Lepidoptera fauna of Namibia . I . Seasonal distribution of moths of the Koakoland ( Mopane ) Savanna in Ogongo , northern Namibia

During the years 2011–2013, moths were collected in Koakoland (Mopane) Savanna in the Cuvelai Drainage System, Ovamboland, northern Namibia. In total, 77 species from 13 families have been identified. Their seasonal occurrence in this habitat was also investigated, with most species recorded in wet season between September and April, but with clear peak in February and March. The family Noctuidae was by far the most speciose (38 recorded species), followed by Crambidae (8 spp.), Sphingidae (6 spp.) and Arctiidae (4 spp.). All other families were represented by 1–3 species. For each species listed date of collection is given, and data on its global distribution.


INTRODUCTION
According to recent quite precise estimate, there are 15 5181 species, 16 650 genera and 121 families of Lepidoptera worldwide (Pouge 2009).
Lepidoptera fauna of Namibia has recently attracted attention of European entomologists.However, thorough surveys were conducted hitherto in a few areas only, such as Brandberg and Hobatere.The northern regions of the country were especially badly neglected.In southern Africa (south of Zambezi and Kunene Rivers) -8 511 species, 2 368 genera and 89 families were recently catalogued (Vári et al. 2002).Respective figures for Namibia are 819 species, 445 genera and 50 families; with 121 species (14.8%) endemic to the country (Barnard 1998).The largest family, Noctuidae, is represented by 1 608 species and 459 genera in southern Africa (Vári et al. 2002), while in Namibia by 147 species and 79 genera (Barnard 1998).This comparison shows rather a poor state of knowledge of southern African Lepidoptera fauna, and even poorer in a country within this region, Namibia.
In the last two decades, moths were regularly collected and studied thoroughly only from a few sites in Namibia, such as Brandberg (Mey 2004ab, 2007 and Hobatere area (Braine 2002).Fragmentary information on Lepidopetera fauna (usually records of dozen or so common species) are available from many other sites (e.g.Oberprieler 1992a, 1992b, Jürgens et al. 2010).Recently, May (2011) has collected butterflies and moths from 80 sites in Namibia, but none of these sites was located in Ovamboland.Although his samplings were relatively representative, he has managed to identify, as most his predecessors, only dozen or so species from each site.In lepidopterological surveys, especially badly neglected were the northern regions of Namibia: Kaokoland, Ovamboland, Kavango and Zambezi (May 2011).This note constitutes, therefore, a contribution to the knowledge of Lepidoptera fauna in this parts of the country.

STUDY AREA
The study was conducted on UNAM Ogongo Campus.It is situated in the BIOTA Observatory 'Ogongo' within the Cuvelai Drainage System, c. 50 km NW of Oshakati, Outapi district, Omusati region, North-Central Namibia (17º70'S, 15º31'E; 1100 m a.s.l.).
The BIOTA Transect and Biodiversity Observatories in Southern Africa is an international research project.It constitutes a transect which starts in the Cape Peninsula and runs through Western Cape, Northern Cape, and in Namibia through Oranjemund, Karios, Nabaos, Windhoek, Okahandja, Sonop and Mutompo, ending in Ogongo (Jürgens et al. 2010;Schmiedel & Jürgens 2010;Hoffmann et al. 2010).In each of these observatories, both plant and animal diversities were subjects of a monitoring program.For some of these observatories, data on Lepidoptera diversity have been provided.However, in the BIOTA Observatory 'Ogongo' (S42), no such studies have been carried out (Jürgens et al. 2010;Schmiedel & Jürgens 2010;Hoffmann et al. 2010).
The Ogongo area situated within the Cuvelai Drainage System is an extensive sandy plain, c. 1100 m a. s. l., partly flooded almost annually (usually December-June).It is located in a prime summer rainfall zone, with mean annual precipitation of 400-500 mm (Mendelsohn et al. 2000).A total of 411 vascular plant species, 3 vegetation classes, 7 associations and 7 subassociations were described there (Kangombe 2007).The Cuvelai Drainage System comprises a network of hundreds of meandering oshanas (canals), separated by sodic sands covered with Koakoland Savanna (Mendelsohn et al. 2000).The system occupies 14 773 km 2 ; of which 5 957 km2 is cleared or fenced, while 1 926 km2 is transformed into cultivated land (Mendelsohn et al. 2000).In 2000, c. 563 000 people inhabited this area.The climate is semiarid.Almost all rains (96%) fall in summer (November-April), with two thirds in January-March.The amount of rain varies from year to year, usually within 400-500 mm per annum (Mendelsohn & Weber 2011).The average temperature of the coolest months (June-August) is 17˚C and that of the warmest months (October-January) 25˚C.

METHODS
Moths were trapped by light 60W (cf.Kopij 2005).The light was set up in a rich mixed savanna close to university buildings on the UNAM campus.The sampling was made throughout the year from February 2011 to January 2013, almost on a daily basis.The collected moths were not counted, neither sexed, and were assigned to particular month, without exact date, as the purpose of the study was to provide a list of identified species for each month.The specimens were deposited in the zoological collection of the Department of Wildlife Management, UNAM, in Katima Mulilo.
As in Kopij (2005), for the identification of moth species Pinhey (1960, 1975), Picker et al. (2002) and Oberplierer (1995) were used, while the systematics, and nomenclature of all taxa follows that of Vari et al. (2002), as the most authoritative and comprehensive checklist of Lepidoptera of southern Africa.The new classification of Noctuidae, which treats the families Arctiidae, Lymanthriidae, Nolidae and Patheidae as subfamilies of the family of Noctuidae (Lafontaine & Fibiger 2006), is not followed here.