Insects (2018) 9 (4 - 194)
Thomas E. Marler and Paris N. Marler (2018)
Rhyzobius lophanthae behavior is influenced by cycad plant age, providing odor samples in a Y-tube olfactometer
Insects 9 (4 - 194)
Abstract: The scale predator Rhyzobius lophanthae Blaisdell was introduced to Guam and Rota to control invasive Aulacaspis yasumatsui Takagi armored scale infestations on the native Cycas micronesica K.D. Hill populations. The predator demonstrated a clear preference for A. yasumatsui infesting adult plants, resulting in 100% seedling mortality due to the lack of a biocontrol of the scale on seedlings. A Y-tube olfactometer was employed to determine if scale-infested seedling leaves were less attractive to R. lophanthae than scale-infested mature tree leaves. Five paired combinations of seedling versus mature tree leaves were used. The R. lophanthae adults navigated toward scale-infested and un-infested leaves of adults and seedlings when paired with an empty chamber. However, a clear preference for adult leaves occurred when paired with seedling leaves. The results were unambiguous in charcoal-filtered air, intermediate in unfiltered air from an open laboratory, and most ambiguous when conducted with unfiltered in-situ air. The number of predators that did not make a choice was greatest for in-situ air and least for charcoal-filtered air. These results indicated that the substrate used in olfactometry influenced the results, and interpretations of charcoal-filtered air assays should be made with caution. Volatile chemical cues are involved in R. lophanthae preferring A. yasumatsui located on C. micronesica adults when infested adult and seedling leaves are present.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Full text of article
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
environment/habitat manipulation
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Aulacaspis yasumatsui | Cycad (Cycas) | Guam | ||
| Rhyzobius lophanthae (predator) | Aulacaspis yasumatsui | Cycad (Cycas) | Guam |
