Mecranium neibense (Melastomataceae), a new species from Hispaniola

Mecranium neibense is described and illustrated from the Sierra de Neiba of the Dominican Republic in broad-leaved cloud and moist pine forests near the border with Haiti. The new species is compared to its closest relative, M. puberulum, a species endemic to the Cordillera Central-Massif du Nord of Hispaniola.     

Miconia zanonii (Melastomataceae: Miconieae), a new species from Hispaniola

Miconia zanonii, which occurs in broad-leaved cloud forests at four localities in the Cordillera Central of the Dominican Republic, is described and illustrated. It is compared withM. krugii andM. samanensis, two probably close relatives withinMiconia sect.Chaenopleura.     

Tylanthera (Melastomataceae), a new genus of two species endemic to Thailand

The new genus Tylanthera and its two species, T. tuberosa and T. cordata , are described. The genus is endemic to Thailand, and the species are known only from their type collections.     

Endozoochory by beetles: a novel seed dispersal mechanism

Background and Aims

Due in part to biophysical sized-related constraints, insects unlike vertebrates are seldom expected to act as primary seed dispersers via ingestion of fruits and seeds (endozoochory). The Mediterranean parasitic plant Cytinus hypocistis, however, possesses some characteristics that may facilitate endozoochory by beetles. By combining a long-term field study with experimental manipulation, we tested whether C. hypocistis seeds are endozoochorously dispersed by beetles.

Methods

Field studies were carried out over 4 years on six populations in southern Spain. We recorded the rate of natural fruit consumption by beetles, the extent of beetle movement, beetle behaviour and the relative importance of C. hypocistis fruits in beetle diet.

Key Results

The tenebrionid beetle Pimelia costata was an important disperser of C. hypocistis seeds, consuming up to 17·5 % of fruits per population. Forty-six per cent of beetles captured in the field consumed C. hypocistis fruits, with up to 31 seeds found in individual beetle frass. An assessment of seeds following passage through the gut of beetles indicated that seeds remained intact and viable and that the proportion of viable seeds from beetle frass was not significantly different from that of seeds collected directly from fruits.

Conclusions

A novel plant–animal interaction is revealed; endozoochory by beetles may facilitate the dispersal of viable seeds after passage through the gut away from the parent plant to potentially favourable underground sites offering a high probability of germination and establishment success. Such an ecological role has until now been attributed only to vertebrates. Future studies should consider more widely the putative role of fruit and seed ingestion by invertebrates as a dispersal mechanism, particularly for those plant species that possess small seeds.     

Functional variation among frugivorous birds: implications for rainforest seed dispersal in a fragmented subtropical landscape

Seed dispersal plays a critical role in rainforest regeneration patterns, hence loss of avian seed dispersers in fragmented landscapes may disrupt forest regeneration dynamics. To predict whether or not a plant will be dispersed in fragmented forests, it is necessary to have information about frugivorous bird distribution and dietary composition. However, specific dietary information for frugivorous birds is often limited. In such cases, information on the seed-crushing behaviour, gape width and relative dietary dominance by fruit may be used to describe functional groups of bird species with respect to their potential to disperse similar seeds. We used this information to assess differences in the seed dispersal potential of frugivorous bird assemblages in a fragmented rainforest landscape of southeast Queensland, Australia. The relative abundance of frugivorous birds was surveyed in extensive, remnant and regrowth rainforest sites (16 replicates of each). Large-gaped birds with mixed diets and medium-gaped birds with fruit-dominated diets were usually less abundant in remnants and regrowth than in continuous forest. Small-gaped birds with mixed diets and birds with fruit as a minor dietary component were most abundant in regrowth. We recorded a similar number of seed-crushing birds and large-gaped birds with fruit-dominated diets across site types. Bird species that may have the greatest potential to disperse a large volume and wide variety of plants, including large-seeded plants, tended to be less abundant outside of extensive forests, although one species, the figbird Sphecotheres viridis, was much more abundant in these areas. The results suggest that the dispersal of certain plant taxa would be limited in this fragmented landscape, although the potential for the dispersal of large-seeded plants may remain, despite the loss of several large-gaped disperser species.     

A new Mecranium (Melastomataceae) from Hispaniola

Mecranium revolutum is described from the Massif de la Hotte of Haiti and compared with three similar species that are also endemic to this interesting region. The lower elevation (1000–1600 m) forests of Parc National Pic Macaya are discussed briefly.     

A new hypothesis for the importance of seed dispersal in time

Most studies on seed dispersal in time have focused on seed dormancy and the physiological triggers for germination. However, seed dispersed by animals with low metabolic and moving rates, and long gut-passage times such as terrestrial turtles, could be considered another type of dispersal in time. This study tests the hypothesis that seeds dispersed in time may lower predation rates. We predicted that seeds deposited below parent trees after fruiting fall has finished is advantageous to minimize seed predators and should show higher survival rates. Four Amazonian plant species, Dicranostyles ampla, Oenocarpus bataua, Guatteria atabapensis and Ocotea floribunda, were tested for seed survival probabilities in two periods: during fruiting and 10-21 days after fruiting. Experiments were carried out in two biological stations located in the Colombian Amazon (Caparú and Zafire Biological Stations). Seed predation was high and mainly caused by non-vertebrates. Out of the four plant species tested, only Guatteria atabapensis supported the time escape hypothesis. For this species, seed predation by vertebrates after the fruiting period increased (from 4.1% to 9.2%) while seed predation by non-vertebrates decreased (from 54.0% to 40.2%). In contrast, seed predation by vertebrates and by non-vertebrates after the fruiting period in D. ampla increased (from 7.9% to 22.8% and from 40.4% to 50.6%, respectively), suggesting predator satiation. Results suggest that for some species dispersal in time could be advantageous to avoid some type of seed predators. Escape in time could be an additional dimension in which seeds may reach adequate sites for recruitment. Thus, future studies should be address to better understand the survival advantages given by an endozoochory time-dispersal process.     

Intraspecific variation in seed dispersal of a Neotropical tree and its relationship to fruit and tree traits

The distribution of wind‐dispersed seeds around a parent tree depends on diaspore and tree traits, as well as wind conditions and surrounding vegetation. This study of a neotropical canopy tree, Platypodium elegans, explored the extent to which parental variation in diaspore and tree traits explained (1) rate of diaspore descent in still air, (2) distributions of diaspores dispersed from a 40‐m tower in the forest, and (3) natural diaspore distributions around the parent tree. The geometric mean rate of descent in still air among 20 parents was highly correlated with geometric mean wing loading^1/2 (r = 0.84). However, diaspore traits and rate of descent predicted less variation in dispersal distance from the tower, although descent rate⁻¹ consistently correlated with dispersal distance. Measured seed shadows, particularly their distribution edges, differed significantly among six parents (DBH range 62–181 cm) and were best fit by six separate anisotropic dispersal kernels and surveyed fecundities. Measured rate of descent and tree traits, combined in a mechanistic seed dispersal model, did not significantly explain variation among parents in natural seed dispersal distances, perhaps due to the limited power to detect effects with only six trees. Seedling and sapling distributions were at a greater mean distance from the parents than seed distributions; saplings were heavily concentrated at far distances. Variation among parents in the distribution tails so critical for recruitment could not be explained by measured diaspore or tree traits with this sample size, and may be determined more by wind patterns and the timing of abscission in relation to wind conditions. Studies of wind dispersal need to devote greater field efforts at recording the “rare” dispersal events that contribute to far dispersal distances, following their consequences, and in understanding the mechanisms that generate them.     

A seed predator drives the evolution of a seed dispersal mutualism

Although antagonists are hypothesized to impede the evolution of mutualisms, they may simultaneously exert selection favouring the evolution of alternative mutualistic interactions. We found that increases in limber pine (Pinus flexilis) seed defences arising from selection exerted by a pre-dispersal seed predator (red squirrel Tamiasciurus hudsonicus) reduced the efficacy of limber pine's primary seed disperser (Clark's nutcracker Nucifraga columbiana) while enhancing seed dispersal by ground-foraging scatter-hoarding rodents (Peromyscus). Thus, there is a shift from relying on primary seed dispersal by birds in areas without red squirrels, to an increasing reliance on secondary seed dispersal by scatter-hoarding rodents in areas with red squirrels. Seed predators can therefore drive the evolution of seed defences, which in turn favour alternative seed dispersal mutualisms that lead to major changes in the mode of seed dispersal. Given that adaptive evolution in response to antagonists frequently impedes one kind of mutualistic interaction, the evolution of alternative mutualistic interactions may be a common by-product.     

A new epiphytic blakea (Melastomataceae) from Panama

Blakea wilburiana is described from the low volcanic uplift of El Valle de Anton in central Panama. Hirsute pubescence, papery leaves, and large, thin floral bracts suggest a marked affinity withB. bracteata Gleason of South America. A character tabulation, comparing the two species, is included together with illustrations of the diagnostic morphological features.     

Aerial seed bank and dispersal traits in Anthemis chrysantha (Asteraceae), a critically endangered species

Mature plant density and fruit production were monitored in the main population of four successive cohorts of the endangered winter annual Anthemis chrysantha (Asteraceae) in southeastern Spain. Experiments were conducted with artificial rainfall and a wind tunnel to determine the temporal and spatial dispersal pattern of the species and the relationship with rain and wind.     

Fecundity,fruiting pattern,and seed dispersal in Piper amalago (Piperaceae), a bat-dispersed tropical shrub

Summary This paper describes the nightly and seasonal production of ripe fruit by Piper amalago (Piperaceae), a patchily distributed, bat-dispersed forest shrub, at Parque Nacional Santa Rosa, Costa Rica. Phenological observations over several years indicate that individuals produce a low (usually 1–3) and variable number of ripe fruit each night for 3–4 wks in the early wet season (June and July). Observations of the disappearance rates of marked fruits and fruit manipulation experiments indicate that fruit removal probabilities are high (often nearly 1.0) and independent of nightly and seasonal ripe fruit crop size. Data from previous feeding and foraging studies of the bat Carollia perspicillata (Phyllostomidae) are used to estimate the mobility of P. amalago's seeds. Most seeds (>90%) are deposited 50 m from parent plants under night feeding roosts. Relatively few seeds move >300 m, and movements this long are more likely to occur early and late in the fruiting season when bats change feeding sites more frequently. Seed experiments indicate that P. amalago seedling establishment probabilities are higher in light gaps than under forest canopy. The dispersal quality (sensu McKey 1975) of P. amalago's chiropteran seed dispersers is directly proportional to the number of seeds they excrete in actual or incipient light gaps.     

A new species of Microlicia (Melastomataceae) from Brazil

A new species of the genusMicrolicia,M. flava, from the highland “campo rupestre” vegetation of Serra da Canastra National Park, São Roque de Minas, Minas Gerais, Brazil, is described and illustrated.     

Cordyceps cuncunae (Ascomycota, Hypocreales), a new pleoanamorphic species from temperate rainforest in southern Chile

Cordyceps cuncunae Palfner sp. nov. is reported from Valdivian rainforest in southern Chile, parasiting larvae of an unidentified ghost moth species (Lepidoptera, Hepialidae) which probably feed on roots of Laureliopsis philippiana. Morphology and anatomy of stromata as well as morphological and molecular characteristics of mycelium in pure culture which produces two anamorphs, one of them Lecanicillium-like, are described. The systematic position of the new taxon within the most recent generic concept is discussed. This is the first record of an endemic Cordyceps species from Chile.     

Ant benefits in a seed dispersal mutualism

Myrmecochorous plant seeds have nutrient rich appendages, elaiosomes, which induce some ant species to carry the seeds back to their nest where the elaiosome is consumed and the seed is discarded unharmed. The benefits to plants of dispersal of their seeds in this way have been well documented, but the benefits to the ants from consuming the elaiosomes have rarely been measured and are less clear. Ant benefits from myrmecochory were investigated in a laboratory experiment using the ant Myrmica ruginodis and seeds of Ulex species. To separate the effects of elaiosome consumption on the development of newly produced larvae versus existing larvae, ten ‘Queenright’ colonies containing a queen were compared to ten ‘Queenless’ colonies. Six measures of colony fitness over a complete annual cycle were taken: sexual production, larval weight and number, pupal weight and number, and worker survival. Queenless colonies fed with elaiosomes produced 100.0±29.3 (mean ± SE) of larvae compared to non-elaiosome fed colonies which produced 49.6±19.0; an increase of 102%. Larval weight increased in both Queenright and Queenless colonies. In colonies fed with elaiosomes, larvae weighed 1.02±0.1 mg, but in non-elaiosome fed colonies larvae weighed 0.69±0.1 mg; an increase of 48%. The food supplement provided by Ulex elaiosomes was trivial in energetic terms, under the conditions of an ample diet, suggesting that these effects might be due to the presence of essential nutrients. Chemical analysis of Ulex elaiosomes showed the presence of four essential fatty acids and four essential sterols for ants.     

A new species of Memecylon (Melastomataceae) from India

Memecylon sivadasanii , a new species of Melastomataceae from India is described and illustrated. The new species is allied to M. angustifolium and M. rivulare.