HABITS OF ADULT MOSQUITOES. 



THE FOOD-HABITS. 



Mosquitoes have engaged the attention of man largely through their bites and 

 on this account they have been considered blood-suckers as a group. This, how- 

 ever, is far from being the case. There are a great many species, perhaps more 

 than half, vi^hich never suck blood at all, while others do so but rarely. On the 

 other hand there are many species in which the craving for blood is evidently 

 very powerful. Everyone will have noticed the impulsiveness of attack in cer- 

 tain mosquitoes. Many of these will attack all warm-blooded animals indis- 

 criminately. Grassi states that with such species the largest animals attract 

 the most ; thus a horse will attract mosquitoes more than a man, a man more than 

 a dog. Certain species of mosquitoes have a decided predilection for certain 

 animals. The yellow-fever mosquito under normal conditions probably feeds 

 exclusively upon man : more than this, it will be seen in the chapter on yellow 

 fever that this mosquito even discriminates between the different races of man. 

 Culex pipiens and Culex quinquefasciatus are closely associated with man yet 

 they do not persecute him with the same persistence as Aedes calopns. There is 

 reason to suppose that these species of Culex are primarily persecutors of poultry. 



It will be remembered that Ross, in India, in his original investigations with 

 a malarial disease of sparrows, found that this was transmitted by Culex quin- 

 quefasciatus. There are malarial diseases of other birds, probably carried by 

 other mosquitoes. MacCallum's original observation in which he discovered the 

 true meaning of the flagellate bodies, the real males of Proteosoma, was made 

 in studying a malarial disease of the American crow. 



Captain James, who investigated the blood diseases of birds, states that " the 

 voracity with which Culex mosquitoes (C fatigans) [ = C. quinquefasciatus'] 

 will gorge themselves upon the blood of sparrows is extraordinary, and if too 

 many mosquitoes are put in the cage with the same sparrow they will literally 

 bleed it to death." 



Goeldi, in discussing the habits of Culex quinquefasciatus in comparison with 

 Aedes calopus, touches upon this adaptation as follows : 



" I have the impression that, in general, Culex fatigans behaves more contrary, 

 obstinate, timid, refractory to domestication and comprehension : I believe 

 that I can perceive significant proof of this in the singular circumstance that in 

 all the trials made with this species of mosquito I only succeeded in inducing a 

 single individual to bite, either among those captured or those bred in captivity. 

 I attribute to it a degree of intelligence decidedly inferior to that of Stegomyia 

 fasciata. This accords well with my idea that, in the same manner as the other 

 blood-sucking insects, this species of Culicid has a primary relation to a definite 

 and determinate species of vertebrate host. I feel induced to say that in Culex 

 fatigans we have a mosquito primitively less addicted to the human species than 

 to certain domestic animals, amongst which, my suspicion points principally 

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