Microstylum sp.

Londt, Jason G. H., 2020, A survey of grassland Asilidae (Diptera) at Jacana Eco Estate, Hilton, South Africa, African Invertebrates 61 (1), pp. 29-48 : 29

15. Microstylum sp. Fig. 12

Remarks.

Microstylum Macquart, 1838, with 90 catalogued Afrotropical species, 79 listed as valid and 11 as synonyms ( Oldroyd 1980), is in great need of modern revision. Oldroyd (1980) lists 39 species as occurring in South Africa alone and so a revision of these large and impressive flies is seen as a high priority. In the absence of any modern keys, no specific name can even be suggested for the species encountered at Jacana. A very similar looking species was collected during a grassland survey undertaken at Queen Elizabeth Park in Pietermaritzburg ( Londt 2002b).

Adults of this summer active species were encountered in large numbers from week 45 through to week 48 when numbers declined. The species was ‘uncommon’ in week 52, the last week of the survey, with only a single specimen being seen and captured.

This large, almost entirely black species was invariably seen flying strongly over the vegetation, mainly in the lower field. Although a number of mating pairs were encountered, none were observed feeding. The species appears to be best accommodated within Londt’s (1994) ecological category 4b (grass tips).

Although Table 4 provides a comparison of flight periods with those recorded for a species collected at Queen Elizabeth Park ( Londt 2002b), a comparison of specimens does not provide sufficient evidence to suggest that these species are conspecific. However, the flight periods were remarkably similar, being weeks 45-52 at Jacana and weeks 45-49 at Queen Elizabeth Park (note that no sampling was undertaken on weeks 50 and 51 of the Queen Elizabeth Park survey).

Figures

Figures 4 - 13. Grassland inhabiting Asilidae encountered at Jacana Eco Estate (arranged alphabetically): 4 Caenoura annulitarsis (Loew, 1858) 5 Damalis monochaetes Londt, 1989 6 Dasophrys fortis Londt, 1981 7 Dasophrys tarsalis (Ricardo, 1920) 8 Dysclytus firmatus (Walker, 1857) 9 Euscelidia vallis Dikow, 2003 10 Ischiolobos mesotopos Londt, 2005 11 Leptogaster sp. 12 Microstylum sp. 13 Rhipidocephala obscurata Oldroyd, 1966. Photos: B. Muller.