25.

Dusky Pipistrelle

Pipistrellus hesperidus

French: Pipistrelle hespéride / German: Abendstern-Zwergfledermaus / Spanish: Pipistrela africana

Other common names: African Pipistrelle

Taxonomy. Vespertilio hesperida [sic] Temminck, 1840,

“Les bords de la Mer rouge vers les cotés d’Abyssinie [= the shores of the Red Sea toward the coast of Ethiopia].”

Pipistrellus hesperidus has generally been considered a synonym of P. kuhliz; however, it is now recognized as a distinct species because of its morphological and genetic distinctions. Pipistrellus hesperidus seems to be sister to P. rusticus based on limited genetic data and chromosomal similarities. Exact distributional limits between P. /esperidus and P. kuhlii are uncertain. Canary Islands populations might represent either species and are tentatively included under P. hesperidus here. There is considerable variation in morphology across the current distribution of P. hesperidus . Subspecies recognized here almost certainly represent distinct species based on genetic and karyological grounds; however, not all populations have been tested, making it difficult to assign them to a species. West African populations mightalso represent a fourth distinct taxon based on high genetic distance and distinct karyotype from southern African populations. There is also considerable divergence between Madagascan and mainland populations, indicating that Madagascar specimens also represent a distinct species, for which the name humbloti might be available (the name was recently allocated to P. hesperidus based on examination of syntypes for the name). Distributions of subspecies are estimates. Three subspecies recognized.

Subspecies and Distribution.

P.h.hesperidusTemminck,1840—EAfricainEritrea,Djibouti,Ethiopia,SWSudan,SouthSudan,andNE&SSomalia.

P.h.fuscatusThomas,1901—EAfricainEDRCongo,Uganda,Kenya,Rwanda,Burundi,andTanzania.

P. h. subtilis Sundevall, 1846 — S Africa in NC, C & W Angola, Zambia, Malawi, Mozambique, Zimbabwe, NC Botswana, E & South Africa, Swaziland, Lesotho, and along the W coast of Madagascar.

There are also records on Canary and Cape Verde Is and in W Africa in W & SE Senegal, N Liberia, SE Ivory Coast, SC Burkina Faso, SE Ghana, SW Niger, NC Nigeria, W Cameroon, and Bioko I, although exact placement of these populations among taxa currently recognized under the P. hesperidus species complex is uncertain. A thorough investigation of records of this species is needed.

Descriptive notes. Head-body 43-55 mm, tail 20-41 mm, ear 6-15 mm, hindfoot 5-9 mm, forearm 27-38 mm; weight 3-5-9 g. The Dusky Pipistrelle is highly variable. Pelage is dense and soft. Dorsum ranges between pale grayish brown and reddish brown to darker dark brown and nearly black pelage. Ventral pelage is cream, creamy orange, orangish red, reddish brown, or dark brown (matching a lighter version of dorsum). Naked face is dark brown, and ears are dark reddish brown, with rounded tips. Tragus is widestjust below mid-height, has rounded tip, and is nearly straight anteriorly; posterior margin is smoothly convex, with small basal lobe. Wing membrane is pale brown to blackish brown, being darker or lighter with pelage, and has no white hind border. Uropatagium is paler than wing membrane and stretches more or lessto tail tip from calcar. Baculum is curved upward near base, has two small lobesat tip, and has notch at base rather than completely splitting into two lobes. Skull is moderate in size and moderately robust compared with other African Pipistrellus; braincase is relatively high and moderate in breadth; and interorbital region is of medium relative breadth. Dorsal margin of orbit is slightly but conspicuously inflated (in dorsal view, upper rim of orbit bulges outward, unlike straight orbit of Kuhl’s Pipistrelle, P. kuhlii); forehead is moderately concave; I? is unicuspid (lacking posterior basal cusp); P* is present and ranges from medium in size to tiny, usually visible above gum and variably within and completely displaced lingually from tooth row; C' and P* vary from being well separated to in contact; M? is large and comparatively broad, with long third ridge and wide gap between protocone and metacone; and lower molars are nyctalodont. Chromosomal complement has FNa =58, and FN = 62 (Senegal) or 2n = 42 and FNa = 50 (southern Africa and Madagascar).

Habitat. [Lowland and relict rainforests, montane forests, forest-grassland mosaics among other montane vegetation, coastal forests, Acacia (Fabaceae) — Commiphora Burseraceae) bushland, miombo woodlands, farmland, and occasionally human settlements from sea level up to elevations of ¢. 3000 m (Ethiopian Highlands). Distribution is determined by annual precipitation. The Dusky Pipistrelle is found where water is available; it is absent from drier regions in South Africa.

Food and Feeding. Dusky Pipistrelles are insectivorous. They forage by slow hawking in areas with moderately cluttered vegetation, such as between tree trunks, in and above canopies, in clearings, around houses, and near water. They eat insects, including Lepidoptera, Coleoptera, Hemiptera, Diptera, Trichoptera, Hymenoptera, Orthoptera, and Blattodea . In summer, they seem to favor Diptera and Hemiptera in KwaZulu-Natal, eastern South Africa. They eat some species that are generally considered pests to agriculture.

Breeding. Litter size of the Dusky Pipistrelle is usually two young, rarely one (at least in Malawi and South Africa). In Malawi, 14 pregnant and two lactating females were captured in October-November; another eight lactating females were captured in December. In the same area, no reproductively active females were captured in May-June, and two post-lactating females were captured in March-April. This chronology suggests that the Dusky Pipistrelle is seasonally monoestrous, with births in November— December (wet season in Malawi). Pregnant females in South Africa were recorded in October-November and non-pregnant females in December, March, and May.

Activity patterns. Dusky Pipistrelles emerge from their roosts at dusk and are active for several hours after sunset, with small activity peak at dawn. Day roosts have been found in a variety of secluded places, including cracks in rock, behind loose bark of dead trees, hollow trees, under roofs, and crevices of buildings. Torpid individuals have been observed during the day at ambient temperatures of 21-24°C in Malawi. Searchphase call shape is steep FM/QCEF, with QCF part varying in duration. In Malawi, calls have start frequencies of 63-86 kHz, end frequencies of 44-50 kHz, peak frequencies of 45-50 kHz, and durations of 2-7 milliseconds. Frequencies of 85-45 kHz have been recorded in Zimbabwe. Recordings in South Africa had start frequency of 65-7 kHz, end frequency of 48-7 kHz, peak frequency of 50-3 kHz, and duration of 3-5 milliseconds (averages). In Swaziland, recordings had minimum frequencies of 41-7-49-1 kHz and durations of 2-4—4-5 milliseconds. Reported predators include the common fiscal (Lanius collaris) in Kenya and the little sparrowhawk (Accipiter minullus) in South Africa.

Movements, Home range and Social organization. Dusky Pipistrelles roost in groups of up to twelve individuals and seem fairly social. When one individual is captured in a mist net, it emits audible calls that attract conspecifics.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Dusky Pipistrelle is widespread throughout Africa, but it does not seem to be particularly common in much of its distribution. No major threats are currently known.

Bibliography. ACR (2018), Babiker Salata (2012), Bates et al. (2006), Eisentraut (1968), Fahr (2007), Goodman, Rakotondramanana et al. (2015), Goodman, Rasoanoro et al. (2014), Hill & Harrison (1987), Kearney (2013g), Kearney et al. (2002), Kemp & Rautenbach (1987), Kock (2001b), Koubinova et al. (2013), Kruskop et al. (2016), Linden et al. (2014), Monadjem, Shapiro et al. (2017), Monadjem, Taylor et al. (2010), Naidoo et al. (2011), Patterson & Webala (2012), Piraccini (2016c¢), Rautenbach et al. (1993), Schoeman & Waddington (2011), Schwan & Hikes (1979), Smithers & Lobao Tello (1976), Stanley & Goodman (2011), Taylor (1998), Taylor, Bohmann etal. (2013), Taylor, Matamba et al. (2017), Taylor, Sowler et al. (2013), Volleth et al. (2001).