Sticky Situation: Evaluating Bycatch Problem of Sticky Trap in Hong Kong's Agricultural Landscapes

To ensure crop yield, various pest control measures are implemented in agricultural landscapes. Nonetheless, these measures can result in undesirable outcomes due to the removal of beneficial insects as bycatch. Worse, this detrimental impact can be amplified in organic farms where higher insect diversity can be found, acting as a potential ecological trap. However, there are limited studies on the sticky trap bycatch problem among different farming practices. To address this, this study investigated the bycatch rates of sticky traps in the agricultural landscape of Hong Kong. We deployed sticky traps of green and yellow, targeting Tephritidae, in 20 organic farms, conventional farms, and nearby open natural habitats, respectively. We hypothesized traps in open natural habitats would have the highest bycatch rate, followed by organic farms and conventional farms. Due to their visual cue, yellow traps were also predicted to have a higher bycatch rate than green traps. We found a higher Tephritidae catch rate in organic farms, but the bycatch rate was not significantly higher compared to conventional farms and open natural habitats, yet still contributed to 76% of the overall catches. Interestingly, although yellow traps yielded a higher captured abundance, their bycatch rate was also higher than green traps. To reduce bycatch and improve trap efficiency, our results revealed green sticky traps might be more suitable as a pest control measure in the agricultural landscape. Adopting a more effective pest control method that protect beneficial insect populations is crucial to support sustainable agricultural practices.