On the colour polymorphism of Philaenus spumarius (L.) (Homoptera, Cercopidae) in Portugal

Abstract

A total of 7,967 specimens (4,354 males and 3,613 females) of the meadow spittlebug Philaenus spumarius (L.) collected in three different habitats at Fontanelas (Sintra) were analysed in terms of the colour morph frequencies. Eleven different morphs were encountered: populi (POP), typicus (TYP), trilineatus (TRI), marginellus (MAR), lateralis (LAT), flavicollis (FLA), gibbus (GIB), ustulatus (UST), quadrimaculatus (QUA), albomaculatus (ALB), and leucophthalmus (LOP). For males and in decreasing order of frequency the following morph groups and morphs proper were found: TYP group (95.38%), TRI group (3.70%), LCE group (0.85%), and LOP group (0.07%); and for females TYP group (88.7g0h), TRI group (4.01 Oh), MAR (3.32%), LOP group (1.88%), LCE group (1.74%), and LAT (0.25%). As expected, the TYP group (POP + TYP) was more frequent in males than in females (about 95% vs. 89%, respectively). Moreover, most melanic morphs were exclusively (MAR, LAT, ALE, and LOP) or better represented (FLA and QUA) in females than in males. Results also show that there appear to be differences regarding females among the three habitats studied, in spite of being practically contiguous. The coolest of all three habitats (a Pinus pinaster woodland with a shrub community dominated mostly by Ulex europaea) showed the highest frequencies of the melanic morphs. It is therefore suggested that among other factors, thermal melanism plays an important selective role in the colour polymorphism of the rneadow spittlebug at Fontanelas.