Ecology and Evolutionary Biology Graduate Research Symposium
Saturday February 26th
Biological Sciences and Physics Building. Room 130
9:00 AM - 5:00 PM
9:00-9:30 Welcome by Vice Provost of Academics Suman Singha
Australia's spiny bush tomatoes: A case study in the
evolution of separate sexes in angiosperms.
How to win an Ant War: Territoriality and Battles.
Ensuring reliability of ethobotanical data: A repeat 'walk in the woods' in Belizean forests.
Fingerprints of the Maya: Impacts of ancient silviculture on the modern forests of Belize.
10:30-11:00 Morning Break
Evolutionary Radiations of the Proteaceae in South Africa and Australia
Do stereotypical adult morphologies reflect conserved developmental pathways in North American Scincid lizards?
From Common Reed (Phragmites australis) to water chestnut (Trapa natans): An invasive path to UConn.
Hanging out in shark guts: An investigation of Tapeworm microthrix morphology.
Variation in a group of South African Proteaceae: Are there adaptative differences?
Population Structure of Anadromous Alewife in Connecticut: Historical and Inter-Location Comparisons.
Asymmetrical genitalia: Size doesn't always matter.
Peristome development and systematic relationships of the moss Timmia megapolitana Hedw.
Morphology and Natural History of Metalmark Moth Immature Stages
From bog beans to floating hearts: A morphological and phylogenetic introduction to the Menyanthaceae.
A comparison of the cestode fauna of the freshwater stingray Himantura chaophraya from two disjunct regions of its range: Northern Australia and Malaysian Borneo.
The distribution and effects of lianas in tropical secondary forests: preliminary studies and plans for future research.
3:00-3:30 -Afternoon Break
Using Historical Records to Reconstruct a Species Past and Help Plan for Its Future.
Habitat Tolerances of the Invasive Celastrus orbiculatus (Oriental Bittersweet) and Native C. scandens (American Bittersweet) in New England.
The Interplay between Tree Species Performance and Edaphic Variation in a Tropical Forest.
Morphological characteristics of moss peristome teeth have been used in classifications since the late 1800s. One long recognized group of mosses are the arthrodontous (jointed) peristomate mosses. Three major lineages within this group (Funariales, Dicranales, and Bryales) have been established both based on molecular data and peristome morphology. However, the ancestral architecture of the arthrodontous peristome remains ambiguous. In recent molecular phylogenies, Timmia megapolitana and other members of the Timmiaceae have been resolved as sister to the three main groups of arthrodontous mosses. I am undertaking an analysis of the peristome development in T. megapolitana in order to determine the group of arthrodontous mosses most closely related to the Timmiaceae. Developmental data will also be interpreted within a phylogenetic framework in order to establish the polarity of peristome character transformations. Additionally, taxonomic concepts within the Timmiaceae have been proposed based on morphological characteristics. These morphological concepts are being tested against a criterion of monophyly, based on inferences from variation in nucleotide sequences of three loci.
There are concerns that some populations of anadromous alewife Alosa pseudoharengus, commonly referred to as river herring, have substantially declined in Connecticut. Current data on river herring populations is lacking. Assessment of historic shifts in population structure may lend insight into processes that have contributed to population decline. Limited data suggests that river herring spawning in major river watersheds have suffered more severe declines than those spawning in coastal stream systems. Inter-location comparisons of population structure and reproductive indices may help explain different levels of population decline. River herring were sampled from Bride Brook, a coastal stream, and Roaring Brook, a tributary of the Connecticut River, in spring 2003 and 2004. Weirs were placed in both streams from March-June 2003 and 2004 for total enumeration of the spawning run. Weekly sampling was performed to assess population structure and reproductive indices. Alewives spawning at Roaring Brook showed lower levels of reproductive indices than alewives spawning at Bride Brook. The age distribution of alewives spawning at Bride Brook displayed a historic shift to younger fish. The dominant age class of spawners at Bride Brook was younger in comparison to Roaring Brook. Estimates of growth at Bride Brook showed little historic shift. Male alewives and young female alewives at Roaring Brook exhibited faster growth than their counterparts at Bride Brook. Preliminary results thus indicate historical and spatial variation in population structure and reproductive condition of river herring in Connecticut.
Critical to effective management of any species is a thorough understanding of its ecological history, particularly how populations have responded to environmental change over time and what protective actions have been attempted. We are constructing an environmental history of rainbow smelt (Osmerus mordax) in Connecticut and surrounding regions, including information on distribution, relative abundance, changes to critical habitat, and early conservation efforts. Rainbow smelt have recently been listed as a NOAA Species of Concern, with steady declines in regional fisheries during the last few decades cited as the primary listing criteria, but little to no information has been reviewed on the historical aspects of this fishery. Our review of the available records indicates a regional population decline in rainbow smelt was identified during the latter part of the 19th century into the early 20th century. Regional records document an active commercial fishery, including state funded stock enhancement operations and implementation of protective legislation, in the early 20th century; however, interest in these programs seems to have waned as a result of continued stock declines. Production of an environmental history represents an important component when developing a regional management plan, as it allows managers to make informed decisions by helping create a comprehensive picture of a species past. Comparing the historical picture being created to our present understanding of the species biology and ecology in the Northeast United States will help identify the reasons and consequences for the dramatic changes to the population over the last several centuries.
Tapeworms are unique among platyhelminths in that they spend their entire adult life suspended in the intestine of their vertebrate host. The secondary loss of the digestive system along with the appearance of attachment organs on the scolex are attributed to the specialized habitat of the adult tapeworm. The tapeworm tegument is covered with a diversity of forms of microtriches with distinct ultrastructure, which are hypothesized to aid in both the absorption of nutrients and attachment to the intestinal mucosa of the host. Studies that examine the complex distribution and morphology of microtriches are numerous and scanning electron microscopy (SEM) reveals elaborate and occasionally species-specific variation that is extraordinary. For this project, I use transmission electron microscopy (TEM) to examine the scolex microthrix morphology of Calliobothrium verticillatum, a multi-loculated tetraphyllidean tapeworm. Three regions are identified on the tapeworm scolex based on microtrix distribution and morphology: A proximal bothridial region with long filiform and large blade-like spiniform microtriches, a distal-proximal boundary with long filiform and large blade-like spiniform microtriches that are always longer then those on the proximal surface and a distal bothridial region with very short filiform microtriches. The structures on the distal bothridial region had been previously classified as small ball-like structures using SEM. The hypothesis that these enigmatic structures are microtriches is investigated using TEM for the first time in this study and are confirmed as short filiform microtriches consistent with published data on microthrix morphogy.
Claire J. Healy:
While cestodes of the freshwater stingrays of South America (the
potamotrygonids) have received much attention, cestodes of the 2 other
freshwater stingray species known worldwide are entirely unknown. Both
of these freshwater stingray species, Himantura chaophraya and H.
signifer, are reported from rivers in southeastern Asia and Australia,
and, at least H. chaophraya, is thought to be entirely restricted to
freshwater. In this study, we examined cestode parasites from 4
specimens of H. chaophraya from a river on the Cape York Peninsula,
Australia and 1 specimen of H. chaophraya from the Kinabatangan River,
Malaysian Borneo. Because of speculation about the conspecificity of
members of disjunct populations of H. chaophraya, individuals from
both localities were photographed in the field, and tissue samples were
preserved for molecular analysis. Cestodes were examined with light
microscopy. In some cases, scanning electron microscopy was conducted
and/or histological sections were prepared. A total of 7 cestode species
were recovered from the Australian specimen of H. chaophraya, and at
least 19 cestode species from the Malaysian specimens of H.
chaophraya. Many, if not all, of these 26 cestode species are new to
science. The orders Tetraphyllidea, Lecanicephalidea, and Trypanorhyncha
were represented in the cestode faunas from both localities. This is the
first report of members of the order Lecanicephalidea from freshwater.
Species in the genera Rhinebothrium, Acanthobothrium,
Polypocephalus, and Tetragonocephalum were found in both localities.
Despite the limited number of individuals of H. chaophraya examined,
this study suggests that all tetraphyllidean and trypanorhynchan species
and most if not all lecanicephalidean species are unique to the hosts in
each locality. The different cestode faunas of these hosts may thus
reflect the different evolutionary histories of these putative species.
In fact, morphological features of the hosts suggest that the members of
the 2 “H. chaophraya” populations sampled here may not be conspecific.
Whereas the cestode fauna of potamotrygonids is somewhat depauperate
compared to that of marine stingrays, the cestode fauna of H.
chaophraya from both localities is more similar in diversity to that of
their marine counterparts.
Plants in the Cape Floristic Region of South Africa (CFR) have undergone a
radiation associated with the onset of Mediterranean climate some 10 million
years ago. The result is high species diversity, primarily resulting from
species turnover across the region. Distributions of closely related species
tend to be allopatric, with little coexistence. To what extent is this
pattern of allopatry caused by niche partitioning by species, versus by
isolation through dispersal limitation? The first year of data from
reciprocal transplants of a representative group of Proteaceae suggest that
1) species tend to perform better in within their native ranges; 2) but some
species can establish and grow outside their home range; and 3) the entire
group is limited by winter cold (at high elevations) and summer drought (at
low elevations). Thus ecological factors reasonably define the group's joint
distribution, but not their allopatric individual distributions.
The ability to understand the biology and success of invasive plant species in their new ranges is increased when there is a sympatric native congener to compare it to. Celastrus orbiculatus is a liana introduced into the United States in the mid-1800s from East Asia as an ornamental plant. Celastrus scandens is native from the east coast of the United States and as far west as Wyoming. In the Northeast, C. orbiculatus is continuing to expand its range while C. scandens appears to be declining. One hypothesis for this decline is that the range of habitats tolerated for invasive C. orbiculatus is greater than that of C. scandens. Thus, if the habitats which C. scandens prefers are no longer available, a contributing factor to the decline of this species may be due to habitat loss. We transplanted these two species into ten different habitats in Connecticut that spanned a range of light and moisture conditions in order to compare their performances in terms of growth and mortality after two years. The two species showed differences in mortality as well as growth depending on the light and moisture available to them, with C. orbiculatus having significantly lower mortality and higher growth across all habitats. The results of this study may point to an additional cause of decline of C. scandens in the Northeast.
Tropical secondary forests are increasing in global extent, with
potentially vast economic and biological consequences. Lianas (woody vines)
are an important structural component of tropical forests, but their role
during forest succession is not well understood. I propose to examine the
density, distribution, and species composition of lianas in forests of
varying age and land use history in the Sarapiquí region of Costa Rica. I
will present results from three vegetation survey transects completed during
the summer of 2004, and plans for future research: more survey transects, a
seedling dynamics study, and a liana removal experiment, designed to
elucidate the role of lianas at various stages of forest succession.
Christopher T. Martine:
A recent expedition was made to northwestern Australia to locate populations of about two dozen uncommon plant species of the Nightshade family. Known in Australia as “bush tomatoes” because of their close relationship to tomatoes, eggplants, and other members of the genus Solanum, this group of species is notable for having unusual sex forms. Roughly half of the bush tomatoes known from northwestern Australia (11 of 23) possess a system of separated sexes known as dioecy, a condition present in only about 10% of all angiosperms and 1% of the large genus Solanum. The frequency of dioecy in the study group, coupled with the co-occurrence of andromonoecy (male and hermaphrodite flowers on each plant), makes this an ideal system to study the evolution of a rare sexual condition. Prior to this expedition, none of these species were in cultivation, many were represented in herbaria by a just a few aging specimens, and some were yet to be discovered and/or described. Over the course of six weeks in the field, the PI traveled and collected, with the help of Australian collaborators, in two primary areas: Kakadu National Park and the northern Kimberley Plateau. 218 collections, representing 23 Solanum species, were made. DNA extractions of field-collected material have been successful and phylogenies have been generated using the ITS nuclear gene region and the trnT-F chloroplast region. Phylogenetic analyses support the hypothesis that dioecy has evolved from andromonoecy in this group, and may have done so twice independently.
Tsitsi Y. McPherson:
The question of what drives tropical diversity patterns continues to confound ecologists. Explanatory factors have ranged from abiotic factors of soil, temperature and rainfall to familiar biotic interactions of resource utilization, competition, predation, and disease. I present results of a floristic study at La Selva, Costa Rica, collected as part of the Carbono Project, established in 1997. All individuals greater than 10 cm diameter at breast height (dbh) were measured in 18 plots, each 0.5 ha. Plots were located on inceptisols and ultisols and at two different topographies, flat and sloped. Results include (i) the role of nutrients in determining species presence or absence for dominant species (Pentaclethra macroloba, Iriartea deltoidea, Socretea exorrhiza, and Welfia regia), subdominant species, low abundance species, palms, and tree size among species; and (ii) the influence of soil nutrients on species composition between plots on different soil types.
Nicola Joy Raine Plowes:
Territoriality in social insects can impact population structure and dynamics by limiting overall numbers of colonies, or establishment of colonies. Territory models have tended to concentrate on the higher level organization of the colony rather than that of the individual. I am interested in how the fighting tactics of individual ants, and their behavioral patterns translate into territory establishment and maintenance by ant colonies. I will introduce the system I am working with, describe my methods, and present some preliminary data.
The fraterna species complex in the scarab genus Phyllophaga is currently comprised of approximately 30 taxa with wildly complex and diverse asymmetrical male genitalia as well as species-specific female genitalia. It is hypothesized that post-copulatory sexual selection is responsible for the observed genitalic diversity among species because external morphology appears evolutionarily static, and females are polygamous. To test this hypothesis, I am integrating inter- and intra-specific analyses of character evolution and patterns of selection. I have begun a molecular phylogeny using 1200 base pairs of the mitochondrial gene cytochrome oxidase subunit I (COI) to determine the evolutionary history of the genitalic morphology. The mitochondrial lineages do not appear to support the boundaries suggested by historical taxonomists, which are based primarily on male genitalic morphology. I have also performed a morphometric analysis of intraspecific shape variation of male and female genitalia in the species P. hirticula to determine if there is sufficient variation upon which selection can act. Indeed, male and female are significantly more variable than an external morphological character presumed to be under stabilizing selection. In addition, female genitalia have significantly higher variation than male genitalia. These initial studies of the evolution of genitalia in this species complex provide preliminary evidence that selection is acting to produce diverse, asymmetric genitalia. Future work will focus on how the interaction of male and female reproductive morphologies can influence post-copulatory sexual selection.
Evolutionary radiations are explosive bouts of speciation that can
result from either adaptive or neutral divergence. They have produced
much of the world’s biodiversity and thus are an important evolutionary
process to study. However, it is not know the extent to which
evolutionary radiations are in general mostly adaptive.
I propose using the Proteaceae of Australia and South Africa to study
the relative roles of neutral and adaptive evolutionary forces in
evolutionary radiations. This family underwent radiations on these two
continents at about the same time. Studying these twin radiations will
allow the types of comparisons that will shed light on these questions
about the evolution of biodiversity.
Nanci J. Ross:
The crisis of biodiversity losses in the New World tropics requires a paradigm for sustainable management of the forest. The ancient Maya culture dominated Mesoamerica for millennia; their silvicultural practices could provide a framework for such a paradigm. The descendants of the ancient Maya practice similar silvicultural methods as their ancestors, tending private orchard gardens. These highly managed “forests” are diverse and closely resemble unmanaged forest. In ancient times, with the high population estimates currently posed for the Maya populations, these individual orchard gardens may have protected forest biodiversity. In addition, the selection of certain key species may have resulted in a pattern of species composition that is still visible in the contemporary forest.
Metalmark moths (Lepidoptera: Choreutidae) are a relatively small
microlepidopteran family. About 400 species have been described. Most
of them are found in the tropical areas. The morphology and natural
history of metalmark moth immature stages are poorly known. Using a few
examples drawn from larvae and pupae of different choreutid genera, I
will demonstrate how morphology and natural history interconnect to
make phylogenetic trees more interesting
The Menyanthaceae are an aquatic plant family of five genera. Species are
distributed worldwide, and all are adapted for aquatic or wetland growth.
They possess a range of floral morphology, including hermaphroditism and
dioecy, as well as heterostyly. In addition, members of the submerged and
floating-leaved genus Nymphoides have a broad suite of vegetative characters
that aid their aquatic growth form. Preliminary analysis of molecular data
support the division of Menyanthaceae into five genera. Further analysis of
DNA characters should answer questions about the origins and evolutionary
trajectories of adaptive features within the family.
Colin A. Young:
With the rampant and increasing rates of deforestation and acculturation of local and indigenous cultures throughout the world, there is a real sense of urgency for ethnobotanical research to prevent the loss of ethnobotanical knowledge. However, while ethnobotanists are often “working against time” to document the ethnobotanical lore of indigenous peoples, very little attention has been placed on the reliability of information obtained from indigenous peoples. Data from repeated “walks in the woods” among Belizean Creole collaborators demonstrate that while “respected” collaborators are very reliable with most taxa, they tend to be unreliable with novel or unknown taxa. Other collaborators are usually only 60-70% reliable and tend to “invent” names and uses of both unknown and relatively common taxa. These results may have important ramifications for the quality of ethnobotanical data collected from local and indigenous collaborators. In addition, these results suggest that!
it is imperative that ethnobotanists conduct reliability checks among their collaborators before publishing.
2005 Symposium committee: