Effect of Habitat on Blow Fly (Diptera: Calliphoridae) Oviposition in Michigan

Forensic entomology applies data gained from insects to aid the criminal justice system. Blow flies (Diptera: Calliphoridae) are usually the first insects to arrive and oviposit (lay eggs) on carrion. Their quick appearance is the foundation for post mortem interval estimations, making any factors that influence their oviposition crucial. This study examined the effects of habitat (forest vs. prairie) on blow fly oviposition timing. Research was conducted in 2015 at Pierce Cedar Creek Institute in Barry County, Michigan. No significant differences were found in oviposition timing or frequency between prairie and forest habitats. Temperature and humidity were not correlated with oviposition timing, which contradicted previous studies. Lucilia coeruleiviridis (Macquart) was the dominant species found, comprising about 90% of collected specimens. The data confirm previous reports that Lucilia species are the first to arrive on carrion

Diurnal Oviposition of Blow Flies in Different Aged Carrion

Blow flies (Diptera: Calliphoridae) are among the first insects to oviposit (lay eggs) on carrion. The timing of blow fly oviposition is critical for determining a postmortem interval (PMI) estimation, which is the time that has passed between death and corpse discovery. The objective of this investigation is to gain more information about the timing of blow fly oviposition in relation to sunrise. Past research in our lab has shown that blow fly oviposition occurs an average of 4.75 hours after sunrise. This year’s research expanded on previous studies by placing six piglets of different ages, in a remote, wooded area one hour after sunrise. To see if there was a difference in the timing of oviposition related to the age of the carrion, three of the piglets had been thawed for 15 hours (new pigs), and the other three had been thawed for approximately 55 hours (old pigs). The piglets were checked once an hour until oviposition occurred, and it was recorded whether flies and eggs were present each hour. Egg masses were collected and reared to the third larval instar stage for identification using taxonomic keys. The timing of oviposition, in hours after sunrise, was compared between treatments and there was no significant difference found (P=.441). The research was repeated five times in the fall of 2017. The most common flies found ovipositing were Diptera: Calliphoridae, Phormia regina (Meigen) and Diptera: Calliphoridae, Lucilia coeruleiviridis (Macquart). This research has importance in both the scientific and forensic communities, as a more accurate PMI can strengthen the validity of a forensic investigation

First Record of the Hairy Maggot Blow fly, Chrysomya rufifacies (Diptera: Calliphoridae) in Indiana

The hairy maggot blow fly, Chrysomya rufifacies (Macquart) is native to Australia but has been spreading to a worldwide distribution and is becoming established in the United States. This paper presents the first documentation of the species in Indiana, specifically Valparaiso, Indiana. The species was found in September 2017 and again in October 2019. Its presence is variable in Northwest Indiana, but seems to be found in the fall when the temperatures are at least 30°C prior to collection

Effect of Habitat on Blow Fly (Diptera: Calliphoridae) Oviposition in Michigan

Forensic entomology applies data gained from insects to aid the criminal justice system. Blow flies (Diptera: Calliphoridae) are usually the first insects to arrive and oviposit (lay eggs) on carrion. Their quick appearance is the foundation for post mortem interval estimations, making any factors that influence their oviposition crucial. This study examined the effects of habitat (forest vs. prairie) on blow fly oviposition timing. Research was conducted in 2015 at Pierce Cedar Creek Institute in Barry County, Michigan. No significant differences were found in oviposition timing or frequency between prairie and forest habitats. Temperature and humidity were not correlated with oviposition timing, which contradicted previous studies. Lucilia coeruleiviridis (Macquart) was the dominant species found, comprising about 90% of collected specimens. The data confirm previous reports that Lucilia species are the first to arrive on carrion

Effect of Water on Blow Fly (Diptera: Calliphoridae) Colonization of Pigs in Northwest Indiana

Forensic entomology is the use of insects in the criminal justice system. Blow flies (Diptera: Calliphoridae) are early colonizers of carrion and any information on factors that influence their oviposition (egg laying) is of vital importance to forensic entomologists. This study examined the effect that being placed in a water environment had on blow fly oviposition. Six pigs were used in this study: three were in water and three were on land (control). Pigs were checked daily to document the arrival time of adult flies, fly eggs, fly larvae, the start of larval migration, and the end of larval migration. Data were analyzed using t-tests to determine if significant differences existed in the timing of blow fly life events between control pigs and pigs in water. Significant differences were seen in the timing of adult flies, fly eggs, fly larva, start of larval migration, and the end of larval migration. Pigs in the water environment initially sank but floated on the water’s surface after four days. Colonization by blow flies occurred five days after field placement on the pigs in water. There was an average of a five day difference in postmortem interval (PMI) estimations between control pigs and pigs in water. The results from this study will be valuable to forensic entomologists because it provides important information about blow fly oviposition, growth and development on pigs in a water environment

Diurnal Oviposition of Blow Flies in Different Aged Carrion

Blow flies (Diptera: Calliphoridae) are among the first insects to oviposit (lay eggs) on carrion. The timing of blow fly oviposition is critical for determining a postmortem interval (PMI) estimation, which is the time that has passed between death and corpse discovery. The objective of this investigation is to gain more information about the timing of blow fly oviposition in relation to sunrise. Past research in our lab has shown that blow fly oviposition occurs an average of 4.75 hours after sunrise. This year’s research expanded on previous studies by placing six piglets of different ages, in a remote, wooded area one hour after sunrise. To see if there was a difference in the timing of oviposition related to the age of the carrion, three of the piglets had been thawed for 15 hours (new pigs), and the other three had been thawed for approximately 55 hours (old pigs). The piglets were checked once an hour until oviposition occurred, and it was recorded whether flies and eggs were present each hour. Egg masses were collected and reared to the third larval instar stage for identification using taxonomic keys. The timing of oviposition, in hours after sunrise, was compared between treatments and there was no significant difference found (P=.441). The research was repeated five times in the fall of 2017. The most common flies found ovipositing were Diptera: Calliphoridae, Phormia regina (Meigen) and Diptera: Calliphoridae, Lucilia coeruleiviridis (Macquart). This research has importance in both the scientific and forensic communities, as a more accurate PMI can strengthen the validity of a forensic investigation

The Effect of Plastic Bags on Decomposition and Necrophagous Fly Composition

Forensic entomology uses insects to help estimate the post-mortem interval (PMI) based on blow fly colonization. The PMI provides an estimate of the time between death and discovery and is of extreme relevance due to its large role in forensic investigations. Nine fetal pigs were thawed from frozen 24 hours before the start of the experiment. Six fetal pigs were covered with plastic bags: three with thin plastic bags (average bag weight of 5.43 g) and three with thick plastic bags (average bag weight of 11.9 g). The remaining three pigs served as the control group. These pigs were placed outside, monitored for 6 days, and checked three times daily to look for the presence of blow fly eggs, adults, and maggots. Third instar maggots were collected for later observance. ANOVA tests were conducted to look for differences in the timing of blow fly oviposition between treatments. There was no significant difference found for any of the life stages in either trial. P-values ranged from 0.22 -1. The maggots were identified to species to look for differences in species composition between treatments. Lucilia coeruleiviridis was the dominant species found. Sarcophagidae flies were found only on bagged pigs. Sarcophagidae larvae have been found very rarely in this field site over the past decade, so this is an interesting finding. Scavenging of the pigs was a problem and future research should aim to reduce the effects of vertebrate scavenging

Maggots in the hot tub

Myiasis is the larval infestation of living tissues by Dipteran larvae, including humans. In forensics, myiasis plays a role in cases of abuse or neglect. Accurate temperatures are crucial for age determination of the larvae. An experiment was conducted to determine the difference between ambient temperature and temperature larvae experience when on a wound. Larvae were placed in a foil cup containing chicken liver. The cups were then placed into a water bath heated to approximately to 37°C. The temperatures inside the cups as well as the ambient temperature were collected every 30 seconds for the duration of the trials through a data logger. After running an anova on the data, it was found that there was a significant difference in the ambient temperature and the temperature within the cups. The f-ratio value found was 841.78851. The p-value is \u3c .00001. Tukey post hoc tests showed that the ambient temperature was significantly different than all of the liver cups. Learning more about the difference between ambient temperature and the temperature of larval infested conditions can assist in the creation of more accurate estimates in relation to the timeline of myiasis. This information can then be used to further improve the investigation of cases of injury or death related to myiasis

An examination of the effect of household chemicals on blow fly oviposition, growth, development, and estimations of the post mortem interval

This study sought to: (1) observe differences in blow fly activity between fresh and frozen-thawed carcasses, (2) observe the effects of chemicals on the timing of blow fly life events, and (3) observe differences among treatments in blow fly species composition. To answer the first objective, seven pigs, frozen for 2 months and then thawed prior to the experiment, were compared with seven pigs killed shortly before the start of the experiment. No differences in time to the appearance of adult flies, eggs, larvae, or the initiation and conclusion of larval migration were observed between refrigerated only and previously frozen pig carcasses. To study the effects of household chemicals on blow fly life events, a study was conducted in West Lafayette, Indiana, in the summer and fall of 2008, spring, summer and fall of 2009 and the spring of 2010. Seven chemicals were tested: muriatic acid, bleach, lime, Raid® (active ingredient permethrin, tetramethrin, d-cis/trans allethrin), OFF!® (active ingredient N,N-Diethyl-meta-toluamide (DEET)), ammonia and gasoline. Pigs with no chemical treatment served as controls. Significant interactions were found between event and season, season and treatment and event and treatment. Pairwise comparisons found significant differences in the amount of accumulated degree hours for blow fly life events to occur between the control and bleach, muriatic acid, OFF!®, and lime. Pigs treated with Raid® were attractive to adult flies but had no oviposition. Following the methods outlined above, a study was conducted at the Anthropological Research Facility at the University of Tennessee, Knoxville in July-August 2010. Using six human bodies, Raid® and ammonia were tested and untreated bodies served as controls. Bodies treated with Raid® had between a 1,000–3,000 accumulated degree hour (ADH) delay in insect activity when compared to controls and ammonia, depending on the insect life event. The application of chemicals can significantly impact a forensic entomologist\u27s estimation of the postmortem interval and the data obtained from this research will help yield more accurate assessments