (L/L) or darkness (D/D) were imposed to the bugs,
suggesting the absence of an endogenous circadian control of this behaviour. Insects submitted to L/L and D/D
photoperiods presented lower global levels of aggregation than those submitted to L/D conditions. The lack of an
endogenous control and the relevance of light cycles as a synchronization signal are discussed as the temporal
modulation of this behaviour might play an important role in the nocturnal habits of this species.
Keywords
triatomines - daily rhythm - aggregation behaviour
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