Eumerus, Meigen, 1822

Adomako, Abigail Kusiwaa, Gasu, Edward Ntim, Mensah, Jehoshaphat Oppong & Borquaye, Lawrence Sheringham, 2020, What do Eumerus Meigen larvae feed on? New immature stages of three species (Diptera: Syrphidae) breeding in different plants, Organisms Diversity & Evolution (New York, N. Y.) 20 (2), pp. 267-284 : 277-278

Eumerus hoverflies feed on a wide range of plants, many with commercial interest

Some species of Eumerus show very polyphagous ranges of host plants for their larvae ( Fig. 8 ). That is the case of E. strigatus , which, according to published records, has been reported from at least 11 different genera of plants. The same occurs for the subsequent most polyphagous species, E. obliquus ( Fabricius 1805) , E. funeralis , and E. amoenus , respectively, reported from nine, eight, and six different plant genera. All four species feed on plants with commercial interest, and some of them are known to be pests of these plants. There are many species of Eumerus reported from single host genera as in the cases of E. alpinus and E. nudus , which only feed on Asphodelus ( Xanthorrhoeaceae ), E. ruficornis Meigen 1822 , which is the only known Eumerus species that feed on Scorzonera L. ( Asteraceae ) and E. tricolor ( Fabricius 1798) , only known from two species of Tragopogon L. ( Asteraceae ). In the case of E. superbus , it was only reported from two species of Zamiaceae plants, thus being the first records of Eumerus for gymnosperms.

Additionally, some plant genera are reported as host plants for different Eumerus species. This is the case of Cistanche and Narcissus , with six Eumerus species each, and Allium L. and Solanum L., with five species each. However, Eumerus species feeding on Cistanche , are not known to feed on any other plant genera. Conversely, Allium , Narcissus , and Solanum are host plants for some Eumerus species able to feed on more than one plant genus. Only three Eumerus species are able to feed on all cited genera of some plant families: E. funeralis in Amaryllidaceae , E. strigatus in Apiaceae , and E. superbus in Zamiaceae .

Among all 34 studied plant taxa, only 4 genera were considered as without current commercial value. Therefore, Eumerus feeds on a higher number of plants with commercial interest rather than without it ( Fig. 8 ).

Figures

Fig. 8 “Bipartite” network between Eumerus species (right) and the genera of host plants (left). Length of the boxes show the number of interactions. Colors of the plant boxes: in red (dark color), genera with at least one species with economic value; in blue (light color), without eco- nomic value. Plant genera followed by plant family abbre- viations as in Table 1