Instars: A Journal of Student Research

A Survey of Acari Species and the found Prevalence of Medically Relevant Ixodes sp. in College Station, Texas

2021-03-16T18:12:37+00:00

Within the Acari species, there are a number of specimens known to spread diseases of medical importance. Of the two most common tick spread diseases found in Texas, Lyme disease and Rocky Mountain Spotted Fever, Lyme disease, caused by Borrelia burgdorferi, has a higher number of incidents and therefore is the focus of the survey. This disease is known to have detrimental effects on the nervous system and heart in humans. Two species are known for being prominent vectors of Lyme disease, Ixodes scapularis, and Ixodes pacificus. Of these two ticks, I. scapularis is a common tick found in Texas and is the primary tick to identify. A survey of ticks obtained from local animal shelters was performed and 29 species were identified. I. scapularis had the highest rate of identification. Due to the high amounts of I. scapularis in the survey, actions can be taken by the community to prevent future outbreaks of Lyme Disease in the College Station and Bryan areas.

Keywords: Ticks, Lyme disease, Ixodes scapularis, disease, vector, survey

Nutritional Preferences of Formicidae in Costa Rica

2021-03-01T21:46:04+00:00

Ant nutrition has been studied across the world and heavily in the United States. The nutritional preferences of Formicidae in tropical environments have little to no research. In order to create the most affective baiting methods for ant colonies, five nutritional treatments were tested among the native ant species of Costa Rica. The transects consisted of 50 vials per transect in three different elevated locations of Pocosol, Soltis, and La Selva. The data yielded significant results of ants preferring different nutritional agents dependent on elevation. The Pocosol location had a p-value of <0.01 and favored the protein treatment. The Soltis location had a p-value of 7.81E-13 and favored the lipid treatment. The La Selva location had a p-value of 0.0365 and favored the lipid and protein treatment. Due to the results showing the varying nutritional preferences of ants in different elevations, the pest ant colonies can be specifically targeted with appropriate baits.

The Attractiveness of Commercial Baits Toward Red Imported Fire Ants Solenopsis invicta (Hymenoptera: Formicidae)

2021-03-01T22:07:39+00:00

From causing painful stings on animals and humans alike to damaging land, the Solenopsis invicta, or Red Imported Fire Ant, is an economic burden to the United States. Insecticidal baits are often used to control these pests, each containing their own proprietary coating. Discovering which formulation of bait is most attractive to fire ants would help inform consumers to select the proper bait for their personal fire ant control. After baiting ants following the method laid out in Kaspari et al. 2008 with six different baits, it was discovered that the most attractive bait attracting the largest percentage of ants was Advion with its lipid blend. Advion was significantly more attractive than the negative control of honey. However, the Advance 375 A protein blend was also significantly more attractive than honey. The success of the Advion bait in attracting a larger percentage of fire ants over the Advance 375 A bait may be due to seasonal timing as this experiment was done in early April. Fire ants may currently be choosing nutrition with a high content of stored energy. More research should be done to see if as fire ants prepare to reproduce in later spring, they may change their foraging bait preference to Advance 375 A’s protein blend in order to support their colony’s larval development with additional protein.

Efficacy of Castile Soap at Reducing Numbers of Demodex spp. (Trombidiformes: Demodicidae) on Females

2021-03-01T22:08:57+00:00

Studies into the complex relationship between Demodex spp.(Trombidiformes: Demodicidae) are important as they may provide insights into the physiology of certain skin conditions. Demodex spp.is a type of mite that feeds off of the oils that are produced in the follicles and pores of the face. Normally, this relationship is harmless and mutualistic in nature. Demodicosis is a skin condition caused by overpopulation of Demodex spp., new, non-invasive treatments for demodicosis are desirable, as they could improve quality of life for individuals that have minimal access to healthcare. In this study, the effects of unscented castile soap are assessed regarding Demodex spp.populations. Liquid glue and tape were used to collect mites; the mites were then placed on a microscope slide for observation. Prior to collection, each non-control subject washed their face with castile soap. Samples were gathered over a nine day period to allow for the observation of potential trends. The results show that there were no significant differences in numbers of face mites by use of castile soap versus water.

Effect of Food Availability on the Rate of Zophobas morio (Coleoptera: Tenebrionidae) (F.) Pupation

2021-03-08T21:33:55+00:00

Zophobas morio (Coleoptera: Tenebrionidae) (F.) larvae are insects that can be found at most pet stores. The larvae are common sources of food for insectivorous pets, but there is a new interest in the potential for these as sources food for humans. The aim of this study was to determine whether the absence of food would affect the time it takes for the larvae to pupate. Larvae were divided into two groups: one with food and one without food. The days it took the larvae to reach the pupal stage were monitored and noted. By the end of the thirty days that were dedicated to this study, only six of the fourteen larvae had pupated. Larvae that either did not pupate or died during the length of the experiment were recorded with a value of zero. Raw data indicated that the group without food pupated nearly twice as fast as the group that did have food. However, the results of a one-tail independent t-test showed that there was no statistically significant difference between the two groups. The t stat value for this test, 0.46, was not greater than the t critical one-tail value, 1.81, indicating that the larvae did not pupate faster in either group and the null hypothesis could not be rejected. The results of this test could have been a due to the small sample size in this experiment as four larvae from one group and two larvae from another group are not a large enough sample to gather accurate data.

Examining Tegmina Polymorphism in Leaf-Masquerading Katydids (Orthoptera: Tettigoniidae)

2021-03-08T21:37:35+00:00

Insects employ a wide array of defensive mechanisms to avoid predation in the wild, evolving highly complex strategies for mimicking a wide range of organisms from other predators to surrounding foliage in the environment, all in an attempt to handicap predators’ ability to maintain a clear record of prey images to hunt. Cryptic insect species often evolve further mimicry strategies such as polymorphs and masquerade in order to provide a far more diverse range of forms, with even further variation of form seen through sexual dimorphism. Frequent and complex instances of polymorphism and cryptic masquerade can be found within the Orthopteran subfamily pterochrozinae (Orthoptera: Tettigoniidae), often posing taxonomic dilemmas as the hugely diverse and convincing forms are unable to be distinguished from eachother. This subfamily contains the genus Mimetica whose precision and accuracy in mimicking leaf appearance, as well as the wide diversity in shape and high color variation, make it an ideal system for observing of polymorphic variation of leaf forms. This experiment attempted to clarify the species relationships within Mimetica, in addition to developing a deeper understanding of the function and importance of polymorphs in insect populations and ecological phenomena in order to ascertain if the katydid species incisa, crenulata, viridifolia, mortuifolia, tuberata, and simoni within Mimetica display a distinct number of cryptically polymorphic forms versus continuous variation by utilizing digital landmark based geometric morphometric software to analyze the tegmina. Tps analyses provided strong support for the existence of sexually dimorphic forms for all species, and a lack of distinction in form within all incisa specimens, suggesting a more effective polymorph. In contrast, simoni and viridifolia specimens displayed the clearest distinction in form, supporting the possibility of the existence of discrete polymorphs in this genus but requiring further refined morphometric analyses.

A Study on The Effects of Different Chemical based and Natural Pesticides on Gryllodes sigillatus

2021-03-08T21:50:57+00:00

Crickets, although not known to be direct vectors for transmitting diseases, they are considered to be a nuisance species and can affect an individual's health indirectly.The cricket Gryllodes sigillatus, also commonly known as the tropical house cricket or as the decorated cricket, is in the order of Orthoptera and family Gryllidae. Much like the cockroach and the common house fly, Gryllodes sigillatus can be found in homes and as a result, can cause problems such as fabric damage, fabric staining, food contamination, and create incessant chirping. Gryllodes sigillatus was chosen as our experimental subject species because of its common distribution around the Southern part of the US border. Our experimental study provides information on the efficiency and effects of different chemically and natural based pesticides can have on the species Gryllodes sigillatus. Specimens were observed over a set time interval in three separate trials, followed by a discussion of the benefits of using natural pesticides instead of chemically based pesticides was made based on our data.

A Comparative Study on the Escape Behaviors of Orthopterans in San Juan de Peñas Blancas, San Ramón, Costa Rica

2021-03-16T18:05:08+00:00

A total of three trials were conducted to compare the escape behaviors of the various Orthopterans Abracris flavolineata (De Geer, 1773), Orophus sp. (Saussure, 1861), Silvitettix sp., Leptomerinthoprora brevipennis (Rehn, 1905). Since many Orthopterans use visual stimuli and react in similar ways to threats, the selected trials tested different kinds of escape behaviors. The first trial testing an approaching vertical stimulus showed no significance in escape behavior between A. flavolineata and Orophus sp. Trial two with a horizontal stimulus also showed no significance, this time between all four species. When looking at solely the grasshopper species in a contingency test from trial two, there was indication that they behaved similarly. Trial three was held outdoors with an approaching downwards angled stimulus, also showing no significance between the four species. When comparing the indoor trials to the outdoor trials, the results were significant, indicative that the specimens reacted faster indoors. A large factor in the results showing insignificance can be traced to the lack of enough specimens to test.

Survey of Mosquitoes on Lake Houston and surrounding Houston Areas

2021-03-30T17:59:32+00:00

After a move from a suburb in the Houston area to Lake Houston (Northeast of downtown Houston), it was observed that the mosquitoes during the summer seemed to be much more prominent on Lake Houston than previously in the suburb. This noticeable difference triggered the question of what types of mosquitoes preferred what kinds of locations and why. To understand and evaluate this question, a survey of various mosquito types across the Houston metropolitan areas was performed. Traps were set up in five cities of different environments, mainly varying in their proximity to specific environmental differences (i.e. lakes, woody areas, downtown etc.) Mosquitoes were collected over a weekend in April, a month reported to have one of the highest rates of mosquitoes present (Nava, 2016). Through research, it was determined that the most prevalent mosquito types in all of the Houston area were Culex species, Anopheles species and Aedes species. Each of this mosquito types have been reported in high numbers during the late Spring and Summer months in all of Houston, but there is little data on how each type is distributed in each area. Through the research, it was hypothesized that Anopheles species would be most prevalent in areas near water and was upheld by the data from the experiment. Knowing this information about the prevalence of certain types of mosquitoes in each area can better help create a mechanism for trapping in each place. Each types of mosquitoes are drawn to various things, for instance, Anopheles prefer to stay on standing water and knowing these preferences can be applied to a better prevention (Mosquito World). With the rise of many serious mosquito transmitted diseases like Zika and West Nile, knowing specifically what mosquitoes are in which area are helpful to each community in protecting themselves from these threats that are associated with each mosquito type.

Survey of the Culex quinquefasciatus (Diptera: Culicidae) Mosquito and the Transmission of West Nile Virus in Brazos County

2021-03-16T18:27:14+00:00

Localities in the College Station area of Texas were surveyed for Culicidae species to examine the prevalence of Culex quinquefasciatus. A recent outbreak of West Nile Virus (WNV) in a nearby suburb of Houston caused by salvarian transmission of Culex q. deems it a medically significant vector worthy of surveillance. Mosquito specimens were collected using Center of Disease Control (CDC) light traps in various recreational parks with proximity to water and moderate human activity, as is preferred by the organism. Collection procedures were implemented during warm, humid months due to mosquito populations peaking at this time. Through trapping, preservation, and identification with pictorial keys, the prevalence of Culicidae species was determined. It was found that while Culex q. poses health threats as a vector of WNV, Aedes aegypti is over three times more abundant in Brazos County. Thus, our research serves to reduce the risk associated with Culex q. and allows for future areas of surveillance that focus on a more widespread species in College Station and surrounding regions.

Effectiveness of Hemp Oil and Orange Citric Oil as Fire Ant (Solenopsis geminata) Repellent

2020-04-22T23:42:34+00:00

More and more people are looking for solutions to their pest problems outside of the mainstream pesticides and pest repellents found in stores and are turning toward “home-remedies” such as essential oils. However, there is limited research about the effectiveness of certain essential oils on repelling and killing arthropods. This experiment covered the use of hemp oil and orange citric oil as possible repellants for fire ants (Solenopsis geminate) common to the Brazos Valley of Texas. Collection of ants was done from an ant mound next to the Texas A&M entomological building and running of the experiment was done inside the building. Petri dishes were used to contain the experiment and the number of times the ants touched the substance was counted and compared against the others. The water control had the height touch count and its average was statistically different (p value= 0.00028805) than the substances tested. Orange citric oil had consistent results among its three trials and there was a statistical difference between it and the control tests. Hemp oil was not as consistent in its results. Although two of the trials had counts very close to each other, the third trial had more than double the counts than the other trials. These results show that orange citric oil was a very effective repellant to Solenopsis geminata compared to the water control. Hemp oil shows promise as a repellent but a larger experiment size would need to be used in order to determine the consistency of its effectiveness. Possible next steps in this line of research include expanding on hemp oil’s effectiveness, determining if the ability of an oil to aerosolize changes its effectiveness, and if other essential oils are effective as repellents against Solenopsis geminate.

A Comparison of Different Sugar Baits for the Capture of Diptera in Texas

2021-03-23T17:41:23+00:00

Identifying the most effective baits to attract Diptera flies is critical for surveillance and control activities. Four different baits consisting of sugar-water, molasses and water, a vinegar-syrup mixture, and a mango mosquito lure were used inside funnel kill traps and placed in various locations in the city of College Station, Tx and left out for five days at a time. Lucilia sericata (Meigen) was the most prevalent species collected, but others included Musca domestica (Linnaeus) and Drosophila melanogaster (Morgan). The molasses bait was the most effective trap, with sugar-water in a close second. The syrup-vinegar mixture did not effectively attract anything.

Key Words: Diptera, Lucilia sericata, fly traps, funnel traps

Diurnal Activity of Gravid Aedes aegypti (Linnaeus) (Diptera: Culicidae) in Toco, Trinidad

2020-04-29T02:49:22+00:00

Abstract: Mosquitoes pose a threat to human health due to a variety of arboviral diseases that they are able to transmit. Many of these diseases are vectored by Aedes aegypti and most are prevalent in many parts of South America and The Caribbean. Gravidity, diurnal activity, and the reproductive capabilities of Aedes aegypti are important to research because future generations of mosquitoes can be studied or eliminated in hopes of reducing future outbreaks of disease. New findings would help researchers obtain new ways of preventing future cases of disease, and would reduce the impact that this health-endangering mosquito has on local communities. A survey of the Jammev Beach Resort in Toco, Trinidad was conducted to determine what time of day had the highest concentration of gravid Aedes aegypti. In order to catch the mosquitoes, diaphoretic clothing was left in an open area. This clothing was used to lure the mosquitoes to the preselected location and sticky cards were used to efficiently catch the mosquitoes. This sweat-baiting method could be replicated and applied to future research in order to test its full potential. Results showed that gravid Aedes aegypti were found in higher concentrations at dawn and at high noon. It was also concluded that both gravidity and mosquito presence decreased as the day progressed. Lengthier studies with more effective trapping methods should be conducted during the wet season to fully understand the activity and reproductive capabilities of Aedes aegypti.

The Effects of Sorghum Volatiles and Sugarcane Aphids on Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) Attraction to Plants

2021-04-22T19:51:56+00:00

Abstract:Coccinella septempunctata and Harmonia axyridis are incredibly effective controls for insect pests in crops. We tested their ability to use olfactory cues to choose the plant with aphids on it. We used two strains of Sorghum bicolorone being the normal susceptible strain while the second was resistant to aphids. The tests conducted were ultimately to determine which strain of sorghum the ladybeetles would favor, and whether or not the ladybeetle would prefer the plants with aphids on them. When aphids were present, no significant difference between susceptible and resistant was found, but when there were no aphids the susceptible plant attracted more predators. This could suggest that there is some kind of chemical or volatile that the susceptible plant has that the susceptible plant does not. Further study of the volatiles that the two strains produce would be necessary as well as more replicants of the two strains with no aphids.

An Analysis of Household Products as Ant Repellents

2021-03-30T17:13:27+00:00

In the summer, harvester ants are responsible for all the ant mounds found across the front and back yard of every household across the country. Pogonomyrmex barbatus are extremely active ants and bites when they feels threaten. The sting from the bite spreads poison along our lymph channels causing irritation and can lead to serious medical complications. However, this does not compare to what danger the chemicals in current ant repellents present to our health. Therefore, we tested the effectiveness of household products as an alternative method as ant repellents. A quarter size of honey was deposited into the center of 7 separate plastic containers. Next, for each container we placed one of the following household products: baking soda, black pepper, vinegar, mustard, coffee grounds, bleach, and crushed up bay leaves completely around the honey as a barrier. Then 10 harvester ants are placed on the outside of the barrier to examine which household product kept the most ants away from the honey after 5 hours. The results presented that coffee grounds was the best repellent, because it successfully kept all the ants away from the honey. However, the bleach, vinegar, and mustard were better ant pesticides killing most to all. Therefore, common household substances can be used as an alternative to effectively repel insects or as pesticides. This would reduce the use of harmful chemicals that are found in ant repellent products.

Comparison of Culicidae Present in Phytotelmata versus Stream Pools at Springfield Station in Dominica, West Indies

2021-03-30T17:26:55+00:00

Mosquito borne diseases are proliferating all around the world. Mosquito habitats can be categorized into temporary and standing pools, both of which influence human health. To understand the extent of their presence in Dominica, a survey of mosquitoes was conducted by observing phytotelmata (plant-held water) and pools in streams present at the Archbold Tropical Research and Education Center (ATREC) in Dominica, West Indies from May 23^rd, 2017 to June 14^th, 2017. To test phytotelmata and pool stream habitats, samples were collected from different water holding plants and standing pools in various areas surrounding the station. The larvae obtained from these samples were then reared and identified. Fifteen mosquitoes were reared from pool streams, and 27 mosquitoes were reared from phytotelmata. The species Aedes busckii (Diptera: Culicidae) (Coquillet) were found to be the most common in phytotelmata, and Culex quinquefasciatus (Diptera: Culicidae) (Say) were found to be the most common in pool streams. Past research suggested that Aedes busckii were the only species found in phytotelmata. However, Culex inflictus (Diptera: Culicidae) (Theobald) was also found to inhabit water-holding plants.

Common Household Reagents that React with Luminol in a Similar Manner as Hemoglobin that Decrease the Reliability of Luminol

2021-03-01T20:49:11+00:00

Abstract: This study was conducted to identify common household reagents, such as bleach or rust, that would react with Luminol in a similar manner as hemoglobin, and thus decrease the reliability of Luminol when used at crime scenes. This experiment was conducted in a household, using 10 samples of the household reagents bleach, rust from pennies, laundry detergent, hoisin sauce, lemon juice, and urine. A small sample of blood in addition to each of the 10 samples of the reagents were placed onto a bed sheet, and liquid Luminol was sprayed over them. The luminescence, or lack thereof, of the Luminol in conjunction with each of the household reagents was then ranked on a scale of 1-4 in terms of how similarly it appeared to that of the hemoglobin. The major findings from this study, were that the bleach reacted with Luminol 95% of the time. Rust on pennies reacted with Luminol 70% of the time, whereas hoisin sauce reacted with Luminol only 17.5% of the time. Urine reacted with Luminol minimally and 7.5% of the time, and lemon juice and laundry detergent reacted with Luminol 0% of the time. Bleach and rust (Copper Oxide) were determined to have a high chance of decreasing the reliability of Luminol. Hoisin sauce, urine, lemon juice, and laundry detergents are common household reagents that do not have much bearing on the reliability of Luminol when it is used at crime scenes.