AdultBiprorulus bibax(Breddin) in southwestern New South Wales showed substantial variation in weight and lipid reserves associated with reproductive condition. Females were reproductive from September to March but contained the greatest number of eggs during spring (September–November). Females were larger and heavier than males. Highest body weights occurred in nonreproductive individuals overwintering on oranges or mandarins. Lowest body weights occurred during summer (December–February). Nonreproductive bugs overwintering on oranges or mandarins (but not lemons)contained substantial lipid reserves (0.040–0.048 g/0.1 g). Lipid levels of summer reproductive bugs were about half those of individuals overwintering on nonlemon citrus. Overwintering survival ofB. bibaxis facilitated by biochemical adjustments associated with reproductive dormancy. The accumulation and storage of energy reserves to enable survival during seasonal adversity are fundamental to the success of this citrus pest in southeastern Australia.