Papers by Peter Bernhardt
Goldblatt, Peter, Bernhardt, Peter, Manning, John C. (2005): Pollination mechanisms in the Africa... more Goldblatt, Peter, Bernhardt, Peter, Manning, John C. (2005): Pollination mechanisms in the African genus Moraea (Iridaceae, Iridoideae): floral divergence and adaptation for pollinators. Adansonia (3) 27 (1): 21-46, DOI: http://doi.org/10.5281/zenodo.5186479
International Journal of Insect Science, 2010
Experimental hand pollinations of the endangered, Hawaiian, endemic, Gossypium tomentosum Nutt. E... more Experimental hand pollinations of the endangered, Hawaiian, endemic, Gossypium tomentosum Nutt. Ex. (Malvaceae) showed that it was self-compatible, but self-pollination resulted in reduced reproductive output. Field observations and pollen tube analyses using fluorescence microscopy showed that mechanical self-pollination in this species included a mechanism known as bending stigmas. A receptive stigma bent backwards and contacted dehiscent anthers in 7% of flowers found on 17 G. tomentosum plants. The yellow flowers were nectarless and were not visited by most anthophilous insects in situ except for the introduced, nitidulid beetle, Aethina concolor Macleay. Collections and insect GI-tract dissections showed that A. concolor carried and ate the pollen of the host flower. Field observations recorded regular contact between beetles and stigma lobes as these insects exited the flowers effecting self-pollination. Behavioral experiments showed that the beetles responded positively to a ...
Based on a characteristic floral presentation and sightings of sunbirds on many flowers with simi... more Based on a characteristic floral presentation and sightings of sunbirds on many flowers with similar morphology, 64 species of Iridaceae in eight genera, Babiana, Chasmanthe, Crocosmia, Gladiolus, Tritoniopsis, Watsonia (sub family Ixioideae), Klattia, and Witsenia (Nivenioideae), are inferred to be pollinated by five sunbird species {Nectarinia: Nectarinidae) in southern Africa. In Ixioideae bird flowers are typified primarily by red to orange colors, gullet or flag forms with elongate flotal tubes mostly 30 to 60 mm in length, and exsetted unilateral stamens. In Nivenioideae flowers are tubular (Witsenia) with included stamens and green and yellow in color, or a head like inflorescence of small, actinomotphic flowers is tightly enclosed in large, leafy bracts that form a nectat reservoir. All bird pollinated species secrete fairly large quantities of nectar, but its volume, the concentration of dis solved sugars and the sucrose to hexose ratio vary both between and within geneta. Elsewhere in the family bird pollination is infered for several species of Gladiolus in tropical Africa and Arabia and in four species of Tigridia (Iridoideae) in Mexico-Centtal America. Sucrose-rich to sucrose-dominant nectar is charactetistic of flowers of subfamily Ixioideae but a few birdpollinated Ixioideae have hexose-dominant nectat, the only type of nectar in Nivenioideae. It is argued that bird pollination predominates Ixioid taxa because this is the largest subfamily and the ancesttal condition is a flower with a perianth tube and bilabiate, zygomorphic perianth which preadapts them for pollen dispersal by specialized passerines.
Plant Evolution in the Mediterranean. By John D Thompson. Oxford and New York: Oxford University Press. $169.50 (hardcover); $89.50 (paper). viii + 293 p + 4 pl; ill.; index. ISBN: 0‐19‐851533‐2 (hc); 0‐19‐851534‐0 (pb). 2005
The Quarterly Review of Biology, 2007
Telopea, 2013
Historically, only a few large flowered species in the genus Thelymitra were identified as obliga... more Historically, only a few large flowered species in the genus Thelymitra were identified as obligate out-breeders. We compared floral presentation, pollen-pistil interactions, pollination ecology, and interspecific hybridization in two populations of T. macrophylla where its flowering periods overlapped with T. antennifera (Tenterden) and T. crinita (Lesmurdie) respectively. Pollen-pistil interactions were studied using glasshouse collections of T. crinita and T. macrophylla at the Kings Park and Botanic Garden (Perth, WA). The number of flowers/inflorescence in T. macrophylla varied significantly between sites. Climatic conditions influenced flower opening and closing regimes differently in T. crinita vs. T. macrophylla. While all three Thelymitra spp. opened on warm, sunny mornings and closed by late afternoon, T. crinita at Lesmurdie was significantly more likely to open its perianth segments on cool days compared to the co-blooming, sympatric flowers of T. macrophylla. The floral...
Telopea, 2014
In Western Australia, Thelymitra crinita Lindl. and T. macrophylla Lindl. are pollinated by femal... more In Western Australia, Thelymitra crinita Lindl. and T. macrophylla Lindl. are pollinated by female, polylectic bees but offer no edible rewards. Flowers of Orthrosanthus laxus (Endl.) Benth. (Iridaceae) offer granular pollen and previous authorities suggest it is a Batesian model of T. crinita. We analyzed the floral fragrances and measured the floral dimensions of the orchid species, their putative hybrid, and O. laxus. Although the ‘scentless’ T. crinita emitted low levels of monoterpenoids and sesquiterpenoids, the pleasantly discernible fragrance of T. macrophylla was dominated by 2-phenylethanol. Their putative hybrid produced slightly lower levels of 2-phenylethanol compared with T. macrophylla and failed to produce any sesquiterpenoids associated with T. crinita. However, the hybrid produced higher volumes of the monoterpene linalool than either parent species. The fragrance of O. laxus contained 2-phenylethanol but lacked the sesquiterpenoids. We also measured perianth area ...
Plant Systematics and Evolution, 2004
Plant Systematics and Evolution, 2000
A literature review of 34 families of flowering plants containing at least one species pollinated... more A literature review of 34 families of flowering plants containing at least one species pollinated primarily by beetles is presented. While the majority of species are represented by magnoliids and basal monocotyledons specialized, beetle-pollinated systems have evolved independently in 14 families of eudicotyldons and six families of petaloid monocots. Four, overlapping modes of floral presentation in plants pollinated exclusively by beetles (Bilabiate, Brush, Chamber Blossom and Painted Bowl) are described. Chamber Blossoms and Painted Bowls are the two most common modes. Chamber Blossoms, found in magnoliids, primitive monocotyledons and in some families of woody eudicots, exploit the greatest diversity of beetle pollinators. Painted Bowls are restricted to petaloid monocots and a few families of eudicots dependent primarily on hairy species of Scarabaeidae as pollen vectors. In contrast, generalist flowers pollinated by a combination of beetles and other animals are recorded in 22 families. Generalist systems are more likely to secrete nectar and exploit four beetle families absent in specialist flowers. Centers of diversity for species with specialized, beetle-pollinated systems are distributed through the wet tropics (centers for Brush and Chamber Blossoms) to warm temperate-Mediterranean zones (centers for Painted Bowls and a few Bilabiate flowers). It is unlikely that beetles were the first pollinators of angiosperms but specialized, beetlepollinated flowers must have evolved by the midlate Cretaceous to join pre-existing guilds of beetle-pollinated gymnosperms. The floras of Australia and western North America suggest that mutualistic interactions between beetles and flowers has been a continuous and labile trend in angiosperms with novel interactions evolving through the Tertiary.
Plant Systematics and Evolution, 1985
The evolution of the androecium in the Orchidaceae shows three major trends. There is a progressi... more The evolution of the androecium in the Orchidaceae shows three major trends. There is a progressive trend in the degree of fusion of the filament(s) and staminode(s) to the gynoecium. Secondly, there is a reduction in the number of fertile anthers. Finally, there is a progressive change in the position of the base of the anther relative to the apex of the stigma; in the more primitive orchids the apex of the stigma is always higher than the base of the anther (this position is reversed in the higher orchids). All three trends reflect variation in the evolution of pollen dispersal and pollen reception mechanisms in the Orchidaceae. Trends in the evolution of the orchid anther(s) tend to parallel trends in the evolution of their pollinaria.
Plant Biology, 2009
Paphiopedilum barbigerum T. Tang et F. T. Wang, a slipper orchid native to southwest China and no... more Paphiopedilum barbigerum T. Tang et F. T. Wang, a slipper orchid native to southwest China and northern Vietnam, produces deceptive flowers that are self‐compatible but incapable of mechanical self‐pollination (autogamy). The flowers are visited by females of Allograpta javana and Episyrphus balteatus (Syrphidae) that disperse the orchid’s massulate pollen onto the receptive stigmas. Measurements of insect bodies and floral architecture show that the physical dimensions of these two fly species correlate with the relative positions of the receptive stigma and dehiscent anthers of P. barbigerum. These hoverflies land on the slippery centralised wart located on the shiny yellow staminode and then fall backwards through the labellum entrance. They are temporarily trapped in the inflated chamber composed of the interconnected labellum and column. The attractive staminode of P. barbigerum strongly reflects the colour yellow (500–560 nm), a colour preferred innately by most pollen‐eating ...
Conservation Biology, 2008
Gordon Allen‐Wardell, BeeMaster, Inc., 1665, E. 18th St., #209, Tucson, AZ 85719, U.S.A.
Peter B... more Gordon Allen‐Wardell, BeeMaster, Inc., 1665, E. 18th St., #209, Tucson, AZ 85719, U.S.A.
Peter Bernhardt, Department of Biology, St. Louis University, 3507, LaClede, St. Louis, MO 63101‐2010, U.S.A.
Ron Bitner, International Pollination Systems, 16645, Plum Rd., Caldwell, ID 83605, U.S.A.
Alberto Burquez, Instituto de Ecologia, Unam, Apartado Postal Hermosilo, Sonora 83000, Mexico
Stephen Buchmann, USDA/ARS, 2000, E. Allen Rd., Tucson, AZ 85719, U.S.A.
James Cane, USDA/ARS Bee Biology and Systematics Lab, Utah State University, Logan, UT 84322‐5310, U.S.A.
Paul Allen Cox, National Tropical Botanical Garden, P.O. Box Lawai, Kauai, HI 96765, U.S.A.
Virginia Dalton, Science Department, Pima College West, Desert Vista, 5901, South Calle Santa Cruz, Tucson, AZ 85709‐6000, U.S.A.
Peter Feinsinger, Department of Biology, Northern University University, 5315, N. Copeland, Flagstaff, AZ 86004, U.S.A.
Mrill Ingram, Arizona‐Sonora Desert Museum, 2101, North Kinney Road, Tucson, AZ 8574...
Annals of the Missouri …, 2004
Field observations, floral dissections of a representative range of Hesperantha species, and poll... more Field observations, floral dissections of a representative range of Hesperantha species, and pollen load analyses of insects captured on many of them indicate that flowers of this African genus are cross pollinated by a relatively broad range of insects. The pollination ecology of Hesperantha can be divided into four overlapping systems that exploit insects of four orders (Coleoptera, Diptera, Hymenoptera, and Lepidoptera). Species of the H. falcata type have erect or nodding, salver-shaped, strongly fragrant, white flowers that open in the mid to late afternoon and evening and are pollinated by long-tongued apid bees and/or noctuid moths. Species of the H. pauciflora type have a virtually identical floral morphology, but the perianth is yellow or pink to mauve or blue and the flowers are usually unscented and are open during the day, closing between midday and late afternoon, ca. 16:30 H. Flowers of this type are also pollinated by apid bees, but in the southern African winter-rainfall zone other effective pollinators include nemestrinid flies (Prosoeca) with relatively short probosces and hopliine scarab beetles. In H. latifolia type flowers the perianth is pink to magenta or red (rarely pale yellow), odorless, opens during the day but has an elongate perianth tube exceeding 18 mm in length. These flowers are pollinated mainly by long-proboscid flies in the genera Prosoeca and Stenobasipteron (Nemestrinidae) or Philoliche (Tabanidae), but the red flowers of H. coccinea are pollinated by a guild of large butterflies including Papilio and the satyrid Aeropetes. Lastly, H. vaginata has odorless and nectarless, short-tubed yellow flowers, usually with contrasting dark markings, that open only during the day and are pollinated exclusively by the hopliine scarab beetle, Clania glenlyonensis. The taxonomic distribution of plant species with these pollination systems makes it clear that shifts in pollination systems have occurred repeatedly across Hesperantha, although floral morphology and nectar biochemistry are relatively conservative. Whether flowers are nocturnal, crepuscular, or diurnal, only four variables affect the floral ecology: length of the perianth tube, presence or absence of floral fragrance, timing of anthesis, and the closely associated trait of perianth color. Thus, species with pink, magenta, red, or yellow flowers close at night and are rarely fragrant, whereas those with white or pale yellow flowers are nearly always fragrant and either open late in the day or only at sunset and remain open for most of the night. Species show considerable variation in nectar volume and sugar concentration, closely correlated with pollination system, while two long-tubed species with floral characters typical of long-proboscid fly pollination produce no nectar and are inferred to be Batesian or guild mimics that achieve pollination by deception.
Annals of the Missouri Botanical Garden, 1987
Twenty-seven bee taxa and 24 wasp laxa were collected on the open inflorescences and/or extraflor... more Twenty-seven bee taxa and 24 wasp laxa were collected on the open inflorescences and/or extrafloral nectaries of eight Acacia species in Victoria, Australia. Despite this superficial similarity in taxonomic diversity, bees outnumbered wasp foragers by 88% of the combined catch of winged Hymcnoptera. Representatives from five families of bees were recorded, with the short-tongued Halictidae and Collelidae comprising the largest unit of native Apoidea on the Acacia species studied. Pollen foraging female bees of the genera Lasioglossum (Halictidae) and Leioproctus (Colletidae) comprised 83% of the combined catch of the two short-tongued families. The number of bee taxa collected on the Acacia species tended to increase from late winter through late autumn. Polylectic foraging bee taxa expanded from mid spring through late summer when the flowering of nectariferous Myrtaceae peaked. There was no correlation between the density and diversity of bees foraging on Acacia species bearing secreting extra-floral nectaries and those species that lacked extra-floral nectar while the inflorescences were blossoming. Representatives of seven families of wasps were collected on the eight Acacia species. No wasps, however, were collected on var. retinodes o{ A. retinodes. Approximately 66% of the wasps collected belonged to the families Sphecidae and Tiphiidae. Wasps repeatedly foraged on extra-floral nectar before foraging on nectarless inflorescences. The density and taxonomic diversity of wasps remained highest on the Acacia species that offered the greatest volume of sucrose-rich, extrafloral nectar (i.e., ^. terminalis). Bees are probably more important pollinators q{ Acacia in southeastern Australia than are wasps. The direct influence of wasps on polyad dispersal appears to be nominal except in those Acacia species bearing functional extra-floral nectaries. Winged Hymcnoptera (bees and wasps) have Knox & Kenrick, 1982). Consebeen observed to forage frequently on inflores-quently, bees, wasps, and certain flies easily colcences of Australian Acacia. In contrast to the lect polyads from the synchronously opening flo-Psyllidae and some Coleoptcra, bees and non-rets in an inflorescence. parasitic wasps are not destructive to the small Female bees are known to collect Acacia polyflowers that comprise an Acacia head or spike ads to feed to their larvae. Foraging bees remove
Annals of the Missouri Botanical Garden, 1998
American Journal of Botany, 2000
Floral development was compared with scanning electron microscopy in 12 Australian species of Hib... more Floral development was compared with scanning electron microscopy in 12 Australian species of Hibbertia representing most of its morphological variation, and in the related Adrastaea (Dilleniaceae). Calyx and corolla arise in quincuncial helices in radially symmetrical species, while the petals initiate unidirectionally from one side in zygomorphic species. Stamen number (3-200ϩ) proliferates by centrifugal addition of individual primordia or by innovations of common primordia and ring meristems. Common primordia arise in single-stamen positions alternately with petals, and each produces one to several stamens centrifugally that remain attached to a shared base and form a stamen fascicle. A ring meristem in Adrastaea initiates a whorl of five stamens, alternate with the first stamens but outside their whorl. In radially symmetrical species of Hibbertia, a first ring of stamens is supplemented centrifugally by additional stamens on a meristem ring. The first stamens in zygomorphic species of Hibbertia initiate as a terminal ridge on the floral apex, with subsequent stamens added centrifugally on one side and two carpels initiated on the opposite side. The carpels arise as a simultaneous ring in radially symmetrical flowers, or as a simultaneous pair in zygomorphic species. Staminodial presence is viewed as of minor significance. Four pollinator syndromes are proposed for Hibbertia, related to differing floral architecture.
Journal of Pollination Ecology, 2014
The conversion rate of flowering into fruiting stems in C. montanum at two sites over four season... more The conversion rate of flowering into fruiting stems in C. montanum at two sites over four seasons was 52-85%. This is high for insect-pollinated, food mimics in this genus and greater than fruit sets recorded in populations of four species native to China and two species native to North America. Comparative measurements of the trap-like labellum of C. montanum showed it was intermediate in size compared to measurements of six other Cypripedium spp. found in North America and China. While visitors to flowers of C. montanum represented three insect orders, at two sites, over four seasons only small- to medium-sized, solitary bees (5-10 mm in length) carried the pollen massulae. Bee-visitation occurred at both sites and began within 24-48 hours following labellum expansion. Female bees in the genus Lasioglossum (Halictidae) were the most common carriers of massulae. However, species of visiting bees differed between sites and years. At both sites the majority of bees entered and esca...
Comparative pollination ecology, fruit and seed set in Corunastylis species (Orchidaceae)
Plant Systematics and Evolution
Pollination Biology of Nivenia (Iridaceae) and the Presence of Heterostylous Self-Compatibility
Israel journal of botany, 1990
Nivenia, a shrubby genus of the Cape Province, South Africa, comprises five distylous species (N.... more Nivenia, a shrubby genus of the Cape Province, South Africa, comprises five distylous species (N. binata, N. capitata, N. corymbosa, N. dispar, N. stenosiphon) and four monomorphic species. Hand pollinations of natural populations of seven Nivenia species have confirmed previous reports of self-compatibility. Pollen deposited on the stigma of all species germinates and pollen tubes penetrate the ovary within 8–20 h whether the pollen comes from the same flower or inflorescence, or from different morphs. The nature of self-compatibility appears to be similar in the two monomorphic species studied (N. levynsiae, N. stokoei) and in the five distylous species. However, in N. capitata a few abortive pollen tubes (±5%) were found in the styles of two long-styled morphs that had been selfed and in one short-styled flower pollinated with pollen from a long-styled plant. Four out of five distylous species have pollen size but not exine dimorphism. The flowers of Nivenia species are unscented...
Journal of Pollination Ecology, 2013
Brown’s peony, Paeonia brownii (Paeoniaceae), is one of only two peony species native to the West... more Brown’s peony, Paeonia brownii (Paeoniaceae), is one of only two peony species native to the Western Hemisphere, yet its pollination ecology and breeding system have never been documented. Using flowering individuals of an endemic colony in the Blue Mountains of Oregon, U.S., we investigated the peony’s pollination system and floral function. We also examined pollen/carpel interactions through experimental pollinations aided by fluorescence microscopy. Paeonia brownii appears to be self compatible and mostly protogynous with floral traits of a generalist pollination system. The flowers appear to attract insects by producing abundant floral nectar secreted from lobes of a perigynous disc throughout their 9-15-days of anthesis. The most common pollen vectors were wasp queens (Vespidae), the large flower fly Criorhina caudata (Syrphidae), and females of Lasioglossum spp. (Halictidae), all of which foraged exclusively for nectar. Whether collected from foraging wasps and flies, anthers,...
Ecology and evolution, 2018
Isolation between species, or taxa sharing a common lineage, depends primarily on the relative st... more Isolation between species, or taxa sharing a common lineage, depends primarily on the relative strengths of various reproductive barriers. Previous studies on reproductive isolation between orchids emphasized mechanical and ethological barriers in flowers of species showing food and/or sexual mimicry. In this study, we investigated and quantified a series of prepollination and postpollination barriers between pink and white forms of sl, a nectar-secreting complex. We generated ML trees based on S-G and K to explore phylogenetic relationships in this species complex. sl segregated from some other congeners, but the white form constituted a distinct clade in relation to the pink form. The white form secreted 2-Phenylethanol as it is a single-scent compound and was pollinated almost exclusively by native, large-bodied and species (Apidae). showed a high floral constancy to this form. The scentless, pink form was pollinated primarily by smaller bees in the genera (Apidae), and members o...
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Papers by Peter Bernhardt