University of Guam, Western Pacific Tropical Research Center - Research for Guam's Future
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Entomology laboratory scientists are engaged in research with practical applications in controlling invasive species and pest management using integrated control methods. The laboratory receives insect specimens for identification from local farmers, government agencies and the general public.

In recent years, WPTRC entomologists have been actively working on the control of two introduced arthropods that are threatening the existence of Guam's cycad populations: Asian cycad scale, Aulacaspis yasumatsui and the cycad blue butterfly, Chilades pandava Horsfield.

Chilades pandava ovipositing on 
Cycas micronesica foliage.
Photo A. Moore.
Chiladess pandava with open wings. 
Photo T. Marler.

Resident entomologists have also been investigating the morphometric, genetic and ecological variation in Aphis gossypii Glover. Aphis gossypii Glover is an extremely cosmopolitan and polyphagous pest of crops and ornamental plants in the tropical Pacific Basin where its high reproductive rate allows it to rapidly build up high populations and kill otherwise healthy plants by direct feeding or by transmitting viruses. The taxonomic status of A. gossypii is still poorly understood. The lack of certainty in identifying A. gossypii renders interpretation of biological information, including host plant-herbivore-natural enemy relationships, questionable and lessens the chance for successful natural enemy introductions against them in classical biological control programs. Similar taxonomic confusion may also exist among the aphid’s aphidiid parasitoid complex, further reducing the chances of successfully establishing an introduced parasitoid on a specific target host while avoiding unanticipated and undesirable non-target activity.

Morphometric analysis of Aphis gossypii Glover.

Field observations made on Guam suggest that the physical appearance of aphids may be altered by altering the host plant upon which the aphids develop.

Collecting and analysis of variation in A. gossypii populations from various sites continues. For each population sampled, an excel spreadsheet is developed for the biometric data and a DNA profile established. Mounted aphid features are photographed through a Zeiss Axiolab microscope using a Nikon Coolpix 990 digital camera at magnifications of 50x-400x.  The features (digital images) are measured using image-measuring software developed by Washington State University. Preliminary data suggest that morphometric variation in A. gossypii corresponds most closely to geographic provenance of the samples, followed by host plant.

To identify a particular insect contact:

Aubrey Moore, Ph.D. 
Tel: 735-2141/2086

The following researchers are involved with this Field of Study:

Ross H Miller - Publications

Aubrey  Moore - Publications

Gadi VP Reddy - Publications

Lee S Yudin


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