Food Plants of the United States Forms of the Leafhoppers of the Genus Agalliopsis

Abstract

The major interest of the writer for many years has been the determination of the food plant relation of the leafhoppers. Each time information accumulates to the point where a summary of a group can be presented, it is interesting to observe how definitely restricted the food habits of the species prove to be. In the majority of cases the food plant limitation is to a single species of plant and usually there will be found to be different leafhoppers on different species of the same plant genus. It is also interesting to note how widely at variance these food habits are to the previous generalizations that have been made. For example, the eastern worker thinks of Cicadas as a tree inhabiting group. If he should spend a few seasons in the West and saw vast areas where Cicadas were swarming, often three and five and sometimes ten to a square foot without a tree in sight, he would be obliged to materially revise his ideas. Within a few years two eastern writers have stated that all of the species of the genus Scolops were grass feeders. The writer (1930) summarized our knowledge of the definite food habits of seven species and since that time three more have been established. Not one of the ten proves to be a grass feeder. Most of their food plants prove to be serious weeds that compete with the grasses for the scant water supply of our range region. When these ranges are overgrazed these weeds tend to increase in numbers and would more effectively prevent the re-establishment of the grasses if it were not for a similar increase in these beneficial leaf-hoppers that hold the weeds in check. The food plants of our species of leafhoppers of the genus Agalliopsis have not been selected for presentation as representing either the beneficial or injurious phases of this problem but because they illustrate two or three of the major fundamentals as follows: