Submitted to: Workshop Proceedings
Publication Type: Other
Publication Acceptance Date: 11/1/2009
Publication Date: 11/4/2009
Citation: Zhu, J.J. 2010. Novel approaches on biting repellency: sensory physiology and behavior. In: Proceedings of the International Chemoreception Workshop on Insects XXXIII, October 31-November 4, 2009, Kailua-Kona, Hawaii. p. 3. Interpretive Summary: Biting flies are the most serious pests that primarily feed on a wide range of livestock animals. Sometimes they even attack pet animals and humans in rural areas. Their feeding on livestock animals has also led to increased disease incidence, reproductive failure and reduction of meat and milk yields, with estimated economic loss up to billions of dollars in beef and dairy industry. Biting fly control consists of chemical control and classical control using insecticides are unsustainable in the long term because of the likelihood of the development of insecticide resistance, and direct spray of insecticides on animals resulted in only marginal effectiveness, especially for those animals in pastures. The current presentation reports our recent discoveries on novel host associated attractants and plant-based fly repellents, as well as their further applications in reducing egg-deposition from gravid females. We hypothesize that those flies rely on a shared set of chemostimuli for their host and oviposition location. Some of those receptors may also respond to repellent compounds. The characterization of the functional morphological structures of fly sensory organs is the first key step to better understand the complex mechanism of fly host location, oviposition site selection and repellency.
Technical Abstract: The present study reports the discovery of several plant-based and food-grade repellent candidates against biting flies. Via SEM study we identified several fly olfactory receptors that vary in shape and size among different locations on antennae, mouth parts maxillary palps and ovipositor, which are adapted for the perception of airborne volatile compounds and semi- or non-volatiles. Most commonly observed olfactory chemosensilla are trichoid (long hairs), basiconic (short hairs), coeloconic (pit-peg), styloconic (subconical structure), clavete (club-like shape), etc. We also identified the first potential contact receptor on mouth part that may be used for contact repellency. The EAG tests on biting fly antennae showed some characteristic responses between the different species to various odorant compounds associated to host animals and manure associated environment surroundings. The dose response curves indicated that higher concentrations may reduce the antennal responses, which are probably due to their sensory adaption. Our EAG responses from fly antennae also showed a spatial repellency on several volatile repellent compounds. The exploration of potential filth fly sensory physiology and their behavior will contribute significantly in their use in future practical applications in fly management using a Push-Pull strategy.