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Relationship between larval habitat characteristics and malaria vectorial capacity of adult Anopheles dirus in Chanthaburi Province, ThailandKitthawee, Sangvorn 01 January 1990 (has links)
Field studies were conducted in Tha-Mai District, Chanthaburi Province. Larval habitat characteristics of 42 gem pits were examined from November 1986 through June 1988. Larvae were found in pits containing clear water under full or partial shade. Relationships between habitat characteristics and density were tested by stepwise regression analysis. High dissolved oxygen and humidity and low pH were associated with higher densities. Populations fluctuated with rainfall. Stepwise logistic regression analysis was used to predict the occurrence of An. dirus. Populations were positively correlated with humidity and collection water temperature but negatively correlated with pH and minimum water temperature. Variations in occurrence and density also were related to predators (Notonectidae and fish). High minimum water temperature and rainfall were correlated with decreases in wing length among both emerging males and females. High turbidity was associated with increased size in male but not in female. Seasonal variation in the size of both sexes was related to rainfall. Minimum water temperature, pH, protein and rainfall were correlated with the survivorship of emerging An. dirus. Adult size was positively correlated with survivorship but not as strongly as in lab-reared populations. Mean wing length of nulliparous females (3.035 mm) was not significantly smaller than parous females (3.039 mm). However, there was a significant difference when seasonal variation was considered. Since size variation was correlated with rainfall and minimum air temperature, females tended to be smaller in the rainy season and larger (with a higher parity rate) in the dry season. On average, $>$40% of dry season An. dirus live long enough to complete the extrinsic incubation period for Plasmodium falciparum. Both P. falciparum and P. vivax were detected and mosquito infection rates determined by ELISA. Malaria sporozoites were found in Anopheles dirus, vagus tessellatus and hyrcanus group so all are potential vectors in this area. Four size classes of An. dirus were reared from different larval densities. Higher densities produced smaller adults with lower survivorship. Larger females took larger blood meals and thereby were more susceptible to infection by artificial feeding with cultured P. falciparum gametocytes. Read more
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Dispersal and diet of the Colorado potato beetle, Leptinotarsa decemlineataWeber, Donald Charles 01 January 1992 (has links)
The Colorado potato beetle (CPB) is a serious pest of potatoes and other solanaceous crops in North America and Europe. Reliance on chemical control has induced pesticide resistance, necessitating alternative management strategies based primarily on biological and cultural tactics. Better knowledge of this insect's movement, particularly its flight, could aid greatly in developing cultural controls. Computer-linked flight mills were used to study flight of overwintered and summer-generation female CPB fed in the laboratory on seven different solanaceous plant species. Over 30 days, flight was greatest with starved overwintered females three to six days postemergence. Flight for the overwintered generation was negatively related to desirability of food, as measured by larval success. Flight for summer females, and fecundity for both generations, was positively related to food desirability. Starved females laid virtually no eggs; starved summer females did not fly. Flight and fecundity of individual females were not related within treatments. Field investigations examined adult immigration to the same plant species over time and space, the distribution of overwintering adults, and disruption of their spring colonization to nonrotated potato crops. Recruitment to plots placed either near or far from potato crops showed that long-distance flight was primarily by starved overwintered adults, and also by fed first summer-generation adults. Two periods of short-distance dispersal occurred with older overwintered adults, and before diapause. Results suggest that the value of crop rotation depends on site-specific factors, not just the distance to overwintering sites or current-year potato crops. Overwintering distribution was studied at three sites over two years. CPB concentrated within woody borders, averaging 60-200/m$\sp2$ in these areas before winter, compared to 8-13/m$\sp2$ within potato fields. Mortality was higher in fields than in borders, and greater near the ground surface. Only 15-44% of live beetles were in potato fields. In experiments with small plots, colonization of fields from woody borders was disrupted by a trap crop, either treated with pesticide or collected daily. Simulation models suggest that this colonization disruption tactic could significantly reduce pesticide applications and eliminate the need for disruptive treatments against adult beetles. Read more
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Behavioral and ecological factors influencing oviposition of Acrobasis vaccinii (Riley) (Lepidoptera: Pyralidae), the cranberry fruitworm, with implications for pest managementRogers, Andrea Kent Osgood 01 January 2000 (has links)
The cranberry fruitworm, Acrobasis vaccinii (Riley) (Pyralidae), is the most important insect pest of Massachusetts cranberries. The female lays her eggs individually in the calyxes of developing fruits. Upon hatching, the larva cats its way into the fruit and consumes it, whereupon it moves to another. Because the immatures are protected inside fruits, insecticides target the adult and egg stages. Growers wishing to practice integrated pest management (IPM) engage scouts to collect and check berries for eggs to determine whether spraying is warranted. However, their protocol was devised with limited knowledge of egg distribution or the relationship between eggs found and yield loss. Better understanding of the oviposition behavior of the female and of egg distributions is essential for effective monitoring. The quest to optimize scouting efficiency led me to explore the physical properties of cranberries and their immediate environment in order to identify factors influencing oviposition. Mechanosensory stimuli, including surface texture, conformation, size, geoörientation, and moisture content of the oviposition substrate, are important determinants in insect oviposition site selection, comprehensively reviewed in Chapter 1. In laboratory choice experiments described in Chapter 2, I manipulated the surface texture, conformation and geöorientation of cranberries and showed that physical contact with a natural calyx is important in eliciting oviposition. In field choice experiments, I showed that females are more likely to oviposit on the uppermost berries and on berries growing in abundant foliage. The balance of my research was designed to characterize the egg spatial distribution in commercial cranberry bogs and to develop an empirically-based IPM scouting protocol. Six bogs were intensively sampled and their egg distributions were modeled in Chapter 3 using Taylor's Power Law (Taylor, 1961), variance = a*meanb. However, exponential and logarithmic versions of the model produced different regressions. Comparisons of their performance demonstrated that exponential models usually produced more satisfactory descriptions of the variance to mean relationship. Analyses of the published data sets Taylor employed, presented in Chapter 4, obtained comparable results. In Chapter 5, I developed and tested a new scouting protocol based on the exponential model, which outperformed the original protocol in field trials. Read more
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Investigation into Listronotus maculicollis (Coleoptera: Curculionidae), a pest of highly maintained turfgrassRothwell, Nikki Lynn 01 January 2003 (has links)
Listronotus maculicollis (Dietz) is a major pest of golf course turf in the northeastern United States. Because the larval stage of this insect causes considerable damage to short-mowed turfgrass, such as tees, greens, fairways, golf course superintendents rely on chemical applications for control. I investigated physiological, ecological, and behavioral characteristics of L. maculicollis to enhance management strategies that will lead to reduced insecticide inputs in golf course turf. Among the cool season turfgrass species, L. maculicollis larvae are reportedly found primarily in Poa annua L., annual bluegrass, among cool-season turfgrass species. To confirm this observation, I conducted a quantitative investigation to determine how abundant L. maculicollis larvae were in P. annua compared with other grasses. I also investigated the influence of mowing height and fertilization on the abundance of larvae. L. maculicollis larvae were present in highly maintained grasses (P. annua and Agrostis palustris Huds., creeping bentgrass) in field studies; no differences in numbers of larvae were detected between P. annua and two types of creeping bentgrass. However, in choice and no-choice tests among five grass types, L. maculicollis were significantly abundant in P. annua. Additionally, one study showed L. maculicollis larvae collected from P. annua weighed more than larvae from other grass types. I found a significant effect of fertilizer application. More L. maculicollis were collected in non-fertilized turf compared to fertilized turf, and more larvae were collected in short-mowed plots than from long-mowed plots. I also investigated adult spring emergence and the distribution of adults and larvae on turfgrass hosts. Golf course superintendents observe primary damage on perimeters of short-mowed areas. In an attempt to corroborate their observations, I examined the distribution of adults and larvae across the width of a golf course fairway, but no differences were detected. Although no more larvae were detected at fairway edges, we determined by visual assessment that the turf on the edge of the fairway was poorer quality, and substandard turf quality is often a result of pest, mechanical, or environmental damage. Therefore, from our results, larval feeding alone does not account for the increased damage in edge areas. I also established that adult L. maculicollis emerge from overwintering sites and walk onto host plants in the spring. These results will be utilized to develop perimeter treatment. (Abstract shortened by UMI.) Read more
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INNOVATION AND LOSS OF A NOVEL SENSORY ORGAN DURING EVOLUTIONARY TRANSITIONS AMONG ECOLOGICAL NICHES IN A PRAYING MANTIS LINEAGEBrannoch, Sydney Kegan, Ph.D. 26 August 2019 (has links)
No description available.
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The Influence of Demography, Development and Death on Seasonal Labor Allocation in the Florida Harvester Ant (Pogonomyrmex Badius)Unknown Date (has links)
Eusocial insect societies are analogous to organisms in that the demography, development and regulation of workers within are shaped by selection acting on whole colony
characteristics. Just as relative investment varies across the lifetime and reproductive cycle of a traditional organism, adaptive patterns of worker allocation are expected to vary with
colony development and need across each annual cycle. Despite these predictions, adaptive patterns of labor allocation remain un-described for most social insect societies. This dissertation
identifies a seasonal pattern of forager allocation in colonies of the Florida harvester ant (Pogonomyrmex badius) and describes its relationship to colony demography, size, reproduction,
worker development rate, death rate, longevity, and neighborhood dynamics. Aging P. badius workers progress through a sequence of interior labor roles before leaving the nest to forage. By
marking and recapturing foragers, forager population size was estimated and foragers were identified as a discrete, age-correlated labor group that resides only in the top 12cm of nests that
may be more than 200cm deep. Excavation and census of whole colonies revealed that foragers were present in a consistent ratio to the colony's larval population from May through August, but
that forager allocation was not a response to larval presence. Proportional allocation to foraging followed an annual pattern, shaped by the interaction of seasonal phases of colony growth
and worker development rate. Forager allocation began in March or April and increased to a peak of approximately 40% of the colony in June, as colonies provisioned alates for mating flights
in the days surrounding the summer solstice. In spring, proportion foraging increased due to an increase in forager number combined with a reduction in colony size. Beginning in late summer,
proportional allocation to foraging decreased, as colonies grew through new worker birth and forager replacement declined. This annual pattern was shaped by a five-fold difference in the age
of summer and autumn-born workers when they entered the forager population (43 vs. 200+ days). The chronological age of foragers was revealed by collecting whole colonies across two annual
cycles, marking age cohorts with colored wire-belts, releasing each colony into a field nest created from melting buried ice chambers, then monitoring the forager population for the
appearance of each marked cohort. Slow-developing workers, produced from late August until mid-October each year, dominated the forager population the following March through mid-July; while
fast developing workers appeared in early June and developed rapidly to become foragers the following month, overlapping with their older sisters. While wild foragers of both types lived an
average maximum of 27 days after entering the forager population, these same foragers were capable of surviving for hundreds of days in the laboratory. Likewise, restricting the foraging
range of wild foragers increased forager longevity by 57%, demonstrating that foraging carries mortality risks and the observed age at death was not part of a developmental program involving
senescence in P. badius. By removing neighboring colonies, this study also showed that interactions with conspecific neighbors can influence the labor thresholds of individual workers, and
the demographic structure of whole colonies, as neighbors account for 30% of forager mortality in the spring. At the colony level, increased forager longevity suppressed the movement of new
workers into the forager population, increasing their time in earlier labor roles and promoting colony growth. In contrast, both removing 50% of the forager population and doubling the larval
population did not induce forager replacement or increase the daily rate of new foragers added within seven days. Together, these results suggest a unidirectional control of labor allocation
in P. badius, where the forager population size is not maintained by workers detecting colony need and filling vacancies, but by workers developing at a rate selected to allow forager
replacement. In essence, the annual cycle of forager allocation emerges as P. badius workers 'age' into behavioral roles at environmentally appropriate times, in the same proportions, on
nearly the same dates each year and experience a predictable death rate. This process allows colonies to divide a limited number of workers between competing functions without a leader.The
findings of this study reinforce our understanding of the organism-like nature of social insect colonies. Like cells in a body, the thousands of individual insects in a P. badius colony are
organized into functional labor groups, which are responsive to cycles of growth, reproduction and dormancy through self-regulating processes. The emergence of measurable, colony-level traits
from the accumulation of thousands of transient individuals, from multiple generations is one of the most striking feats of social organization across taxa. / A Dissertation submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2014. / October 2, 2014. / ant colony behavior, division of labor, Florida harvester ant, Pogonomyrmex badius, labor allocation, social inhibition, superorganism / Includes bibliographical references. / Walter R. Tschinkel, Professor Directing Dissertation; Emily H. DuVal, Committee Member; Lisa C. Lyons, Committee Member; Jeanette L. Wulff, Committee
Member. Read more
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A biogeographical study of currently identified Oregon pseudoscorpions with an emphasis on western Oregon formsBenedict, Ellen Maring 01 January 1978 (has links)
The biogeography of the 50 currently identified Oregon species is reported from analyses of data from 2220 Berlese samples collected in a stratified, extensive sampling procedure, and from collection data on several hundred specimens from major private and public collections of pseudoscorpions. Individual species accounts including maps and data relating to geographical and seasonal distribution and habitats are provided, distributional areas and habitat types are categorized, dispersal mechanisms including examples of phoresy are presented and an illustrated key to Oregon species is given.
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A Phylogeny of Genera Spirobolomyia and Blaesoxipha (Diptera:Sarcophagidae)Gierek, Stephanie 30 October 2018 (has links)
No description available.
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Influence of Winter Annual Cover Crops and Insect Management Strategies on Insect Pests of Mississippi SoybeanWhalen, Daniel Adam 14 December 2018 (has links)
An increasing cultural practice in soybean, Glycine max (L.), production is the use of winter annual cover crops before planting. Species of grasses, legumes, and forbs are planted for many agronomic purposes during the fall months. In the spring, cover crops are killed and soybean planted into the residue. When the termination of the cover crops is delayed for longer lasting benefits, insect pest issues can arise. The movement of insect pests from cover crops to subsequent cash crops happens through a connection known as the “Green Bridge”. Pests found in cover crops such as the pea leaf weevil, Sitona lineatus L. (Coleoptera: Curculionidae), can be particularly damaging to immature soybean plants. Experiments were conducted to tests how cover crops influence insect populations in soybean. Also, various chemical control options, soybean planting populations, and the timing of cover crop termination prior to planting were tested in these cover crop-soybean systems. Lastly, an experiment was conducted to measure how various species of cover crops and neonicotinoid seed treatments affect arthropod diversity in soybean fields.
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Revision of certain pyrgomorphid genera previously included in the Orthacridini (Orthoptera), together with descriptions of closely related new genera.Singh, Asket. January 1964 (has links)
No description available.
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