Distribution and Ecology of Anopheles

8/8/2019 Distribution and Ecology of Anopheles

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DISTRIBUTION AND ECOLOQY OF CARIBBEAN ANOPHELINES 99tributed from Brownsville, Texas (King1937), to the northern part of South Amer-ica. King doubts the identity of specimenstaken in New Orleans, and although a num-ber of adults were captured by MacDonellin Key West in 1904, the species did notbecome established there (King 1937).According to Hoffmann (1932, 1938a), itsrange in Mexico includes the Gulf Coastfrom Brownsville to the State of QuintanaRoo, but north of Tampico it is ratherscarce. South of Tampico it is the predomi-nant Anopheline, and breeds not only in thelittoral, but extends inland to an altitude of400 meters along the river valleys. Thenorthern part of the Peninsula of Yucatanis very dry, and here A. albimanus is foundnear villages and other human habitationswhere water is stored in artificial reservoirs.Swamps that form in isolated areas alongthe coast during the rainy season are in-habited by the species. In the southernpart of the Peninsula there are more natu-ral breeding places ; here Hoffmann alsotook the species inland in uninhabited for-est areas. On the Pacific coast of Mexicoit is distributed from Guatemala to thenorthern part of the State of Sinaloa. Thisregion is much drier than is the Gulf Coast ;thus A. albimanus is not so abundant here.Although the natural range of A. albimanusin Mexico is limited to the coastal areas,occasionally it is found farther inland athigher altitudes, especially during the rainyseason. Hoffmann records it from Monter-rey, Nuevo Leon, 545 meters above sea level,and from the village of Autlan, in the Stateof Jalisco, 1,003 meters above sea level.

Molloy (1932) says that A. albimanus is constantly encroaching on the highlands ofCentral America, and de Leons (1933b)map shows it to be not only along the At-lantic and Pacific coasts of Guatemala, butinland as far as Guatemala City, at an alti-tude of 4,500 feet. It has been taken in anumber of localities in El Salvador (LardeArthes 1921; Sutter 1939). Nicaragua(Kumm 1929b), Spanish Honduras (Whit-more, Roberts and Jantzen 1929), andBritish Honduras (Kumm 1940b). InCosta Rica it is the predominant species

(Barber and Komp 1927 ; Kumm, Kompand Ruiz 1940; Kumm and Ruiz 193913;Root 1924c), especially in the lowlands, butbreeding may be heavy in drying river bedsat elevations of 2,500 feet (Salisbury andCorrigan 1927). Kumm and Ruiz (193913)found it in 85 localities at less than 1,000feet elevation, in six from 1,000 to 3,000feet, and not at all above 3,000 feet.

Published records from Panama, except-ing those from the Canal Zone, seem to berather meagre, but there are enough toshow that the species is present throughoutthe country, at least in the coastal areas(Barber, Komp and Newman 1929a ; Dunn1934; Komp 1929a; Komp 1929b; Kumm1929b).

A. albimanus is found in many of theWest Indian Islands. It appears to inhabitalmost all of Cuba (Carr, Melendez and Ros1940; Kumm 192913 Malaret 1929)) butCarr, Melendez and Ros (1940) state that inthe Province of Oriente it is most abundantin areas less than 1,000 feet above sea level.Hoffman (1926), Root (1927) took it in anumber of localities in Haiti, including LaVanneau with an elevation of 2500 feet, butit is more prevalent at lower altitudes(Mink 1933). It is distributed throughoutPuerto Rico, from the mountains to theseashore (Earle 1930b; Root 1922; Tulloch1937)) and although it may be taken in mostparts of Jamaica, it seems to be scarce inthose areas of the Island that have an ele-vation of 500 feet or more, while it is espe-cially abundant in the lowlands (Boyd andAris 1929). Russo (1927) says that it is themost important anopheline in Santo Do-mingo. It has been reported from St.Thomas (Hoffman 1930), St. Croix (Kumm1929b), Culebra (Hoffman 1940), Vieques(Howard, Dyar and Knab 1917b), Tortola(Hoffman 1930)) Nevis (Hoffman 1930),Montserrat (Hoffman 1930)) Antigua (Ed-wards and Box 1940), St. Vincent (Senevet1936)) Dominica (Senevet 1936), Guade-loupe (Francois-Julien 1930 ; Senevet1938)) and Barbados (Kumm 1940b ; Seagar1928). It is absent from Grenada (Earle1936b ; Root and Andrews 1938), St. Lucia(Earle 1936b), Martinique (Senevet 1936))


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100 MBLBRIAand although Beattie (1932) records itfrom Trinidad, Eomp showed that thisrecord is probably erroneous, in whichF. W. Edwards concurs (Romp 1937b,1940b).As King (1937) has pointed out, its dis-tribution shows that 8. albimanus is essen-tially a mosquito of hot, humid climates.Although outside of the area covered bythis Symposium, it is of interest to considerbriefly the distribution of LI.. aEbimanus innorthern South America, where, for noapparent reason, we find the southern limitof its range. Campos record from Guaya-quil, Ecuador, has been confirmed by Kingand Stone, who examined the male termi-nalia of Campos specimens (King 1937).Komp (1937b) says it occurs for some dis-tance up the Magdalena River in Colombia,but Antunes (1937) did not include it inhis list of species from the interior of Co-lombia (Intendancia of Meta). In thesewestern countries the mountains and cli-mate may form a natural barrier to asouthward extension of the ~4..aEbimanusrange. In Venezuela, Gabaldon (1938,1939a) has taken a. albimanus in largenumbers in certain localities on or near thecoast, but not in others farther inland.Gabaldon states that the eastern limit of therange is Carupano; Komp (193713) couldnot find it near the mouth of the San JuanRiver, in the Orinoco drainage.

A. albimanus breeds in a great variety ofwater collections, either fresh or brackish,and the chief requisite for breeding seemsto be an abundance of sunlight. During therainy season t is found in rain pools; otherfavored breeding places are seepages, rriga-tion ditches (Earle 1930b), and quiet, sun-lit waters of lakes, backwashes of streams,swamps, and ponds. Hoffmann (1938c)says that the breeding water must be in abiological equilibrium, exposed to sun, andrich in microorganisms but without putre-faction; as these conditions are more apt toexist in permanent and semi-permanentwater collections, temporary rain pools arenot suitable for breeding at the beginningof the rainy season, but require time to de-velop a biological equilibrium. In larger

bodies of water A. albimanus larvae mustfind protection from fish in various types offloating aquatic vegetation. Of these theCharaceae, Utricularia, and Naias are espe-cially favorable, when the water level issuch that these plants can form thick matson the surface. In these mats A. albimanuslarvae not only are protected from theirenemies, but find enough food to enablethem to breed in tremendous numbers. Inthe Canal Zone, Curry (1934) has describedthe great abundance of the larvae amongthese plants during the dry season, whenthe level of Gatun Lake drops several feet,allowing the plants to reach the surface ofthe water and form extensive mats. Hoff-man (1930, 1940) collected larvae in crabholes in Haiti, Nevis, and Montserrat; thewater in these crab holes was as low as twofeet below the surface of the ground. Per-haps the species becomes adapted to theseunusual breeding places during periods ofdrought. Certain artificial water collec-tions may become favorable breedingplaces; thus in the dry coastal areas of thenorthern part of the Peninsula of Yucatan,A. albimanus is dependent for its existenceupon the tanks, water troughs, and similarartificial containers that are used for thestorage of water near the villages (Hoff-mann 1938a), while Clark (1932) foundlarvae in barrels and troughs in which algaewere growing on the bottom and sides. InCuba, water is piped from the hills to allparts of the Preston Division of the UnitedFruit Company, and excess water fromthe terminal pipes forms water-faucet drains, which were ideal for A. aZbimanusbreeding (Malaret 1929). Eumm, Kompand Ruiz (1940) call attention to their dis-covery of larvae in an iron drum full ofrain water.

The adult is a strong flier. In Panama,towards the close of the dry season, a sud-den rise occurs in the number of adultsfound in sanitated areas. Curry (1934)believes that these mosquitoes originate inthe mats of aquatic plants far away inGatun Lake ; therefore they must be able tofly 12 miles or more. Curry does not con-sider this to be a single, sustained flight,


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DISTRIBUTION AND ECOLOGY OF CARIBBEAN ANOPHELINES 101but that the distance is covered in a seriesof short flights, during. which the mosqui-toes feed on gametocyte carriers outside ofthe sanitated areas, causing many of themosquitoes to become infected with malaria,thus carrying the disease to inhabitants ofthe sanitated areas. According to Le Princeand Orenstein (1916), who observed flightsof large numbers of LI_.albimanus and 8.aquas&s in the Canal Zone, the mosquitoesbecome active during twilight; in the even-ing they flew from a brackish water area toGatun, and in the early morning they re-turned to the breeding places. These mos-quitoes flew from a half mile to a mile atright angles to the strong dry season winds,above ground that had very little protectionin the form of bush or grass. Judging fromthe actions of birds feeding on the flyinginsects, flight took place from less than sixfeet to 30 or 40 feet above the surface of theground. Jobbins (1940) in Panama alsoobserved flight of a. albimanus between6: 30 and 7 : 30 P.M. Apparently copula-tion takes place only during twilight hours(Rozeboom 1936).

The seasonal abundance of a. albimanusseems to be directly related to rainfall.Gabaldon (1939a) shows this in his Vene-zuelan records. Nevertheless, in some areaswhere breeding is largely confined to im-pounded waters or rivers, the dry seasonfavors the appearance of certain types ofaquatic vegetation in which breeding isespecially heavy. This is the case in GatunLake in the Canal Zone (Curry 1934), andin the Chagres River, where Jobbins (1940)and Clark, Komp and Jobbins (1940) notedthe peak of emergence in 1939 to be inApril, several weeks before the onset of therainy season. In Mexico there is a markedreduction of A. albimanus during the drywinter season, and in some areas the larvaedisappear, while the females pass throughthe winter in a state of inactivity (Hoff-mann 1938a). Giaquinto Mira (1936)noted that during the long dry season atChamperico, Guatemala, the females re-mained in crab holes containing water anddid not mature their eggs until the comingof the rainy season.

The females feed readily on man, but alsoattack animals; in fact, the observations ofEarle and Howard (1936) in Puerto Ricoindicate a marked preference by ~4. albi-manus for horses and oxen, and while goatsand pigs were not so attractive as horsesand oxen, the mosquitoes fed on them asreadily as they did on man. Le Prince andOrenstein (1916) noticed that a horse wasmore attractive than men. In the villagesof Las Guacas and Santa Rosa, in Panama,Rozeboom (1938a) caught 578 Anopheles innative huts, of which 472 were A. albi-manus, but of 349 female anophelines takenwhile they were feeding on pigs near thesevillages, only four were A. albimanus.

The females are very domestic, andwithin most of its range A. albimanus is themost common anopheline found in houses.But the females do not remain long inhouses; most of them return to the jungleor to their breeding places, soon after feed-ing or early in the morning (Barber andKomp 1927; Green 1922). They do notseem to congregate in preferred daytimeresting places (Earle and Howard 1936 ;Rozeboom 1938a), although Le Prince andOrenstein (1916) saw large numbers on theleeward side of trees near extensive breed-ing places.A. triannulatus was described by Neivaand Pinto (1922) ; unfortunately this mis-leading name has priority over A. bach-manni Petrocchi, 1925 (Galvao and Bar-retto 1938). The species was describedfrom Brazil, but it has been collected as farnorth as Puntarenas, Costa Rica (Kumm,Komp and Ruiz 1940). In Panama thelarvae are found within the cup-shadedenclosure formed by the crown of leaves ofPis tia (water-lettuce), and where extensiveareas of these plants exist, triannuZatus maybe very abundant. In other countries, thelarvae may breed among other aquaticplants ; even in Panama they are oftenfound among the floating stems of Jussiaeanatans (Curry 1931b ; Rozeboom 1935).Adults of triannulatus have been observedattacking man outdoors (Rozeboom 1935))but they do not seem to enter human dwell-ings readily, even in the immediate vicinity


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102 MALARIAof the breeding places; on the other handlarge numbers have been observed feedingon pigs (Rozeboom 1938a). Hill (1934)concluded that this mosquito definitely pre-fers animal blood.

a. strodei was described from Brazil, butin the Caribbean region it has been reportedfrom Panama (Curry 1932), Costa Rica(Kumm, Komp and Ruiz 1940), and re-cently from Veracruz, Mexico, by Vargas(1940b). This species breeds in a varietyof water collections. During the rainy sea-son it may be found in rain pools, but inPanama its chief breeding places are clear,cool pools in drying creeks. Kumm, Kompand Ruiz (1940) state that in Costa Ricathe larvae were taken from slowly runningstreams in the sunshine; however, the larvaemay also be abundant in partially shadedwaters. In Panama the larvae are mostabundant at the end of the rains, in Janu-ary. Little is known concerning the habitsof the adults. Occasionally the females maybe captured in houses, but they seem to beattracted to animals more than to man(Kumm, Komp and Ruiz 1940) ; however,in a locality in Sao Paula, Brazil, Correa(1938) found that 95.3 per cent of theanophelines he captured in houses were A.strodei, and two of 163 females dissectedshowed oocysts.

A. aquasalis was considered to be a vari-ety of A. tarsimaculatus by Curry (1932),who distinguished it from var. aquacaelestis(= oswaZdoi) on morphological charactersand by its breeding habits. Rozeboom andGabaldon (1941) consider A. tarsimacu-latus to be a synonym of A. albimanus,while aquasalis, a member of a group ofmosquitoes lumped under the name tarsi-maculatus, was raised to specific rank bythese authors. In Panama the species isfound only along the Atlantic coast. Thebrackish water tarsimaculatus listedfrom Costa Rica by Kumm, Komp and Ruiz(1940) is also this species. Hoffmann(1929b) discovered a few specimens of tarsimacula tus (=strodei ?) in Vera-cruz (Panuco) , but considered that theywere accidentally introduced. The tarsi-maculatus that Root and Andrews (1938)

concluded was the malaria vector in Gre-nada is really aquasalis, and perhaps so isthe brackish water tarsimaculatus ofTrinidad. Senevet (1936, 1938) reports tarsimaculatus9 from Martinique andGuadeloupe, and Edwards and Box (1940)include it in their list of mosquitoes fromAntigua. The larvae breed in brackishwater along the seacoast, n swamps, ditches,and similar situations. Occasionally theywill breed in fresh water; in Costa Rica,Kumm, Komp and Ruiz (1940) found themonce in a fresh-water stream about fiftyyards from the sea, while in Trinidad, intimes of great abundance, they develop tem-porarily several miles inland in rice fields,drains, and other collections of fresh water(de Verteuil 1933 ; de Verteuil and Spence1937). Beattie (1932) states that A. aqua-salis has no apparent preference for light orshade ; Curry (1932) believes it prefersfairly well shaded places ; Kumm, Kompand Ruiz (1940) made three collections inCosta Rica, all of them in water exposedto sunlight. Earle (1936b) noted that inGrenada it would breed in densely shadedmangrove swamps. The adults are strongfliers; Curry (1932) speaks of the hugeswarms that used to fly into Colon andCristobal, in Panama, from swamps locatedseveral miles from these cities, and in Trini-dad adults migrate inland from the coastalswamps at least three miles away (deVerteuil and Spence 1937). It is puzzlingthat this mosquito, considered to be a vectorof malaria in some of the Lesser Antilles,is not attracted to man in Panama, where,in former years, the appearance of greatnumbers of A. aquasalis in the cities wasnot followed by a rise in the malaria rate(Curry 1932). This is a marked contrastto the observations of Earle (1936b), whohad no difficulty in finding A. aquasalisadults in houses in Grenada and St. Lucia.The biting and trapping experiments ofEarle and Howard (1936) showed that inthese islands A. aquasaEis was attracted toman much more readily than to a calf or adonkey.A. oswaldoi has been reported from Pan-ama (Curry 1932), Trinidad (de Verteuil


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DISTRIBUTION AND ECOLOGY OF CARIBBEAN ANOPHELINES 1031933), and from several South Americancountries, but it has not been found as farnorth as Costa Rica (Kumm, Komp andRuiz 1940). It breeds in fresh, well shadedwater in pools or swamps. Being a jungle mosquito, it is not closely associ-ated with man, and although it will attackman when its haunts are invaded, it doesnot seem to be attracted to mans habita-tions (Curry 1932; Rozeboom 1938a).

A. rangeli is a species recently describedby Gabaldon, Cova-Garcia and Lopez(1940). Perhaps this species should not beincluded with the Caribbean anophelines,but it is mentioned because we know thatit is present in Trinidad, and because it hasbeen confused with A. aquasalis. Roze-boom and Gabaldon (1941) have foundspecimens of A. rangeli among material col-lected by Root in Venezuela and Trinidad;the species must be quite common in thesecountries. It breeds in fresh, shaded waterthat contains an abundance of vegetation(Gabaldon, Cova-Garcia and Arevalo 1940).

A. anomalophyllus is a rare mosquito.The type specimens were collected as larvaefrom the running water of a small, shadedstream near Almirante, Panama (Komp1936b). It was found recently in CostaRica by Kumm, Komp and Ruiz (1940).

A. albitarsis is widespread in SouthAmerica; the northern limit of its rangeseems to be Costa Rica (Kumm, Komp andRuiz 1940). It ia evident that the speciesis composed of several races or subspecies(Galvgo and Lane 193713; Root 1926, Roze-boom 1937a), although the taxonomic rela-tionships between the races are not yetentirely clear. In Panama the larvaebreed in a rather restricted area of GatunLake, in the mats of Chara, Naias, andUtricularia that produce such large num-bers of A. albimanus; these mats are ex-posed to full sunlight (Curry 1934). InCosta Rica the larvae were taken from asunny pond with algae, and vertical andhorizontal vegetation (Kumm, Komp andRuiz 1940). The rice fields of Trinidadfurnish suitable water for larval develop-ment (de Verteuil 1933), while Gabaldon(1939a) says that the most important breed-

ing places in Venezuela are lakes full ofPistia and Eicchornia. Although it is adangerous mosquito in parts of SouthAmerica, in Panama it does not attack manand does not enter mans habitations, evenin the immediate vicinity of the breedingplaces (Curry 1934).

A. argyritarsis is distributed throughoutthe Caribbean region, from tropical Mexico(Hoffmann 1929b) to South America(Clark 1926; Curry 1925 ; Giaquinto Mira1936 ; Hoffmann 1932 ; Komp 1937a ; Kumm,Komp and Ruiz 1940; Kumm and Ruiz1939b ; de Leon 1936b ; Martini 1935 ; Sutter1939) ; it also inhabits much of SouthAmerica, and some of the Caribbeanislands : Trinidad (Beattie 1932 Howard,Dyar and Knab 1917b), Grenada (Earle193613 Howard, Dyar and Knab 1917b;Root and Andrews 1938)) St. Lucia (Earle1936b; Howard, Dyar and Knab 1917b;Senevet 1936), Guadeloupe (Francois-Julien 1930 ; Senevet 1938), Dominica(Hoffman 1930; Howard, Dyar and Knab1917b ; Senevet 1936)) Martinique (Howard,Dyar and Knab 1917b; Montestruc 1936;Senevet 1936)) St. Vincent (Howard, Dyarand Knab 1917b ; Senevet 1936), and An-tigua (Edwards and Box 1940 ; Howard,Dyar and Knab 1917b). Theobalds recordsof the species from the Greater Antillesprobably concern A. albimanus (Boyd andAris 1929 ; Howard, Dyar and Knab 1917b).A. argyritarsis breeds in clear waters ofsmall, partly shaded or sunlit streams ; it isfound along the grassy edges of runningstreams, and it also breeds in quiet pools instreams, and in pools in drying stream beds,as well as in grassy rain pools. The femalesdo not seem to attack man readily, and arenot often found in mans habitations (Earle193613 Hoffmann 192913 Kumm, Komp andRuiz 1940).

A. darlingi was described by Root (1926)from specimens collected in Brazil. It iswidespread in South America, and for sometime it was thought that records from Vene-zuela and Colombia represented its mostnorthern distribution, but in 1940 Kompproved that it is also present in Guatemalaand British Honduras. Shannon (1933)


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10 4 MAIARIAconsiders that in the Amazon Valley thelarvae are especially adapted to flood-water.In Brazil, Barrett0 (1938) could find fewA. darlingi larvae in ditches, small pools,and small swamps, but obtained many lar-vae from the edges of an impoundment,where the water was deep, without current,and well shaded by trees with branchesreaching down into the water; thesebranches prevented wave action in thewater underneath them, and in this pooledwater, where there was some floatage butlittle vegetation, the larvae were concen-trated. In British Honduras, Kumm(1940b) collected larvae along the edges ofstreams, in deeply shaded water. Theadults feed readily on man, and can betaken in large numbers in mans habitations(Davis 1931; Gabaldon 1938 ; Giglioli 1940 ;Shannon 1933).

A. eiseni has a range which includes muchof South America and extends northwardthrough Central America as far as tropicalMexico (Aguilar 1931; Curry 1931b ; Dyar1928 ; Giaquinto Mira 1936; Howard, Dyarand Knab 1917b; Kumm, Kemp and Ruiz1940; Kumm and Ruiz 1939b; de Leon1936b ; Martini 1935), but it seems to havebeen found on none of the islands, exceptTrinidad (Beattie 1932). It is another jungle mosquito, breeding in denselyshaded, clear, fresh waters of small streams,pools, and swamps. Simmons (1939) col-lected many larvae from coconut husks,while Kumm, Komp and Ruiz (1940) foundthem even in tree holes and bromeliads.Locally the species may be very abundant;for example, Simmons (1939) says that itwas one of the most common species on theFort Sherman Reservation in the CanalZone during the fall and winter of 1935 and1936. Very little is known concerning thebiology of the adults, but the females do notseem to be attracted to man and seldomenter houses (Gabaldon 1939a ; Simmons1939).

A. grabhami has been reported fromCuba (Carr, Melendez and Ros 1940), Ja-maica (Boyd and Aris 1929 ; Howard, et al .1917b ; Theobald and Grabham 1905)) Haiti(Clark 1926; Mink 1933), Santo Domingo

(Howard, Dyar and Knab 1917b), PuertoRico (Earle, 1936a; Howard, Dyar andKnab 1917b ; Tulloch 1937 ; Wells 1930), andSt. Thomas (Hoffman 1930). Theobald andGrabham (1905) noted that in Jamaica thelarvae would develop in any stagnant water,and Boyd and Aris (1929) also found themin all types of breeding water on the island,including upland streams with swift cur-rents, and brackish water along the coast,where they were associated with the larvaeof a. albimanus. Earle (1936a) showedthat in Puerto Rico the larvae are much lesstolerant of salt than are the larvae of A.albimanus, and that they will occur indensely shaded waters, including pastureswhere the growth of grass is so dense thatones weight is almost supported on it as itovergrows water courses. The adults willattack man ; some authors (Root 1922 ; The-obald and Grabham 1905) consider the spe-cies to be an ardent blood sucker that feedson man readily in the evening, but others(Boyd and Aris 1929 ; Earle 1936a) con-clude that it prefers the blood of animals.It is not often found in houses (Earle andHoward 1936), and is not especially abun-dant.

a. crucians has been found in Cuba(Carr, Melendez, and Ros 1940; Kumm1929b), Jamaica (Boyd and Aris 1929Kumm 1929b), along the Caribbean littoralof Mexico (Hoffmann 1932), and Britishand Spanish Honduras (Clark 1926 ; Kumm1929b, 1940b ; Martini 1935 Whitmore, Rob-erts and Jantzen 1929). Martini (1935)gives a record from Iguala, State of Guer-rero, Mexico, and another from Lago Peten,Guatemala. Tulloch (1937) includes A.crucians in his list of brackish-water mos-quitoes from Puerto Rico. In Jamaica,Boyd and Aris (1929) collected larvae fromstreams, seepages, and ponds, in sunlit orslightly shaded water ; no larvae were foundin brackish water. According to Vargas(1940a), both A. crucians var. crucians andvar. bradEeyi are present in Mexico, in thestates of Tamaulipas and Veracruz.

A. punctipennis was reported from Ja-maica by Theobald and Grabham (1905) ;however, Boyd and Aris (1929) point out


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DISTRIBUTION AND ECOLOGY OF CARIBBEAN ANOPHELINES 10 5that this record is doubtful; ,4.. pulncti-pennis has never been taken in Jamaicasince Grabhams time. Hoffmann (1932)speaks of its presence in the littoral zoneof the Gulf of Mexico and in the northernzone of Mexico; Martini (1935) givesrecords from Sonora, Tamaulipas (Tam-pica), and Veracruz (Pueblo Viejo). Hoff-mann (1937) collected larvae from a shadedpool near Ixmiquilpan, in the state ofGuanajuato, Mexico.

A. pseudopunctipenni is the most wide-spread of the New World Anophelini, rang-ing from Oklahoma and California to Ar-gentina. Shannon, Davis, and de1 Ponte(1927) show that its distribution coincidesto a great extent with that of the westernmountains, and that apparently it is essen-tially a mountain species, occurring in thelowlands only where special conditions per-mit its existence. According to Hoffmann(1932) it inhabits almost all of Mexico be-tween the eastern and western mountainranges; only areas that are six or seventhousand feet above sea level are free fromit. It extends along the entire MexicanPacific littoral, from California to Guate-mala, but does not seem to be so abundantalong the Caribbean coast, although it ispresent in the littoral zone north of Vera-cruz. South of Veracruz it appears onlyin the winter. It is found in the villages ofYucatan. It has been collected in all of theCentral American countries (Aguilar 1931;Barber and Komp 1927; Clark 1926 ; Gia-quint0 Mira 1936 ; Howard, Dyar and Knab1917b; Komp 192913; Kumm, Komp andRuiz 1940; Kumm and Ruiz 193913; LardeArthes 1921; Martini 1935; Molloy 1932;Sutter 1939)) and also in Trinidad (Kumm1929b) and Grenada (Earle 193613; Rootand Andrews 1938).

The larvae of A. pseudopunctipennisrequire a great deal of sunlight for theirdevelopment, and the preferred breedingplaces are pools and eddies in shallow ordrying streams, especially those containingmats of green algae. In streams the larvaecan be found not only in such mats of algae,but also in shallow, quiet or running water,where they cling to leaves or other bits of

floatage dammed behind rocks or sand bars.Other breeding places are seepages, espe-cially those in dry beds of subterraneanstreams (Hoffmann 1932), ground pools,and even artificial water containers such asfountains and tanks (Hoffmann 1932).Because the preferred breeding places areshallow, drying streams, this species s espe-cially abundant in mountainous areas, andat the time of the year when the streamsare not flushed out by heavy rains. Thus,in Panama and in parts of Central America,A. pseudopunctipennis is most prevalentduring the dry season (Clark 1932; Molloy1932; Simmons 1939). However, in someregions the dry season causes a diminutionin the number of favorable breeding places,so that the numbers of the mosquito de-crease. In northwestern Argentina the low-land breeding places disappear during theprolonged dry season, and A. pseudopuncti-pennis must maintain itself during thisunfavorable period in springs and otherfresh water collections in the mountains(Shannon 1930). Rainfall is the most im-portant climatic factor in determiningabundance in the Rimac Valley of Peru, andhere too the mosquito survives the dry sea-son by breeding in the restricted freshwater collections in the mountains, reestab-lishing itself in the more numerous lowlandbreeding places after the onset of the rainsin the higher altitudes results in the forma-tion of pools along the margins of riversand streams. Here the peak of abundanceoccurs between January and June, therainy season of the highlands (Shannon1930). Hoffmann (1938b) calls the typicalstreampools winter breeding places of con-centration ; this author says that when therains come the larvae are washed from thesepools and are distributed over wide areas.In the Valley of Mexico the species is lessabundant during the dry winter months;during December, January, and February,when the temperature drops below thefreezing point at night, only large larvaeare found in the breeding places, whilesmall larvae appear about the middle ofMarch. During the cold weather the males


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106 MUIAdisappear, and only the females are foundin the resting places (Hoffmann 1929a).

The habits of the adults seem to differ invarious parts of the A. pseudopunctipennisrange. In the highlands of Mexico the fe-males will fly for considerable distances toenter houses and feed on man (Hoffmann192913; Vargas 1938). The species is con-sidered to be a dangerous malaria carrier inthe highlands of Guatemala (GiaquintoMira 1936 ; Molloy 1932)) but in Costa Rica,where Kumm, Komp and Ruiz (1940) col-lected many larvae, only a few adults werecaptured in houses by these workers. Thefemales do not fly far, and are not attractedto houses, in the Canal Zone (Curry 1925) ;they are not attracted to man in Grenada(Earle 1936b), although in this island, dur-ing July and August at least, A. pseudo-punctipennis is the most common Anoph-eline (Root and Andrews 1938). In Argen-tina it is a dangerous blood-sucker (Davis1927). The suspicion that the species isdivided into geographical races or sub-species has not been confirmed on mor-phological grounds, although there are twokinds of A. pseudopunctipennis eggs inCalifornia (Herms and Freeborn 1920 ;Herms and Frost 1932), both of which areunlike the eggs from Panama (Rozeboom1937b), Costa Rica (Kumm 1940a), andMexico (Vargas 1939b). The writer hasexamined A. pseudopunctipennis eggs fromwestern Oklahoma which were identical inmorphology with those he described fromPanama. Vargas (1939b) considers theform in California, the egg of which wasdescribed by Herms and Frost (1932), tobe different enough to merit specific rank;he calls this mosquito A. boydi.A. parapunctipertnis ranges through thehighlands from Mexico to Panama (Kummand Ruiz 193913; Vargas 1940a). Komp(1936a) collected larvae in a large coldspring on the slopes of Chiriqui Volcano inwestern Panama. This rare species wasfirst found by Dampf (Martini 1935) in thestate of Chiapas.A. hectoris was described from Guate-mala by Giaquinto Mira (1931) ; it is alsofound in the mountains of Mexico. Dampf

(Martini 1935) took it near San Cristobal,Chiapas, 2,000 meters above sea level. Ap-parently only the adult had been capturedin Mexico until April, 1940, when Mazzottidiscovered larvae in Ciudad de las Casas,Chiapas (Vargas 1940a, 1940b). Accordingto de Leon (1936a, 193613) it is the charac-teristic anopheline species in the highermountain regions of Guatemala, and breedsin small, shallow, slowly-flowing streamsfilled with algae. The adults are said toattack man (Molloy 1932).

A. vestitipennis is comparatively rare,but it ranges from the tropical regions ofMexico to South America (Aguilar 1931;Barber and Komp 1927 ; Clark 1926 ; Curry1931a; Dyar 1928 ; Giaquinto Mira 1936 ;Hoffmann 192913, 1932; Kumm 1940b;Kumm, Komp and Ruiz 1940; de Leon1936b ; Martini 1935), and is also presentin Cuba (Carr, Melendez and Ros 1940),Puerto Rico (Wells 1930), Jamaica (Boydand Aris 1929), and Dominica (Dyar 1928).The larvae develop in shaded, fresh-waterstreams, seepages, ponds, and rain pools(Boyd and Aris 1929 ; Kumm, Komp andRuiz 1940). The adult females will attackman, and Hoffmann (1929b) has foundadults in houses.

A. punctimacula has a wide distributionin the New World tropics, including all ofthe Central American countries (Aguilar1931; Barber and Komp 1927; Clark 1926 ;Curry 1931a, 1931b; Howard, Dyar andKnab 1917b; Kumm 1940b; Kumm, Kompand Ruiz 1940; Kumm and Ruiz 1939b ;Simmons 1939; Sutter 1939) and tropicalMexico (Hoffmann 1932 ; Martini 1935). Itbreeds in clear, cool, densely shaded watersin small streams, ponds, and swamps, whereit may be associated with larvae of A. eiseni,A. oswaldoi, and A. apicimacula. Theadults will feed on man as well as on ani-mals, and will visit human habitations insearch of blood (Kumm, Komp and Ruiz1940 ; Rozeboom 1938a; Simmons 1936a,1939).A. apicimacuZa has been reported fromMexico (Hoffmann 1932 ; Howard, Dyarand Knab 1917b ; Martini 1935), all of theCentral American countries (Aguilar 1931;


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DISTRlBUTION AND ECOLOGY OF CARIBBEAN ANOPHELINES 107Clark 1926 ; Curry 1931a, 1931b ; GiaquintoMira 1936 ; Howard, Dyar and Knab 1917b ;Kumm, 1940b; Kumm, Komp and Ruiz1940; Kumm and Ruiz 193913; de Leon1936a, 1936b; Martini 1935; Sutter 1939),Trinidad (Beattie 1932)) and several SouthAmerican countries. Its breeding placesare similar to those of A. punctimacula, A.eiseni, and A. oswaldoi. Only a few adultshave been taken inside houses, and the fe-males seem to feed on animals much morereadily than they do on man (Kumm, Kompand Ruiz 1940 ; Simmons 1939).

Martini (1935) identified specimens col-lected by Dampf in Yucatan, British Hon-duras (Blue Creek, Rio Cacao) and Guate-mala (San Miguel, Lago Peten), as A. inter-medius; this species has not been foundsince in Mexico (Vargas 1940a).A. quadrimaculatus inhabits the Gulfcoast of Mexico as far south as Tuxpan,Veracruz, but records from the interior ofMexico actually refer to a race of A. maculi-pennis (Dampf 1935 ; Hoffmann 1935).

A. maculipennis var. axtecus was de-scribed by Hoffmann (1935) from the statesof Guanajuato and Michoacan, Mexico.The larvae breed in canals, irrigation chan-nels, and clear water pools in which algaeand protozoa are present. This form is notso dependent on clean water as is A. pseudo-punctipennis, so that it is replacing thelatter species in the outskirts of MexicoCity, where urbanization results in a pollu-tion of the water available to the mosqui-toes. The larvae are encountered in the

breeding places throughout the year, evenwhen a layer of ice forms over the surfaceof the water (Hoffmann 1935). The fe-males do not seem to be attracted to man,and Vargas (1939a) has described a condi-tion of anophelism without malaria in alocality in the State of Mexico, in which thisform was the only anopheline present.

Vargas (1940b) reports the finding ofA. maculipennis var. freeborni at Imuris,Sonora.A. atropos is included in this list becauseCarr, Melendez and Ros (1940) discoveredit recently in Cuba. It was found once, inHavana Province, in an animal-baited trap.Martini (1935) reported it from the in-terior of Mexico, but Hoffmann (1936)points out that Martinis specimens werereally A. a&ecus.

A male of A. walkeri has been taken inTuxpan, Veracruz, Mexico (Vargas 1940a).A. barberi was discovered by Sr. A.Martinez Palacios at Imuris, Sonora, Mexico(Vargas 194Oc).

A. neiwai breeds only in water caught inthe leaf-bases of certain water-holdingplants, such as the epiphytic and terrestrialbromeliads. The species ranges from tropi-cal Mexico to Panama, and southwards intoEcuador ; records of cruxii, from Panamanorthwards, actually refer to A. neiwai(Komp 1937a). It may be quite abundantand may bite man freely, in the neighbor-hood of its breeding places (Komp 1937a).A. xelajuensis was described from Guate-mala by de Leon (1938).

Distribution and Ecology of Anopheles

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