Nathan Muchhala

University of Missouri–St. Louis | UMSL · Department of Biology

The genus Burmeistera consists mostly of cloud forest species occurring from Guatemala to Peru. Molecular work on this group has revealed previously established subgeneric groupings to be non-monophyletic, while also identifying several monophyletic groups with recognizable synapomorphies. One such monophyletic group is a clade of species with recu...

Plant–hummingbird interactions are considered a classic example of coevolution, a process in which mutually dependent species influence each other’s evolution. Plants depend on hummingbirds for pollination, whereas hummingbirds rely on nectar for food. As a step towards understanding coevolution, this review focuses on the macroevolutionary consequ...

Nectarivorous bats have evolved various adaptations to feeding from flowers, such as long, extensible tongues and the ability to hover. The champion of tongue length, Anoura fistulata , can extend its tongue to 150% of its body length, yet little is known about its interactions with flowers in the wild. Here we analyzed the diet of A. fistulata and...

Seminal hypotheses in ecology and evolution postulate that stronger and more specialized biotic interactions contribute to higher species diversity at lower elevations and latitudes. Plant-chemical defenses mediate biotic interactions between plants and their natural enemies and provide a highly dimensional trait space in which chemically mediated...

Pollen plays a key role in plant reproductive biology. Despite the long history of research on pollen and pollination, recent advances in pollen-tracking methods and statistical approaches to linking plant phenotype, pollination performance, and reproductive fitness yield a steady flow of exciting new insights. In this introduction to the Special I...

Premise: Many tropical plants are bat-pollinated, but these mammals often carry copious, multispecific pollen loads making bat-pollinated plants susceptible to heterospecific pollen deposition and reproductive interference. We investigated pollen transfer between sympatric bat-pollinated Burmeistera species and their response to heterospecific pol...

Animal pollinators directly affect plant gene flow by transferring pollen grains between individuals. Pollinators with restricted mobility are predicted to limit gene flow within and among populations, whereas pollinators that fly longer distances are likely to promote genetic cohesion. These predictions, however, remain poorly tested. We examined...

Background and Aims The centropogonid clade (Lobelioideae: Campanulaceae) is an Andean-centered rapid radiation characterized by repeated convergent evolution of morphological traits, including fruit type and pollination syndromes. While previous studies have resolved relationships of lineages with fleshy fruits into subclades, relationships among...

Background and Aims- The centropogonid clade (Lobelioideae: Campanulaceae) is an Andean-centered rapid radiation characterized by repeated convergent evolution of morphological traits, including fruit type and pollination syndromes. While previous studies have resolved relationships of lineages with fleshy fruits into subclades, relationships among...

Anoura Gray, 1838 are Neotropical nectarivorous bats and the most speciose genus within the phyllostomid subfamily Glossophaginae. However, Anoura species limits remain debated, and phylogenetic relationships remain poorly known, because previous studies used limited Anoura taxon sampling or focused primarily on higher-level relationships. Here, we...

Supplementary Material of the manuscript Morphology and genetics concur that Anoura carishina is a synonym of Anoura latidens (Chiroptera, Glossophaginae). https://doi.org/10.1515/mammalia-2020-0183

Anoura carishina was described based on cranial and dental morphology, but the original analyses did not include Anoura latidens , a similar species of Anoura . We used morphological, morphometric, and genetic analyses to evaluate the taxonomic identity of A. carishina. We performed a principal components analysis to evaluate the correspondence bet...

Six species of Burmeistera H. Karst. & Triana are described as new from Ecuador: B. chrysothrix Mashburn & Muchhala, B. crocodila Mashburn & Muchhala, B. erosa Mashburn, B. lingulata Mashburn & Muchhala, B. sierrazulensis Mashburn & Muchhala, and B. valdiviana Mashburn. These discoveries bring the total number of Burmeistera species in Ecuador to c...

Three species of Burmeistera discovered during fieldwork in Ecuador are described here. Burmeistera velutina and Burmeistera catulum are unusual in being nearly completely covered in indumentum, short and velvety in the former and remarkably long (up to 4 mm) and silky in the latter. Burmeistera jostii possesses bright red corollas, rare in a genus...

Nectarivory or the habit of feeding on nectar and pollen from flowers occurs in nearly 5% of all bat species. Nectarivorous bats are found in tropical and subtropical regions around the world and possess a suit of adaptations to find flowers, extract nectar, metabolize sugars and nutrients from nectar and pollen, and fly long distances to find enou...

Anoura latidens Handley, 1984 is a nectarivorous bat with a wide elevational and latitudinal distribution, from Venezuela and Guyana to southeastern Peru. We reviewed mammal collections of the genus Anoura Gray, 1838 and identified two individuals previously attributed to A. caudifer (É. Geoffroy Saint-Hilaire, 1818) as A. latidens based on their p...

Evaluating the factors that drive patterns of population differentiation in plants is critical for understanding several biological processes such as local adaptation and incipient speciation. Previous studies have given conflicting results regarding the significance of pollination mode, seed dispersal mode, mating system, growth form, and latitudi...

Plants sometimes suffer mechanical injury. The nonlethal collapse of a flowering stalk, for example, can greatly reduce plant fitness if it leads to ‘incorrect’ floral orientation and thus reduced visitation or poor pollination. When floral orientation is important for accurate pollination, as has been suggested for bilaterally symmetrical flowers,...

A new taxon belonging to the genus Burmeistera (Campanulaceae, Lobelioideae) is described from El Quimi Biological Reserve in Morona Santiago Province, southeast Ecuador. Burmeistera quimiensis is characterized by its red-violet stems and veins, spiral phyllotaxy, bullate, ascending leaves with a revolute margin, puberulous abaxial leaf surface, cu...

Targeted sequence capture is a promising approach for large-scale phylogenomics. However, rapid evolutionary radiations pose significant challenges for phylogenetic inference (e.g. incomplete lineages sorting (ILS), phylogenetic noise), and the ability of targeted nuclear loci to resolve species trees despite such issues remains poorly studied. We...

This article is a Commentary on Minnaar et al., 224: 1160–1170.

Premise of research. Heterospecific pollen deposition on stigmas can impact plant reproduction by decreasing seed set or inducing fruit abortion. Pollinating bats often carry pollen from many species on their fur, and thus bat-pollinated flowers may exhibit tolerance to heterospecific pollen deposition, but to our knowledge this has never been stud...

Understanding how pollen moves between species is critical to understanding speciation, diversification, and evolution of flowering plants. For co-flowering species that share pollinators, competition through interspecific pollen transfer (IPT) can profoundly impact floral evolution, decreasing female fitness via heterospecific pollen deposition on...

Understanding how pollen moves between species is critical to understanding speciation, diversification, and evolution of flowering plants. For co-flowering species that share pollinators, competition through interspecific pollen transfer (IPT) can profoundly impact floral evolution, decreasing female fitness via heterospecific pollen deposition on...

These two experiments were designed to determine the DNA extraction protocol which would result in the highest Qubit assay concentration. Four variations of two DNA extraction protocols were performed on six species within the Campanulaceae family. The organisms used and their corresponding experiment codes were: In this experiment, four tissue sam...

Nectarivorous bats have evolved various adaptations to feed from nectar, such as long, extensible tongues. The champion of tongue length, Anoura fistulata, can feed on flowers more than 80 mm deep. However, little is known about its ecology and coevolution with its floral guild. In this study, we analyzed the diet of A. fistulata and co-occurring n...

Nectarivorous bats have evolved various adaptations to feed from nectar, such as long, extensible tongues. The champion of tongue length, Anoura fistulata, can feed on flowers more than 80 mm deep. However, little is known about its ecology and coevolution with its floral guild. In this study we analyzed the diet of A. fistulata and co-occurring ne...

The Anoura geoffroyi species complex is composed of 3 large species: A. geoffroyi, A. peruana, and A. carishina. Several inconsistencies arise from the description of A. carishina, and given the lack of a comparison with the dentition and external characters of A. latidens, here we compare the taxonomic characters of these species. To understand th...

Interspecific pollen transfer (IPT) may greatly impact fitness when it occurs between closely related, co-flowering plant species. This has been documented in many pollination systems, but remains little studied for bat-pollinated plants. In Ecuador, we investigated the effects of IPT on female fitness for two sympatric species of the genus Burmeis...

Two new species of Burmeistera endemic to Ecuador are described and their relationship with other species are discussed. Burmeistera pterifolia has an extremely narrow distribution on the northwestern foothills of the Andes in the Pichincha province, and it is easily differentiated from its congeners by its pinnatilobate leaf margin and large calyx...

Anoura fistulata is the most specialized nectarivorous bat of the genus Anoura. Its relationships with other species of the genus are uncertain given its external morphological resemblance to all 4 species in the A. caudifer species complex. Here, we show how to properly diagnose A. fistulata and how the glossal tube, unique to this species, should...

Plant-pollinator interactions are critical to ecosystems. However, when artificial nectar feeders are available in an area, they could draw pollinators away from plants. We tested the effects of artificial nectar feeders in an Ecuadorian cloud forest on four aspects of bat-plant interactions: (1) bat relative abundance; (2) bat pollen loads; (3) fl...

While specialized interactions, including those involving plants and their pollinators, are often invoked to explain high species diversity, they are rarely explored at macroevolutionary scales. We investigate the dynamic evolution of hummingbird and bat pollination syndromes in the centropogonid clade (Lobelioideae: Campanulaceae), an Andean-cente...

Examining dispersal is critical for understanding the diversity of Andean-centered plant lineages, like Burmeistera (Campanulaceae). One-third of its species present an unusual inflated berry. Unlike the bright colors of non-inflated fruits in the genus, these fruits are typically dull-green; however, the fact that the seeds are loosely held in the...

The nectar bat genus Anoura is one of the most diverse genera within the subfamily Glossophaginae, however species limits and phylogenetic relationships within the genus are unclear. We present a morphological study using 16 cranial and 11 external measurements. Our sampling represents all ten species hypothesis in the genus, including the type ser...

Given their small size and high metabolism, nectar bats need to be able to quickly locate flowers during foraging bouts. Chiropterophilous plants depend on these bats for their reproduction, thus they also benefit if their flowers can be easily located, and we would expect that floral traits such as odor and shape have evolved to maximize detection...

Abstract— Two new species of Burmeistera (Campanulaceae: Lobelioideae) from the Cordillera de Talamanca are described, illustrated, and discussed with reference to similar species. One species, B. serratifolia , is endemic to Panama, while the second, B. monroi , is known from both Panama and Costa Rica. Additionally, these species are included in...

The neotropical plant genus Drymonia displays a remarkable variety of floral shapes and colors. One feature that is particularly important to coevolution with pollinators involves the variable shapes and widths of corolla tubes. To evaluate the evolutionary context for changes in corolla shape, we constructed a phylogeny of 50 of the 75 species of...

Burmeistera zamorensis Muchhala & Á. J. Pérez (Campanulaceae, Lobelioideae) is described from cloud forests in Zamora Chinchipe, Ecuador. It is distinctive in possessing inflated fruit with thick, fleshy walls, and in the maroon coloration of the ventral surface of its leaves, which contrasts sharply with the dark green of the dorsal leaf surfaces....

• The species-rich Neotropical genera Centropogon, Burmeistera, and Siphocampylus represent more than half of the ∼1200 species in the subfamily Lobelioideae (Campanulaceae). They exhibit remarkable morphological variation in floral morphology and habit. Limited taxon sampling and phylogenetic resolution, however, obscures our understanding of rela...

While nectar bats have been found to carry nearly seven times as much pollen as hummingbirds, many other details of pollen transport by these nocturnal pollinators remain poorly understood. For bees, the majority of the pollen they pick up from a flower is deposited on the following one or two flower visits because they groom heavily, while for hum...

One classic explanation for the remarkable diversity of flower colors across angiosperms involves evolutionary shifts among different types of pollinators with different color preferences. However, the pollinator shift model fails to account for the many examples of color variation within clades that share the same pollination system. An alternate...

Passiflora unipetala P. Jørg., Muchhala & J. M. MacDougal (Passifloraceae) is described from two cloud forest remnants in Pichincha, Ecuador, and is assigned to the Andean endemic Passiflora L. supersect. Tacsonia (Juss.) Feuillet & J. M. MacDougal. This new species with yellowish green flowers is distinguished from all other passionflowers by havi...

1. Although competition for pollination is often invoked as a driver of broad‐scale evolutionary and ecological patterns, we still lack a clear understanding of the mechanics of such competition. When flower visitors alternate between two species of flower, heterospecific pollen transfer takes place. The impact of these mixed loads on the female re...

Specialization in pollination systems played a central role in angiosperm diversification, yet the evolution of specialization remains poorly understood. Competition through interspecific pollen transfer may select for specialization through costs to male fitness (pollen lost to heterospecific flowers) or female fitness (heterospecific pollen depos...

One floral characteristic associated with bat pollination (chiropterophily) is copious pollen production, a pattern we confirmed in a local comparison of hummingbird- and bat-adapted flowers from a cloud forest site in Ecuador. Previous authors have suggested that wasteful pollen transfer by bats accounted for the pattern. Here we propose and test...

In a hypothesis that has remained controversial since its inception, Darwin suggested that long-tubed flowers and long-tongued pollinators evolved together in a coevolutionary race, with each selecting for increasing length in the other. Although the selective pressures that flowers impose on tongue length are relatively straightforward, in that lo...

A number of different types of flower-visiting animals coexist in any given habitat. What evolutionary and ecological factors influence the subset of these that a given plant relies on for its pollination? Addressing this question requires a mechanistic understanding of the importance of different potential pollinators in terms of visitation rate (...

A 3.7 kilobase region of chloroplast DNA that includes atpB, rbcL, and their intergenic spacer was sequenced in 61 samples from 45 species of South American Lobeliaceae plus two outgroup samples from Australia. A clade of four hexaploid Lobelia species from Chile is sister to a clade comprising Lysipomia, Siphocampylus, Centropogon, and Burmeistera...

It has been proposed frequently, from Darwin’s time onwards, that specialized pollination increases speciation rates and thus the diversity of plant species (i.e. clade species richness). We suggest here that the correlation between clade species richness and floral specialization is real, but that clade species richness is frequently the cause, no...

Aim We review several aspects of the structure of regional and local assemblages of nectar‐feeding birds and bats and their relationships with food plants to determine the extent to which evolutionary convergence has or has not occurred in the New and Old World tropics. Location Our review is pantropical in extent and also includes the subtropics o...

What causes flowers to diverge? While a plant's primary pollinator should strongly influence floral phenotype, selective pressures may also be exerted by other flower visitors or competition with other plants for pollination. Species of the primarily bat-pollinated genus Burmeistera (Campanulaceae) frequently cooccur, with up to four species in a g...

Coexisting plants that share pollinators can compete through interspecific pollen transfer. A long-standing idea holds that divergence in floral morphology may reduce this competition by placing pollen on different regions of the pollinator's bodies. However, surprisingly little empirical support for this idea exists. Burmeistera is a diverse neotr...

Evolution toward increased specificity in pollination systems is thought to have played a central role in the diversification of angiosperms. Theory predicts that the presence of trade‐offs in adapting to different pollinator types will favor specialization, yet few studies have attempted to characterize such interactions in nature. I conducted fli...

Evolution toward increased specificity in pollination systems is thought to have played a central role in the diversification of angiosperms. Theory predicts that the presence of trade-offs in adapting to different pollinator types will favor specialization, yet few studies have attempted to characterize such interactions in nature. I conducted fli...

Specialization in pollination systems has been a central process in the evolution and diversification of angiosperms. However, we still lack an understanding of why plants specialize or switch pollination modes. I studied various aspects of the pollination and floral evolution of the neotropical subshrub, Burmeistera (Campanulaceae). Videotaping fl...

Bats of the subfamily Glossophaginae (family Phyllostomidae) are arguably the most specialized of mammalian nectarivores, and hundreds of neotropical plants rely on them for pollination. But flowers pollinated by bats are not known to specialize for bat subgroups (unlike flowers that have adapted to the length and curvature of hummingbird bills, fo...

The floral traits of plants with specialized pollination systems both facilitate the primary pollinator and restrict other potential pollinators. To explore interactions between pollinators and floral traits of the genus Burmeistera, I filmed floral visitors and measured pollen deposition for 10 species in six cloud forest sites throughout northern...

The importance of bat pollination has been demonstrated for many plant species. Yet this mutualism has rarely been studied on a community-wide level. In this paper we present results of a yearlong study of a bat-flower community in cloud forests on the western slopes of the Ecuadoran Andes. Of eight plant-visiting bat species caught, only Anoura ca...

Quito, Ecuador (LAV) Here we describe a new species of Anoura from the Andes of Ecuador, distinguished from all other species of Anoura by its elongated tubelike lower lip and its much longer tongue. Based on size and other characteristics, Anoura n. sp. appears most similar to Anoura caudifer, but averages approximately 10% larger and has a wider...

Burmeistera auriculata is described from a cloud forest remnant in Pichincha, Ecuador. Although allied to B. borjensis, this new species is distinguished from all known congeners by its au- riculate calyx. RESUMEN. Se describe Burmeistera auriculata de un remanente de bosque nublado en Pichincha, Ec- uador. Aunque aliado a B. borjensis, esta especi...

New World nectar-feeding vertebrates occur primarily in the mammalian family Phyllostomidae (subfamilies Glossophaginae and Phyllonycterinae with a total of about 34 species) and the avian family Trochilidae (about 330 species). In this paper we compare and contrast patterns and processes in the community structure of these two groups to identify e...

Soleichthys maculosus, described from six specimens collected in shallow waters (37–63m) off northern Australia, is readily distinguished from congeners by its unique ocular-side pigmentation featuring numerous, conspicuous white spots and blotches nearly as large as the eye diameter on a uniformly dark brown background without any crossbands, and...

In this study I documented the degree of specialization in the pollination systems of Burmeistera cyclostigmata and B. tenuiflora (Campanulaceae) to explore the potential role of floral isolation in the diversification of the genus. I asked which floral characteristics are important in specializing on either bat or hummingbird pollination, and whet...

The fruit flag (Stiles 1982) and the bicolored fruit display (Willson and Thompson 1982) hypotheses state that plants with fruit displays that provide contrast within the infructescence, the plant, or their surrounding environment, serve to attract birds, thereby increasing fruit consumption and seed dispersal. We simulated fruit flags by attaching...