R e v i s t a d a S o c i e d a d e B r a s i le i r a d e M e d ic in a T r o p ic a l 2 7 ( 4 ) : 2 5 9 , o u t - d e z , 1 9 9 4 .
COMUNICAÇÃO
RESISTANCE OF U NFED FIRST INSTAR D 1 P E T A L O G A S T E R M A X I M U S
TO
DIFFERENT ENVIROMENTAL CONDITIONS
Marco Tulio Garcia-Zapata, Manoel Vidai and Philip Davis Marsden
W e have already determined the favourable tem perature and hum idity conditions for rearing D i p e t a l o g a s t e r m a x i m u s 1. In each o f the two experim ents described here two newly hatched lots o f 40 first instar bugs w ere studied. One group was m aintained in our insectary at a mean temperature o f 2 8 0 C (range 27-30) and a mean humidity o f 50 % (range 47-50 %). The second group was maintained in the laboratory during the period October to March when conditions were colder (22°C, range 10- 34) and drier (40 % range 10-90). Time to death o f these unfed bugs was recorded for all experimental insects.
The results are expressed in Figure 1. They
show that first instar bugs kept in drier, colder conditions live significantly longer (mean 145 days, range 94-178) than those kept under our insectary conditions (mean 89 days, range69-103) (x2= 0 .5 8 2 , p = 0.4555). W hile our insectary is favourable for rapid rearing o f fed bugs1, it shortens the life o f unfed first instars. These data are com patible w ith field observations2. F irst instars survived in the cold nocturnal conditions of the Baja California Peninsula to run over sunlit stony ground from 9 a.m. in search o f the rare blood meal. Their resistance to starvation is a biological adaptation to an inhospitable ecology.
1. Barreto A C , Prata A R , Marsden PD , Cuba CC
Trigueiro CP. A spectos biológicos e criação em
m assa de D ip e ta lo g a s te r m ax im u s ^Jlher, 1894)
(Triatominae). Revista do Instituto de Medicina Tropical de São Paulo 23:18-27, 1981.
REFERENCES
2 M arsden PD , Cuba C C, Alvarenga NJ, Barreto AC.
Report on a field collection o f D ip e ta lo g a s te r
m axim u s. Revista do Instituto de M edicina Tropical de São Paulo 21:202-206, 1979.
U N D P /W orld B ank/FN S/M S and N úcleo de M edicina T ropical e Nutrição, U niversidade de Brasília, Brasília, D F , Brasil. A d d r e s s t o : D r. M arco T úlio G arcia-Zapata. N M TN /U nB , 70910-900 Brasília, D F , Brasil.
R ecebido para publicação em 10/06/94.
