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" Flower-Visiting, Florivory and Pollination by Orthoptera in Southeast Asia "
Tan, Ming Kai
Tan, Hugh T. W.
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Latin Dissertation
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English
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| Record Number
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1106548
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TLpq2402508324
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| Main Entry
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Tan, Hugh T. W.
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Tan, Ming Kai
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| Title & Author
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Flower-Visiting, Florivory and Pollination by Orthoptera in Southeast Asia\ Tan, Ming KaiTan, Hugh T. W.
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| College
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National University of Singapore (Singapore)
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| Date
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2019
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| student score
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2019
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| Degree
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Ph.D.
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| Page No
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208
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| Abstract
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Studies of flower-visitation, florivory and to some extent pollination, are still neglected in the tropics, especially in the biodiverse Southeast Asia. Insect groups, which are not often associated with flower-visitation and pollination, have also been overlooked and these include the Orthoptera. I addressed these deficiencies by investigating flower-visiting, florivory and pollination by orthopterans from Southeast Asia and demonstrated that (1) knowledge of the natural history of flower-visiting orthopterans can provide insights on pollination and florivory; (2) the flower-visiting orthopterans respond to floral resources and exhibit personality types; (3) flower-visiting orthopterans (i) respond to and (ii) drive variations in floral traits. More than 41 flower-visiting orthopteran species were discovered, a considerably higher number than what was previously known. This was based on natural history observations made in five Southeast Asian countries: Brunei Darussalam, Indonesia, Malaysia, Thailand and Singapore. Field observations in Singapore showed that a floriphilic katydid, Phaneroptera brevis, is a relatively frequent flower-visitor of the forest edge and only second to bees and flower-visiting crab spiders. This katydid also visits flowers of at least 13 species, the highest among flower-visiting orthopterans that have been examined. Behavioural experiments also showed that P. brevis helps in pollination by gently removing pollen grains with its mandibles without extensively damaging the flowers and thus represents only the second case of an orthopteran aiding in pollination. Based on this information, P. brevis was used as a model organism to address other research questions. In line with the predictions of the neural constraint hypothesis, which is central to the understanding of insect-plant interactions, laboratory-based experiments demonstrated that (i) more choices in food resources and (ii) a higher density of flowers lead to this katydid becoming more inefficient in foraging. Animal personality is important to understand the influence of individuality on ecological and evolutionary processes but remains underexplored among florivores. A behavioural assay also demonstrated, for the first time, that this katydid exhibits individual- and population-level personality types. Shy individuals are more efficient in foraging on flowers and larger individuals are more exploratory than smaller individuals. Individuals from different populations exhibit different levels of boldness. Lastly, this katydid also shows consistent inter-individual differences in foraging performance, but foraging performance also improves over time. This suggests that the katydid is capable of at least some form of habituation or learning. These behavioural studies in turn provided me with the basis to study the ecology of florivory and floral traits. P. brevis was found to prefer ray florets of different food-plant Asteraceae species with a suite of traits representing higher palatability of the florets. The study was carried out by modifying leaf traits that correlate with herbivory into the study of florivory (e.g., specific floret area derived from specific leaf area). Nursery experiments indicated that florivory by P. brevis can induce short-term changes in leaf blade punch resistance. These findings have contributed to the ecology and behaviour of orthopterans but broad-based studies of underappreciated flower-visitors (including orthopterans) in highly threatened biodiversity hotspots are still necessary. Investigation into the genetic basis of behaviour will reveal also mechanistic insights of flower-visiting orthopteran behaviour.
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Entomology
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