J. Dylan Maddox

Field Museum of Natural History

Multiple factors potentially affect nestling survival and maternal reproductive success. However, little is known about the relative importance of different factors when operating simultaneously or whether the same factors are important for nestlings and their mothers. We determined the effect of hatching asynchrony, individual egg size, mean egg s...

The occurrence of extrapair paternity (EPP) in socially monogamous species varies greatly among species and across latitudes. Recent work suggests that birds residing in less seasonal, tropical environments will have lower levels of EPP than seasonal tropical and temperate species. Less seasonal tropical birds are predicted to have the lowest rates...

The factors that affect survival until reproduction are essential to understanding the organization of life histories within and among species. Theory predicts, for example, that survival until reproduction influences the optimum level of reproductive investment by parents, which might partly explain prolonged parental care in species with high fir...

Despite the general importance of replication in science, relatively few behavioral ecology studies are repeated. Here we repeat the seminal 1977 research of H. F. Howe, who found that the proportion of male nestlings at hatching in nests of Common Grackles (Quiscalus quiscula) increased as the breeding season progressed. Howe interpreted this patt...

In many animals large size at birth enhances offspring survival, but comparative evidence remains equivocal for birds. Failure to consider asynchronous hatching (ASH) may have confounded previous analyses. We assessed effects of egg size and ASH on growth and survival of common grackle (Quiscalus quiscula) nestlings to test the hypothesis that fema...

The Amazonian shrub Myrciaria dubia (Kunth) McVaugh, known as "camu-camu", produces vitamin C-rich fruits of growing commercial interest. However, sustainable utilization requires assessment and protection of the genetic diversity of the available germplasm. We hypothesized that the ex situ M. dubia germplasm bank assembled from eight river basins...

Hybridization is a known source of morphological, functional and communicative signal novelty in many organisms. Although diverse mechanisms of established novel ornamentation have been identified in natural populations, we lack an understanding of hybridization effects across levels of biological scales and upon phylogenies. Hummingbirds display d...

Africa’s montane ecosystems are noteworthy not only for their isolation but for their morphologically similar bird populations that inhabit geographically disparate localities. Many species possess range disjunctions in excess of 2,000 km and appear to represent populations that have been isolated since at least the last Ice Age, including the Nort...

Epigenetic mechanisms may play a central role in mediating phenotypic plasticity, especially during range expansions, when populations face a suite of novel environmental conditions. Individuals may differ in their epigenetic potential (EP; their capacity for epigenetic modifications of gene expression), which may affect their ability to colonize n...

Ankistrodesmus falcatus strain UCP001 is a native oleaginous microalgae isolated from the Peruvian Amazon basin. In this study we sequenced, de novo assembled, and functionally annotated the complete mitochondrial genome of the native oleaginous microalgae Ankistrodesmus falcatus strain UCP001 (Accesion number MT701044). This mitogenome is a typica...

A plausible strategy to mitigate socioeconomic problems in the Peruvian Amazon is through the sustainable exploitation of biodiversity resources, such as native microalgae. Several studies worldwide affirm that these microorganisms are excellent sources of higher value products for human nutrition and possess health-promoting biochemicals, but thes...

Synopsis Epigenetic potential, defined as the capacity for epigenetically-mediated phenotypic plasticity, may play an important role during range expansions. During range expansions, populations may encounter relatively novel challenges while experiencing lower genetic diversity. Phenotypic plasticity via epigenetic potential might be selectively a...

Myrciaria dubia “camu-camu” is a native shrub of the Amazon that is commonly found in areas that are flooded for three to four months during the annual hydrological cycle. This plant species is exceptional for its capacity to biosynthesize and accumulate important quantities of a variety of health-promoting phytochemicals, especially vitamin C [1],...

Microalgae are photosynthetic organisms with cosmopolitan distribution (i.e., marine, freshwater and terrestrial habitats) and possess a great diversity of species [1] and consequently an immense variation in biochemical compositions [2]. To date genomic information is available mainly from the model green microalga Chlamydomonas reinhardtii [3]. H...

Microsatellites are useful in studies of population genetics, sibship, and parentage. Here, we screened for microsatellites from multiple elasmobranch genomic libraries using an enrichment protocol followed by sequencing on an Illumina platform. We concurrently screened five and then nine genomes and describe the number of potential loci from each...

The white-sands forests or varillales of the Peruvian Amazon are characterized by their distinct physical characteristics, patchy distribution, and endemism [1,2]. Much research has been conducted on the specialized plant and animal communities that inhabit these ecosystems, yet their soil microbiomes have yet to be studied. Here we provide metagen...

Camu-camu is a shrub, native to the Amazon that thrives in areas where floodin is frequent. Genetically, the plant is characterized by a diploid genome and moderate genetic diversity. Several parts of the plant are used in traditional folk medicine to treat a variety of acute and chronic diseases. For over 50 years, the exceptionally high vitamin C...

Despite its status as a global biodiversity hotspot there is still much to be discovered about the birds of Madagascar, including a full accounting of species-level diversity and the avifauna's origins. The Bernieridae is a Malagasy endemic family that went unrecognized by science for decades and unnamed until 2010. This cryptic family has long rep...

Las microalgas son microorganismos fotosintéticos con gran potencial para abastecer las demandas energéticas mundiales. Sin embargo, los limitados conocimientos que se tienen de estos organismos, en particular a nivel molecular de los procesos metabólicos, han limitado su uso con estos propósitos. En esta investigación se ha realizado el análisis i...

Xylophagaid bivalves link terrestrial and deep-sea ecosystems by making energy and nutrients from sunken wood available to other animals. They bore into what can be sulphide-rich wood with their valves and digest it using bacterial enzymes. The evolutionary history of the roughly 60 named xylophagaid species remains largely unknown. We sequenced 18...

Accurately assigning hatchlings to the eggs from which they hatched is a prerequisite to understanding how the composition and environment of eggs affect the growth and survival of nestlings. Correctly assigning hatchlings to their eggs can be a challenging endeavor, however, because multiple eggs within the same clutch can hatch at essentially the...

Biodiesel production from microalgae triacylglycerols is growing, because this feedstock is a more sustainable and advantageous alternative. In this study, we isolated and identified fourteen strains of native microalgae from the Peruvian Amazon. These strains showed great heterogeneity in biomass productivity, lipid productivity and lipid content,...

Microalgae are a very diverse group of microorganisms with great potential for biotechnological applications. To best exploit these organisms is necessary to expand our knowledge at its molecular levels. To realize these studies, however, it is essential to have efficient and reproducible methods for total RNA isolation. The objective of this resea...

The three species in the genus Claravis (Aves: Peristerinae) are unique among members of the small New World ground-dove clade. All three species inhabit forested areas rather than open scrubby habitat, and exhibit obvious sexual dichromatism. However, the phylogenetic relationships within Claravis remain unknown. The only molecular phylogenetic st...

Myrciaria dubia 'camu-camu' is a rich source of several bioactive phytochemicals and vitamin C (L-ascorbic acid, AsA). To gain insights about the genes involved in AsA biosynthesis in this plant species and consequently with potential use for its biotechnological production, here we report the isolation and molecular cloning of partial gene sequenc...

Myrciaria dubia is an Amazonian fruit shrub that produces numerous bioactive phytochemicals, but is best known by its high L-ascorbic acid (AsA) content in fruits. Pronounced variation in AsA content has been observed both within and among individuals, but the genetic factors responsible for this variation are largely unknown. The goals of this res...

The aim of this work was to elucidate the molecular and biochemical mechanisms that control L-ascorbic acid (AsA) content variation in Myrciaria dubia. The AsA was quantified by high-performance liquid chromatography, gene expression by real-time quantitative PCR, and enzyme activities by spectrophotometric methods from leaves and immature fruits o...

The aim of this work was to elucidate the molecular and biochemical mechanisms that control L-ascorbic acid (AsA) content variation in Myrciaria dubia. The AsA was quantified by high-performance liquid chromatography, gene expression by real-time quantitative PCR, and enzyme activities by spectrophotometric methods from leaves and immature fruits o...

We describe a simple, cost-effective procedure for the in-house production of a 725 bp size standard that is suitable for use on automatic DNA analyzers. Using an orange fluorescent dye to label fragments of known sizes on the pUC-19 plasmid, our size standard enables the use of all four fluorescent dyes, and thus maximizes throughput on five dye s...

We used complementary methods to assess potential impacts of the EJ&E railroad corridor on composition and reproductive ecology of the breeding bird communities in nine natural areas from 2009–2012. We used a paired habitat comparison design in which we assessed the breeding bird communities in belts of habitat within 50 m of the EJ&E right-of-way...

We used complementary methods to assess potential impacts of the EJ&E railroad corridor on composition and reproductive ecology of the breeding bird communities in nine natural areas from 2009–2012. We used a paired habitat comparison design in which we assessed the breeding bird communities in belts of habitat within 50 m of the EJ&E right-of-way...

We used complementary methods to assess potential impacts of the EJ&E railroad corridor on composition and reproductive ecology of the breeding bird communities in nine natural areas from 2009–2012. We used a paired habitat comparison design in which we assessed the breeding bird communities in belts of habitat within 50 m of the EJ&E right-of-way...

Maternal effects are typically thought to enhance rather than reduce offspring performance, but asynchronous hatching (ASH) in birds typically produces a size hierarchy within a clutch that frequently reduces the growth and survival of nestlings from eggs that hatch later. Given that yolk steroids can significantly affect offspring phenotype and th...

Past studies of offspring sex ratios in birds have often relied on sexually size dimorphic species where nestling sex could be determined based on weight at a given age. DNA-based sexing techniques allow us to assess the accuracy of those techniques and to refine them for use when costs or convenience make DNA methods impractical. Using nestling Re...

We determined whether nests that did not receive eggs was attributable to cryptic nest predation (i.e. predation of eggs laid between nest checks) or nest abandonment in Common Grackles (Quiscalus quiscula). Nest predation was extremely low (∼2%), whereas more than 44% of 427 nests found during nest building never received an egg; this indicates th...

We examined nesting by seven native bird species in Illinois wetland habitats containing native cattail (Typha spp.) and non-native purple loosestrife (Lythrum salicaria) as nesting substrates in 2000 and 2001. Over the two seasons, we found 146 nests of seven species: 111 in cattail and 35 in purple loosestrife. Marsh wrens (Cistothorus palustris)...

We estimated and described the arthropod fauna on purple loosestrife (Lythrum salicaria) plants in northeastern Illinois wetlands. A total of 1063 individual arthropods were collected-930 insects and 133 arachnids. The average number of arthropods ranged from 19.00 to 86.75 individuals per loosestrife plants of a single root crown. We collected ind...

We observed male Dickcissels (Spiza americana) commonly feeding nestlings in Conservation Reserve Program (CRP) fields in 1997 in east-central Illinois. Male Dickcissels fed nestlings at six of the eight nests we observed, accounting for 37% of the total nest visits. Overall, females made significantly more nest visits than males. However, at the s...