Foibles of insects and men / by William Morton Wheeler.

  • Wheeler, William Morton, 1865-1937.
Date:
1928
Catalogue details

Licence: In copyright

Credit: Foibles of insects and men / by William Morton Wheeler. Source: Wellcome Collection.

    74/264 (page 44)
    size and shape of the thorax is also revealed by a comparative study of insects like the Odonata, Hymenoptera, Diptera and Coleoptera, in which the relative volumes of the meso- and metathoracic segments are clearly correlated with the relative size and efficiency of their respective pairs of wings. The physiognomy of the insect abdomen, however, is not determined so much by the development of the musculature of the various segments as by the volume of the viscera, i.e., the alimentary canal, reproductive organs and fat-body. The phenomenon of “physogastry,” or hypertrophy of the abdomen is in some cases due to an enormous increase in the contents of the crop, as in the honey-ants, in others to enlargement of the ovaries or fat- body, as in the aged queens of termites (fig. 47) and certain ants (Dorylina:, Anergates) and the various termitophiles of the more extreme type (Coro- toca, Spirachtha, etc.). This physogastry is really of considerable physio¬ logical interest but its adequate consideration would unduly expand this article. In conclusion we may revert briefly to some of the general types observed in man—the dysplastics, giants, dwarfs and acromegalics. Stockard has shown that very similar types may be clearly recognized among the various breeds of dogs, such as the St. Bernard (acromegalic), bull-dog (achondro¬ plastic dwarf), black-and-tan (ateleotic dwarf), etc. Many cases of giantism and nanism might be cited among the insects, and among the dwarfs the soldiers of certain ants (Pheidole, Acanthomyrmex, etc.) are in many respects strangely analogous to the achondroplastics (fig. xitf), while the small workers (fig. 2.1/) are even more like the ateleotics. The development of these forms evidently depends on both genetic and endocrine factors, but the pro¬ portional intervention and interrelation of these factors have not been established. Owing to lack of knowledge of the precise functions of the various glands which in insects might be regarded as analogous to the endocrine glands of vertebrates, we are unable to frame any satisfactory physiological explanation of the Hexapod dwarfs. If certain ants have really learned to produce achondroplastics and ateleotics ad libitum and to turn over to them the main asexual activities of the colony, we should have another fine example of the extraordinary ability of insects to exploit to the utmost everything in their environment. As yet man has learned to employ his achondroplastics, ateleotics and other dysplastics only as court pets, court jesters and circus freaks.