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Glochidion (Phyllanthaceae; leafflower trees) is a genus of trees which is widely reported to be pollinated by leafflower moths (Gracillariidae: Epicephala) in temperate and subtropical Asia, Australia, and the Pacific islands. However, the pollination ecology of Glochidion is not well described from tropical Asia, the region where it is most species-rich at both local (≤9 spp.) and regional (~200 spp.) scales. Here we report investigations of pollination biology and species-specificity of five Glochidion species in tropical Southeast Asia (Cambodia). Through nocturnal observations and fruit dissections, we find that at least three and likely five Glochidion species in Cambodia are pollinated by seed-parasitic leafflower moths. We find no evidence that any of these leafflower moths are non-mutualistic parasites, despite known examples of such parasites of this mutualism elsewhere in Asia. While the presence of a single larva in a fruit results in only a fraction of seeds being consumed, the presence of more than one larva per fruit—a frequent occurrence in some species—can result in almost all seeds within the fruit being infested. Multilocus phylogenetic analysis indicates that there are five different minimally monophyletic leafflower moth clades, each of which pollinates a unique Glochidion host species. Our results indicate that in its center of diversity in tropical Asia this system is an obligate pollination mutualism as previously described at the global margins of its distribution. These findings provide insights into the processes that generate and maintain biodiversity and maintain mutualism stability in plant–insect interactions in this biodiversity hotspot.

A comprehensive taxonomic revision of the genus Glochidion J.R. Forst. & G. Forst. from Taiwan in China was carried out based on the examination of herbarium specimens and filed investigations. Eight species and three varieties are recognized, including a new species endemic to Taiwan, G. lanyuense Gang Yao & S.X. Luo, which is described and illustrated. Three names, viz. G. chademenosocarpum Hayata, G. kusukusense Hayata, and G. ovalifolium F.Y. Lu & Y.S. Hsu, are reduced to the new synonyms of G. rubrum Blume, G. lanceolatum Hayata, and G. ellipticum Wight, respectively. Two names, viz. G. lanceolatum Hayata and G. suishaense Hayata, are lectotypified here. A key to the Glochidion species in Taiwan is provided.

Based on morphological studies performed on live plants in the field and specimens deposited in herbaria, a new species, Glochidionshanense Gang Yao & Shixiao Luo (Phyllantheae, Phyllanthaceae), is here described and illustrated. The species is morphologically most similar to G.ellipticum Wight, but can be distinguished from the latter by having hairy branchlets, longer pedicels, uniseriate and narrowly triangular sepals of female flowers, 4–5-locular ovaries, stout and cylindric persistent style on fruits.

The globally distributed family Phyllanthaceae comprises 1745 species, all of which produce unisexual flowers, and most of the species occur in the tropics. The few species in which the pollination system has been studied are pollinated by flies, wasps, or specialized moths, and at least two species are duodichogamous. Here we report on the flowering phenology and pollination of the Chinese species Bridelia stipularis and Cleistanthus sumatranus, which were studied on the tropical Hainan Island. Both species are duodichogamous and indicated to be fly-pollinated. The calliphorid species Chrysomya megacephala, Isomyia isomyia, Pierretia sp., Hemipyrellia sp., and Achoetandrus tufifacies were the most frequent flower visitors to B. stipularis; some of these species together with syrphids (Meliscaeva cinctella, Dideopsis sp., and Eristalis sp.) were the most abundant visitors to Cl. sumatranus flowers. Fruit set in hand-pollinated flowers was higher than in open-pollinated flowers, but because of natural fruit abortion the difference was not significant, indicating that fly pollinators do not limit reproduction of these Phyllanthaceae species. This study provides an addition to the limited Asian literature on pollination by flies and the even more limited literature on duodichogamy. It could help to broaden our understanding for analysis of the evolution of duodichogamy in future research, but the specific ecological factors behind the evolution of this rare sexual system are still difficult to generalize.

Phyllanthus comprises approximately 1,270 species, making it one of the world's largest plant genera. Molecular data so far are of limited value for understanding Phyllanthus because of the sheer size of the genus. They can, however, help sort-out cryptic species and provide information on the origin of suspected introduced species. One of the seemingly most widespread species is P. reticulatus, which has been recorded from Asia, Australia, Africa, and Jamaica. The name is based on a mixed collection from tropical Asia now in the Lamarck herbarium, and we lectotypify it here. We use nuclear ITS sequences to test the broad treatment of P. reticulatus in recent floras, identify records of “P. reticulatus” from Africa, and investigate the origin of P. reticulatus on Jamaica. A maximum likelihood tree for accessions of P. reticulatus from throughout its supposed range (plus relevant outgroups) shows that the Jamaican plants represent the Asian species, that the African plants called P. reticulatus be...

Flowering plants commonly separate male and female function in time, but rarely are the two stages synchronized within and among individuals. One such temporal mating system is duodichogamy in which each plant produces two batches of male flowers that are temporally separated by a batch of female flowers, with within-individual synchrony and among-individual asynchrony to ensure mating partners. Duodichogamy is known only from a few species in four genera in unrelated families. We report on duodichogamy in the Chinese tree species Bridelia tomentosa (Phyllanthaceae), a common colonizer of disturbed habitats. In three populations monitored over 2 yr, most trees flowered in the order male ! female ! male, and resting periods between flowering bouts precluded selfing almost completely. Individuals flowered for several weeks, with the onset of flowering slightly asynchronous among trees. Pollination was by flies, and experimental pollen supplementation of a subset of a tree’s flowers did not increase fruit set, suggesting high levels of insect visitation and possible resource limitation. Nineteen percent of the 166 trees monitored skipped the first male phase, and another 13% skipped the female phase, remaining male in both years (and also a third year). The regular presence of pure males, if genetically fixed, would make B. tomentosa androdioecious in addition to duodichogamous. Comparison of duodichogamous taxa known so far shows that all have few ovules, fitting with the hypothesis that duodichogamy may result from male competition for access to a small supply of ovules. Cross-pollinating plants are under selection to synchronize pollen export and stigma receptivity among individuals. At the same time, individuals are under selection to separate pollen release and stigma receptivity to reduce stigma clogging, pollen discounting, and selfing (Lloyd and Webb, 1986). These two selective pressures have resulted in intricate temporal sexual patterns, namely, dichogamy, duodichogamy, and heterodichogamy. The most common of these is dichogamy, which involves male and female phases that may or may not be synchronized within and among individuals (Lloyd and Webb