Neotropical Plant Species Research Articles

Phylogeography of Neotropical trees

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Palaeodistribution modelling does not support disjunct Pleistocene refugia in several Central American plant taxa

AbstractAim We combine evidence from palaeoniche modelling studies of several tree species to estimate the extent of Central American forest during the Last Glacial Maximum (LGM). In particular, we ask whether the distributions of these species are likely to have changed since the LGM, and whether LGM distributions coincide with previously proposed Pleistocene refugia in this area.Location Central American wet and seasonally dry forests.Methods We developed ecological niche models using two simulations of Pleistocene climate and occurrence data for 15 Neotropical plant species. We focused on palaeodistribution models of three ‘focal’ tree species that occur in wet and seasonally dry Central American forests, where recent phylogeographic data suggest Pleistocene differentiation coincident with previously proposed refugia. We added predictions from six wet‐forest and six seasonally dry‐forest obligate plant species to gauge whether Pleistocene range shifts were specific to habitat type. Correlation analyses were performed between projected LGM and present distributions, LGM distributions and previously proposed refugia. We also asked whether modelled palaeodistributions were smaller than their current extents.Results According to our models, the ranges of the study species were not reduced during the LGM, and did not correlate with refugial models, regardless of habitat type. Relative range sizes between present and LGM distributions did not indicate significant range changes since the LGM. However, relative range sizes differed overall between the two palaeoclimate models.Main conclusions Many of the modelled palaeodistributions of study species were not restricted to refugia during the LGM, regardless of forest type. While constrained from higher elevations, most species found suitable habitat at coastal margins and on newly exposed land due to lowered sea levels during the LGM. These results offer no corroboration for Pleistocene climate change as a driver of genetic differentiation in the ‘focal’ species. We offer alternative explanations for genetic differentiation found in plant species in this area.

Colletotrichum gloeosporioides s.l. associated with Theobroma cacao and other plants in Panamá: multilocus phylogenies distinguish host-associated pathogens from asymptomatic endophytes

Colletotrichum interacts with numerous plant species overtly as symptomatic pathogens and cryptically as asymptomatic endophytes. It is not known whether these contrasting ecological modes are optional strategies expressed by individual Colletotrichum species or whether a species’ ecology is explicitly pathogenic or endophytic. We explored this question by inferring relationships among 77 C. gloeosporioides s.l. strains isolated from asymptomatic leaves and from anthracnose lesions on leaves and fruits of Theobroma cacao (cacao) and other plants from Panamá. ITS and 5′-tef1 were used to assess diversity and to delineate operational taxonomic units for multilocus phylogenetic analysis. The ITS and 5′-tef1 screens concordantly resolved four strongly supported lineages, clades A–D: Clade A includes the ex type of C. gloeosporioides, clade B includes the ex type ITS sequence of C. boninense, and clades C and D are unidentified. The ITS yielded limited resolution and support within all clades, in particular the C. gloeosporioides clade (A), the focal lineage dealt with in this study. In contrast the 5′-tef1 screen differentiated nine distinctive haplotype subgroups within the C. gloeosporioides clade that were concordant with phylogenetic terminals resolved in a five-locus nuclear phylogeny. Among these were two phylogenetic species associated with symptomatic infections specific to either cacao or mango and five phylogenetic species isolated principally as asymptomatic infections from cacao and other plant hosts. We formally describe two new species, C. tropicale and C. ignotum, that are frequent asymptomatic associates of cacao and other Neotropical plant species, and epitypify C. theobromicola, which is associated with foliar and fruit anthracnose lesions of cacao. Asymptomatic Colletotrichum strains isolated from cacao plants grown in China included six distinct C. gloeosporioides clade taxa, only one of which is known to occur in the Neotropics.

Piper umbellatum L.: A comparative cross-cultural analysis of its medicinal uses and an ethnopharmacological evaluation

This review assesses the botany, traditional medicinal uses, phytochemistry, pharmacology and toxicology of P. umbellatum. Information on P. umbellatum was gathered via the internet (using Scirus, Google Scholar, CAB-Abstracts, MedlinePlus, Embase, Scielo, and Web of Science) and libraries. Additionally, previously unpublished work on the traditional uses of P. umbellatum from our National Study of the Medicinal Plants of the Dominican Republic has been included. Piper umbellatum is a Neotropical plant species widely distributed in Mexico, Central America, South America and the West Indian Islands. It has also been introduced to Africa and South-East Asia. Traditional uses for this plant are recorded in 24 countries in three continents, America, Africa and Asia for a wide range of ailments such as kidney, women diseases, diarrhea, skin affections, burns, rheumatism, malaria, intestinal parasites, inflammation and fever. We have analyzed the cross-cultural agreement among traditional uses in different countries and found a high degree of consensus for the indications kidney/diuretic, stomachache and wounds. Phytochemical studies of P. umbellatum have demonstrated the presence of terpenes (mainly found in the essential oil), alkaloids, flavonoids, sterols and other classes of secondary metabolites. The extracts and pure compounds derived from P. umbellatum show a wide spectrum of pharmacological activities including antibacterial, anti-inflammatory, analgesic, antioxidant, cytotoxic, antimalarial, antileishmanial, and antitrypanosomal activity. A first commercial product is in development, based on the plant's protective characteristics against UV irradiation. The interesting biological activities of P. umbellatum need further research in in vivo experiments and clinical studies. The outcome of these investigations will determine the possible development of drugs from P. umbellatum.

Efficient floristic inventory for the assessment of tropical tree diversity: A comparative test of four alternative approaches

Biodiversity inventory as a tool for guiding conservation planning at a local scale is under used, especially in tropical countries where technical capacity is often limited. Here four inventory protocols (one ad hoc, one fixed count and two fixed area methods) are tested for their efficiency and statistical robustness when applied to the woody floras of a Mexican seasonally dry tropical forest. They are tested for their ability to distinguish between sites not only by number of species (richness), but also by number of threatened species, and finally in their application to complementary reserve selection exercises. Whilst the ad hoc method is shown to have the advantage of high efficiency and is technically undemanding, where possible the statistically more robust fixed count or fixed area methodologies are recommended. However, the much used fixed area method of Gentry [Gentry, A.H., 1982. Patterns of neotropical plant species diversity. Evol. Biol. 15, 1–84] that uses 2 m × 50 m plots is shown to be inefficient. Only when comparison with other previously published assessments is a priority should the 2 m × 50 m fixed area method be considered, and then efficiency may be increased by widening the plots and distinguishing between those stems that fall within a notional 2 m plot and those outside of it. Both prioritisation by number of species and complementarity analysis, using the ‘greedy’ algorithm, are shown to be sensitive to choice of inventory protocol, suggesting that consideration is given to how species lists are obtained in reserve selection exercises.

Nectar in Hummingbird-pollinated Neotropical Plants II: Interactions with Flower Visitors1

ABSTRACT We documented the diurnal pattern of nectar volumes in flowers of seven Neotropical hummingbird-pollinated plant species that were open to flower visitors and compared these standing crop data to nectar volumes in flowers protected from visitors. Standing crop of nectar bore little relationship to nectar in bagged flowers either in terms of volume or temporal pattern of availability. There was almost no nectar in open flowers except in those collected at dawn and those of Aphelandra sinclairiana; these were apparently too abundant to be depleted by visitors. Nectar volumes in open flowers were even more variable than in bagged flowers. We argue that understanding the evolution of plant– pollinator interactions requires understanding the relationship between nectar production and standing crop, as well as the impact of high variability on decisions by foraging animals. We conducted experiments to determine the effect of nectar removal on nectar production. Nectar removal via simulated legitimate v...

Dyssochroma viridiflorum (Solanaceae): a reproductively bat-dependent epiphyte from the Atlantic rainforest in Brazil.

Few Neotropical plant species seem to depend on the same animal type both for pollination and seed dispersal, and the known instances refer mostly to birds as the agents in these two phases of a plant reproductive cycle. Dyssochroma viridiflorum (Solanaceae), an epiphyte endemic to the Atlantic rainforest in south-eastern Brazil, was found to be visited by phyllostomid bats for nectar as well as for fruits, with the pollination and seed dispersal of the plant ensured by these flying mammals. The greenish flowers open at night and are visited by the nectar-feeding bat Glossophaga soricina, whereas the yellowish-white fruits are consumed by two species of fruit-eating bats, Carollia perspicillata and Sturnira lilium. Only clinging visits, an uncommon behavioural pattern for glossophagine bats while feeding on flowers, were recorded. The small seeds of D. viridiflorum are swallowed along with the fruit pulp and later defecated on the bats' flying pathways. It is suggested that species of Dyssochroma and two other solanaceous bat-pollinated genera, Merinthopodium and Trianaea, form a derived and bat-dependent clade within the Juanulloeae.

OPERATIONAL TONGUE LENGTH IN PHYLLOSTOMID NECTAR-FEEDING BATS

Abstract Glossophagine bats (Phyllostomidae, Glossophaginae) are specialized visitors to the flowers of several hundred species of neotropical plants. They are able to exploit flowers in hovering flight by imbibing nectar with a highly protrusile brush-tip tongue. As tongue extension is achieved by muscular and vasohydraulic mechanisms, its operational length can be inferred only from actively feeding animals. For this study, we measured maximum tongue extensions during nectar feeding in 9 species of glossophagine bats. We trained bats to feed from vertically oriented glass test tubes (9- and 15-mm inside diameter). The maximum depth of nectar drainage by a bat was recorded as maximum operational tongue length. Measured operational tongue lengths were in the range of the total body length of bats. The record length was 77 mm (in tubes with 15-mm inside diameter) in the 17-g flower specialist Choeronycteris mexicana. This compares with only 11–24 mm in the nonglossophagine frugivorous bat Carollia perspici...

Acoustic guide in bat-pollinated flower

Several hundred species of neotropical plants are pollinated by glossophagine bats1,2. These bats use their highly developed sonar system for orientation, so we might expect bat-pollinated flowers to have evolved acoustically conspicuous structures to make them easier to detect. We find that the bat-pollinated neotropical vine Mucuna holtonii directs its echolocating pollinators to its flowers by means of an acoustic nectar guide. The flower contains a small concave ‘mirror’ that works like an optical cat's eye, but in the acoustic domain, reflecting most of the energy of the bats' echolocation calls back into the direction of incidence.

Covariance and decoupling of floral and vegetative traits in nine Neotropical plants: a re‐evaluation of Berg's correlation‐pleiades concept

Nearly forty years ago R. L. Berg proposed that plants with specialized pollination ecology evolve genetic and developmental systems that decouple floral morphology from phenotypic variation in vegetative traits. These species evolve separate floral and vegetative trait clusters, or as she termed them, "correlation pleiades." The predictions of this hypothesis have been generally supported, but only a small sample of temperate-zone herb and grass species has been tested. To further evaluate this hypothesis, especially its applicability to plants of other growth forms, we examined the patterns of phenotypic variation and covariation of floral and vegetative traits in nine species of Neotropical plants. We recognized seven specific predictions of Berg's hypothesis. Our results supported some predictions but not others. Species with specialized pollination systems usually had floral traits decoupled (weak correlation; Canna and Eichornia) or buffered (relationship with shallow proportional slope; Calathea and Canna) from variation in vegetative traits. However, the same trend was also observed in three species with unspecialized pollination systems (Echinodorus, Muntingia, and Wedelia). One species with unspecialized pollination (Croton) and one wind-pollinated species (Cyperus) showed no decoupling or buffering, as predicted. While species with specialized pollination usually showed lower coefficients of variation for floral traits than vegetative traits (as predicted), the same was also true of species with unspecialized or wind pollination (unlike our prediction). Species with specialized pollination showed less variation in floral traits than did species with unspecialized or wind pollination, as predicted. However, the same was true of the corresponding vegetative traits, which was unexpected. Also in contrast to our prediction, plants with specialized pollination systems did not exhibit tighter phenotypic integration of floral characters than did species with generalized pollination systems. We conclude that the patterns of morphological integration among floral traits and between floral and vegetative traits tend to be species specific, not easily predicted from pollination ecology, and generally more complicated than R. L. Berg envisaged.

Conservation and monographic research on the flora of Tropical America

Monographs provide fundamental data critical to making informed conservation decisions. Do modern monographs, however, contribute to our knowledge of the diversity of the Neotropical flora or has most of the enumeration of species already been accomplished in older monographs, floristic treatments, and other research? How well monographed is the Neotropical flora and what is the approximate number of Neotropical plant species new to science that await description? Authors of 76 recent monographs of the Neotropical flora recognized a total of 8711 species, of which 2487 (29%) were new species described by the author of the monograph during the course of the research. The number of species of flowering plants new to science remaining to be described is estimated to be ca. 22000, or about 25 percent of the total flora. These estimates show the critical importance of the contributions of monographers to an accurate and complete inventory of Neotropical plant diversity.

Secondary Metabolites in Fleshy Fruits: Are Adaptive Explanations Needed?

1. Department of Botany, Stockholm University, S-106 91 birds, their presence has been considered to be an evoluStockholm, Sweden; tionary paradox. 2. Department of Ecological Botany, Uppsala University, Cipollini and Levey (1997) provide a list of ingenious Villavagen 14, S-752 36 Uppsala, Sweden and interesting hypotheses focusing on the potential functions of the secondary metabolites for enhancing Submitted December 8, 1997; Accepted April 9, 1998 plant seed dispersal, for example, by providing foraging cues, as regulators of seed germination, as mechanisms to force frugivores not to stay too long at the same plant, as mechanisms to manipulate seeds’ gut passage rate, and as

Feeding Preferences of Common Bush-Tanagers for Insect-Infested Fruits: Avoidance or Attraction?

The pulp of ripe fruit of many neotropical plant species is infested by pulp-mining insect larvae, whose presence might affect fruit selection by birds through preference for or avoidance of infested fruits. At Monteverde, Costa Rica, common bush-tanagers (Chlorospingus ophthalmicus) consume fruits of plant species infested with insect larvae. I examined whether common bush-tanagers choose infested or uninfested fruits, and whether a preference can be elicited by the presentation of simulated «infested» fruits that were pierced by the investigator

Pollination of Some Rain Forest Plants by Non-Hovering Birds in Veracruz, Mexico

This paper gives an account of observations carried out on five plant species in the rain forest of Veracruz, Mexico, and indicates that non-hovering birds such as vireos, warblers, tanagers, finches, orioles, blackbirds, and honeycreepers are important as flower visitors and should be investigated in the future as pollinators of American rain forest plants. ECOLOGICAL STUDIES on pollinators of Neotropical rain forest plants have been initiated in different animal groups such as bees (Janzen 1971), sphinx moths (Young 1972), hummingbirds (Linhart 1973, Stiles 1975), and bats (Heithaus, Baker, and Opler 1974). However, very little attention has been paid to the role played by many species of nectar-feeding birds such as vireos, warblers, tanagers, finches, orioles, blackbirds, honeycreepers, and other occasionally nectariphagous birds of rain forests. Ornithological observations show a high number of species of these birds visiting a significantly high number of flowering species of Neotropical plants (Skutch 1962, Alvarez del Toro 1963, Leck 1970, Timken 1970, Snow 1971), and evidence exists that in some bird groups the adaptive modifications producing new evolutionary lines have been based on nectar-feeding diets (Beecher, 1950, 1951a, 1951b), a finding which implies a long history of attainable

Foraging Behaviour of Solitary Bees: Implications for Outcrossing of a Neotropical Forest Tree Species

Most flowering plants of neotropical forests display adaptations for animal pollination (see references cited by Frankie, Baker & Opler (1974a) and by Frankie (1975, 1976)), but, since little information is available on the foraging behaviour of the animals involved, there has been considerable speculation as to whether widely spaced, conspecific plants in these forests are selfor cross-pollinated (Corner 1954; Baker 1959; Fedorov 1966; Ashton 1969; Bawa 1974). Bees constitute one of the major groups of visitors to a large proportion of tree species occurring in certain lowland forests (Janzen 1967; Frankie 1975). The potential for interplant movement of bees in Central America has been emphasized by Janzen (1971, 1974), who found that certain euglossine bees in Lowland Wet forests may forage over distances of several kilometres. Janzen has also suggested that members of other bee genera (e.g. Bombus, Centris, Ptiloglossa and Xylocopa) may forage over similar distances. Experimental studies on the nature of breeding systems of tree species in a Costa Rican Dry forest indicate that of the tested species (many of which are bee-pollinated), most have obligate outbreeding systems (Bawa 1974). Bawa's findings strongly imply that bees and other anthophilous animals effect pollination through inter-plant movement. However, patterns of pollinator foraging behaviour in relation to breeding systems have yet to be experimentally investigated for any neotropical plant species. In this paper experimental data are presented on the breeding system of a papilionaceous tree, Andira inermis (Swartz) H.B.K., and on the movements of its pollinators. Early experiments (detailed below) showed that A. inermis is self-incompatible. The flowers show clear adaptation for pollination by bees. The specific questions asked in this study were as follows. (i) What kinds of bees visit Andira flowers and what are their patterns of inter-tree movements ?