Decomia Poppius

Genus Decomia Poppius

Discussion. This is the most speciose genus group among the tribe Decomiini, composed of approximately 40 valid species. It is, except for a few members, easily recognized by the broadly hyaline forewing, apices of the corium across embolium and cuneus often each with a dark or reddish mark (Fig. 1), tumid metafemur, semicircularly enlarged pulvilli, and J-shaped endosoma (Schuh, 1984), in addition to the anteriorly extending posterior wall of bursa copulatrix (Fig. 5).

Each species usually exhibits the distinctive color pattern (reddish, brownish or fuscous, as in Fig. 1), but it seems that the color pattern is not significantly correlated to the morphological characters of the genitalia. We are currently less certain that the interspecific color variation is simply a result of parallelism. For instance, D. nigrissima, in spite of being nearly identical with fuscous members, such as D. cephalotes Poppius and P. torreviasi Schuh, by external characters alone, has the remarkably shortened, tiny endosoma which is structurally most similar to that of D. perparvula Schuh and D. schuhi Yasunaga; both of the latter two have pale or reddish general coloration (cf. Fig. 1 E vs. F). The present examination suggests that the female bursa copulatrix is similarly small in the species with a dwarf endosoma, as evidenced by D. schuhi and D. nigrissima (Fig. 5). However, the female genitalic structures in Decomia are currently known only for seven species shown in this work; therefore, further efforts are required, to acquire morphological information for much greater numbers of congeners.

Nothing is known about the ecology and breeding hosts of Decomia members. We have collected specimens either using UV light traps or sweeping flowers of broadleaf trees; in central Thailand, sweeping the racemose inflorescences of the following plants have produced more than a few Decomia specimens in particular: Elaeocarpus grandiflorus Sm. (Elaeocarpaceae) (D. anthophila, D. indochinensis and D. taksini, Fig. 1 A, C, G), Shorea obtusa Wall (Dipterocarpaceae) (D. indochinensis, Fig. 1 D), Mangifera indica L. (mango, Anacardiaceae) (D. chiangdaoensis and D. indochinensis) and Terminalia spp. (Combretaceae) (D. taksini and D. panayensis Yasunaga in Visayas, Philippines as well). The adults of these bugs apparently prefer pollen and floral honey dew; however, no immature forms are yet to be confirmed from those plants that attract the adults (see also Yasunaga, 2010, Yasunaga & Duwal, 2015).