College of Agriculture & Natural Resources
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Variations in Vocalizations of Fin Whales, Balaenoptera physalus, in the St. Lawrence River(1980) Edds, Peggy Louise; Buchler, Edward; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)Recordings were made of vocalizations from fin whales, Balaenoptera physalus from a fixed hydrophone in the St. Lawrence River between 28 June and 27 September 1979. Land-based observers monitored activity from a hillside hut while recordings were being made from a shoreline site. Photographs of dorsal fin variations were used to identify distinctive individuals. The 1522 sounds recorded were classified into 11 categories based on frequency and temporal characteristics. The predominant call was a descending sweep of frequencies. Parameters measured for this downsweep exhibited a dichotomy of characteristics which indicates calls with initial frequencies below 40 Hz have less variability than calls with initial frequencies above 40 Hz. In general, solitary animals produced primarily the lower frequency downsweeps. Higher frequency downsweeps were recorded from pairs or trios of fin whales. Solitary individuals did not exhibit unique variations in downsweep parameters. No clusters of values which might indicate uniquely individual ranges were consistently present in multiple animal recordings. The data suggest that the variability of fin whale vocalizations is primarily contextual rather than individual.Item Infant and Juvenile-Directed Care Behaviors in Adult Toque Macaques, Macaca Sinica(1985) Baker-Dittus, Anne; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)The identity of care-givers, and the distribution of care to young are examined in a free-ranging polygynous primate, Macaca sinica. Care behavior is used as one measure of investment in young. There is no evidence that dominance rank influences offspring sex, but high-ranking mothers provide more care to newborn infants than do low-ranking mothers. Mothers provide more care to infant and first year sons than to daughters. This supports Dittus's suggestion (1979, 1980) that mothers should schedule care to sons and daughters differently, providing high levels of care to sons before they emigrate from the natal group. Care to daughters is low per unit time, but continues over a long period because daughters remain in the natal group. Adult females, other than the mother, tolerate, groom and support young. These behaviors are low cost, relative to the high cost behaviors of nursing and carrying, which only mothers provide. Young tend to associate with adult female relatives. Unlike male-biased maternal care, adult female care is biased towards female young; and female young return care more than do male young . Adult female rank is positively correlated with the amount of support adult females provide to female young, and the amount of grooming they receive from female young. Adult female rank has no effect on any measure of association between adult females and male young. Taken together these findings suggest that reciprocal altruism has been important in shaping adult female interactions with young. Adult and subadult M. sinica males direct the low cost, affiliative behaviors of hugging, carrying and grooming towards male infants; and direct aggressive behaviors towards female infants. I suggest that the distribution of behaviors reflects their value to male and female young. Affiliative behaviors to male infants, and aggressive behaviors to female infants serve to channel infants into association with adults from whom they can learn appropriate sex-typical behaviors, and as such benefit both male and female infants. High cost care behaviors of support in agonistic interactions, and protection are provided only by the adult male, and are provided to male and female young equally.Item The Life Cycles, Ecology, and Evolution of the Witch-hazel Leaf Gall Aphid, Hormaphis hamamelidis (Fitch) (Homoptera: Aphidida)(1987) von Dohlen, Carol Dean; Gill, Doulgas E.; Zoology; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)Two divergent life cycles based on geographic location have been documented for the witch-hazel leaf gall aphid, Hormaphis hamamelidis (Fitch, 1851). At low elevations in northern Virginia, the aphid was found to have seven distinct generations alternating between the primary host, Witch-hazel (Hamamelis virginiana L.), and a secondary host, river birch (Betula nigra L.). These findings confirm the original published life cycle description from the same locality. A second, abbreviated life cycle consisting of only three generations restricted to witch-hazel was discovered at high (1000 m) elevations in north central and northwestern Virginia. Aphids with each life cycle were sympatric at an intermediate elevation site. Based on available life cycle and geographic data, a preliminary Phylogeny of the tribe Hormaphidini is proposed that suggests an unusual polarity in the evolution of aphid life cycles. Several features of intraspecific interactions and host-plant relations were examined in both lowland and highland populations of Hormaphis. In contrast to previous publications documenting severe competition, density effects, and habitat heterogeneity for another galling, host-alternating aphid, Pemphigus betae on Populus angustifolia, the effects of density and host-plant qualities on Hormaphis hamamelidis were fewer and more benign. Aphids did not compete for gall sites, and gall Position and final leaf area did not influence reproduction. High gall densities negatively affected gall growth and aphid fecundity. Factors accounting for the differences in Population dynamics between Hormaphis and Pemphigus are hypothesized and discussed.Item Age, Nutrition, and Bone Metabolism: Analyses of Effects Using a Short-Term In Vivo Bone Model(1987) Sinha, Rashmi; Soares, Jos; Nutritional Sciences Program; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)The preventative effects of dietary calcium, zinc, and vitamin D metabolites on the net loss of bone were assessed using rats of different ages. Biochemical changes were monitored in femurs, humeri, mandibles, scapulas, and tibias. In addition femora were sectioned into epiphyses-metaphyses and diaphyses to evaluate nutritional influences on the trabecular and cortical type bone. since measurable bone degradation due to aging and nutritional status requires long period of time, a short-term in vivo system was developed to simultaneously examine bone formation and resorption. The system consisted of subcutaneous implantation of demineralized (DB) and mineralized (MB) bone powders. There was evidence of bone formation and resorption in the DB and MB implants respectively, as assessed by marker enzyme (formation-alkaline phosphatase; resorption-acid phosphatase) activities, mineral concentrations, radioisotope incorporation, and histological studies. The results indicated that several different bone samples are required to adequately predict changes occurring in the skeletal system. The epiphysesmetaphyses of long bone is a useful sample site examining changes occurring in trabecular bone while the diaphysis can assess cortical bone status. There was decreased bone formation and resorption as assessed by alkaline and acid phosphatase activity in the MB and DB implants in the 24 month-old rats as compared to 2 month-old rats. Dietary calcium and zinc levels did not affect the overall status of the bones and implants in the aged rats. Conversely, in 2 month-old rats dietary calcium at 1.0% stimulated bone formation in the DB implant, whereas 0.2% calcium increased bone resorption in the MB implants. Furthermore, 75 ng dietary 1,25-dihydroxycholecalciferol (l,25(OH) 2 D) per day increased resorption in MB implant and inhibited mineralization of DB implants in the young rats. Dietary zinc at 300 ppm reduced bone calcification in 2 month-old. The results of these studies indicated that neither high levels of dietary calcium, nor zinc, act as prophylaxes to counteract bone loss due to aging. The dietary use of l,25(OH) 2 D in old animals needs to be investigated further, since results in young animals are contradictory with reports in older rats.Item Vertical Resource Partitioning and Sexuality of Three Sympatric Species of Red Sea Sandfishes (Xyrichtys melanopus, Labridae; Trichonotus nikii, Trichonotidae; Gorgasia sp., Congridae)(1988) Krall, Marianne Martha; Clark, Eugenie; Zoology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)Three species of marine sandfishes were studied from 1984 to 1986. Their inter- and intraspecific behavior was monitored during the daylight hours to examine interactions that could result in the vertical stratification of the species over the sandy bottom within the fringing and patch reefs in the north Red Sea. Horizontal plankton tows were taken at three heights and three times a day. These samples were compared to stomach contents of the fishes to determine the trophic relationships in the community and their affects on spatial relations between the species . Prey specificities of the fishes were determined by using an electivity measure. Using paraffin histology, Xyrichtys melanopus was determined to be a monandric protogynous hermaphrodite and Trichonotus nikii, a gonochorist. Previous work on the mating systems and territoriality of all three sandfish species helped in part to explain the vertical spatial arrangement of the sandfish species within the community. Effects of pollution on the b iota of the Northern Gulf of Aqaba are noted.Item The Biology of the Silphidae (Coleoptera): A Coded Bibliography(Maryland Agricultural Experiment Station, 1983-07) Young, Orrey P.This bibliography of Silphidae through 1981 includes primarily: 1. Publications in the United States containing information other than taxonomy and distribution. 2. Non-United States publications after 1927 containing any information on silphids. 3. Non-United States publications prior to 1928 containing information other than taxonomy and distribution.Item Pueraria lobata Willd. (Ohwi) kudxa: Limitations to Sexual Reproduction(1983) Abramovitz, Janet Naomi; Teramura, Alan H.; Botany; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)The success of kudzu, Pueraria lobata Willd. (Ohwi), as a weedy invader in the southeastern United States is a result of its rapid growth rate, high leaf area index and ability to reproduce vegetatively. Populations at three sites near College Park, Maryland varied in their growth and reproduction, leaf area index, specific leaf weight, vine elongation rates, raceme density and seed production and dispersal. Soil characteristics, air temperature, humidity and photosynthetically active radiation (PAR) were measured at each site. The site which had the greatest vegetative productivity received significantly higher levels of PAR. Virtually no flowers or seeds were produced at the other two sites. At the site which produced a large number of flowers, successful sexual reproduction was limited by insufficient pollinator service during some periods of the season and low germination and seedling survivorship. Measurements of specific leaf weight, leaf area index, biomass, raceme production and seed set suggest that kudzu is a sun adapted plant. Even though it is capable of establishing itself in habitats of low or moderate irradiance, a greater ability for sexual reproduction was apparent in sun populations versus no sexual reproduction was apparent in sun populations versus no sexual reproductive success in populations occurring in shaded habitats. While its primary mode of reproduction is vegetative, successful sexual reproduction may occur despite several limiting factors.Item The State of Water and Cell Morphology In Deep Frozen Populus(1985) Hirsh, Allen Gene; Solomos, Theophanes; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md)By using differential scanning calorimetry, electron microscopy, light microscopy, and freezing survival experiments, it is shown that superhardy Populus balsamifera v. Virginiana (Sarg.) is capable of withstanding liquid nitrogen (LN 2) temperatures because of the formation during cooling, at a temperature of about -30°C and cooling rates less than 30°C/hr, of aqueous glasses in the intracellular solutions. In more detail, the major findings concerning the state of intracellular water are: (1) the bulk of the intracellular contents go through an equilibrium glass transition at about -28°C during slow (<5°C/hr) cooling; (2) smaller additional amounts of intracellular material go through equilibrium glass transitions at about -47°C and -70°C; (3) as a result of the resistance to homogeneous nucleation of these glass forming intracellular solutions when they are in equilibrium with extracellular ice at<.-20°c, cooling/warming at any combination of rates from 3°C/hr to 1200°C/min between -20°c and -196°C is non-injurious to fully hardened wood; (4) death associated with quench cooling in LN2 from -15°C is correlated with the devitrification, (cold crystallization) near -90°C upon warming of the very low temperature glass forming component, followed by further devitrification of the higher temperature components, especially between -30°c and -20°c; and (5) the vacuolar compartment appears least resistant to devitrification and capable of thereby causing death even when the cytoplasm resists devitrification. In addition, it was found that when fully superhardy wood is cooled slowly (3°C/hr) after being imbibed with water (doubling total water content) massive intracellular freezing occurs. Despite the fact that total tissue water of tender Populus (summer wood) is 2x that of the artifically water loaded hardy wood on a gram H20/gram dry weight basis, tender wood cooled at 3°C/hr to -50°c does not display intracellular freezing. It is killed by -2°C. It is shown that in both tender and hardy wood <10% of water is extracellular. Thus a significant excess of extracellular water appears to cause intracellular freezing and this may be a major reason for the large water loss seen in the fall 'hardening off' of most temperature zone woody plants. It is also shown that during slow cooling, the plasma membranes of both hardy and tender Populus cells stick to and collapse the cell wall, but that these membranes stay smooth in the case of superhardy cells and wrinkle markedly in the case of tender cells. Membrane-associated particles appeared to clump in the membranes of slowly cooled tender cells but not in the slowly cooled hardy cells.Item Periparturient Behavior of Beef Cows and Calves(1987) Ramli, Abdullah Sani; Stricklin, W.R.; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)Crossbred and purebred gestating Angus and Hereford cows were monitored during the 1985 and 1986 spring calving seasons (number of calvings = 375). Cows were assigned randomly to one of two treatment groups that were balanced by breed-class, age and expected date of calving. The control group was fed corn silage at 0900 hours, and hay was available free choice. The treated group was fed the same diet but at 2100 hours, and time of access to the hay was restricted to between 2100 and 0900 hours. Each group was kept in a 3.2 ha paddock and observed continuously during the 1985 calving season. During 1986 similar treatments were used, but observations were not continuous. Data recorded were behavioral signs of parturition, times and locations of parturition and behaviors of cow-calf pairs observed continuously until 8 hours post-partum. Group diurnal activity patterns were recorded over 61 consecutive days in 1985. Post-partum behavior variables of the dam were time to first standing and grooming and total time spent standing, lying, grooming, browsing and eating. Calf variables were initial standing, teat seeking, mobility, suckling, total time spent on these activities and body weight at weaning. A significant (P <.05) shift in the diurnal activity patterns of the cows occurred when the feeding schedule was altered, but treatment did not affect (P>.10) the time of day when parturition occurred. The percentage of cows calving between 0600 and 1800 hours were 55 and 60 for the control and the treated groups, respectively. During the first 8 hours post-partum, differences in the time of onset and total time spent on some behaviors were determined to be related to breed of sire and dam, parity and sex of calf. Multiple regression of weaning weight on periparturient behavioral traits resulted in R2 values of 54 and 24% for heifer and bull calves, respectively. It was concluded that night-time feeding does not result in a significant increase in day-time calvings, and there is at least a moderate relationship between cow-calf behavior in the first 8 hours after birth and the calf's weaning weight.Item A REVISION OF THE GENUS ODONTONEMA (ACANTHACEAE)(1982) Baum, Vicki M.; Reveal, James L.; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md)Odontonema Nees (Acanthaceae, Acanthoideae, Acanthatae, Odontonemeae) is a New World tropical or subtropical genus of 26 species and two varieties. Members of the genus are distributed from coastal central Mexico southward throughout Latin America into northern South America, with one species located on the southeastern coast of Brasil (a second species from Brasil is from an unknown location). Odontonema also is found on the Caribbean Islands. The genus consists of four major groups which, at this time, are not given formal taxonomic recognition: 1) red-purple (rarely white) flowered species (O. callistachyum and its relatives); 2) red flowered species with typically a bottle-shaped corolla (O. schornburgkianum and its relatives); 3) white-purple flowered species with a more strongly bilabiate corolla (O. nitidum and its relatives); and 4) yellow flowered species (O. hondurense and its relatives). Although a few members of Odontonema may be seen in cultivation, the present revision is based on an examination of herbarium material found in both New and Old World herbaria, a numerical analysis of macromorphological features, and an examination of pollen morphology. The four groups within Odontonema defined above were established after the numerical analysis, and all species save one (O. cuspidaturn) were found to have 3-colporate pollen characteristic of sect. Odontonemeae. Descriptions were prepared of each species based on available herbarium specimens...