Evolutionary Trends in Heteroptera

Evolutionary Trends in Heteroptera. Part II. Mouthpart-Structures and Feeding Strategies

“…Many parallel events occurred such as the gradual loss of the tripartite ending of the rostrum and intercalary sclerites, the widening of the maxillary salivary canal, and the increasing guiding function of the mandibular stylets (all these modifications took place before any Heteroptera had become phytophagous) ; other parallel changes appeared in reproductive organs, embryogénie processes, salivary glands, etc. Such parallelisms are difficult to explain as having arisen by action of external selection pressure, although Ross (1969) attributed the many parallelisms shown in my study on the egg-systems of Heteroptera, to be due to factors of natural selection.…”