TY - JOUR T1 - Distance and quality of natural habitat influence hawkmoth pollination of cultivated papaya JF - International Journal of Tropical Insect Science Y1 - 2009 DO - 10.1017/S1742758409990208 A1 - Martins, D.J. A1 - Johnson, S.D. SP - 114 EP - 123 KW - AGRICULTURE KW - AGRIUS KW - CARICA KW - CONSERVATION KW - HIPPOTION KW - KENYA KW - NEPHELE KW - POLLINATION KW - SPHINGIDAE AB -
"Crop pollination by wild pollinators is an ecosystem service of immense value to modern agriculture. Pollination by wild insects is under-researched in the tropics, where many crops may require or benefit from wild pollinators. Papaya is a dioecious tree crop widely cultivated throughout the tropics. In East Africa, papaya is an important component of rural smallholder farming systems. Traditional agricultural systems are currently under stress due to landscape degradation. These trends are of special concern with respect to pollination services provided by wild insects. Investigation of the role of hawkmoths as pollinators of papaya on subsistence farms in Kenya was conducted over a period of 3 years. Hawkmoths were the most abundant and reliable visitors to both ‘female’ pistillate and ‘male’ staminate papaya flowers. Hawkmoths accounted for .95% of legitimate visits and xenogamous pollination of papaya flowers. Hippotion celerio, Nephele comma and Agrius convolvuli were the main pollinators. Sites in two districts with similar climates and natural vegetation, but different levels of habitat degradation were chosen for comparison of pollinators and pollination services. Hawkmoth abundance and visitation rates declined sharply with increasing distance of natural habitat patches from the crop. Fruit set was also reduced at sites with high levels of disturbance/poor agricultural practices. Natural habitat containing larval food plants and other nectar resources for hawkmoths therefore supports adjacent cultivated papaya with pollination services. Understanding the links between wild biodiversity, in this case pollinating hawkmoths, and agricultural productivity can help bridge the gap between agricultural development and biodiversity conservation."
VL - 29 IS - 3 ER - TY - JOUR T1 - Hawkmoth pollination of aerangoid orchids in Kenya, with special reference to nectar sugar concentration gradients in the floral spurs JF - American Journal of Botany Y1 - 2007 A1 - Martins, D.J. A1 - Johnson, S.D. SP - 650 EP - 659 KW - AERANGIS KW - AGRIUS KW - COELONIA KW - DAPHNIS KW - FLORAL MORPHOLOGY KW - FLORAL SCENT KW - HIPPOTION KW - KENYA KW - NECTAR COMPOSITION KW - ORCHIDACEAE KW - POLLINATION KW - POLLINATOR SPECIFICITY KW - RANGAERIS KW - SPHINGIDAE AB -"The African orchid flora has a high proportion of species with long-spurred white flowers. Few data exist to test the prediction that this floral syndrome pattern reflects an important role for hawkmoth pollination in the evolution and ecology of these orchids. The pollination biology of five aerangoid orchid species (Rangaeris amaniensis, Aerangis brachycarpa, A. confusa, A. thomsonii, and A. kotschyana) was investigated in Kenya. Four of these have long spurs (.10 cm) and were pollinated by Agrius convolvuli and Coelonia fulvinotata. Aerangis confusa, which has relatively short spurs (ca. 4 cm), was pollinated by the short-tongued hawkmoths Hippotion celerio and Daphnis nerii. Nectar frequently filled the entire spur in some of the study species, even at anthesis. Sugar concentration of the nectar of four species was found to vary from ca. 1% at the mouth of the spur to 20% at the tip. Gradients were expressed more strongly in species with long, straight spurs. Species with spirally twisted spurs showed both steep and shallow nectar gradients. These gradients, previously unknown in plants, may function as a ‘‘sugar trail,’’ enticing long-tongued hawkmoths to probe deeply into spurs without incurring the cost of filling an entire spur with concentrated nectar. In addition, the most concentrated nectar is kept out of reach of short-tongued pollinators."
VL - 94 IS - 4 ER - TY - JOUR T1 - Pollination of the long-spurred African terrestrial orchid Bonatea steudneri by long-tongued hawkmoths, notably Xanthopan morganii JF - Plant Systematics and Evolution Y1 - 2019 DO - 10.1007/s00606-019-01605-2 A1 - Balducci, M.G. A1 - Martins, D.J. A1 - Johnson, S.D. SP - 765 EP - 775 KW - AGRIUS KW - ANGRAECUM KW - BONATEA KW - COELONIA KW - COEVOLUTION KW - FLORAL SCENT KW - KENYA KW - ORCHIDACEAE KW - POLLINATION KW - POLLINATOR SPECIFICITY KW - SPHINGIDAE KW - XANTHOPAN AB -"Charles Darwin correctly predicted the existence of an extraordinarily long-tongued hawkmoth in Madagascar, based on the length of the floral spur of an Angraecum orchid. This hawkmoth, Xanthopan morganii, is also the longest-tongued hawkmoth on the African mainland, but its ecological role as a pollinator has been virtually unknown outside of Madagascar. We investigated whether X. morganii pollinates Bonatea steudneri, an orchid with floral spurs that vary from 10 to 21 cm in length among populations. At a forest locality in central Kenya, we observed X. morganii individuals with tongues ca. 16 cm in length pollinating B. steudneri plants with spurs ca. 15 cm in length. At other localities in Kenya, we observed visits by the hawkmoths Agrius convolvuli (tongue c. 12 cm) and Coelonia fulvinotata (tongue ca. 10 cm). Pollinaria of B. steudneri are attached to the eyes of hawkmoth visitors. Flowers of B. steudneri show several adaptations for hawkmoth pollination, including anthesis at dusk and nocturnal emission of scent dominated by the volatile compound linalool. This study highlights the potential for predicting certain highly specialized interactions among species by matching of their respective morphological dimensions."
VL - 305 UR - https://doi.org/10.1007/s00606-019-01605-2 ER - TY - JOUR T1 - From dusk till dawn: camera traps reveal the diel patterns of flower feeding by hawkmoths JF - Ecological Entomology Y1 - 2019 DO - 10.1111/een.12827 A1 - Johnson, S.D. A1 - Balducci, M.G. A1 - Bijl, A. A1 - Castañeda-Zárate, M. A1 - Cozien, R.J. A1 - Ortmann, C.R. A1 - van der Niet, T. SP - [1 EP - 5] KW - AGRIUS KW - BASIOTHIA KW - CAMERA TRAPS KW - DIEL ACTIVITY KW - HABENARIA KW - HIPPOTION KW - NOCTUIDAE KW - ORCHIDACEAE KW - POLLINATION KW - PROBOSCIS KW - SOUTH AFRICA KW - SPHINGIDAE AB -"1. Diel rhythms of foraging activity by animal flower visitors can reflect niche partitioning and are considered an important component of selection on floral traits. However, it has been notoriously difficult to obtain objective information on the patterns of flower visitation by crepuscular and nocturnal insects.
2. Motion-activated cameras were used for field-based studies of hawkmoth foraging behaviour on six African plant species.
3. The results showed that short-tongued hawkmoth species forage mainly around dusk and then sporadically throughout the night, whereas long-tongued hawkmoth species feed consistently throughout the night, with a peak shortly before midnight.
4. These results provide the first quantitative estimates of diel patterns of interactions between multiple hawkmoth and plant species and, when combined with qualitative reports from other studies, suggest that differences in diel activity between the two main hawkmoth functional groups (short- and long-tongued) are consistent across the Old and New Worlds."
"1. Proboscis length has been proposed as a key dimension of plant pollination niches, but this niche space has not previously been explored at regional and global scales for any pollination system. Hawkmoths are ideal organisms for exploring pollinator niches as they are important pollinators in most of the biodiverse regions of the earth and vary greatly in proboscis length, with some species having the longest proboscides of all insects.
2. Using data sets for nine biogeographical regions spanning the Old and New World, we ask whether it is possible to identify distinct hawkmoth pollination niches based on the frequency distribution of proboscis length, and whether these niches are reflected in the depths of flowers that are pollinated by hawkmoths. We also investigate the levels of specialization in hawkmoth pollination systems at the regional and community level using data from interaction network studies.
3. We found that most regional hawkmoth assemblages have bimodal or multimodal distributions of proboscis length and that these are matched by similar distributions of floral tube lengths. Hawkmoths, particularly those with longer proboscides, are polyphagous and at the network level show foraging specialization equivalent to or less than that of bees and hummingbirds. In the case of plants, shorter-tubed flowers are usually visited by numerous hawkmoth
species, while those that are longer-tubed tend to exclude shorter-proboscid hawkmoths and thus become ecologically specialized on longer-proboscid hawkmoth species. Longer-tubed flowers tend to have greater nectar rewards, and this promotes short-term constancy by longproboscid hawkmoths.
4. Our results show that pollinator proboscis length is a key niche axis for plants and can account for the patterns of evolution in functional traits such as floral tube length and nectar volume. We also highlight a paradoxical trend for nectar resource niche breadth to increase according to proboscis length of pollinators, while pollinator niche breadth decreases according to the tube length of flowers."
"Background and Aims Unrelated organisms that share similar niches often exhibit patterns of convergent evolution
in functional traits. Based on bimodal distributions of hawkmoth tongue lengths and tubular white flowers in
Africa, this study hypothesized that long-tongued hawkmoths comprise a pollination niche (ecological opportunity)
that is distinct from that of shorter-tongued hawkmoths.
Methods Field observations, light trapping, camera surveillance and pollen load analysis were used to identify
pollinators of plant species with very long-tubed (>8 cm) flowers. The nectar properties and spectral reflectance of
these flowers were also measured. The frequency distributions of proboscis length for all captured hawkmoths and
floral tube length for a representative sample of night-blooming plant species were determined. The geographical
distributions of both native and introduced plant species with very long floral tubes were mapped.
Key Results The convolvulus hawkmoth Agrius convolvuli is identified as the most important pollinator of
African plants with very long-tubed flowers. Plants pollinated by this hawkmoth species tend to have a very long
(approx. 10 cm) and narrow flower tube or spur, white flowers and large volumes of dilute nectar. It is estimated
that >70 grassland and savanna plant species in Africa belong to the Agrius pollination guild. In South Africa, at
least 23 native species have very long floral tubes, and pollination by A. convolvuli or, rarely, by the closely related
hawkmoth Coelonia fulvinotata, has been confirmed for 11 of these species. The guild is strikingly absent from the
species-rich Cape floral region and now includes at least four non-native invasive species with long-tubed flowers
that are pre-adapted for pollination by A. convolvuli.
Conclusions This study highlights the value of a niche perspective on pollination, which provides a framework
for making predictions about the ecological importance of keystone pollinators, and for understanding patterns of
convergent evolution and the role of floral traits in plant colonization."
"In this year celebrating the bicentenary of the birth of Darwin and the sesquicentennial of the publication of Darwin's On the Origin of Species, the present paper aims to assess the impact of Darwin's legacy on the history of orchid pollination biology. To illustrate the major contribution of Darwin to this fascinating biological field, we focus on the large angraecoid orchid group and propose an overview of the complex relationships that these orchids have developed with specific pollinators. We further discuss how Darwin's seminal work on the angraecoid orchid Angraecum sesquipedale triggered the beginning of a long debate about the evolution of long floral spurs and why his idea of reciprocal evolution or ‘coevolution’ was one of the great contributions to evolutionary biology."
VL - 161 UR - https://academic.oup.com/botlinnean/article/161/1/1/2418453 ER - TY - JOUR T1 - Interactions between hawkmoths and flowering plants in East Africa: polyphagy and evolutionary specialization in an ecological context JF - Biological Journal of the Linnean Society of London Y1 - 2013 A1 - Martins, D.J. A1 - Johnson, S.D. SP - 199 EP - 213 KW - COEVOLUTION KW - KENYA KW - NECTAR COMPOSITION KW - PHENOLOGY KW - POLLINATION KW - POLLINATOR SPECIFICITY KW - SPHINGIDAE VL - 110 UR - https://academic.oup.com/biolinnean/article/110/1/199/2415668 IS - 1 ER - TY - JOUR T1 - Specialization for hawkmoth and long-proboscid fly pollination in Zaluzianskya section Nycterinia (Scrophulariaceae) JF - Botanical Journal of the Linnean Society of London Y1 - 2002 A1 - Johnson, S.D. A1 - Edwards, T.J. A1 - Carbutt, C. A1 - Potgieter, C. SP - 17 EP - 27 KW - NEMESTRINIDAE KW - POLLINATION KW - SCROPHULARIACEAE KW - SPHINGIDAE KW - ZALUZIANSKYA AB -"The evolution of pollination systems has been investigated in Zaluzianskya section Nycterinia (Scrophulariaceae), a group characterized by very long-tubed flowers (up to 60 mm) that open either only at night (19 species) or during the day (one species). Field observations of three species: Z. natalensis, Z. elongata and Z. pulvinata, revealed that their flowers are pollinated shortly after dusk by hawkmoths. Further observations showed that Z. microsiphon, the sole species to have flowers that open only during the day, is pollinated exclusively by long-proboscid flies belonging to the family Nemestrinidae. A phylogenetic analysis of Z. sect. Nycterinia based on morphological characters indicates that Z. microsiphon evolved within a clade of night-flowering species. The shift from hawkmoth to long-proboscid fly pollination in Zaluzianskya was probably facilitated because long corolla tubes, white petals and dilute nectar in hawkmoth-pollinated flowers are pre-adaptations for pollination by long-proboscid flies. However, the autapomorphic features of Z. microsiphon, such as zygomorphy, diurnal flower anthesis and lack of scent, can be regarded as adaptations for long-proboscid fly pollination. Breeding system experiments on Z. natalensis and Z. microsiphon revealed the existence of genetic self-incompatibility."
VL - 138 UR - https://doi.org/10.1046/j.1095-8339.2002.00005.x IS - 1 ER -