Abstract:
Biotic and abiotic factors influence how insects respond to stimuli. This can make it challenging to interpret captures in
traps used to monitor pest abundance in management programmes. To address this, the lure response of three pest fruit
flies (Diptera: Tephritidae) was evaluated in a semi-field setting with respect to several physiological and environmental
factors. Using standardised methods with known fly numbers in field cages, the response to Biolure (food-based lure) was
evaluated for Ceratitis capitata, Ceratitis cosyra and Bactrocera dorsalis. Response to the male lures was tested: E.G.O
PheroLure for C. capitata and C. cosyra, Trimedlure for C. capitata, and methyl eugenol for B. dorsalis. The physiological
variables evaluated were fly age, sex, weight, and total body nutritional composition. The environmental effects of temperature,
relative humidity and light intensity were also assessed. Protein-deprived adults responded more strongly to Biolure.
The response to Biolure was not sex-specific. Fly age influenced the response of all species to all tested lures. However,
this effect was species and lure specific. Temperature was the most influential environmental factor, with response generally
increasing with temperature. Lower thresholds for lure response, despite the proximity of responsive flies, range from
12.21 to 22.95 °C depending on the species and lure tested. These results indicate that trapping systems and management
activity thresholds must take physiological and environmental variation into account to increase their accuracy.
