Research Article |
Corresponding author: Terence Bellingan ( t.bellingan@am.org.za ) Academic editor: Yasen Mutafchiev
© 2021 Terence Bellingan, John Midgley, Georg Goergen, Kurt Jordaens.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Bellingan T, Midgley J, Goergen G, Jordaens K (2021) Notes on the Afrotropical hover fly genus Meromacroides Curran (Syrphidae, Eristalinae). African Invertebrates 62(2): 383-397. https://doi.org/10.3897/AfrInvertebr.62.68360
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The African endemic hover fly Meromacroides meromacriformis (Bezzi, 1915) (Syrphidae, Eristalinae) was described more than a century ago and its monotypic status established in 1927, but subsequent collections and publications are rare. Only the male has been described and nothing is known about its biology. We re-describe the male, including geographic variation, describe the female for the first time and provide the first DNA barcodes for the species. Despite the large range and observed variations, there is insufficient evidence to describe additional taxa in the genus. Biological observations are presented, which may shed some insight into this rare and enigmatic hover fly, whose known distribution now spans the Afrotropical Region.
Africa, Afrotropical Region, DNA barcoding, flower fly, taxonomy
The African endemic hover fly species Meromacroides meromacriformis (Bezzi, 1915) (subfamily Eristalinae) was described as Eristalis meromacriformis by
The males studied by
Information about the species is sparse: the description given by
Study material was obtained from the following institutions:
Morphological terminology follows
Procedures for DNA barcoding followed
Meromacroides Curran, 1927 57: 69.
Eristalis meromacriformis Bezzi, 1915 (by original designation).
Eristalis meromacriformis
Meromacroides meromacriformis
(Bezzi) –
Meromacroides meromacriformis can be distinguished from any other hover fly species in the combination of the following characters: Postpronotum pilose; compound eye pilose; wing membrane microtrichose in apical 1∕3; wing vein R4+5 strongly sinuate; wing cell r1 closed and bulbous apically; thorax with triangular part of anepimeron and katepimeron weakly pubescent; metafemur greatly swollen.
Holotype
: Male from South Africa (
While the holotype was described by
Benin. • 1 ♀; Pobè Forest; 6.963116, 2.674033; 10 Mar 2019; G. Goergen leg.;
(Figs
Head
(Fig.
Thorax
(Figs
Legs
(Figs
Wing
(Fig.
Abdomen
(Fig.
Genitalia
(Figs
(Figs
A female Meromacroides meromacriformis (Bezzi, 1915) live pictures 13 female hovering above a rot-hole in the stem of a Voacanga thouarsii (Apocynaceae) tree at Mtunzini, KwaZulu-Natal (South Africa) 14 female alighted in a rot-hole, idem 15 relative size of the rot-hole illustrated with a 30 cm steel ruler, idem.
As male, except for the following characters:
Head
(Fig.
Thorax
(Figs
Legs
(Fig.
Abdomen
(Fig.
Male and female specimens from Western, Central and Southern Africa differ in subtle characters (summarised in Table
Table
Sequences from NCBI GenBank for Meromacroides meromacriformis (Bezzi, 1915) specimens from Togo and South Africa.
Species | Museum acronym | Voucher number | GenBank accession no. |
---|---|---|---|
Meromacroides meromacriformis |
|
|
MZ303633 |
Meromacroides meromacriformis |
|
|
MZ303634 |
Meromacroides meromacriformis |
|
RMCA-1088B03 | MZ303635 |
Meromacroides meromacriformis |
|
RMCA-1088B04 | MZ303636 |
Meromacroides meromacriformis |
|
RMCA-1224A02 | MZ303637 |
Geographic morphological variation observed from Meromacroides meromacriformis (Bezzi, 1915) specimens from West, Central and Southern Africa.
Region | West African specimens | Central African specimens | Southern African specimens |
---|---|---|---|
Character | |||
Head | |||
Eye pile length | Four times the diameter of an ommatidium | Three times the diameter of an ommatidium | Four times the diameter of an ommatidium |
Thorax | |||
Scutum ground colour | Dark brown | Dark brown | Dark reddish-brown |
Pleura ground colour | Black-brown | Dark brown | Dark reddish-brown |
Scutum pollinosity | Two pale pollinose vittae | Two pale pollinose vittae | Two dark pollinose vittae |
Legs | |||
Colour of spines on coxa and trochanter | Dark brownish – black | Light brown | Light brown |
Wing | |||
Calypter colour | Dark grey | Brownish-grey | Brownish-grey |
Calypter fringe colour | White | Yellowish-white | Yellowish-white |
Haltere colour | White | Yellowish-brown | Yellowish-brown |
Infuscation colour on wing margin | Light brown | Dark brown | Very dark brown |
Abdomen | |||
Tergites II–III dorsal posterior border colour | Yellowish-white | Orange-brown | Orange-brown |
Pollinosity colour and density | Greyish-white, sparser | Yellowish-white, denser | Yellowish-white, denser |
Genitalia | |||
Cerci | Dorsally rounded | Genitalia missing | Dorsally angular |
Epandrium | Dorsal and ventral margins straight and parallel | Genitalia missing | Dorsal margin rounded, not parallel with ventral margin |
(Based on material examined, except as noted) Benin, Democratic Republic of the Congo (
The collector, RW Plant, moved to South Africa in 1850 and died on an expedition in 1858. During his time in South Africa, he lived in KwaZulu-Natal and there is no record of his travelling to other parts of South Africa. The only collecting trip he undertook that produced appreciable specimens was in 1858, to northern KwaZulu-Natal. The exact route of the expedition is unknown (
We observed two males and a female hovering inside a rot-hole in a single Voacanga thouarsii Roem. and Schult. (Apocynaceae) tree filled with termite frass (Termitidae: Termitinae: Amitermes?) and other biological material (Mtunzini, KwaZulu-Natal, South Africa) (Figs
Here, we have re-described the male and described the female of Meromacroides meromacriformis, an enigmatic monotypic hover fly genus of the Afrotropical Region. Our study is the first to provide high-resolution pictures of the general morphology (but see
The occurrence of the species in Benin and Togo (West Africa) indicates that the species is widespread over the Afrotropical Region and has been recorded from West (Benin, Togo), Central (Democratic Republic of the Congo), East (Kenya, Uganda) and Southern Africa (South Africa). While nothing is known on the ecology of the species or the larval stages, our observations provide potential insights. The observed behaviour suggests that rot-holes may be used as both mating and oviposition sites and, if this is true, then the species may be restricted to very old, mature forests where this specific habitat type may be more abundant. The upper layers of termite frass and rotting vegetable material were screened for eggs and larvae, but neither were found.
With a total of 27 specimens (18 males, eight females and one of unknown sex which is currently missing) known so far and the largest known series consisting of only four specimens, the species is very rare. The combination of limited habitat and low density drive this rarity, despite the wide geographic range within which the species is distributed.
We would like to thank N Wyatt and A H Kirk-Spriggs (