Phototactic behavior and compound eye structure of Diaphorina citri

Objective  To study phototactic behavior of Diaphorina citri Kuwayama (Asian citrus psyllid)in different light waves, research the microstructure of adult compound eye and its changes under light- and dark-adaptation, and lay a foundation for developing non-chemical prevention and control technology of D. citri.

Method  Phototactic test instrument was used to test phototactic rate ofD. citri adult towards lights with different wavelengths. The scanning electron microscopy and histological sections were used to observe the structures of compound eyes of D. citri adults.

Result  The phototactic rates of D. citri adults towards different lights were different. The phototactic rate was the biggest for ultraviolet (365−370 nm), which was 66.62%−71.38%, and followed by blue light (470−475 nm, 47.17%−50.88%), green light (520−525 nm, 39.37%−44.26%), yellow light (590−592 nm, 28.18%−31.32%) and red light (620−630 nm, 14.68%−18.33%). The adult compound eyes were located on the antenna bases at both sides of the head, which were in the shape of a half circle, had a smooth surface without the auxiliary structure, and belonged to the typical parallel eyes. The ommatidium was composed of cornea, crystalline cone, retinula cells, basement membrane and pigment cell. The ommatidium was typical hexagonal in the central region of compound eyes and nearly circular near the periphery of compound eyes. Female and male adults ofD. citri consisted of 225−254 and 238−252 ommatidias per compound eye, respectively.

Conclusion  D. citri adults are more tending to ultraviolet, blue light and green light than white light. There is no difference in the structure and morphology of compound eyes between female and male adults of D. citri. This research provides a reference for studying the phototactic mechanism.