Small is superior: Plant-provided prey refuges, predator-prey dynamics and biological control
Peter de Ruiter
7 July 2016
Number of pages
Faculty of Science (FNWI)
Institute for Biodiversity and Ecosystem Dynamics (IBED)
Herbivorous prey are known to employ various strategies to avoid predation. In this thesis, I investigated interactions of
eriophyid mites, important agricultural pests, which hide inside refuges, where they are temporarily safe, and their natural
enemies. I found that only a smaller member of the predatory mite guild on coconut trees was able to enter refuges of the
coconut mite, consisting of the area of the coconut covered by the perianths. However, they could only do so after the distance
between the perianth and the coconut surface had increased with time. To further understand the role of this refuge, I experimentally
increased its entrances in the field, and found that successful control of the pest critically hinged on refuge opening and
predator size. I furthermore prove that this predatory mite and a larger, commercially available species responded to prey-associated
volatiles, but only the smallest mite was able to move into narrow spaces such as the prey refuge. Although it has been suggested
that larger predators have the advantage to easily subdue their prey, being small thus seems advantageous when prey hide inside
refuges. I furthermore demonstrate that this small predator can control the dry bulb mite on Dutch tulip bulbs. These mites
hide between bulb scales and cannot be reached by the conventionally used larger predatory mites. Thus, I show that a small
tropical predatory mite from the tropics can be used to control an important pest of Dutch tulip bulbs.
Research conducted at: Universiteit van Amsterdam
If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let
the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible
and/or remove it from the website. Please Ask the Library, or send a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands.
You will be contacted as soon as possible.