DefinePK

Abstract

Apis mellifera L. face growing threats from sub-lethal pesticide exposure that disrupts their physiology and behavior, endangering colony survival and pollination efficiency. The present study evaluated the residual sub-lethal effects of bifenthrin on key health biomarkers, social interactions, and foraging behavior of worker honey bees under laboratory and semi-field conditions. Bees were exposed to four bifenthrin treatment levels along with a control group. Phenoloxidase (PO) activity, lifespan, antennation, trophallaxis, and foraging behavior were assessed using standard protocols and subjected to statistical analysis. PO activity was highest in the control group (26.64 ± 1.11 U/mg tissue) and lowest in the T1 treatment (8.90 ± 0.59 U/mg tissue). Lifespan declined from 43.00 ± 0.58 days (control) to 34.33 ± 0.33 days (T1). Similarly, antennation and trophallaxis frequencies decreased from 65.00 ± 4.93 and 45.00 ± 4.04 bees/event (control) to 37.00 ± 3.46 and 21.33 ± 3.18 bees/event (T1), respectively. Foraging activity, including incoming and pollen-carrying bees, also declined significantly, from 349.00 ± 17.58 to 237.00 ± 11.59 bees/5 min and from 121.67 ± 6.12 to 76.33 ± 5.93 bees/5 min, respectively. Strong positive correlations were observed among behavioral and physiological parameters, indicating their interdependence in maintaining colony performance. These findings demonstrate that residual sub-lethal exposure to bifenthrin significantly impairs immunity, longevity, social interaction, and foraging efficiency in A. mellifera , posing serious risks to colony health. Future studies should clarify the mechanisms of these impairments, employ diverse biomarkers, and develop pollinator-safe pest management strategies.