Carrion-associated arthropods in rural and urban environments

Preferences of arthropods are important in forensic entomology, as the species collected can help determine the postmortem interval or if remains have been moved. This study looked at arthropods that are attracted to pig carcasses in rural and urban habitats in Northwest Indiana. The species and number of carrion-associated arthropods that are found at a carcass vary with habitat type, month, and stage of decomposition. Lucilia sericata (Diptera: Calliphoridae) is a synanthropic species that was found in higher numbers in urban locations for both adults and larvae. Though L. sericata had higher numbers in urban habitats, caution must be exercised when using the information in a criminal case, as adults and larvae were still collected in rural habitats, and thus presence of L. sericata does not conclusively show that remains were previously located in an urban habitat. No other Diptera or Coleoptera species showed a preference for habitat type. Isopoda were found in higher numbers in urban habitats. Calliphoridae species, except for L. sericata, had differences in numbers between the months studied (June-October). Most adult taxa and all larval taxa showed differences in numbers between decomposition stages. Succession tables for all arthropods and non-arthropods collected were created to show when taxa that were found at the carcasses. Crickets (Orthoptera: Gryllidae) were observed feeding on the carcass, and feeding holes left in the carcasses by dipteran larvae. The cricket feeding modified the appearance of the holes, which could be confused for antemortem or perimortem wounds in a criminal investigation

Genome sequence of Phormia regina Meigen (Diptera: Calliphoridae): implications for medical, veterinary and forensic research

BACKGROUND: Blow flies (Diptera: Calliphoridae) are important medical, veterinary and forensic insects encompassing 8 % of the species diversity observed in the calyptrate insects. Few genomic resources exist to understand the diversity and evolution of this group. RESULTS: We present the hybrid (short and long reads) draft assemblies of the male and female genomes of the common North American blow fly, Phormia regina (Diptera: Calliphoridae). The 550 and 534 Mb draft assemblies contained 8312 and 9490 predicted genes in the female and male genomes, respectively; including > 93 % conserved eukaryotic genes. Putative X and Y chromosomes (21 and 14 Mb, respectively) were assembled and annotated. The P. regina genomes appear to contain few mobile genetic elements, an almost complete absence of SINEs, and most of the repetitive landscape consists of simple repetitive sequences. Candidate gene approaches were undertaken to annotate insecticide resistance, sex-determining, chemoreceptors, and antimicrobial peptides. CONCLUSIONS: This work yielded a robust, reliable reference calliphorid genome from a species located in the middle of a calliphorid phylogeny. By adding an additional blow fly genome, the ability to tease apart what might be true of general calliphorids vs. what is specific of two distinct lineages now exists. This resource will provide a strong foundation for future studies into the evolution, population structure, behavior, and physiology of all blow flies

A seasonal distribution study of muscoid flies of Kansas

Call number: LD2668 .T4 1959 R3

Effects of Temperature and Tissue Type on the Development of Megaselia scalaris (Loew) (Diptera: Phoridae)

The scuttle fly, Megaselia scalaris (Loew), is a Dipteran from the Phoridae family of medical, veterinary, and forensic importance. In the case of the latter, M. scalaris is commonly associated with indoor death scenes and its larvae are useful in determining time of colonization (TOC). This is the first developmental study on the effects of different temperatures and tissues from two different vertebrate species on the growth rate and larval length of M. scalaris, and consequently, on estimated TOC. A validation study of these data was also conducted. Immature M. scalaris were reared on either bovine or porcine biceps femoris at 24°C, 28°C, and 32°C. Temperature significantly impacted immature development including egg hatch, development from hatch to pupa, and from pupa to adult. From egg to hatch, development had a growth rate difference of 32.1% from 24°C to 28°C, 13.9% from 28°C to 32°C, and 45.5% from 24°C to 32°C. Development of larva to pupation displayed similar results with differences of 30.3% between 24°C and 28°C, 15.4% between 28°C and 32°C, and 45.2% between 24°C and 32°C. Development from pupation to adult emergence, likewise, displayed a 44.4% difference from 24°C and 28°C, 7.3% from 28°C to 32°C, and 51.2% from 24°C to 32°C. From oviposition to adult emergence, M. scalaris needed approximately 32.7% more hours to complete development when reared at 24°C than 28°C, 8.5% when reared on 28°C rather than 32°C, and 38.4% more time when reared on 24°C over 32°C. Tissue type did not significantly impact development. A preliminary validation study was conducted within four different indoor environments (two different attics, a closet, and a shower) spanning two different buildings. Utilizing minimum and maximum lengths, time of colonization estimates were underestimated in all instances. In all cases, the range generated encompassed the actual time of colonization. On average, time of colonization estimates when using minimum length were underestimated by 26%, but overestimated by only 1.4% when using maximum development range. Data gathered from this research could be useful when estimating a time of colonization of decomposing vertebrate remains. Future research will need to examine development for each instar in order to increase precision of such estimates

Life-History Traits Of Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae) And Its Associated Non-Consumptive Effects On Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae) Behavior And Development

Blow fly (Diptera: Calliphoridae) interactions in decomposition ecology are well studied; however, the non-consumptive effects (NCE) of predators on the behavior and development of prey species have yet to be examined. The effects of these interactions and the resulting cascades in the ecosystem dynamics are important for species conservation and community structures. The resulting effects can impact the time of colonization (TOC) of remains for use in minimum post-mortem interval (mPMI) estimations. The development of the predacious blow fly, Chrysomya rufifacies (Macquart) was examined and determined to be sensitive to muscle type reared on, and not temperatures exposed to. Development time is important in forensic investigations utilizing entomological evidence to help establish a mPMI. Validation of the laboratory-based development data was done through blind TOC calculations and comparisons with known TOC times to assess errors. A range of errors was observed, depending on the stage of development of the collected flies, for all methods tested with no one method providing the most accurate estimation. The NCE of the predator blow fly on prey blow fly, Cochliomyia macellaria (Fabricius) behavior and development were observed in the laboratory. Gravid female adult attraction was significantly greater to resources with predatory larvae rather than prey larvae and oviposition occurred on in the presence of heterospecific (predatory) and conspecific larvae equally. However, the life stages necessary for predation to occur never overlapped and so these results may not be as surprising as they seem. Conversely, exposing prey larvae to predator cues through larval excretions/secretions led to larger prey larvae and faster times to pupariation when appropriate life stages overlapped. Differences in size and development times of prey larvae in the presence of predatory cues could lead to errors when estimating the mPMI. These data also partially explain the ability of C. macellaria to survive in the presence of Ch. rufifacies. Colonization of a resource with late instar Ch. rufifacies enhanced development and size of resulting larvae indicating that lag colonization, rather than being a primary colonizer, could become an alternate strategy for C. macellaria to survive the selective pressures of the predator, Ch. rufifacies. The differing effects of temperature on Ch. rufifacies and C. macellaria may also lend an advantage to C. macellaria over the predacious Ch. rufifacies in an environment with variable temperatures unlike what Ch. rufifacies is adapted for

Influence of microbial inoculant on the oviposition and completion of life cycle of chrysomya megacephala and chrysomya rufifacies infesting rabbit carcasses

Considering any surrounding factors as well as the cunning use of microbial inoculants to cover the smell of decomposing bodies could potentially alter (delay or speed up) the time of initial oviposition and developmental rate of insects infesting the corpses, thereby resulting in erroneous estimation of post mortem interval (PMI); such factors led to the initiation of this research. This research was conducted to assess the influence of a commercially available microbial inoculant (EM.1®) on the initial oviposition and developmental rate that lead to completion of life cycle of the two prevalent necrophagous flies (Chrysomya megacephala and Chrysomya rufifacies) in Malaysia infesting rabbit carcasses. In this research, nine rabbit carcasses were equally divided into control (C) and two treated (T1 and T2) groups. The T1 and T2 carcasses were individually sprayed with two different concentrations at 1:500 and 1:100 of the same microbial inoculant, respectively. The durations taken for each species of fly to first oviposit and complete their life cycle in treated carcasses were compared with that of control carcasses. Results revealed that single application of the microbial inoculant on both the treated carcasses did not statistically impede oviposition of both species as well as their subsequent developmental patterns (Kruskall-Wallis H: P > 0.05) when compared to the control carcasses. Since this is the first research that reported on the time of initial oviposition and completion of life cycle for C. megacephala and C. rufifacies in the presence of microbial inoculant, the results observed here may prove useful for estimating PMI in Malaysia particularly in cases where the use of microbial inoculant was suspected