Biology Commons^™

Arthropod Organic Anion Transporting Polypeptides In Tick-Borne Bacterial And Viral Infections, Vikas Kumar Taank

Biomedical Sciences Theses & Dissertations

Vector-borne diseases (VBDs) are human illness transmitted by an arthropod vector. World Health Organization (WHO) estimates that VBD has a huge impact worldwide that is responsible for affecting a billion people and causes 700,000 deaths annually. In recent years, there has been a continuous increase in the incidences of tick-borne diseases such as Lyme diseases and human anaplasmosis as reported by Center for Disease Control and Prevention. Very few reliable VBD control strategies have emerged till now. Transmission-blocking vaccines can provide effective management of VBDs but requires identification and characterization of novel vector-pathogen conserved molecules that play a significant role …

Coupling Metaproteomics With Taxonomy To Determine Responses Of Bacterioplankton To Organic Perturbations In The Western Arctic Ocean, Molly P. Mikan

OES Theses and Dissertations

Understanding how the functionality of marine microbial communities change over time and space, and which taxonomic groups dominate distinct metabolic pathways, are essential to understanding the ecology of these microbiomes and the factors contributing to their regulation of elemental cycles in the oceans. The primary goal of this dissertation was to investigate the community metabolic and taxonomic responses and the degradation potential of two compositionally distinct marine microbiomes within the shallow shelf ecosystem of the Chukchi Sea after rapid fluctuations in algal organic matter availability. Novel bioinformatics tools were collaboratively developed and used together with community proteomics (metaproteomics) to characterize …

Cryptic Herbivorous Invertebrates Restructure The Composition Of Degraded Coral Reef Communities In The Florida Keys, Florida, Usa, Angelo Jason Spadaro

Biological Sciences Theses & Dissertations

Coral reefs have been on a trajectory of decline for nearly a century due to a variety of factors that have contributed to the shift in these communities away from dominance by reef-building corals, with commensurate changes on community composition and function. Florida’s reefs are a compelling example of a degraded system that has undergone a phase shift, and thus offered an excellent model system for my study of the effects of grazing by cryptic herbivores on community composition and their potential restoration value. I had four major objectives: (1) determine the suitability of Maguimithrax spinosissimus for manipulating grazing intensity …

Cryptic Lineages And A Population Damned To Incipient Extinction? Insights Into The Genetic Structure Of A Mekong River Catfish, Amanda S. Ackiss, Binh T. Dang, Christopher E. Bird, Ellen E. Biesack, Phen Chheng, Latsamy Phounvisouk, Quyen H.D. Vu, Sophorn Uy, Kent E. Carpenter

Biological Sciences Faculty Publications

An understanding of the genetic composition of populations across management boundaries is vital to developing successful strategies for sustaining biodiversity and food resources. This is especially important in ecosystems where habitat fragmentation has altered baseline patterns of gene flow, dividing natural populations into smaller sub-populations and increasing potential loss of genetic variation through genetic drift. River systems can be highly fragmented by dams built for flow regulation and hydropower. We used reduced-representation sequencing to examine genomic patterns in an exploited catfish, Hemibagrus spilopterus, in a hotspot of biodiversity and hydropower development- the Mekong River basin. Our results revealed the …

Selective Distant Electrostimulation By Synchronized Bipolar Nanosecond Pulses, Elena C. Gianulis, Maura Casciola, Carol Zhou, Enbo Yang, Shu Xiao, Andrei G. Pakhomov

Bioelectrics Publications

A unique aspect of electrostimulation (ES) with nanosecond electric pulses (nsEP) is the inhibition of effects when the polarity is reversed. This bipolar cancellation feature makes bipolar nsEP less efficient at biostimulation than unipolar nsEP. We propose to minimize stimulation near pulse-delivering electrodes by applying bipolar nsEP, whereas the superposition of two phase-shifted bipolar nsEP from two independent sources yields a biologically-effective unipolar pulse remotely. This is accomplished by electrical compensation of all nsEP phases except the first one, resulting in the restoration of stimulation efficiency due to cancellation of bipolar cancellation (CANCAN-ES). We experimentally proved the CANCAN-ES paradigm by …

Modeling The Seasonal Cycle Of Iron And Carbon Fluxes In The Amundsen Sea Polynya, Antarctica, P. St-Laurent, P. L. Yager, R. M. Sherrell, H. Oliver, M. S. Dinniman, S. E. Stammerjohn

CCPO Publications

The Amundsen Sea Polynya (ASP) is distinguished by having the highest net primary production per unit area in the coastal Antarctic. Recent studies have related this high productivity to the presence of fast-melting ice shelves, but the mechanisms involved are not well understood. In this study we describe the first numerical model of the ASP to represent explicitly the ocean-ice interactions, nitrogen and iron cycles, and the coastal circulation at high resolution. The study focuses on the seasonal cycle of iron and carbon, and the results are broadly consistent with field observations collected during the summer of 2010–2011. The simulated …

Habitat Saturation Results In Joint-Nesting Female Coalitions In A Social Bird, Sahas Barve, Walter D. Koenig, Joseph Haydock, Eric L. Walters

Biological Sciences Faculty Publications

Joint nesting by females and cooperative polyandry—cooperatively breeding groups with a male-biased breeder sex ratio—are little-understood, rare breeding systems. We tested alternative hypotheses of factors potentially driving these phenomena in a population of joint-nesting acorn woodpeckers (Melanerpes formicivorus). During periods of high population density and thus low independent breeding opportunities, acorn woodpecker females formed joint-nesting coalitions with close kin. Coalitions were typically associated with groups with a male bias. We found strong evidence for both inter- and intrasexual conflict, as joint nesting conferred a fitness benefit to some males, a significant fitness cost to females, and no gain in per …

Seasonal Spatial Segregation In Blue Sharks (Prionace Glauca) By Sex And Size Class In The Northeast Pacific Ocean, Sara M. Maxwell, Kylie L. Scales, Steven Bograd, Dana K. Briscoe, Heidi Dewar, Elliott L. Hazen, Rebecca L. Lewison, Heather Welch, Larry B. Crowder

Biological Sciences Faculty Publications

Aim: Animal tracking can provide unique insights into the ecology and conservation of marine species, such as the partitioning of habitat, including differences between life history stages or sexes, and can inform fisheries stock assessments, bycatch reduction and spatial management such as dynamic management.

Location: Northeast Pacific Ocean.

Methods: We used satellite tracking data from 47 blue sharks (Prionace glauca) from the Northeast Pacific to determine movements and home range along the west coast of North America, and sex–size class (immature females, mature males) specific habitat preferences using boosted regression trees. Using a suite of static and dynamic …

Dynamics Of Two Pathogens In A Single Tick Population, Alexis White, Elsa Schaefer, Chelsea Wright-Thompson, Christopher M. Kribs, Holly Gaff

Biological Sciences Faculty Publications

A mathematical model for a two-pathogen, one-tick, one-host system is presented and explored. The goal of this model is to determine how long an invading pathogen persists within a tick population in which a resident pathogen is already established. The numerical simulations of the model demonstrate the parameter ranges that allow for coexistence of the two pathogens. Sensitivity analysis highlights the importance of vector-borne, tick-to-host, transmission rates on the invasion reproductive number and persistence of the pathogens over time. The model is then applied to a case study based on a reclaimed swampland field site in southeastern Virginia using field …

Field Testing Integrated Interventions For Schistosomiasis Elimination In The People's Republic Of China: Outcomes Of A Multifactorial Cluster-Randomized Controlled Trial, Gail M. Williams, Yue-Sheng Li, Darren J. Gray, Zheng-Yuan Zhao, Donald A. Harn, Lisa M. Shollenberger, Sheng-Ming Li, Xinglin Yu, Zeng Feng, Jia-Gang Guo, Jie Zhou, Yu-Lan Dong, Yuan Li, Biao Guo, Patrick Driguez, Marina Harvie, Hong You, Allen G. Ross, Donald P. Mcmanus

Biological Sciences Faculty Publications

Despite significant progress, China faces the challenge of re-emerging schistosomiasis transmission in currently controlled areas due, in part, to the presence of a range of animal reservoirs, notably water buffalo and cattle, which can harbor Schistosoma japonicum infections. Environmental, ecological and social-demographic changes in China, shown to affect the distribution of oncomelanid snails, can also impact future schistosomiasis transmission. In light of their importance in the S. japonicum, lifecycle, vaccination has been proposed as a means to reduce the excretion of egg from cattle and buffalo, thereby interrupting transmission from these reservoir hosts to snails. A DNA-based vaccine (SjCTPI) …

Editorial: Advances In The Biology And Conservation Of Marine Turtles, Sara M. Maxwell, Annette C. Broderick, Peter H. Dutton, Sabrina Fossette-Halot, Mariana M.P.B. Fuentes, Richard D. Reina

Biological Sciences Faculty Publications

(First Paragraph) Marine turtles have been the subject of research over many decades, inspired by their unique life history and necessitated by their declining populations from a suite of human impacts including direct harvest, bycatch in marine fisheries, pollution, and climate change. Despite this, much about marine turtle biology has remained a mystery (Godley et al., 2008; Rees et al., 2016; Wildermann et al., 2018), but the rate of scientific discovery is increasing rapidly. As research techniques and conservation practices expand, the marine turtle research community has kept abreast of these developments and their application to marine turtles. In this …

Vitellogenin Receptor As A Target For Tick Control: A Mini-Review, Robert D. Mitchell Iii, Daniel E. Sonenshine, Adalberto A. Pérez De León

Biological Sciences Faculty Publications

While much effort has been put into understanding vitellogenesis in insects and other organisms, much less is known of this process in ticks. There are several steps that facilitate yolk formation in developing oocytes of which the vitellogenin receptor (VgR) is a key component. The tick VgR binds vitellogenin (Vg) circulating in the hemolymph to initiate receptor-mediated endocytosis and its transformation into vitellin (Vn). The conversion of Vg into Vn, the final form of the yolk protein, occurs inside oocytes of the female tick ovary. Vn is critical to tick embryos since it serves as the nutritional source for their …

Multistate Survey Of American Dog Ticks (Dermacentor Variabilis) For Rickettsia Species, Joy A. Hecht, Michelle E.J. Allerdice, Elizabeth A. Dykstra, Laura Mastel, Rebecca J. Eisen, Tammi L. Johnson, Holly D. Gaff, Andrea S. Varela-Stokes, Jerome Goddard, Benedict B. Pagac, Christopher D. Paddock, Sandor E. Karpathy

Biological Sciences Faculty Publications

Dermacentor variabilis, a common human-biting tick found throughout the eastern half and along the west coast of the United States, is a vector of multiple bacterial pathogens. Historically, D. variabilis has been considered a primary vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever. A total of 883 adult D. variabilis, collected between 2012 and 2017 from various locations in 12 states across the United States, were screened for rickettsial DNA. Tick extracts were evaluated using three real-time PCR assays; an R. rickettsii-specific assay, a Rickettsia bellii-specific assay, and a Rickettsia genus-specific …

Demographic Response Of The Gambian Gerbil To Seasonal Changes In Savannah Fallow Fields, Safianu Rabiu, Robert K. Rose

Biological Sciences Faculty Publications

The Savannah gerbil, Gerbilliscus gambianus (Muridae: Gerbillinae) is important to the ecological relations of the dry grassland ecosystem of West Africa, as well as, being a zoonotic agent of human diseases and po-tential crop pest. We examined the impact of seasonal changes on the population dynamics of G. gambianus in northern Nigeria, by completing population estimates using capture–mark–recapture (CMR) and indirect population density indices (PDI) methods. The latter included fecal pellet counts and limited spotlightening. During 1990–1992 we collected both CMR and PDI data, and established their relationship by regression, thus calibrating the PDI values to CMR estimator. We also …

Anti-C1q Autoantibodies Are Frequently Detected In Patients With Systemic Sclerosis Associated With Pulmonary Fibrosis, C. Liaskos, S. Rentouli, T. Simopoulou, A. Gkoutzourelas, G. L. Norman, A. Brotis, I. Alexiou, C. Katsiari, D. P. Bogdanos, L. I. Sakkas

Biological Sciences Faculty Publications

BACKGROUND: Anti-C1q autoantibodies (autoAbs) are associated with systemic lupus erythematosus (SLE) but their presence in other rheumatic diseases has not been adequately investigated.

OBJECTIVE: We aim to assessanti-C1q autoAbs and circulating immune complexes (CICs) in systemic sclerosis (SSc).

METHODS: One hundred twenty four patients with SSc (106 females; median age 59.4 years, range 25-81.4; 75(60.5%) with limited cutaneous SSc[lcSSc], and 49(39.5%) with diffuse cutaneous SSc[dcSSc]), were studied. Twenty-five patients with Sjögren's syndrome (SjS), 29 with rheumatoid arthritis (RA), and 38 patients with systemic lupus erythematosus (SLE) and 53 healthy controls (NC) were also included. ELISAs with high and low salt …

Exosomes Mediate Zika Virus Transmission Through Smpd3 Neutral Sphingomyelinase In Cortical Neurons, Wenshuo Zhou, Michael Woodson, Michael B. Sherman, Girish Neelakanta, Hameeda Sultana

Biological Sciences Faculty Publications

The harmful effects of ZIKA virus (ZIKV) infection are reflected by severe neurological manifestations such as microcephaly in neonates and other complications associated with Guillain-Barre syndrome in adults. The transmission dynamics of ZIKV in or between neurons, or within the developing brains of the foetuses are not fully understood. Using primary cultures of murine cortical neurons, we show that ZIKV uses exosomes as mediators of viral transmission between neurons. Cryo-electron microscopy showed heterogeneous population of neuronal exosomes with a size range of 30-200 nm. Increased production of exosomes from neuronal cells was noted upon ZIKV infection. Neuronal exosomes contained both …

Prime-Boost Vaccine Regimen For Sjtpl And Sjc23 Schistosome Vaccines, Increases Efficacy In Water Buffalo In A Field Trial In China, Akram A. Da'dara, Changlin Li, Xinling Yu, Mao Zheng, Jie Zhou, Lisa M. Shollenberger, Yue-Sheng Li, Donald A. Ham

Biological Sciences Faculty Publications

Schistosomiasis remains a serious zoonotic disease in China and the Philippines. Water buffalo and cattle account for the majority of transmission. Vaccination of water buffalo is considered a key strategy to reduce disease prevalence. Previously, we showed that vaccination of water buffalo with SjC23 or SjCTPI plasmid DNA vaccines, induced 50% efficacy to challenge infection. Here, we evaluated several parameters to determine if we can develop a two dose vaccine that maintains the efficacy of the three dose vaccine. We performed four trials evaluating: (1) lab produced vs. GLP grade vaccines, (2) varying the time between prime and boost, (3) …

Clonally Expanded Alpha-Chain T-Cell Receptor (Tcr) Transcripts Are Present In Aneurysmal Lesions Of Patients With Abdominal Aortic Aneurysm (Aaa), Song Lu, John V. White, Raquel I. Judy, Lisa L. Merritt, Wan Lu Lin, Xiaoying Zhang, Charalambos Solomides, Ifeyinwa Nwaneshiudu, John Gaughan, Dimitri S. Monos, Emilia L. Oleszak, Chris D. Platsoucas

Biological Sciences Faculty Publications

Abdominal aortic aneurysm (AAA) is a life-threatening immunological disease responsible for 1 to 2% of all deaths in 65 year old or older individuals. Although mononuclear cell infiltrates have been demonstrated in AAA lesions and autoimmunity may be responsible for the initiation and account for the propagation of the disease, the information available about the pathogenesis of AAA is limited. To examine whether AAA lesions from patients with AAA contain clonally expanded α-chain TCR transcripts, we amplified by the non-palindromic adaptor-PCR (NPA-PCR)/Vα-specific PCR and/or the Vα-specific PCR these α-chain TCR transcripts. The amplified transcripts were cloned and sequenced. Substantial proportions …

Mapping Status And Conservation Of Global At-Risk Marine Biodiversity, Casey C. O'Hara, Juan Carlos Villaseñor-Derbez, Gina M. Ralph, Benjamin S. Halpern

Biological Sciences Faculty Publications

To conserve marine biodiversity, we must first understand the spatial distribution and status of at‐risk biodiversity. We combined range maps and conservation status for 5,291 marine species to map the global distribution of extinction risk of marine biodiversity. We find that for 83% of the ocean, >25% of assessed species are considered threatened, and 15% of the ocean shows >50% of assessed species threatened when weighting for range‐limited species. By comparing mean extinction risk of marine biodiversity to no‐take marine reserve placement, we identify regions where reserves preferentially afford proactive protection (i.e., preserving low‐risk areas) or reactive protection (i.e., mitigating …

Parasitic Dinoflagellate Hematodinium Perezi Prevalence In Larval And Juvenile Blue Crabs Callinectes Sapidus From Coastal Bays Of Virginia, H. J. Small, J. P. Huchin-Mian, K. S. Reece, K. M. Pagenkopp Lohan, Mark J. Butler Iv, J. D. Shields

Biological Sciences Faculty Publications

The parasitic dinoflagellate Hematodinium perezi infects the American blue crab Callinectes sapidus and other decapods along the Eastern seaboard and Gulf of Mexico coast of the USA. Large juvenile and adult blue crabs experience high mortality during seasonal outbreaks of H. perezi, but less is known about its presence in the early life history stages of this host. We determined the prevalence of H. perezi in megalopae and early benthic juvenile crabs from multiple locations along the Virginia portion of the Delmarva Peninsula. The DNA of H. perezi was not detected in any megalopae collected from several locations within …

Natural History Of The Eastern Harvest Mouse In Southeastern Virginia, Robert K. Rose

Biological Sciences Faculty Publications

The Eastern Harvest Mouse, Reithrodontomys humulis, has been studied extensively in southeastern Virginia since 1979, using a combination of live and pitfall trapping methods. This smallest rodent of eastern North America also is one of most versatile, occupying a range of habitats in southeastern Virginia from old fields in different stages of succession, brushy edges, and forests of different types. As with other species of Reithrodontomys, R. humulis often is associated with the Hispid Cotton Rat, Sigmodon hispidus, with both reaching modest densities in old fields. Two capture-mark-release studies of small mammal communities in southern Chesapeake lasting …

Metagenomic Sequencing Identifies Highly Diverse Assemblages Of Dinoflagellate Cysts In Sediments From Ships' Ballast Tanks, Lixia Shang, Zhangxi Hu, Yunyan Deng, Yuyang Liu, Xinyu Zhai, Zhaoyang Chai, Xiaohan Liu, Zifeng Zhan, Fred C. Dobbs, Ying Zhong Tang

OES Faculty Publications

Ships' ballast tanks have long been known as vectors for the introduction of organisms. We applied next-generation sequencing to detect dinoflagellates (mainly as cysts) in 32 ballast tank sediments collected during 2001-2003 from ships entering the Great Lakes or Chesapeake Bay and subsequently archived. Seventy-three dinoflagellates were fully identified to species level by this metagenomic approach and single-cell polymerase chain reaction (PCR)-based sequencing, including 19 toxic species, 36 harmful algal bloom (HAB) forming species, 22 previously unreported as producing cysts, and 55 reported from ballast tank sediments for the first time (including 13 freshwater species), plus 545 operational taxonomic units …

High-Frequency Temperature Variability Mirrors Fixed Differences In Thermal Limits Of The Massive Coral Porites Lobata, Daniel J. Barshis, Charles Birkeland, Robert J. Toonen, Ruth D. Gates, Jonathon H. Stillman

Biological Sciences Faculty Publications

Spatial heterogeneity in environmental characteristics can drive adaptive differentiation when contrasting environments exert divergent selection pressures. This environmental and genetic heterogeneity can substantially influence population and community resilience to disturbance events. Here, we investigated corals from the highly variable back-reef habitats of Ofu Island in American Samoa that thrive in thermal conditions known to elicit widespread bleaching and mortality elsewhere. To investigate the relative importance of acclimation versus site of origin in shaping previously observed differences in coral tolerance limits at Ofu Island, specimens of the common Indo-Pacific coral Porites lobata from locations with differing levels of thermal variability were …

Emerging Roles Of The Membrane Potential: Action Beyond The Action Potential, Lina Abdul Kadir, Michael Stacey, Richard Barrett-Jolley

Bioelectrics Publications

Whilst the phenomenon of an electrical resting membrane potential (RMP) is a central tenet of biology, it is nearly always discussed as a phenomenon that facilitates the propagation of action potentials in excitable tissue, muscle, and nerve. However, as ion channel research shifts beyond these tissues, it became clear that the RMP is a feature of virtually all cells studied. The RMP is maintained by the cell's compliment of ion channels. Transcriptome sequencing is increasingly revealing that equally rich compliments of ion channels exist in both excitable and non-excitable tissue. In this review, we discuss a range of critical roles …

Local Adaptation Signatures In Thermal Performance Of The Temperate Coral Astrangia Poculata, Hannah Elise Aichelman

Biological Sciences Theses & Dissertations

The Northern Star Coral (Astrangia poculata) is an understudied temperate scleractinian coral that provides unique opportunities to understand the roles of phenotypic plasticity and local adaptation in coral physiological tolerance limits. Astrangia poculata inhabits hard bottom ecosystems from the northwestern Atlantic to the Gulf of Mexico and withstands an annual temperature range up to 20°C. Additionally, A. poculata is facultatively symbiotic and co-occurs in both symbiotic (“brown”) and aposymbiotic (“white”) states. Here, brown and white A. poculata were collected from Virginia (VA) and Rhode Island (RI), USA and exposed to heat (18-32°C) and cold (18-6°C) temperature assays during …

Arthropod Transcriptional Activator Protein-1 (Ap-1) Aids Tick-Rickettsial Pathogen Survival In The Cold, Supreet Khanal, Vikas Taank, John F. Anderson, Hameeda Sultana, Girish Neelakanta

Biological Sciences Faculty Publications

Ixodes scapularis ticks transmit several pathogens to humans including rickettsial bacterium, Anaplasma phagocytophilum. Here, we report that A. phagocytophilum uses tick transcriptional activator protein-1 (AP-1) as a molecular switch in the regulation of arthropod antifreeze gene, iafgp. RNAi-mediated silencing of ap-1 expression significantly affected iafgp gene expression and A. phagocytophilum burden in ticks upon acquisition from the murine host. Gel shift assays provide evidence that both the bacterium and AP-1 influences iafgp promoter and expression. The luciferase assays revealed that a region of approximately 700 bp upstream of the antifreeze gene is sufficient for AP-1 binding to promote …

Identifying Marine Key Biodiversity Areas In The Greater Caribbean Region, Michael S. Harvey

Biological Sciences Theses & Dissertations

Anthropocene biodiversity extinction rates are increasing, suggesting a possible sixth global mass extinction event. Biological conservation planners are consequently seeking ways to more effectively protect species at national, regional and global scales. In 2010, the Convention on Biological Diversity (CBD) issued a number of conservation goals (Aichi Targets), including the establishment of protected areas (PA) in terrestrial, freshwater and marine areas of eminent conservation concern by 2020 to reduce and eventually eliminate species’ extinctions, as well as preserve hotspots of biodiversity and dynamic ecosystems. While well-established, adequately enforced PAs increase the likelihood of preserving species and habitats most at risk …

Zika Modulates Arthropod Histone Methylation In Mosquito Cells, Telvin Lee Harrell

Biological Sciences Theses & Dissertations

Epigenetics is the heritable series of covalent modifications that affect chromatin structure, gene expression, and protein function. Methylation is one such epigenetic modification that involves the addition of chemical modifying entities, such as methyl groups, on nucleic acids or proteins. Recent studies have reported that Zika virus (ZIKV) modulates methylation of human and viral RNA important for its replication in vertebrate cells. However, little is known whether ZIKV exerts methylation in arthropod vectors. In this study, I show that ZIKV modulates S-adenosyl methionine (SAMe) synthase, an enzyme involved in the production of SAMe, and histone methylation for its survival in …

Potential Interaction Analysis Of Offshore Wind Energy Areas And Breeding Avian Species On The Us Mid-Atlantic Coast, Jeri Lynn Wisman

Biological Sciences Theses & Dissertations

Due to increasing US interest in developing wind energy sites in offshore waters, we synthesized existing data on colonial breeding seabird populations with the potential risk of interacting with lease areas in the mid-Atlantic. Previous efforts by BOEM and NOAA have predicted avian density using at-sea survey data; we seek to complement this work by focusing specifically on birds during the critical and energetically demanding breeding life history stage. We combined colony size and location for each species along the mid-Atlantic coast with buffers around the colonies that correlate with the species’ foraging range. We integrated population size, vulnerability to …

Reproductive Correlates Of A Perineal Gland In The Hispid Cotton Rat, Robert K. Rose, Julie A. Winchell

Virginia Journal of Science

During studies of the annual cycle of reproduction in the hispid cotton rat (Sigmodon hispidus) in southeastern Virginia, we discovered an anal (more specifically, perineal) gland that is present only in males during the breeding season.  The perineal gland encircles the lower end of the rectum and has ductal connections to the urethra, through which its secretions probably are delivered.  This fatty gland is highly developed in breeding males but, like the testes and seminal vesicles, regresses during the winter non-breeding season. The prominence and cyclicity of the perineal gland suggest that it somehow facilitates normal reproduction.  The …