The genus Aeolothrips haliday in North America (Thysanoptera: Aeolothripidae)

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The genus Aeolothrips of the insect order Thysanoptera is generally known to most entomologists as “the banded-winged thrips.” So far as is known, this group of insects are beneficial, since they prey only upon plant-feeding thrips, other small insects, and mites. No previous detailed study of this group of insects in North America has been prepared. The number of known species has grown continually, and there are many references in the literature to their predaceous habit. This report attempts to bring together all known information on this group of insects in North America, to describe new species, and to set forth various accumulations of data on distribution, host plants, and seasonal habits.

Biology

The majority of the forms we have studied and collected over a period of about twenty years has been found definitely associated with specific host plants and with definite periods of seasonal appearance. Aeolothrips fasciatus Linné is the most widespread and is found on a great number of hosts throughout the growing season from late March to October. It is not single brooded as the majority of the species appears to be. It is seen much more frequently on grasses, row and field crops, and wild and cultivated flowers than on trees and shrubs. It reaches a seasonal peak of abundance in early summer in the western states. In this area, nasturtii is most commonly associated with it, particularly in meadows. This latter species is not nearly so abundant. In northeastern California and in Oregon and Washington, auricestus Treherne is also found in this association. In the eastern and southern states, alhicinctus Hal. and ‘bicolor Hinds likewise are most commonly found on grasses.

On fruit trees, native flowering trees, and woody shrubs, several Aeolothrips species are commonly found. The most numerous and widespread in the west is kuwanaii Moulton. It is very abundant in early spring, and rapidly disappears as the hot weather approaches.