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Visits by the first author to major Colombian herbaria (COAH, COL, CUVC, HUA, JAUM, MEDEL, TULV, UDBC, and VALLE) in 1997 and 1999 brought to light abundant material of several previously undescribed species of Siparuna, a genus that we are monographing (Renner & Hausner, 1995, 1996, 1997). Three of the species are now known from flowering and fruiting collections. However, we are still awaiting fully fruiting material of S. vasqueziana. Siparuna vasqueziana is unique in the genus in its flower size and morphology and can therefore be keyed out easily even in the absence of mature fruits.

While revising the Melastomataceae for the Flora of Thailand, we discovered two new species of Sonerila, as well as the need for transferring two species of Tylanthera endemic to Thailand into Phyllagathis. Sonerila urceolata and S. loeiensis are endemic to the southeast and the northeast of Thailand, respectively. The first is allied to the widespread S. erecta Jack, from which it differs mainly in the strongly urceolate capsule and the sessile fruit placenta; the second is distinguished from other acaulescent species of Sonerila by its extremely long-petiolate large leaves and long-pedunculate inflorescence. The new combinations, Phyllagathis tuberosa (Hansen) Cellinese & Renner and P. siamensis Cellinese & Renner nom. nov., are made because both taxa lie inside the morphologic and phylogenetic bounds of Phyllagathis.

Siparuna campii, S. guajalitensis, and S. pubancura from central Ecuador, S. multifora and S. conica from northwestern Ecuador and western Colombia, S. verticillata from Amazonian Ecuador, and S. cascada from southeastern Ecuador are described, illustrated, and discussed as to their relationships with morphologically similar species. Macrophotographs of male and female flowers illustrate the unusual details of Siparuna floral struc

A complex behavior pattern of pollen robbing by several species of the large tropical bee genus Trigona (Apidae: Meliponinae, tribe Trigonini) is described. These bees probe pollen from the apical pores of tubular Melastomataceae anthers as far as their tongues reach and then cut off the top of the anther to expose more pollen. This is repeated several times. A summary of observations of this syndrome in 34 species of Brazilian Melastomataceae and records from other neotropical countries are presented. The significance of these pollen robbers' adaptations is examined. NECTAR-ROBBING BY Trigona is well known and its possible influence on plants' breeding systems has received attention recently (Mc Dade & Kinsman 1980, Roubik 1982). The less obvious pollen-robbing has not received the same attention. During a 2-year study of the pollination and breeding biology of Amazonian Melastomataceae, I was impressed by the frequency with which these flowers suffered destruction of the anthers by bees belonging to the large genus Trigona. I consequently searched systematically for damaged anthers in flowering material from various Brazilian herbaria. Observations during visits to central and southern Brazil, the literature on Melastomataceae pollination, and personal communications from other students of this family confirmed that anther destruction is common in neotropical Melastomataceae. MATERIAL AND METHODS Melastomataceae are abundant as herbs, shrubs or medium-sized trees along roadsides, embankments and in secondary vegetation in Brazil. They are also frequent in primary forest, where they may be large trees. Some flowering activity occurs all year, and many species flower continuously. Observations were made in the lowland forest of Amazonian Brazil between October 1980, and October 1982, with the exception of February/March 1981 and 1982, when observations were made in southern Brazil. Studies of Melastomataceae in primary forest were conducted in forest reserves 26, 45, and 120 km east and north of Manaus, as well as near Sao Gabriel on the upper Rio Negro (August 1981). Observations of savanna species were made in the natural savannas near HumaitA on the Madeira River, 800 km south of Manaus (October 1981), and on MaracA Island in the Rio Uraricoeira, 140 km west of Boa Vista in the state of Roraima (November 1980 and May 1982). The characteristic open vegetation of white sand areas ("campinas") was studied in the reserve 45 km north of Manaus and along the embankment of the Rio Negro near Manaus. Secondary vegetation was studied at various sites near Manaus and Belem. In southern Brazil several days were spent in the National Parks "Serra dos Orgaos" and "Serra de Itatiaia," both situated between 800 and 1200 m altitude in the Serra de Mantiqueira mountain range, the former in the state of Rio de Janeiro, the latter at the meeting point of the states of Rio, Sao Paulo and Minas Gerais. Additional observations were made in gardens in Teres6polis, Ibiuna, near Sao Paulo, and the Botanical Gardens of Sao Paulo and Rio. When examining material in the herbaria of Manaus (INPA), Belem (IAN, MG), Belo Horizonte (BHMH), Rio (R, RJ), and Sao Paulo (SP, SPF) plants from 13 more species contained severed anthers. Because these anthers looked exactly like the ones destroyed by Trigona bees in the field, the 13 species are mentioned in the report although the bees working on their anthers were not collected. Observations of insect visitors were made from 5:30 A.M. until noon; insect activity ceased almost completely after midday. To establish flowering time in those species known to open before 5:30 A.M., one "night survey" was made consisting of 1 and 3 A.M. checks. At each stand, detailed notes were taken on the behavior patterns of flower visitors, and lengths of visits were timed. Photographs documented positions of bees on flowers. Individual Trigona were marked with a spot of white paint on the thorax to allow behavior to be monitored on consecutive days. For the year-round flowering species Bellucia imperialis and Rhynchanthera grandiflora, Trigona activity was assessed by censuses at least once a week (except for February/March) and once a month, respectively. The exploitation of Melastomataceae anthers by Trigona was quantified for Mouriri nervosa. The bees were caught with an insect net for identification and to obtain samples of pollen loads. It was posBIOTROPICA 15(4): 251-256 1983 251 This content downloaded from 157.55.39.94 on Sun, 17 Apr 2016 05:53:02 UTC All use subject to http://about.jstor.org/terms TABLE 1. Brazilian Melastomataceae species that show anther destruction by Trigona bees. Species Locality Trigona (Trigona) species Aciotis acuminifolia wet sites near Manaus fulviventris fulviventris Bellucia acutata savannas around Humaita hyalinata amazonensis B. axinanthera roadside near Humaita hyalinata amazonensis B. dichotoma roadside near Manaus hyalinata branneri B. grossularioides roadside near Manaus dallatorreana B. imperialis roadside near Manaus dallatorreana, fulviventris fulviventris Clidemia hirta roadside near Manaus fulviventris fulviventris C. japurensis primary forest near Sao Gabriel fulviventris fulviventris Comolia veronicaefolia savanna west of Boa Vista fulviventris guianae Desmoscelis villosa savanna near Sao Gabriel dallatorreana H. horridula on sandy soil near Manaus dallatorreana Miconia alata roadside near Manaus fulviventris guianae M. argyrophylla forest on sandy soil north of Manaus fulviventris guianae M. aff. lepidota forest on sandy soil north of Manaus fulviventris guianae M. nervosa primary forest near Manaus fulviventris guianae M. radulaefolia roadside near Manaus fulviventris guianae Mouriri nervosa forest on sandy soil north of Manaus williana Myriaspora egensis near Rio Negro banks, Manaus fulviventris guianae Nepsera aquatica wet sites near Manaus fulviventris guianae Rhynchanthera grandiflora wet sites near Manaus williana, fulviventris guianae R. virgata wet sites in savannas west of Boa Vista fulviventris guianae Sandemania hoehnei white sand area north of Manaus fulviventris guianae Tibouchina arborea Serra de Mantiqueira, 800 m alt. sp. T. aspera savanna west of Boa Vista fulviventris fulviventris T. gardneriana Serra de Mantiqueira, 800 m alt. fulviventris fulviventris T. granulosa Serra de Mantiqueira, 800 m alt. fulviventris fulviventris T. maximiliana garden in Teres6polis fulviventris fulviventris T. moricandiana Serra de Mantiqueira and Botanical Garden SP fulviventris guianae T. mutabilis Serra dos Orgaos, 900 m alt. fulviventris fulviventris T. spruceana savanna south of Rio Negro near Manaus fulviventris guianae T. stenocarpa Botanical Garden SP fulviventris fulviventris Tococa bullifera primary forest near Manaus fulviventris guianae T. coronata Madeira banks near Humaita hyalinata amazonensis T. longisepala black water flooded forest near Manaus williana, fulviventris guianae sible to catch all species of Trigona except for those working on the tall tree Tibouchina arborea. These were observed through binoculars and severed anthers were collected below the tree. Pollen analysis was done by staining pollen loads from bees in cotton blue and lactophenol overnight and scanning for non-melastomataceous pollen grains. A permanent preparation of pure pollen from each melastome species was prepared.

Observations sur la biologie de reproduction d'especes du Bresil et du Venezuela. L'etude comporte des donnees sur la classification, la morphologie, la cytologie, le spectre de pollinisation, le mode dispersion des graines, et enfin sur l'evolution des deux familles