Apple pollen as a supplemental food for the western flower thrips, Frankliniella occidentalis: Response of individuals and populations
Zhi J1,3, Fitch GK2, Margolies DC3,4, Nechols JR3
1.Department of Plant Protection, Agricultural College, Guizhou University, Guiyang 550025, China
2 Department of Biology, Avila University, 11901 Wornall, Kansas City MO 64145
3 Department of Entomology, Kansas State University, 123 West Waters Hall, Manhattan KS 66056.
Correspondence: dmargoli@oznet.ksu.edu, jnechols@oznet.ksu.edu
Experiments were performed to investigate the influence of apple pollen, plant diet, and relative humidity on individual life history traits and on population growth of the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). In experiments with individual thrips, availability of bean pods plus a mixture of apple pollen and lycopodium shortened larval development time, and hence time from egg to adult, compared to bean pods alone. Similarly, total number of eggs laid and mean number of eggs laid per female per day were greater in the presence of pollen plus bean pods than on bean pods alone. Diet did not affect survival or length of the preoviposition and oviposition periods. A diet including bean pods plus pollen shortened the generation time and population doubling time, and increased net reproductive rate and the intrinsic rate of increase, compared to bean pods alone. In experiments on populations, growth was measured with different amounts of pollen on bean pods under two relative humidities, ca. 38 and 66%, and on two bean substrates, pods or leaves, at 70% RH. The presence or amount of pollen had no effect on population growth regardless of the other variables. Greater population growth occurred under the higher relative humidity regardless of substrate. Population growth was greater on bean pods than on bean leaves. Despite reports on the nutritional benefit of pollen for F. occidentalis, this benefit may be affected by pollen type, host plant, and other factors. In situations in which pollen has little influence on the growth of F. occidentalis populations, pollen that benefits a thrips predator could be used in an integrated management plan for controlling thrips.
