Sendero la Laguna. Gamboa, Colón, Panamá

These Trigona bees chewed the tops off the Justicia flowers apparently to get at the pollen. McDade & Kinsman 1980 describe similar behavior of Trigona bees on Aphelandra:

"Trigona bees often removed both pollen and nectar in one extended visit. Bees typically settled on the upper corolla lip and chewed through the folded corolla lobes to collect pollen from the concealed anthers, then flew to the base of the flower and chewed holes through the corolla tube to extract nectar. Since the stigma is exserted several mm beyond the anthers, the bees are unlikely to contact the stigma in a pollen-gathering bout and are thus not pollinating. In fact, while in the process of gathering pollen, bees frequently chewed through or severely damaged the style at the level of the anthers, resulting in no chance of seed set from such flowers."