A DODEA student working on a science fair project sent me questions about the greater banded hornet situation on Guam. I am posting my answers here so that they are shared with others who are interested. For an overview of the Vespa tropica situation on Guam, please refer to the most recent fact sheet for this pest and don’t hesitate to contact me (Aubrey) directly for more info.
Q: Can you tell us a little about yourself…
A: Dr. Aubrey Moore, Entomologist, University of Guam (firstname.lastname@example.org; cell 686-5664)
Q: How big is the problem of the Greater Banded Hornet?
A: Compared to other invasive species problems on Guam, such as the coconut rhinoceros beetle, this is a minor problem.
Q: What is their effect on the island of Guam?
A: Vespa tropica feeds on the grubs of other social wasps and bees. On Guam, they have been seen raiding honeybee hives and nests of the small paper wasps we refer to as ‘boonie bees’. V. tropica will probably suppress the ‘boonie bee’ population. When they have killed much of their prey, the V. tropica population will probably crash due to food limitation. V. tropica is a ‘nuisance’ pest. These wasps are dangerous only when they are defending their nests or when they are trapped. Individual wasps should be left alone. However, nests in critical locations such as parks, school grounds, and backyards should be removed by certified pest control operators to prevent people from being stung.
Q: What are you doing to reduce the amount of the Hornets on the Island?
A: A delimiting survey indicated that V. tropica was already well established on Guam and could not be eradicated with available resources. Based on this information, the Guam Invasive Species Council decided to do nothing about this invasive species problem, apart from providing information to the public.
Q: Why and how did this species get on Guam?
A: We don’t know. V. tropica probably arrived in the form of a nest in an large space such as an empty container or ship hold. Invasive species such as this are considered ‘hitch-hikers’. Because they are not associated with any particular commodity, it is hard to develop biosecurity procedures to detect these critters.
Q: What can we do, and the citizens of Guam do, to contribute to the reduction of the Greater Banded Hornet and possibly get rid of them?
A: The citizens of Guam have already helped in reporting sightings of V. tropica during the delimiting survey. With this particular species, the public is advised to leave individual wasps alone. However, if a nest is found, this should be reported to the invasive species hotline at 475-PEST (475-7378). This number should also be used to report animal or plant which are suspected of being new invasive species.