Crickets belong to the family Gryllidae (Orthoptera) and are common in houses, fields, pasture, meadows, and some inhabit trees and shrubs. Most of them feed on plants and grains but some occasionally feed on other insects. Several species of crickets overwinter as eggs, laid generally in the moist ground or vegetation, while others in tropical climates pass the winter either as nymphs of late instars, or as adults. They are among the most familiar insects. In Italy and North Africa crickets, which are best known for the musical sounds made by the male, are kept in cages tor the sake of their notes.

This is a study in comparative animal morphology. The method used is entirely descriptive, and most of the conclusions cannot be tested experimentally. The validity of these conclusions for any particular reader must, therefore, depend upon the degree to which the evidence and reasoning impress him as adequate and logical. To assist the reader in thus assessing the conclusions and suggestions that are presented, l will attempt to outline, as briefly as possible, the point of view from which the study was carried out.

Plan B paper--University of Minnesota, Duluth : 2007. / Computer printout. Includes bibliographical references (l. 36-38).

<p> Development rate is a quantitative trait that displays significant variation within many species, including <i>Cochliomyia macellaria</i> Meigen (Diptera: Calliphoridae). Calliphorids are a family of dipterans known as blow flies and are commonly used in forensic entomology to estimate the minimum postmortem interval (PMI_MIN), given some assumptions are made. In order to dissect the genetic underpinnings of development rate variation in this species, artificial selection for fast and slow development with population-based resequencing was used. The objective of this study is to isolate and characterize genomic regions that are correlated to development rate variation in blow flies. The first approach used known regulatory development genes from <i> Drosophila melanogaster</i> Meigen (Diptera: Drosophilidae) and isolated variants that were associated with development time changes in artificially selected fast and slow development <i>C. macellaria</i> strains. Three variants located in <i>Ras</i> and <i>Eip74EF</i> were associated with fast or slow development in selection strains with a significant change in allele frequency. The second approach involved the comparison of pooled artificially selected fast and slow <i>C. macellaria</i> genomes to investigate the genetic basis of development rate variation. When comparing the fast and slow genomes, 699 sequences were identified that contained 7290 variants with consistent changes in allele frequency. The variants indicated that the genomic regions that are associated with development rate were associated with developmental processes, including regulation of RNA polymerase II activity, and transporter activity, such as protein dimerization. Of the 699 sequences, 69 sequences were related to <i>Achaete-scute complex</i> and 14 were related to <i>Cyp12A7</i>. The identification of the genomic regions that associated with development rates from this study provides an important resource for future studies in identifying potential genetic markers to increase the effectiveness of PMI_MIN estimates. By using significantly associated variants as <i>a priori</i> candidates for future studies, the data increases the understanding of natural development variation in blow flies.</p><p>

abstract: A phylogenetic revision of the broad-nosed weevil genera Minyomerus Horn, 1876, and Piscatopus Sleeper, 1960 (Entiminae: Tanymecini) is presented. These genera are distributed throughout western North America, from Canada to Mexico and Baja California, primarily in arid and desert habitats, and feed on shrubs such as creosote (Larrea tridentata (DC.) Coville: Zygophyllaceae) and several Asteraceae. Piscatopus was considered monotypic, comprised solely of P. griseus Sleeper, 1960, whereas Minyomerus formerly was comprised of seven species: M. innocuus Horn, 1876 (designated as the type species for Minyomerus in Pierce, 1913), M. caseyi (Sharp, 1891), M. conicollis Green, 1920, M. constrictus (Casey, 1888), M. languidus Horn, 1876, M. laticeps (Casey, 1888), M. microps (Say, 1831). This revision includes comprehensive redescriptions of the previously described species in these genera and descriptions of ten new species: M. imberbus sp. nov., M. caponei sp. nov., M. reburrus sp. nov., M. cracens sp. nov., M. trisetosus sp. nov., M. puticulatus sp. nov., M. bulbifrons sp. nov., M. politus sp. nov., M. gravivultus sp. nov., and M. rutellirostris sp. nov. A cladistic analysis using 46 morphological characters of 22 terminal taxa (5 outgroup, 17 ingroup) was carried out in WinClada and yielded a single most-parsimonious cladogram (length = 82, consistency index = 65, retention index = 82). The monophyly of Minyomerus is supported by the preferred cladogram. The results of the cladistic analysis place Piscatopus griseus within the genus Minyomerus as sister to M. rutellirostris. Therefore, Piscatopus is demoted to a junior synonym of Minyomerus and its sole member P. griseus, is moved to Minyomerus as M. griseus (Sleeper), new combination. Additionally, the species M. innocuus Horn, 1876 is demoted to a junior synonym of M. microps (Say, 1831), based on the principle of priority, and M. microps is elevated to the rank of type for the genus. The species M. languidus, M. microps, and M. trisetosus are putatively considered parthenogenetic, and lack male specimens over a broad range of sampling events. The diversity in exterior and genitalic morphology, range of host plants, overlapping species distributions, and geographic extent suggests an origin during the Miocene (~15 mya). / Dissertation/Thesis / M.S. Biology 2014

<p> Sorghum, <i>Sorghum bicolor</i>, is increasing importance as human food, animal forage, and a source for biofuel production. Since 2013, sugarcane aphid, <i>Melanaphis sacchari</i> has become a perennial and significant pest in the southern United States. Natural plant resistance to this pest offers the best option for sustainable low-cost management. Screening for the resistance of cultivars is usually conducted in greenhouse trials where plants are grown in controlled environments and infested with aphids from a colony of <i>M. sacchari</i>. The recent adoption of LED pink growth lights at The United States Department of Agriculture greenhouses in Stillwater OK has reduced energy costs. However, sorghum plants grown under these certain types of lights appeared to be different with more leaves, shorter height, and chlorosis compared to plants grown under normal light. I conducted experiments using known resistant and known susceptible sorghum lines that were grown under normal and LED lights. Plants grown under pink light had more root and aboveground biomass, but were shorter with fewer leaves, and exhibited less chlorophyll than the same plants grown under conventional lights. When infested with aphids, both growing conditions supported a similar number of aphids but plants grown under LEDs had higher damage ratings than those under conventional lights. Based on the results of this experiment, greenhouse trials used to detect sorghum resistance should not use pink LED lights. In the second set of experiments, sorghum lines obtained from a Texas breeder were screened for resistance to sugarcane aphid. Replicated trials were conducted with 34 sorghum lines for compared with two known resistant and two known susceptible lines respectively. Based on these trials, two new lines were identified as having resistance. The second set of trials focused on these lines and quantified aphid survival, reproduction and population growth. The two newly identified pollinator lines, R.11143 and R.11259 exhibited substantial antibiosis and are recommended to be used in breeding programs for developing resistant sorghums threatened by the sugarcane aphid.</p><p>

Resistance of several commercial rice varieties widely grown in Louisiana was assessed against the rice water weevil (Lissorhoptrus oryzophilus Kuschel), the major insect pest of rice in the United States. A five-year field study was conducted to identify resistant genotypes among conventional inbred, herbicide tolerant, conventional hybrid, and herbicide tolerant hybrid varieties. Resistance was evaluated in two different locations to enable selection of rice varieties with wide adaptability over diverse environments. There were no large differences in the resistance found amongst commercial rice varieties over the five-year field study. Jefferson was frequently found to support lower larval densities than other varieties, while Jupiter often supported higher larval densities. Another assessment involved greenhouse experiments that evaluated adult preference for oviposition and survivorship of larvae on different varieties. Numbers of weevil eggs per plant differed significantly among varieties in choice tests but not in no-choice tests, while 1st instar densities in both choice and no-choice tests showed no significant differences between varieties. This suggests that inconsistency of oviposition preferences exist among the varieties. Nevertheless, analysis of mature instar data from the no-choice test showed that numbers of mature instars were significantly different among the varieties Cheniere, CL111, CL151, Cocodrie, Jefferson, and Jupiter. Percentage of larval survival showed no statistical difference between the four varieties tested. Our results from the field and the greenhouse suggest that none of the commercial varieties tested showed high levels of resistance to rice water weevil infestation, although Jupiter appears to be more susceptible than other varieties and Jefferson appears to be somewhat more resistant.

The plum curculio, Conotrachelus nenuphar (Herbst), is a major pest of stone and pome fruit in eastern North America. I determined generalized olfactory and visual cues guiding plum curculios to host plants as a first step in the creation of a reliable monitoring trap for this important tree fruit pest. Olfactory attraction of overwintered adults to volatiles from extracts of McIntosh apple tissues was evaluated in the laboratory using a still-air dual choice bioassay system to determine the most attractive odor sources. For hexane-extracted or water-extracted volatiles from McIntosh apple tissues (twigs, leaves or fruit) at seven phenological stages of development (pink through 5 weeks after bloom), greatest numerical responses were recorded to volatiles from extracts made between bloom and 2 weeks after bloom. This same laboratory bioassay system was used to evaluate the influence of barometric pressure on degree of olfactory discrimination by adult females; response indices used as a measure of discrimination were significantly and positively correlated with barometric pressure. Olfactory attraction of overwintered adults to individual volatile components of unripe plum odor was evaluated in the laboratory and in the field using baited boll weevil traps placed on the ground beneath the canopy of unsprayed apple trees. Two compounds, ethyl isovalerate and limonene, were significantly attractive in both laboratory bioassays and field experiments. Olfactory attraction of overwintered adults to volatiles released from same- and opposite-sex conspecifics alone, synthetic grandisoic acid alone, wild plums alone, or combinations of live single-sex conspecifics or grandisoic acid with plums was observed in the laboratory. Females may produce a sex pheromone attractive to males, but in general both male and females were strongly attracted to host plum volatiles and only mildly attracted to conspecific odors or synthetic grandisoic acid, with little evidence for synergy or enhancement of host plum odors when combined with conspecific odors or synthetic grandisoic acid. Laboratory, semifield, and field experiments were conducted to determine the most visually-stimulating and acceptable version of a branch-mimicking trap (PVC cylinder topped with an inverted screen funnel) to capture adults in the canopy of host fruit trees. Tall cylinder traps (50 cm tall x 6 cm diam) coated with flat black latex paint were significantly more visually stimulating than cylinder traps of lesser height and/or different diameter. Lining inverted screen funnels with paper cones and joining cylinders to inverted screen funnels with wooden inserts increased surface acceptability of traps. I conclude that a reliable monitoring trap for adult plum curculios should be baited with attractive host fruit volatiles, and a trap placed in the canopy of fruit trees should include visual cues provided by a supernormal branch-mimicking cylinder.

Studies were undertaken to observe: (1) the role of trans -sialidase (TS) on Trypanosoma cruzi parasite load in Rhodnius prohius, (2) behavioral implications of T. cruzi infection in Rhodnius prolixus and (3) movement and attraction of laboratory R. prolixus within a simulated field environment. Laboratory R. prolixus were infected with T. cruzi parasites (Silvio strain) with or without various TS types. The addition of Trypanosoma TS or any recombinant TS type did not consistently affect the parasite load. However, the addition of 1.0 μg TS monoclonal antibody/ml blood did significantly increase parasite load. Fractionated T. cruzi subpopulations (Silvio strain), based on the phenotypic expression of TS, were fed to R. prolixus . Bugs ingesting parasites lacking TS expression (TS-parasites) produced significantly higher parasite loads than bugs ingesting either TS+ parasites (parasite phenotypically expressing TS) or unfractionated populations. Two other strains of T. cruzi (Tulahuen and Montalvania-13) were fractionated by TS phenotype and fed to bugs. Fractionated Tulahuen parasites only weakly produced differential parasite loads, the highest of which was produced by TS-parasites, but Montalvania-13 TS-parasites produced significantly larger parasite loads than either TS+ parasites or unfractionated parasites. The feeding and defecation behavior of T. cruzi infected vs. uninfected insects were observed on an artificial membrane-feeding system, as well as on a live host (guinea pig) feeding system. Fifth instars were the best vectors, followed by adult females, 4th instars and finally, adult males. Bugs fasted for longer periods of time (5–6 months) took smaller blood meals but defecated significantly earlier than bugs fasted for shorter periods of time (2–3 months). A field environment was simulated within a styrofoarn box. Movement of R. prolixus into various refuge types was observed. Fifth instars were more likely to seek a refuge than 3rd instars. Fed nymphs were more likely to seek a refuge than fasted nymphs. Potential bug attractants were tested within an olfactometers; ammonium hydroxide (NH4OH) was incorporated into refuges placed in the simulated field environment. Fasted fourth instars significantly preferred to rest in refuges containing NH4OH whereas fed third instars seemed to actively avoid refuges containing this chemical.

Recent data show that wild Aedes aegypti feed frequently and almost exclusively on humans without ingesting sugar for energy, and egg production is attributed to low concentrations of isoleucine in human blood. However, human blood is reportedly sub-optimal for Ae. aegypti compared with other types of blood. To understand why this species prefers to repeatedly feed on blood that is reproductively sub-optimal, groups of females were provided natural, low-isoleucine human blood, human blood supplemented with isoleucine and natural chick and rodent blood in a series of experiments. Egg production, energy reserves, feeding frequency and blood volume were compared. No differences in egg production were found among females offered low isoleucine blood compared with isoleucine-supplemented human blood, or among those offered chick and rodent blood, contradicting previous reports. When females were maintained on both sugar and blood (a common rearing practice, but unnatural wild behavior), rodent-fed females produced more eggs than human-fed females. Greater energy reserves were found in human-fed mosquitoes. Females ingested smaller meals from human hosts than rodents, yet fed with greater frequency on human blood. A life table study demonstrated greatest survival and fitness with females offered human blood alone. Field survival of Ae. aegypti was investigated. Two age cohorts (3 and 13 days) were released and recaptured in 3 experiments in Puerto Rico and Thailand. Regression analysis demonstrated a greater probability of daily survival for the older cohort. Greater survivorship among older females changes the current view of dengue transmission dynamics. Collapsible black fabric resting boxes were evaluated for surveillance of adult Ae. aegypti over a 10 month period in two regions of Thailand. Thirty percent of total females were collected from two resting boxes in each house. Resting boxes, as a surveillance tool, also decrease sampling time. Satisfactory control of Ae. aegypti was not achieved with deltamethrin impregnated resting boxes placed inside Thai houses. Females were susceptible to topical application, but contact irritancy with deltamethrin-treated fabric was observed. Lambdacyhalothrin treated boxes were more effective. Treated resting boxes place low resistance selection pressure on populations and may be an inexpensive and sustainable control method for Ae. aegypti.