Browsing by Subject "Pollination"

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    Comparative morphology of the mouthparts of the megadiverse South African monkey beetles (Scarabaeidae: Hopliini): feeding adaptations and guild structure
    (2016) Karolyi, Florian; Hansal, Teresa; Krenn, Harald W; Colville, Jonathan F
    Although anthophilous Coleoptera are regarded to be unspecialised flower-visiting insects, monkey beetles (Scarabaeidae: Hopliini) represent one of the most important groups of pollinating insects in South Africa’s floristic hotspot of the Greater Cape Region. South African monkey beetles are known to feed on floral tissue; however, some species seem to specialise on pollen and/or nectar. The present study examined the mouthpart morphology and gut content of various hopliine species to draw conclusions on their feeding preferences. According to the specialisations of their mouthparts, the investigated species were classified into different feeding groups. Adaptations to pollen-feeding included a well-developed, toothed molar and a lobe-like, setose lacinia mobilis on the mandible as well as curled hairs or sclerotized teeth on the galea of the maxillae. Furthermore, elongated mouthparts were interpreted as adaptations for nectar feeding. Floral- and folial-tissue feeding species showed sclerotized teeth on the maxilla, but the lacinia was mostly found to be reduced to a sclerotized ledge. While species could clearly be identified as floral or folial tissue feeding, several species showed intermediate traits suggesting both pollen and nectar feeding adaptations. Mismatches found between mouthpart morphology and previously reported flower visiting behaviours across different genera and species requires alternative explanations, not necessarily associated with feeding preferences. Although detailed examinations of the mouthparts allowed conclusions about the feeding preference and flower-visiting behaviour, additional morphological and behavioural investigations, combined with greater taxon sampling and phylogenetic data, are still necessary to fully understand hopliine host plant relationships, related to monkey beetle diversity.
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    Open Access
    Scent chemistry and patterns of thermogenesis in male and female cones of the African cycad Encephalartos natalensis (Zamiaceae)
    (2010) Suinyuy, Terence; Donaldson, John; Johnson, S D
    Most, if not all, extant cycads are pollinated by insects which use the cones as larval brood sites. These interactions appear to be mediated by cone volatiles, and, in some species, by patterns of thermogenesis. We investigated the chemical composition of volatile emissions and patterns of thermogenesis in cones of the South African cycad Encephalartos natalensis, using a gas chromatograph–mass spectrometer (GC–MS) and miniature temperature data loggers (ibuttons), respectively. This was done during various developmental stages (before and during receptivity and pollen release) for both female and male cones. A total of 31 compounds were identified in headspace samples; 17 of which were common to both sexes, 12 found only in male cones, and two found only in female cones. The major volatiles in pollen and female cones are (3E)-1,3-octadiene (averaging 54.25% and 15.82% of total emissions), (3E,5Z)-1,3,5-octatriene (averaging 13.37% and 47.66%), and α-pinene (averaging 16.29% and 12.24%). Female cones were not thermogenic before and during receptivity whereas pollen cones were thermogenic during pollen shedding. Thermogenesis of male cones occurred between 1400 h and 1530 h on successive afternoons, reaching an average of c. 10.5 °C above ambient temperature. Volatile emissions and thermogenesis occurred in association with insect activity on the cones suggesting that they both play a role in regulating insect behaviour.