On the vectors of cutaneous
leishmaniasis in the Central Amazon of Brasil.
3. Phlebotomine sand fly stratification in a terra firme forest 0)
Abstract
Stratification studies showed that the vast ma-jority of sand fly species in the Manaus region are found in tree canopies (15m), and that there are two dominant species which are the vectors of Leishmania braziliensis guyanensis. It took 43 weeks of trapping to capture all 50 species of sand flies collected.
INTRODUCTION
The s y s t e m a t i c s , e c o l o g y and behaviour o f sand f l i e s in areas w h e r e Leishmania brazilien-sis guyanenbrazilien-sis is e n d e m i c , has been t h e subject of m u c h r e s e a r c h in t h e past d e c a d e . Recently the t a x o n o m i c s t a t u s of t h e p r i n c i p a l v e c t o r s p e c i e s of "pian boib" w a s c l a r i f i e d
(Ware & Fraiha, 1977) and Lutzomyia umbratilis
w a s i n d i c a t e d as b e i n g t h e p r i n c i p a l v e c t o r both in the M o n t e Dourado and Manaus a r e as of n o r t h e r n Brazil (Lainson ef al., 1976; A r i a s & Freitas, 1977b). In t h e Manaus area, A r i a s & Freitas (1977a) i n d i c a t e d L. anduzei as a secondary v e c t o r of Le(3
) • b. guyanensis
w h i l e Lainson el al. (1981b) i n d i c a t e d L. whit-man/ as a secondary v e c t o r in t h e Jari a r e a . Even t h o u g h t h e range of L- anduzei d o e s extend t o t h e Jari r e g i o n , and p r o m a s t i g o t e s
have been f o u n d in its d i g e s t i v e t r a c t , t h i s sand f l y s p e c i e s has not been s h o w n t o be a secondary v e c t o r in Jari ( L a i n s o n , S h a w & Ready, personal c o m m u n i c a t i o n ) . L whitmani,
on t h e o t h e r hand, has not been t a k e n in t h e Central Amazon around M a n a u s .
O t h e r s t u d i e s of A r i a s ef al. ( 1 9 8 1 ) , A r i a s & Naiff (1981) and Lainson ef al. (1981a, 1981b) have s h o w n that t h e natural r e s e r v o i r host of t h i s Leishmania are arboreal m a m m a l s , as s u g g e s t e d by A r i a s & F r e i t a s ( 1 9 7 8 ) .
( 1 ) -( ? )
[ 3 )
-Jorge R, Arias (2) Rui A . de Freitas Ï)
Sand f l y s t r a t i f i c a t i o n in o t h e r regions of t h e N e w W o r l d has been done by Disney ( 1 9 6 3 ) , W i l l i a m s (1970), C h a n i o t i s ef al
(1971a, 1971b), S h a w ef al. ( 1 9 7 2 ) , and near Manaus by A r i a s & F r e i t a s ( 1 9 7 7 b ) . A l l authors s h o w e d t h a t t h e r e w e r e s t r a t i f i c a t i o n differ-ences b e t w e e n sand f l y s p e c i e s , s o m e species being caught p r e d o m i n a n t l y in the canopy and o t h e r s p e c i e s being c a u g h t p r e d o m i n a n t l y on t h e f o r e s t f l o o r .
MATERIAL AND METHODS
M o d i f i e d C D C m i n i a t u r e l i g h t t r a p s w e r e u t i l i z e d t h r o u g h o u t t h e s t u d y . The s l i g h t modi-f i c a t i o n s i n c l u d e d r e p l a c e m e n t omodi-f t h e c o l l e c t o r sack w i t h one of a f i n e r m e s h s c r e e n and by a d d i n g a s m a l l s t y r o f o a m c o n t a i n e r c o n t a i n i n g a p p r o x i m a t e l y 800g. of dry i c e . The s t y r o f o a m box w a s c o m p l e t e l y t a p e d c l o s e d t o a l l o w s l o w e r release of t h e C 02 gas, and t h e n taped
t o t h e s i d e of t h e t r a p s . The p o w e r source for each t r a p w a s t w o r e c h a r g e a b l e 6-volt motor-c y motor-c l e b a t t e r i e s . Two t r a p s w e r e set at 15 m e t e r s and t w o at 1 m e t e r above the f o r e s t f l o o r .
Each of t h e c o l l e c t i o n s i t e s r e m a i n e d t h e same t h r o u g h o u t t h e s t u d y , and w e r e located at INPA's Ducke Forest R e s e r v e , 26 k i l o m e t e r s NE of t h e c i t y of Manaus on the AM-010 h i g h w a y . This is a t e r r a f i r m e f o r e s t that is f r e q u e n t l y e n t e r e d by man and is m a i n t a i n e d as a b i o l o g i c a l r e s e a r c h s t a t i o n . A m o r e de-t a i l e d d e s c r i p de-t i o n of de-t h i s area can be f o u n d in Penny & A r i a s ( 1 9 8 2 ) .
Leishmania braziliensis guyanensis hes
been isolated f r o m sand f l i e s ( A r i a s & Freitas,
This research was partly supported by CNPq's GrrrHes Endemias PDE 2222-8-087/80 and INPA's project 3017. Instituto Nacional de Pesquisas da Amazonia. Manaus.
1978), f r o m w i l d a n i m a l s ( A r i a s et al., 1 9 8 1 ; A r i a s & Naiff, 1982), and man ( A r i a s , u n -p u b l i s h e d data) f r o m t h i s area s t u d i e d .
A l l sand f l i e s w e r e s o r t e d a t INPA in M a -naus, s l i d e m o u n t e d in Berlese s o l u t i o n , and i d e n t i f i e d a c c o r d i n g to t h e s y s t e m a t i c s pro-posed by L e w i s et al. (1977) ( " ) .
RESULTS
Figure 1 s h o w s t h e p e r i o d of t i m e t h a t i t took us t o c a p t u r e 1 0 0 % of t h e f l i e s t a k e n in light t r a p s . The f i r s t w e e k w e c a p t u r e d 4 6 % of all s p e c i e s w e f o u n d at t h e Ducke Reserve at all h e i g h t s d u r i n g t h e 62 w e e k s . By t h e second w e e k w e had t a k e n o v e r 5 0 % of t h e s p e c i e s . W e s u r p a s s e d t h e 7 5 % m a r k a f t e r che f i f t h w e e k of c a p t u r e s , t h e 8 0 % mark a f t e r 12 w e e k s , t h e 9 0 % m a r k a f t e r 22 w e e k s , 9 5 % mark a f t e r 33 w e e k s , and only a f t e r 43 w e e k s d i d w e t a k e all s p e c i e s c a p t u r e d d u r i n g t h i s s t u d y . No p r e v i o u s l y u n c o l l e c t e d s p e c i e s w e r e taken d u r i n g the last 19 w e e k s o f t h e s t u d y .
Figure 2 s h o w s t h e p o p u l a t i o n d e n s i t y of the d i f f e r e n t sand f l y s p e c i e s t a k e n . Even t h o u g h a g r e a t v a r i e t y of s p e c i e s w e r e t a k e n , the m a j o r i t y of i n d i v i d u a l s c o l l e c t e d w e r e t w o s p e c i e s . These t w o s p e c i e s are L. umbratilis
100
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o 5 0
L anduzei.
-1
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i
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1 S H
& '
i
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-1 . • 0 0 %
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•ow Í •
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5 0 5 5 4 0 4 5 5 0 O f C A P T U R E
to
Fig. 1 — Time elapsed to capture all species of sand flies taken in light traps over a 62 week period at the
Ducke Forest Reserve, Manaus, Brazil.
* 0 » T 0 T 4 L C A P T U R E
Fig. 2 — Population density of the sand fly species taken in light traps over a 62 week period at the Ducke
Forest Reserve, Manaus, Brazil.
Here w e can see t h a t t h e s e t w o s p e c i e s r e p r e s e n t over 7 0 % of all i n d i v i d u a l s c a p t u r e d . O n l y 10 s p e c i e s w e r e c o l l e c t e d in a f r e q u e n c y of o v e r 1 % , and all t h e s e c o m p r i s e d a l m o s t 9 0 % of the sand f l i e s t a k e n . The r e m a i n i n g 38 s p e c i e s c o m p r i s e d 1 0 % of all sand f l i e s t r a p p e d .
Table 1 s h o w s t h e t o t a l o f sand f l i e s t a k e n at both one and 15 m e t e r s in t h e s t u d y s i t e . Only one of t h e s e , B. pintoi, w a s in t h e genus
Brumptomyia, 37 s p e c i e s w e r e in t h e genus
Lutzomyia and 12 s p e c i e s w e r e in t h e genus
Psychodopygus. Three d i f f e r e n t f e m a l e s in the migonei group w e r e t a k e n , and it is possi-ble that t h e y c o r r e s p o n d t o k n o w n m a l e s of o t h e r s p e c i e s not t a k e n in t h i s s t u d y . Shanno-ni group f e m a l e s are t h o s e c o r r e s p o n d i n g t o
L scaffi, L shannon! or L. dendrophila, w h i c h at p r e s e n t w e c a n n o t s e p a r a t e . Five s p e c i e s are c i t e d as "like" or w i t h a n u m b e r and are being s t u d i e d f u r t h e r and w i l l be d e s c r i b e d s e p a r a t e l y . The t o t a l number of sand f l i e s c o l l e c t e d w a s 21,026, of w h i c h 18,215 ( 8 6 . 6 % ) w e r e t a k e n at 15 m e t e r s , and only 2,811
( 1 3 . 4 % ) w e r e t a k e n a t one m e t e r . Only f i v e s p e c i e s w e r e t a k e n at t h e one m e t e r h e i g h t , and not at t h e 15 m e t e r l e v e l . These a r e : P.
chagasl, of w h i c h only one m a l e w a s t a k e n a t one m e t e r ; L. evangelistai, also of w h i c h o n l y one m a l e s p e c i m e n w a s t a k e n a t one m e t e r ;
L. flaviscutelata w i t h f i v e m a l e s t a k e n a t one
TABLE 1 — Species composition and frequency of sand flies taken over a 62 week period at the Ducke Forest Re-serve, Manaus, Brazil.
1 Mt 15Mts % Total %
Brumptomyia pintoi 1 .04 2 .01 3 .01
Lutzomyia abonnenci 0 0 20 .11 20 .10
L. anduzei 418 14.87 7479 41.06 7897 37.56
L. antunesi 0 0 1 .01 1 <.01
L. aragaoi 23 .82 153 .84 176 .84
L. bacula 0 0 1 .01 1 < . 0 1
L. begonae 71 2.53 27 .15 98 .47
L. campbelli 0 0 2 .01 2 < . 0 1
L. dasymera 0 0 1 .01 1 < . 0 1
L. dendrophyla ü 0 6 .03 6 .03
L. dreisbachi 0 0 3 .02 3 .01
L. evangelistai 1 .04 0 0 1 < . 0 1
L. flaviscutellata 5 .18 0 0 5 .02
L. fureata 15 .53 52 .29 67 .32
L. inpai 1 .03 0 0 1 < . 0 1
L. longispina (like; n. s p . ) 7 .25 23 .13 30 .14
L. lutziana 0 0 3 .02 3 .01
L. monstruosa 58 2.06 5 .03 63 .30
L. nordestina (like) 49 1.74 13 .07 62 .29
L. olmeca nociva 96 3.42 6 .03 102 .49
L. pacae 2 .07 0 0 2 <-01
L. pilosa 4 .14 6 .03 10 .05
L. punctigeniculata 0 0 1 .01 1 <.01
L. rorotaensis 351 12.49 416 2.28 767 3.65
L. ruii 239 8.50 575 3.16 814 3.87
L runoides 0 0 1 .01 1 < . 0 1
L. sericea 31 1.10 42 .23 73 .35
L. shannoni 7 .25 27 .15 34 .16
L. spathotricha 6 .21 70 .38 76 .36
L. spinosa 0 0 6 .03 6 .29
L. triacantha 4 .14 4 .02 8 .04
L. trichopyga 18 .64 118 .65 136 .65
L. trispinosa 4 .14 15 .08 19 .09
L. tuberculata 49 1 .74 102 .56 151 .72
L. umbratilis 395 14.05 6560 36.01 6955 33.08
L. williamsi 0 0 24 .13 24 .11
L. 1.01.2.06 31 1.10 4 .02 35 .17
L. 1.01.2.09 0 0 1 01 1 <.01
Série Cruciata 9 9 51 1.81 102 .56 153 .73
Gp. Migonei 9 9 4 .14 2 .01 6 .03
Gp. Migonei 9 9 0 0 4 .02 4 .02
Gp. Migonei 9 9 4 .14 3 .02 7 .03
Sg. Pressatia 9 9 29 1.03 83 .46 112 .53
Gp. Shannoni 9 9 7 .25 45 .25 52 .25
L. sp 3 3 9 9 140 4.98 174 .96 314 1.49
Psychodopygus amazonensis 8 .28 31 .17 39 .19
P. ayrozai 24 .85 279 1.53 303 1.44
P. bispinosa 2 .07 8 .0-1 10 .05
P. chagasi 1 .04 0 0 1 < . 0 1
P. claustrei 68 2.42 92 .51 160 1.31
P. corossoniensis 11 .39 154 .85 165 .78
fABLE 1 — (Continuaçăo).
1 Mt % 15 Mts % Total °.b
p guyanensis 14 .50 219 1.20 233 1.11
p hirsutus 1 .04 28 .15 29 0.14
p. paraensis 27 .96 306 1.68 333 1.58
p squamiventrts squamiver.tris 407 14.48 178 .98 585 2.78
p n. sp. near davisi 0 0 5 .03 5 .02
p sp. 5 ? 78 2.77 135 .74 213 1.01
2.811 18.215 21.026
m e t e r ; L. inpai, a l s o w i t h o n l y one male taken at one m e t e r ; and L. pacae, of w h i c h t w o indi-viduals w e r e taken a t one m e t e r . On t h e o t h e r hand, 11 s p e c i e s w e r e t a k e n at 15 m e t e r s , yet not at one m e t e r . These t a k e n at 15 m e t e r s w e r e : L. abonnenci ( 2 0 ) , L. antunesi ( 1 ) , L. bacula ( 1 ) , L. campbelli ( 2 ) , L. dasymera ( 1 ) ,
L. dendrcphila ( 6 ) , L dreisbachi ( 3 ) , L. lutziana ( 3 ) , L. punctigeniculata ( 1 ) , /.• runoides ( 1 ) .
L. spinosa ( 6 ) , L. williamsi ( 2 4 ) , s p e c i e s 1 . 0 1 . 2 . 0 9 ( 1 ) , ( i n t h e s u b g e n u s Lutzomyia),
and P. n. s p . near davisi ( 5 ) .
A t t h e one m e t e r h e i g h t , there w e r e 5 d o m i -nant s p e c i e s w h i c h c o m p r i s e d a l m o s t 6 5 % of t h e total sand f l y c a t c h e s . These w e r e : L. anduzei, w h i c h c o m p r i s e d 1 4 . 8 2 % , L rorotaen
sis, 12.49%, L ruii, 8 . 5 0 % , L. umbratilis 1 4 . 5 0 %
P. s. SQuamiventris 14.48%.
On t h e other h a n d , t h e r e w e r e o n l y t w o species w h i c h c o u l d be c o n s i d e r e d d o m i -nant at t h e 15 m e t e r c a p t u r e s i t e s . These w e r e . L. anduzei, w h i c h c o m p r i s e d 4 1 . 0 6 % and L umbratilis, w h i c h c o m p r i s e d 3 6 . 0 1 % .
Of the t o t a l s a n d f l y p o p u l a t i o n c a p t u r e d at both h e i g h t s , w e can see t h a t t h e r e are t w o d o m i n a n t s , L. anduzei and L umbratilis, having captured 3 7 . 5 6 % and 3 3 . 0 8 % r e s p e c t i v e l y
Figure 3 s h o w s t h e i n c i d e n c e of all sand f l i e s per t r a p per w e e k as caught at t h e one and 15 m e t e r h e i g h t s . W e see here t h a t t h e r e appears to be a h i g h initial p o p u l a t i o n w h i c h drops readily after 5 w e e k s of t r a p p i n g and h.38 peaks d u r i n g t h e end of t h e m o n t h of No-v e m b e r and m o n t h of D e c e m b e r , 1977 and a
larger peak d u r i n g t h e m o n t h of M a y , 1978
AUC S t PT OCT MOV DtC JAN F t ! WAR APR MAY JUW JUL AUG « P T
1 0 7 7 l » 7 t
D o t t of c o l l e c t i o n
Fig. 3 — Seasonal distribution of all sand flies captured in light traps over a 62 week period at the Ducke Forest Reserve, Manaus, Brazil (from Penny & Arias, 1982). The curves represent 4 week moving averages as in
Cha-niots et al. (1971b).
H o w e v e r , c o m p a r i n g t h i s Figure w i t h Figure 4
(L. anduzei) and Figure 12 (L. umbratilis), w e see t h a t t h e peak i n f l u e n c e s are due t o t h e high n u m b e r of s p e c i m e n s of t h e s e t w o s p e c i e s . D u r i n g t h e m o n t h o f M a y , 1978 t h e r e
AUG S E P T OCT N O V DEC J A N FEB MAR APR MAY J U N J U l A U G SEPT
1 9 ? ?
D o l t of c o l l e c t i o n 1 9 7 «
t o reduce t h e size of t h e graph and maintain t h e s m a l l e r pe,';ks. It can be seen here that t h e initial population appears t o drop rapidly after an initial peak, s l o w l y r i s i n g around No-v e m b e r of 1977, dropping at the end of De-cember, and having another large peak in May of 1978. The one m e t e r p o p u l a t i o n appears t o be at its h i g h e s t d u r i n g t h e l i r s t part of t h e c o l l e c t i o n p e r i o d , dropping d o w n and main-t a i n i n g a l o w level of i n c i d e n c e main-t h r o u g h o u main-t main-t h e
c o l l e c t i o n t i m e .
Figure 5 s h o w s t h e a c t i v i t y of P. ayrozai
This species had t w o peaks of a c t i v i t y around December, 1977 and M a r c h , 1978 at t h e 15 meter h e i g h t . A t the one meter height t h i s species w a s not p r e s e n t at ail t i m e s and had a s l i g h t peak of a c t i v i t y d u r i n g M a r c h , 1978.
Figure 6 s h o w s t h e p o p u l a t i o n a c t i v i t y of
P. davisi. This s p e c i e s has a main peak of a c t i v i t y at 15 m e t e r s d u r i n g t h e m o n t h of February and lesser peaks of a c t i v i t y through-out t h e y e a r . A t one m e t e r the a c t i v i t y of t h i s species appears to be s l i g h t t h r o u g h o u t the c a p t u r i n g p e r i o d .
Fig 4 — Seasonal distribution of L. anduzei captured in light traps over a 52 week period at the Ducke Forest Reserve, Manaus, Brazil. The curves represent 4 week
moving averages as in Chaniotis et al. (1971b).
solid bars across the graphs at three d i f f e r e n t intervals r e p r e s e n t periods of t i m e w h e n t w i c e as many traps (4) w e r e set at both h e i g h t s t o assess " t r a p p i n g o u t " , w h i c h did not appear t o o c c u r . The peak of sand f l y a c t i v i t y at both heights d u r i n g t h e end of N o v e m b e r and t h r o u g h o u t t h e m o n t h of D e c e m b e r may be due
to the s e c o n d c o m p l e m e n t of traps s e t . This may account f o r a large e x i s t i n g adult popu-lation ( p a r t i c u l a r l y L. anduzei and L. umbratilis) w h i c h is taken i n i t i a l l y , and s u b s e q u e n t captures r e p r e s e n t t h e f o r e s t p r o d u c t i v i t y of sand f l i e s . One s e c o n d p o s s i b i l i t y for an increase in population at t h i s t i m e is t h e change in season, b e g i n n i n g of rainy season, w h i c h has been s h o w n t o t r i g g e r a c t i v i t y in some i n s e c t f a m i l i e s (Penny & A r i a s . 1982) .
Figure 4 s h o w s t h e seasonal i n c i d e n c e of
L. anduzei. It m u s t be noted here that t h e graph is s h o w n w i t h t w o scales on the left hand side
Figure 7 s h e w s t h e a c t i v i t y of P. guyanen-sis- A t both t h e 15 and t h e one meter heights t h i s s p e c i e s w a s nonapparant until November, 1977. This a c t i v i t y is noted until around A u g u s t of 1978 w h e n i t s t o p s . A t one
Fig. 5 — Seasonal distribution of P. ayrczai captured in light traps over a 62 week period at the Ducke Forest Reserve, Manaus, Brazil. The curves represent 4 week
D O l l Of C o l l e c t i o n
Fig. 6 — Seasonal distribution of P. davisi captured in
light traps over a 62 week period at the Ducke Forest Reserve, Manaus, Brazil. The curves represent 4 week
moving averages as in Chaniotis et al. (1971b).
meter t h i s s p e c i e s appears in l o w n u m b e r and f o l l o w s a p p r o x i m a t e l y t h e s a m e a c t i v i t y but at g r e a t l y reduced l e v e l s ; it w a s not c a p t u r e d again a f t e r July, 1978. The l o w p e r i o d s of a c t i v i t y of P. guyanensis c o r r e s p o n d d i r e c t l y w i t h t h e dry season in our area (Penny S
A r i a s , 1 9 8 2 ) .
Figure 8 s h o w s t h e p o p u l a t i o n a c t i v i t y o f P. paraensis. A g a i n at t h e 15 m e t e r level the peak a c t i v i t y is d u r i n g t h e m o n t h of February. This s p e c i e s has t w o s u b s e q u e n t peaks of a c t i v i t y d u r i n g t h e l a t t e r p a r t of t h e y e a r . The i n i t i a l p o p u l a t i o n , like t h a t of L. anduzei and
L. urr.bratilis, s t a r t e d high o n l y t o drop rapidly. A t one m e t e r h e i g h t t h e p o p u l a t i o n a c t i v i t y w a s l o w , s p o r a d i c a l l y appearing in t h e c a p t u r e s .
Figure 9 s h o w s t h e p o p u l a t i o n a c t i v i t y o f
L. roroiaensis. This s p e c i e s w a s one of t h e f e w s p e c i e s w h i c h w a s c o n s i d e r a b l y m o r e active at t h e o n e m e t e r level t h a n at t h e 15 m e t e r l e v e l . A t t h e 15 m e t e r level t h i s s p e c i e s was p r e s e n t at a l o w i n c i d e n c e , h a v i n g a s l i g h t peak of a c t i v i t y d u r i n g t h e end of 1977. A t t h e one m e t e r h e i g h t t r a p s it w a s c o l l e c t e d in great n u m b e r s and s h o w e d a s m a l l peak of a c t i v i t y d u r i n g O c t o b e r , 1977. It had i t s g r e a t e s t peak of a c t i v i t y d u r i n g N o v e m b e r D e
-c e m b e r , 1977. A f t e r t h i s , t h e p o p u l a t i o n d r o p p e d only t o have a s l i g h t peak of a c t i v i t y d u r i n g late June o f 1978.
Figure 10 s h o w s t h e a c t i v i t y of a new s p e c i e s of sand fly in t h e s u b g e n u s Trichopho
romyia ( A r i a s & Y o u n g , 1982), w h i c h f o r n o w is c a l l e d 1.20.1.20. A s L- anduzei, P. p3raensis
and /... umbratilis, t h i s s p e c i e s s h o w s great ac-t i v i ac-t y aac-t ac-t h e b e g i n n i n g of ac-t h e ac-t r a p p i n g p r o g r a m and d r o p s a f t e r t h e f i r s t 5 w e e k s . The t w o f o l l o w i n g peaks of a c t i v i t y at t h e 15 m e t e r level o c c u r d u r i n g t h e m o n t h s of N o v e m b e r . 1977 and M a r c h . 1978. T h i s is o n e of t h e f e w s p e c i e s w h i c h s h o w e d c o n s i d e r a b l e a c t i v i t y at both t h e o n e and 15 m e t e r l e v e l s , even t h o u g h t h e r e w a s g r e a t e r a c t i v i t y at t h e 15 m e t e r level M o s t of t h e one m e t e r level a c t i v i t y peaks c o r r e s p o n d w i t h t h o s e at t h e 15 m e t e r l e v e l .
Figure 11 s h o w s t h e a c t i v i t y of P. s.
squo-miventris- The 15 m e t e r a c t i v i t y w a s l o w and fairly c o n s t a n t t h r o u g h o u t t h e c a p t u r e p r o g r a m . H o w e v e r , at t h e o n e m e t e r l e v e l the a c t i v i t y was m o r e p r o n o u n c e d . H e r e w e f i n d a c t i v i t y peaks d u r i n g late N o v e m b e r — early De-c e m b e r , 1977 and late M a r De-c h and e a r l y A p r i l .
1978. This s p e c i e s , once c o n s i d e r e d t o be P.
maripaensis by A r i a s & Freitas (1977a, 1977b. 1978), has r e c e n t l y b e e n s h o w n to be P. s.
squamiventris by Ready et zl. (1982) .
Figure 12 s h o w s t h e a c t i v i t y of L. umbra-tilis. A s m e n t i o n e d b e f o r e , t h i s s p e c i e s s h o w e d
• L, a»niCtfialo
O a t * of C M I a c H o n i t M
Fig. 7 — Seasonal distribution of P. g-jyanensis
AUQ M F T OCT NOV OrC JAN FEB HAN AFM MAY JUN JUL AUO I E F T
I t T T liTI
D o t * of e o : I • c 11 o •
Fig. 8 — Seasonal distribution of P. paraensis captured
in light traps over a 62 week period at the Ducke Forest Reserve. Manaus, Brazil. The curves represent 4 week
moving averages as in Chaniotis et al. (1971b).
high p o p u l a t i o n a c t i v i t y at t h e b e g i n n i n g of the t r a p p i n g p r o g r a m , a lesser peak of a c t i v i t y in late N o v e m b e r — early D e c e m b e r , 1977 and a high peak of a c t i v i t y d u r i n g M a y , 1978 w h e r e t h e catches in t w o trap n i g h t s w e r e e x t r e m e l y h i g h . A t the one m e t e r level t h e p o p u l a t i o n a c t i v i t y appears to be c o n s t a n t and w i t h o u t m u c h s i g n i f i c a n t c h a n g e .
The seasonal p o p u l a t i o n a l a c t i v i t y f o r t h e r e m a i n i n g species w a s s o low that only sporadic c a p t u r e s w e r e f o u n d and no con-c l u s i o n s con-could be d r a w n .
DISCUSSION
A t least 22 w e e k s of t r a p p i n g w e r e r e q u i r e d t o get 9 0 % of the species of sand f l i e s u t i l i z i n g CO"2 baited CDC light t r a p s . Even t h o u g h w e
ran our t r a p s for 62 w e e k s , and w e had captured all t h e s p e c i e s by t h e 43rd w e e k , w e did not c a p t u r e all t h e s p e c i e s f o u n d in t h e a r e a . O t h e r s t u d i e s i n t h e same Ducke Re-s e r v e area have p r o d u c e d at leaRe-st 5 other species w h i c h w e did not c a p t u r e h e r e , and w e e x p e c t t h a t in t h e f u t u r e w e w i l l f i n d m o r e species as new c a p t u r i n g t e c h n i q u e s are a p p l i e d ; c o l l e c t i o n s of s o m e sand f l y species being very s p e c i f i c as t o c a p t u r e m e t h o d .
L-dendrophila is a s p e c i e s that is v e r y commonly t a k e n in t r e e base c a p t u r e s , yet w e only took 6 i n d i v i d u a l s in light t r a p s and these w e r e t a k e n at 15 m e t e r s . L. spinosa, another species f o u n d r e s t i n g on t r e e bases, w a s also only taken in t r a p s a t 15 m e t e r s .
The r e l a t i v e l y s m a l l number of c o m m o n l y c a p t u r e d sand f l i e s , and t h e large number of i n f r e q u e n t l y t a k e n s p e c i e s r e f l e c t s w h a t appears t o be the t r e n d of species compo-s i t i o n compo-s in t h e A m a z o n i a n f o r e compo-s t ( N e w , 1979:
M e i n a n d e r & Penny, 1982) . Very f e w species are taken very c o m m o n l y and many species are hard to f i n d . The capture m e t h o d utilized also s t r o n g l y i n f l u e n c e s t h e species t a k e n . H o w e v e r , s u m m a r i z i n g all m e t h o d s of capture w e have u t i l i z e d in t h e past ( A r i a s & Freitas. 1977a, 1977b, 1978), t h e r e s t i l l e x i s t s a vast number of species that are not at all frequent.
Since t h e t w o d o m i n a n t species of sand f l i e s c a p t u r e d d u r i n g this p r o g r a m w e r e the v e c t o r s of " p i a n b o i s " in t h e M a n a u s region of t h e A m a z o n ( A r i a s & Freitas, 1977a, 1978), t h e p r e d o m i n a n c e of t h e s e s p e c i e s at the canopy level (15 m e t e r s ) of t h e t e r r a f i r m e f o r e s t , is of great s i g n i f i c a n c e c o n s i d e r i n g the r e c e n t f i n d i n g s in t h e i d e n t i f i c a t i o n s of the natural r e s e r v o i r h o s t s of Leishmania brazilien-sis guyanenbrazilien-sis • It has been s h o w n that the s l o t h is the principal s i l v a t i c natural reservoir host (Lainson ef al., 1981a) and that t h e o p o s s u m is a p r i n c i p a l natural r e s e r v o i r host in d i s t u r b e d t e r r a f i r m e f o r e s t ( A r i a s & Naiff
, 4 W L U J U U t l i l
O o l * ol e o l l F G t l o n
Fig. 10 — Seasonal distribution of L. 1.20.1.20
cap-tured in light traps over a 62 week period at the Ducke Forest Reserve, Manaus, Brazil. The curves represent 4 week moving averages as in Chaniotis et al. (1971b).
1982) . Human bait captures in t e r r a f i r m e f o r e s t near Manaus also s h o w t h a t even though L. umbratilis is a causual man b i t e r at the forest f l o o r , i t is t h e p r i n c i p a l man b i t e r at the 15 m e t e r level ( A r i a s & Freitas. 1977b; Ready & A r i a s , u n p u b l i s h e d data) . V e c t o r and a n t h r o p o p h i l i c s p e c i e s have been s h o w n t o have d i f f e r e n t b i t i n g and p o p u l a t i o n peaks at d i f f e r e n t h e i g h t s in t h e f o r e s t f r o m Belize,
British Honduras ( D i s n e y , 1968; W i l l i a m s . 1970), and Panama (Johnson ei al., 1963; That-cher, 1968; C h a n i o t i s ef al., 1971a, 1971b) to Brazil (Shaw ef al., 1968; A r i a s & Freitas 1978). Usually it has been noted t h a t t h e b i t i n g habits of the v e c t o r s p e c i e s is v e r y c l o s e l y related to the habitats of the natural r e s e r v o i r h o s t . If t h e natural r e s e r v o i r host is a g r o u n d d w e l l e r , t h e v e c t o r s p e c i e s usually is a g r o u n d level b i t e r ; and if the natural r e s e r v o i r host is a t r e e c l i m b e r , t h e vector s p e c i e s is a canopy b i t e r (Shaw et al., 1968; A r i a s & Frei-t a s , 1 9 7 8 ) .
Even t h o u g h t h e r e is a s t r a t i f i c a t i o n a l p r e f e r e n c e of sand f l i e s , it appears f r o m t h e s e results that the sand f l i e s in t h e N o r t h e r n Central A m a z o n prefer t h e canopy to t h e f o r e s t f l o o r . Of all t h e s p e c i e s , only f i v e w e r e m o r e f r e q u e n t l y caught on t h e o n e m e t e r t r a p s . This appears to be in c o n t r a s t w i t h t h e r e s u l t s of light t r a p p i n g in Panama ( C h a n i o t i s et al..
1971b) w h e r e only t w o species w e r e m o r e f r e q u e n t l y c a p t u r e d in t h e canopy l i g h t t r a p s . In our w o r k , a l m o s t 9 0 % of all sand f l i e s t a k e n w e r e in the canopy light t r a p s , w h i l e in t h e Panama w o r k less than 2 5 % w e r e t a k e n in
canopy light t r a p s . M a y b e t h e i n f l u e n c e of C 02, w h i c h w a s p r e s e n t in our t r a p s and n o t
in t h e i r s , a c c o u n t s f o r t h e s e d i f f e r e n c e s . In a n o t h e r w o r k ( C h a n i o t i s et el. 1971a), t h e y s h o w e d that w i t h man b i t i n g captures a l m o s t 5 0 % w e r e t a k e n at t h e canopy l e v e l .
Several t i m e s our s t u d y s h o w e d that t h e r e w a s an i n i t i a l p o p u l a t i o n peak that s h a r p l y f e l l d u r i n g the f i r s t f i v e w e e k s . S u b s e q u e n t l y t h e r e w a s a s m a l l e r peak d u r i n g t h e m o n t h o f O c t o b e r . It is b e l i e v e d t h a t the o r i g i n a l popu-lation is high and t h e l i g h t traps r a p i d l y reduce t h i s , in the i m m e d i a t e area and the s u b s e q u e n t c o l l e c t i o n s are i n d i c a t o r s o f lateral m i g r a t i o n t h r o u g h the f o r e s t and e m e r g e n c e of n e w sand f l i e s . W e feel t h i s is t h e case because the s m a l l e r peak in O c t o b e r c o r r e s p o n d s t o t h e i n t r o d u c t i o n of t h e 4 a d d i t i o n a l t r a p s t h a t w e r e set c u t to see if w e w e r e " t r a p p i n g o u t " t h e p o p u l a t i o n . The f i r s t f e w catches in t h e extra s e t s of traps w e r e u s u a l l y higher t h a n t h e traps that r e m a i n e d t h r o u g h o u t t h e e n t i r e
s t u d y .
The large c a t c h e s w h i c h c o r r e s p o n d t o t h e very large peak in M a y , 1978 may have r e s u l t e d f r o m a " b o n a n z a " p o p u l a t i o n (Penny & A r i a s . 1982) . There w a s o n l y one trap at 15 m e t e r s w h i c h had t h i s e x c e p t i o n a l l y high n u m b e r o f sand f l i e s , p a r t i c u l a r l y L. anduzei and L. umbra-tilis; t h i s w a s d u r i n g t w o c o n s e c u t i v e w e e k s t h e f i r s t w e e k w i t h over 4000 sand f l i e s in t h e t r a p . P- s. squamiventris is t h e m o s t avid man b i t e r at g r o u n d l e v e l , y e t does n o t appear
Fig. 11 — Seasonal distribution of P. s. squamiventris
captured in light traps over a 62 week period at the Ducke Forest Reserve. Manaus, Brazil. The curves re-present 4 week moving averages as in Chaniotis et al.
L. u m p r o t i l i s
AUO SEPT O C T NOV J A N F E B MAR APR M A T JUN JUL AUS SEPT 1 . 7 6 D o t * o f c o l l e c t i o n
Fig. 12 — Seasonal distribution of L. umbratilis cap-tured in light traps over a 62 week period at the Ducke Forest Reserve, Manaus, Brazil. The curves represent 4 week moving averages as in Chaniotis et al. (1971b).
to go up into t h e canopy e x c e p t in r e l a t i v e l y s m a l l n u m b e r s . The peak a c t i v i t y in t h e t r a p s c o r r e s p o n d s w i t h t h o s e of A r i a s & Freitas
(1977b) w h e n d o i n g horse and human b a i t s t u d i e s .
The m o s t f r e q u e n t peak of s p e c i f i c a c t i v i t y is t h a t in late N o v e m b e r and t h r o u g h o u t
De-c e m b e r . This may be due t o one of t w o f a De-c t o r s . First, t h a t t h e s e c o n d c o m p l e m e n t of t r a p s e n c o u n t e r e d an o l d e r p o p u l a t i o n t h a t had not been p r e v i o u s l y t a k e n . If t h i s w e r e t r u e , it is logical t h a t t h e peak w o u l d not be as a c c e n t u -ated as t h e i n i t i a l peak because a) t h e r e is a
d i l u t i o n f a c t o r of 2 o t h e r t r a p s (those w h i c h had been r u n n i n g f o r a l o n g e r p e r i o d of t i m e ) and b) b e c a u s e of t h e use o f a 4 w e e k r u n n i n g mean, w h i c h t e n d s to r e d u c e e x t r e m e " p e a k s and v a l l e y s " . The s e c o n d p o s s i b l e e x p l a n a t i o n f o r t h i s peak is t h a t t h e r e is a s l i g h t e-m e r g e n c e of i n s e c t s in g e n e r a l at t h i s t i e-m e of
year (Penny & A r i a s , 1982) w h i c h c l o s e l y c o r r e s p o n d s w i t h the o n s e t of t h e rainy s e a s o n .
ACKNOWLEDGMENTS
W e w o u l d l i k e to thank Joγo F. V i d a l f o r his f i e l d and l a b o r a t o r y a s s i s t a n c e , and A r t e -m i o C o e l h o da Silva f o r the d r a w i n g s .
Resumo
Estudos de estratificaçăo mostram que a maioria das espécies de flebσtomos, na regiăo de Manaus é encontrada na copa da floresta, espécies das quais duas săo dominantes, funcionando como vetores de Leishma-nia braziliensis guyanensis. Gastaram-se 43 semanas de capturas para coletar todas as 50 espécies encontra-das e é de supor-se existir uma populaçăo de flebσ-tomos por espécie na floresta.
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