Daily and Seasonal Patterns in Abdominal Color in <I>Diaphorina citri</I> (Hemiptera: Psyllidae)

Abstract

Diaphorina citri Kuwayama, a psyllid vector of huanglongbing (citrus greening disease), exhibits three more or less distinct abdominal colors in the adult psyllid: gray/brown, blue/green, and orange/yellow. We explored the daily (in individuals in the laboratory) and seasonal (in a field population) patterns in abdominal color of adult D. citri to clarify the biology of this species in relation to abdominal color and investigated the relationship between abdominal color and the reproductive state of adults (i.e., whether an individual is reproductively mature, has mated, or—in females—is gravid). Females were predominantly blue/green throughout their lives, with a small portion of individuals being gray/brown, especially just after emergence. Approximately 86% of mated females developed an orange/yellow abdominal color after mating, but they ultimately turned back to blue/green within several days to 1 mo after mating. Only 31% of virgin females turned orange/yellow. Males were predominantly blue/green early in life, but a greater portion of males relative to females were gray/brown. The orange/yellow color in females reflected the presence of eggs in the abdomen; in males it seemed to derive from the color of the internal reproductive organs, and it was generally only evident in older males. The preponderance of blue/green females, rarity of gray/brown females relative to gray/brown males, and rarity of orange/yellow males and females was largely reflected in sticky card trap captures from the field. Abdominal color is of essentially no value in discerning the state of sexual maturity and of only limited value in discerning whether females have mated.