Food-selection by the booklouse, Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae)

A series of experiments, using a choice-chamber apparatus, were conducted to observe the food selection behaviour of Liposcelis bostrychophila. Following 4 days without food, groups of 50 adult insects were exposed to choices between pairs of different stored products: buckwheat, pot barley, brown rice flour, yellow millet and wheatgerm. Insects moved onto whole yellow millet in preference to whole buckwheat, whole pot barley and wheatgerm. Whole pot barley was preferred to brown rice flour. Ground grains were selected by insects in preference to whole grains. Furthermore, the distribution of insects between ground grains was different from that observed for whole grains. Carbohydrates affected the selection between foods which were equally attractive to L. bostrychophila: specifically, ground buckwheat (GBW) and ground yellow millet (GYM). Fewer booklice congregated on foodstuffs impregnated with glucose (0.5, 0.7 or 1 M). In contrast, L. bostrychophila preferred GBW with glucose (0.1 or 0.3 M) to GYM. GBW was preferred to GYM with fructose (0.5, 0.7 or 1 M), however, selection was not affected when fructose was added to GBW. Booklice preferred GBW or GYM with yeast added, to GBW or GYM without yeast. Furthermore L. bostrychophila preferred uncooked to cooked foods. These results are discussed in relation to the development of traps or lures for this increasingly prevalent domestic pest.