Recipient Organization
UNIV OF HAWAII
3190 MAILE WAY
HONOLULU,HI 96822
Performing Department
MOLECULAR BIOSCIENCES & BIOSYSTEMS
Non Technical Summary
Coqui frogs are reproducing rapidly in Hawaii because they lack natural predators. Their levels are about ten times the levels in their native Puerto Rico. They disturb the sleep of residents and visitors and may put endangered bird species at risk by competing for food insects and serving to raise populations of rats and mongooses which are predators of both frogs and native birds. The purpose of the project is to control coqui frog populations through use of pesticides. Part of the problem is to understand the biochemical mode of action of pesticides.
Animal Health Component
70%
Research Effort Categories
Basic
30%
Applied
70%
Developmental
(N/A)
Goals / Objectives
1) Determine whether laboratory studies using pyrethrins and culled coffee bean extracts are efficacious in the field. Initiate toxicology on coqui frog eggs. Hot water and hydrated lime treatments will be tried in another project. 2) Along with this, determine the effect of pesticide treatments on non-target species. 3) Explore whether other potential pesticides are cheaper and/or more efficacious on Eleutherodactylus including, 3-trifluoromethyl-4-nitrophenol, other pyrethrins, and nicotine. 4) A larger scope objective is to develop a larger data base on amphibian and reptile toxicology. 5) Understand the biochemistry and physiology of caffeine and pyrethroids as much as possible including the reasons they are selectively toxic to target species. 6) Work with local growers to assess possible issues with phytotoxicity and with local communities to assure as much as possible that control methods are sustainable and self-starting over time. Obtain time frames for
re-treatment.
Project Methods
1) To determine whether laboratory studies using pyrethrins and culled coffee bean extracts are efficacious in the field, conduct field trials. Initiate toxicology on coqui frog eggs to see whether eggs are killed too. Current lab work has been very promising. Current results suggest that Pyronyl Crop Spray and culled coffee bean extracts give a 100% kill rate after a single application. All field trials would require that population estimates be done both before and after any treatment to determine the efficacy of spraying. Noise levels generated by the frogs and its reduction will also be measured. 2) Along with this, determine the effect of pesticide treatments on non-target species. Preliminary results indicate that caffeine kills introduced species of toads, insects and lizards (Campbell, manuscript in preparation). Such results are very promising for other alien pest species. 3) Explore whether other potential pesticides are cheaper and/or more efficacious on
Eleutherodactylus including, 3-trifluoromethyl-4-nitrophenol, other pyrethrins, and nicotine. These will be tested in the laboratory initially. 4) A larger scope objective is to develop a larger data base on amphibian and reptile toxicology. While there are academic studies using frogs as model species, we have been unable to find studies on the control of amphibians or reptiles. Moreover, we have only been able to find pyrethrin studies. The literature is silent-as far as we can tell-on caffeine toxicology. 5) Understand the biochemistry and physiology of caffeine and pyrethroids as much as possible including the reasons they are selectively toxic to target species. We intend to use antagonists to elucidate the mode of action of caffeine and pyrethrins. These would include curare, succinyl choline, dantrolene, ryanodyne, verapamil and so on. Determination of caffeine levels in the blood at various times after treatment should yield useful information as to its catabolic breakdown to
clarify its role as a toxin. Glycogen, blood glucose, and blood lactate levels will be measured to see whether the toxicity of caffeine may be a simple metabolic one. The pyrethrins may be a stressor. Caffeine may be a metabolic stressor by increasing cAMP levels, which may turn on lipid and glycogen mobilization. Frogs may be overstressed and killed by hypoglycemia. 6) Work with local growers to assess possible issues with phytotoxicity and with local communities to assure as much as possible that control methods are sustainable and self-starting over time. Obtain time frames for re-treatment.