Seasonal Polymorphism in Elytral Coloration Pattern of Anomala flavipennis Burmeister (Coleoptera: Scarabaeidae) in Mexico
Elytral polychromatism in Anomala flavipennis Burmeister was detected in both spring and fall generations in northeastern Mexico from 2000 to 2002. Four distinctive coloration patterns were observed: (a) immaculated, (b) one-spotted, (c) two-spotted, and (d) striped. These categories were represented by 0, 1.4, 7.8, and 28.0% respective levels of melanization of elytral area. A significant interaction was detected between elytral pattern and generation, with melanized forms occurring more commonly during the spring and clearer forms during the fall. Weighted mean of elytral melanized area in the population ranged from 1.46% for fall to 7.80% for spring generations. Linear regression models suggested (R2 ≥ 0.93) an inverse association between temperature during pupation-adult ecdysis and elytral melanized area. The rationale and advantage for A. flavipennis responding to temperature by elytral melanization remain unknown, particularly because of the crepuscular-nocturnal habits of adults.