Effects of Environmental Temperature on Life Tables of Rhodnius neivai Lent, 1953 (Hemiptera: Reduviidae) under Experimental Conditions
Vol. 94(5): 709-714
Daniel R Cabello
Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, 5101 Venezuela
Changes in life tables of Rhodnius neivai due to variations of environmental temperature were studied, based on nine cohorts. Three cohorts were kept at 22°C, three at 27°C and three at 32°C. Cohorts were censused daily during nymphal instars and weekly in adults. Nine complete horizontal life tables were built. A high negative correlation between temperature and age at first laying was registered (r=-0,84). Age at maximum reproduction was significantly lower at 32°C. Average number of eggs/female/week and total eggs/female on its life time were significantly lower at 22°C. Total number of egg by cohort and total number of reproductive weeks were significantly higher at 27°C. At 32°C, generational time was significantly lower. At 27°C net reproductive rate and total reproductive value were significantly higher. At 22°C, intrinsic growth, finite growth and finite birth rates were significantly lower. At 22°C, death instantaneous rate was significantly higher.
Key words: temperature - vital statistics - Triatominae - Rhodnius neivai - Venezuela
From the beginning of the decade of 70, life tables have been developed for several species of triatomines and population characteristics have been determined (Rabinovich 1972a,b, Feliciangeli & Rabinovich 1985, Cabello et al. 1987, Guarneri et al. 1998); however, these works have not considered the effect of different environmental temperatures on life tables of a particular triatomine species.
Rhodnius neivai Lent (1953) has a restricted geographic distribution, limited to arid areas in center western Venezuela (MachadoAllison & Ramírez Pérez 1967) and northeastern Colombia (Lent & Wygodzinsky 1979), usually in human dwelling (Lent & Jurberg 1969). Although it has been considered of little importance as Chagas disease vector, because of its aggressive behavior, its vital statistics have been studied (Cabello et al. 1987) and concluded that it has a wide ecologic valence.
In this work, changes on vital statistics of R. neivai, reared under different environmental temperatures were studied to evaluate its adaptation capacity.
ACKNOWLEDGMENTS
To the anonymous reviewers whose suggestions improved the original manuscript.
Fig.1 | Fig.2 | Fig.3
TABLE I | TABLE II | TABLE III | TABLE IV | TABLE V
Fax: +58-74-401286. E-mail: cabellod@ciens.ula.ve
Received 1 December 1998
Accepted 10 May 1999
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