Date of Award


Document Type


Degree Name

Master of Science (MS)


Plant and Environmental Science

Committee Chair/Advisor

Juang Horng Chong

Committee Member

Carlyle Brewster

Committee Member

Francis Reay-Jones


Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae) larvae are voracious generalist predators and important biological control agents on greenhouse crops. This study investigated the prey preference of second-instar C. rufilabris for three common greenhouse pests, namely the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), the Madeira mealybug, Phenacoccus madeirensis Green (Hemiptera: Pseudococcidae), and the melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae). This study also investigated the influence of prey density ratios on the preference of C. rufilabris larvae for T. urticae and A. gossypii. Prey species preference was evaluated in no-choice, two-choice, and all-choice laboratory bioassays. In the no-choice bioassays, C. rufilabris larvae demonstrated the same propensity to consume mealybugs (27.8% of offered individuals consumed), spider mites (26.1%), and aphids (22.4%). In the two-choice bioassays, C. rufilabris larvae did not exhibit preference for any particular species when two prey species were offered in pairs. In the all-choice bioassay, C. rufilabris larvae did not demonstrate preference for aphids (6.6 out of 10 individuals consumed), mealybugs (6.3 individuals consumed), or spider mites (5.8 individuals consumed). When the predator was offered A. gossypii and T. urticae at the density ratios of 75:25, 50:50, and 25:75, they did not exhibit detectable preference for either prey species. Results of this study suggest that second-instar C. rufilabris was truly a generalist predator which fed on the melon aphid, the Madeira mealybug, and the twospotted spider mite at similar consumption rates.

Included in

Entomology Commons



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