Susceptibility of Cat Flea (Siphonaptera: Pulicidae) to Systemic Pesticides

• Main Authors: Yi-Ju Chen, 陳怡如
• Other Authors: Wen-Jer Wu
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/07360809353823137274

碩士 === 臺灣大學 === 昆蟲學研究所 === 98 === The cat flea (Ctenocephalides felis) is a common pet ectoparasite. Besides the discomfort caused to humans, the cat flea may also carry zoonotic organisms. Spraying insecticides on pets and around homes are effective ways to control fleas. Chemical control has been demonstrated to be effective at cutting the flea’s life cycle; however, this may result in rapid development of resistance. There is growing evidence to suggest that fleas have developed resistance to several insecticides. At present, systemic pesticides used for flea control in Taiwan are fipronil and imidacloprid, which are spot-on and spray formulations. Overseas, spinosad in tablet form is currently the latest systemic pesticide in use. We were curious as to whether fleas in the field develop resistance to these newer systemic insecticides over time, therefore, we examined the susceptibility of cat flea larvae and adults from two sources, using a single larval bioassay with 96-well plates (a new technique for detecting flea susceptibility), and WHO filter paper adult bioassay. The first source of cat fleas was from a laboratory colony, and the second from a recent field collection at Taipei animal shelter. The responses to insecticides were different between larvae and adult fleas. Both sources of flea larvae exhibited the lowest susceptibility to imidacloprid and the highest to fipronil. However, adult flea susceptibility to Advantage™ (imidacloprid) was higher than for Frontline®spray (fipronil). The results also indicated that flea larvae had a higher resistance ratio (RR) to fipronil (RR = 4.9) than imidacloprid (RR = 1.10) and spinosad (RR = 0.65). This implies that frequent use of systemic pesticides may reduce susceptibility. Because of this, the susceptibility of cat flea populations to these systemic insecticides should be closely monitored. Detecting flea resistance distribution in the field can help us formulate suitable management strategies to overcome or avoid its effects on flea control in the future.