SAJB-00783; No of Pages 4 Available online at www.sciencedirect.com South African Journal of Botany 81 (2012) 15–18 www.elsevier.com/locate/sajb Short Communication First record of pollination in the Afro-Eurasian Dipcadi Medik. (Hyacinthaceae): pollination of D. brevifoliumi by the owlet moth Syngrapha circumflexa (Noctuidae) ⁎ J.C. Manning a,b, , P. Goldblatt c, E. Parker d, R. Kaiser a a Compton Herbarium, South African National Biodiversity Institute, Private Bag X7, Claremont 7735, Cape Town b Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa c B.A. Krukoff Curator of African Botany, Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166, USA d Elandsberg Nature Reserve, Bo-Hermon, South Africa Received 4 January 2012; received in revised form 19 March 2012; accepted 20 March 2012 Abstract Flowers of Dipcadi brevifolium (Hyacinthaceae) exhibit the characteristics associated with phalaenophily, or pollination by settling moths, notably a dull-coloured, shortly tubular perianth with included anthers, and nocturnal scent. Flowers are self-incompatible and produce an unusual, sour/acrid floral scent dominated by isobutyric acid, 2-methylbutyric acid and jasmine. The moth Syngrapha circumflexa (Noctuidae) was recorded as a pollinator, representing the first pollination record for the species and for the genus. © 2012 SAAB. Published by Elsevier B.V. All rights reserved. Keywords: Dipcadi; Hyacinthaceae; Moth pollination; Pollination biology; Scent chemistry; Syngrapha 1. Introduction southern Africa but extending into central Asia, Madagascar and India (Speta, 1998). All have characteristic, dull-coloured, tubular Hyacinthaceae are a large and florally diverse family of±900 flowers with included anthers, and several of the southern African spp. that has speciated primarily in southern Africa with a species at least become fragrant at night, leading Vogel (1954) secondary radiation in the Mediterranean (Speta, 1998). Pollina- and Manning et al. (2002) to propose that they are adapted for tion systems in the family have been remarkably little studied moth pollination. Here we provide the first documented evidence since initial speculations on the subject (Vogel, 1954), who for moth pollination in the species D. brevifolium (Thunb.) inferred pollination by bees, birds, butterflies and moths on the Fourc., including a chemical analysis of the unusual, acrid floral basis of floral morphology. It is only recently that rodent and scent and observations on self-incompatibility. other non-flying mammal pollination has been documented in the southern African genus Massonia Thunb. ex Houtt. (Johnson et 2. Materials and methods al., 2001; Wester et al., 2009; Wester, 2010, 2011). Other systems have yet to be studied, among them the pollination of the small 2.1. Study species and study site genus Dipcadi Medik., which comprises±30 spp., primarily in Dipcadi brevifolium is a small, deciduous geophyte wide- ⁎ Corresponding author at: South African National Biodiversity Institute Compton Herbarium Private Bag X7 Claremont, Cape Town 7735 South spread through the winter-rainfall zone of southern Africa Africa. Tel.: +021-799 8660; fax: +021-761 4151. (Obermeyer, 1963). Flowering occurs from spring through late E-mail address: [email protected] (J.C. Manning). summer in different localities depending on the rainfall. At this 0254-6299/$ -see front matter © 2012 SAAB. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.sajb.2012.03.012 16 J.C. Manning et al. / South African Journal of Botany 81 (2012) 15–18 time a secund raceme of nodding, greenish to brownish, tubular 2.3. Floral visitors flowers 12–20 mm long is produced (Fig. 1). The tepals are united in the lower half and the filaments are appressed to the Plants were examined at various periods throughout the day inner surface of the tepals, the anthers thus apparently sessile, and early evening, from±08:00 until 21:00, on 20 and 25 Oct and included within the floral tube, along with the short style 2010 and again on 15 Oct 2011. After nightfall, examination and stigma. was carried out by the light of torches masked with red plastic We studied the species in the Elandsberg Nature Reserve foil, during which time 10–15 plants were monitored. All insect east of Bo-Hermon in Western Cape in October 2010 and 2011. visitors to the flowers were captured and examined for pollen Plants are widespread through the reserve in Swartland Alluvial under a dissecting microscope. Specimens are deposited at the Fynbos and Renosterveld shrublands (Mucina and Rutherford, South African Museum, Cape Town. 2006). Voucher specimens are deposited in the Compton Herbarium, South African National Biodiversity Institute. 2.4. Nectar measurement and sugar concentration Five flowers from five randomly selected plants were 2.2. Floral longevity, self-pollination and pollination success sampled for nectar in the late afternoon, ±17:00, thus allowing a full day for nectar accumulation. Nectar was extracted by Self-compatibility was assessed by enclosing ten budding inserting a 5 μl capillary tube into the mouth of the floral tube stems in fine-mesh tubes to exclude floral visitors, and examining to the base. The percentage of sucrose equivalents in fresh them periodically over the following two weeks for fruit set. nectar was measured using a Bellingham and Stanley hand- Natural pollination success was estimated as the percentage of held refractometer (0-50%). capsules developed on twenty open (uncovered) stems from the same population. Floral longevity was initially determined on 2.5. Scent analysis five flowering stems that were picked and held in a vase indoors under natural light conditions. One mature bud from the base of Flowering stems were sniffed throughout the day and early the raceme on each of the five stems was tagged and monitored evening for any noticeable scent. Freshly picked flowers were each day until it withered. Flowers above the tagged buds sampled for floral scent in the early evening±1 h after scent continued to open successively for more than a week afterwards, emission began by placing five stems in water and enclosing suggesting that picking had no influence on flower development, the racemes in a glass container to concentrate the scent. The and this was confirmed by checking undisturbed inflorescences head space was sampled for 4 h onto glass capillary tubes in the pollinator exclusion experiment. packed with Poropack by drawing air through the tubes with a vacuum pump. Floral scent chemistry was analysed by gas chromatography using a DB-Wax Capillary column (Kaiser, 1993). 3. Results 3.1. Floral phenology Buds opened gradually over 2 days, with maximum perianth expansion achieved in the evening of day 3, and open flowers withered by day 10. Individual flowers were thus open for 7 nights. At anthesis on day 1 the style was short, with the stigma positioned below the anthers, but elongated slightly during the life of the flower so that by the time that the flower withered the stigma was positioned near the tips of the anthers. Flowers were entirely unscented during the day but became fragrant at sunset, ±18:30. They were again unscented by morning, 07:00. 3.2. Scent 3.2.1. Chemical analysis Analysis of floral scent identified the following constitu- ents, arranged in order of decreasing percentage composition: jasmine 57.0%, 2-methylbutyraldehyde oxime ((E)+(Z)) 20.2%, isobutyric acid 11.3%, 2-methylbutyric acid 2.4%, 2-methyl-1-nitrobutane 2.3%, 2-methyl-1-nitropropane 1.8%, Fig. 1. Dipcadi brevifolium flowers showing short tube and included anthers. butyric acid 1.3%, p-vinylphenol 0.5%, octan-3-one 0.4%, J.C. Manning et al. / South African Journal of Botany 81 (2012) 15–18 17 2-methylburyronitrile 0.1%, isobutyraldehyde oxime ((E)+(Z)) the anthers and stigmas. The probosces of the moths measured 0.6%, α-pinene 0.05%, (E)-4,8-dimethylnona-1,3,7-triene 0.05%, 12–15 mm in length, and every individual that we examined β-pinene 0.03%, 6-methylhept-5-en-2-one 0.03%, octanal 0.03%, carried few to many (b20–N200) adherent pollen grains 3-methylbutyraldehyde oxime ((E)+(Z)) 0.03%, oct-1-en-3-ol scattered along the entire length of the proboscis but usually 0.05%. concentrated in the distal half. Pollen grains were monosulcate and thus evidently monocotyledonous. Dipcadi brevifolium 3.3. Nectar was the only monocot species in flower at the locality and it is thus possible to infer that the grains were from that species. Individual flowers contain trace amounts of nectar, 0.25- 0.35 μl, visible as solitary droplets at the mouth of each of the 4. Discussion secretary pores at the base of the ovary septa. The nectar is moderately concentrated, 22–31% sucrose equivalents (Mean= We confirm that the floral syndrome of moth-pollination in 26%, n=5). Dipcadi brevifolium is indeed associated with pollination by noctuid or owlet moths as previously inferred. At our study site 3.4. Fruit set we only observed visits by Syngrapha circumflexa but it remains to be demonstrated that other moths do not visit the No fruits were set by the bagged plants. Initial swelling of species elsewhere across its range. Syngrapha circumflexa itself the ovaries occurs, suggesting that self-pollination has been is widely distributed through Africa, Europe and Asia, and in effected, but they soon abscise spontaneously, indicating that southern Africa has been documented as pollinating species of they are self-incompatible. Fruit set in open, unbagged plants is Babiana Ker Gawl. and Gladiolus L. (Iridaceae) (Goldblatt and moderate to high, with 20=83% of flowers developing capsules Manning, 2002, 2007), Satyrium Sw. (Orchidaceae) (Johnson, (Mean=45%, n=20). 1997) and Struthiola L. (Thymelaeaceae) (Makholela and Manning, 2006).