Cattle skin twitching as a behavioral indicator of trap-based stable fly activity under seasonal and thermal conditions

The stable fly, Stomoxys calcitrans (Diptera: Muscidae), is a blood-sucking pest of livestock worldwide. Cattle respond to stable fly attacks with evasive behaviors such as skin twitching, foot stamping, and tail flicking. Although such behaviors may be useful indicators of biting fly pressure, their relationship with trap-based stable fly activity across seasons remains unclear. We conducted year-round hourly observations of stable fly flight activity and cattle skin twitching in a dairy barn in Fukuoka, Japan. Stable fly flight activity was monitored using blue sticky traps, and cattle skin twitching was recorded simultaneously. Model-based analyses showed that stable fly flight activity was concentrated during daytime, varied seasonally, and had a nonlinear relationship with air temperature. The predicted maximum daytime flight activity occurred at 26.7 °C. Cattle skin twitch frequency was associated with stable fly activity and air temperature. These results suggest that cattle skin twitching may serve as a practical supplementary indicator of stable fly activity, although its interpretation should account for seasonal and thermal conditions.