Taxonomy concerning Mosquito Populations

Abstract

The public health importance of the mosquitoes has made them one of the most thoroughly studied families of insects, and one may ask whether there is any need for additional research on their taxonomy. Aside from the direct contribution such studies can make to evolutionary theory, there is a continuing practical need for accurate and rapid identification of mosquito species in ecological and epidemiological investigations and for persons trained to make such identifications. Taxonomy should be based not only on morphological structures, but also on genetical, biological, and physiological characteristics; examples of such criteria are taken from comparative studies on the Culex pipiens complex. The practical importance of such studies on field populations is seen in the physiological and behavioristic responses of anophelines to insecticides in the malaria eradication campaigns and in the epidemiological work on viral and other mosquito-borne diseases. It is suggested that the future of mosquito taxonomy should include the following: 1. Classical morphological descriptions to complete the assembling of suspected species and subspecies. 2. Experimental studies on the genetical relationships and biochemical and physiological characteristics of species and subspecies. 3. Ecological studies of these populations in their natural environments. 4. Analysis of the data obtained from various sources so as to establish subspecific and specific limits and to arrange the taxa into a natural classification. Here the newer mathematical techniques, including factor analysis and electronic computers, may prove to be of great assistance. These objectives will require the cooperation of people of diverse skills and interests, and progress will be enhanced with mutual understanding and respect for the contribution each specialist can make. Taxonomy may be defined as the description and classification of biological entities by persons who are considered by themselves and sometimes even by others to be sufficiently knowledgeable of their group of animals or plants to permit them to pursue this activity. The criteria for specific or for supraor subspecific limits ordinarily are morphological. The measurable discontinuities in morphological features between organisms, or between two or more series or populations of organisms, must undergo some sort of analysis and interpretation by the specialist. These procedures are becoming progressively more complex and sophisticated for the purpose of reducing the degree of subjective interpretation. Whereas, formerly the taxonomist could assemble his animals into small groups because they looked alike, and would select one from each group as the type specimen which he deemed the most representative, we lear from Rohlf and Sokal (1962) that what he really should do is to subject the alleged dissimilarities between Received for publication 13 August 1962. groups and similarities within groups to factor analysis, and Ehrlich (1961a) predicts that by 1970 electronic computers will be an essential tool of the taxonomist. The medical importance of the mosquitoes has caused them to be one of the most thor ughly studied families of insects, although, of c urse, much remains to be done, especially with respect to their biochemistry and physilogy. The question which we must now ask is this: Is there any real need for additional taxonomic studies of the Culicidae, and if so, what should be the object of such work in order to achieve the maximum benefit? Taxonomy for its own sake: We will not have a complete picture of the phylogenetic structure of the family Culicidae until all of the blank spaces have been filled. In their recent catalog of the mosquitoes of the world, Stone, Knight, and Starcke (1959) list 2,428 species and 111 genera and subgenera (see also Stone, 1961) exclusive of the nonhemophagous Dixinae and Chaoborinae. In many of these, one or more stages of the life cycle are unknown. Irrespective of the possible lack of practical