Sasha C. Voss

Abstract: This study presents differences in rate of decomposition and insect succession between exposed carcasses on the soil surface and those enclosed within a vehicle following carbon monoxide (CO) poisoning. Nine 45-kg pigs were used as models for human decomposition. Six animals were sacrificed by CO gas, half of which were placed within the driver’s side of separate enclosed vehicles and half were placed under scavenger-proof cages on the soil surface. A further three animals were sacrificed by captive headbolt and placed under scavenger proof cages on the soil surface. The pattern of insect succession and rate of decomposition were similar between surface carcasses within trials regardless of the mode of death. Progression through the physical stages of decomposition was 3–4 days faster in the enclosed vehicle due to higher temperatures there compared to external ambient temperatures. Patterns of insect succession also differed between the vehicle and surface treatments. Carcass attendance by representatives of the Calliphoridae was delayed within the vehicle environment by 16–18 h, while oviposition was not observed until 24–28 h following death. In contrast, attendance by Calliphoridae at surface carcasses occurred within 1 h of death, and oviposition occurred within 6–8 h of death. Typical patterns of insect succession on the carcasses were also altered. Carcass attendance by representatives of the Coleoptera occurred during the bloat stage of decomposition at surface carcasses but was delayed until the onset of wet decomposition (as defined by carcass deflation and breakage of the skin) within the vehicle environment. This study provides baseline data outlining the decomposition patterns of a carcass enclosed within a vehicle following CO poisoning in Western Australia. Understanding how variations in decomposition situations impact on the rate of decomposition and patterns of insect succession is essential to obtaining an accurate estimate of minimum post-mortem interval (PMI).

Abstract: This study considered annual, seasonal and shorter term variation in patterns of insect succession onto decomposing remains at two contrasting locations in Western Australia, bushland and agricultural. The degree of consistency in insect succession patterns over spatial and temporal scales was evaluated through multivariate analysis of occurrence-based distance matrices. Insect assemblages were strongly correlated between locations, within corresponding time periods, indicating that patterns of insect succession were similar between localised sites within the same broad geographic area. This suggests that there is reasonable scope for the application of baseline succession data generated at a single study site to a range of decomposition sites within a given region. Differences were largely due to species absences at the agricultural site. Three species of Coleoptera were identified as possible representatives of bushland habitat, Ptomaphila lacrymosa (Silphidae), Omorgus tatei (Trogidae) and Helea castor (Tenebrionidae), and may be indicative of post mortem movement between habitat types. Within locations, variation in insect assemblages was not significant between years. Within years, insect assemblages varied significantly over time on a seasonal time scale and as decomposition progressed through defined decomposition stages. Forensically relevant data detailing the seasonal pattern of insect succession onto decomposing remains for Western Australia are reported. Additional focus has been directed towards hymenopteran parasitoids that frequent decomposing remains and parasitise Diptera colonisers. Parasitoids can be used to provide an extended PMI timeframe in cases where traditional forensic indicators have completed their development.

Abstract: The effect of clothing on carcass decomposition and patterns of insect succession onto remains were investigated in two separate years during autumn in Western Australia. The progression of decomposition differed between clothed and unclothed carcasses in both years of the study. The presence of clothing markedly prolonged the wet decay stage in both years with larval feeding occurring across the moist skin surface underneath clothing, as well as within and under the carcasses. Ambient temperatures were higher in the second year of the study and corresponded to marginally faster rates of decay throughout decomposition. Within years, insect arrival and oviposition were largely consistent between clothed and unclothed carcasses with a few notable exceptions. The green blow fly, Lucilia sericata Meigen (Diptera: Calliphoridae) oviposited one day earlier on clothed than unclothed carcasses in both years of the study. The black carrion fly, Australophyra rostrata Robineau-Desvoidy, (Diptera: Muscidae) colonised clothed carcasses in two distinct waves of succession but only one wave of ovipoistion was observed on unclothed carcasses in either year. Correspondingly, clothed carcasses supported larval feeding by A. rostrata for a longer duration than unclothed carcasses. Finally, dipteran larval masses were more widely distributed across the carcass surface and were present for a longer period of time on clothed carcasses than on unclothed carcasses in both years. Forensically relevant data detailing the seasonal pattern of insect succession onto clothed and unclothed decomposing remains in Western Australia are reported.

Abstract: To assess the relative impact of a range of habitat variables on spider abundance, field and laboratory experiments were conducted on populations of the urban wall spider Oecobius navus in suburban Perth, Western Australia. Habitat characteristics investigated were: substrate type, wind speed, rainfall, sunlight exposure, relative humidity, air temperature, substrate temperature, artificial lighting and prey type/abundance. In the field, O. navus was found to be associated with high humidity, low air tempera- ture and shelter from sunlight and rainfall. Oecobius navus was more abundant at sites with greater prey abundance. The most common prey item was the red meat ant Iridomyrmex chasei. Juvenile spiders were more abundant than adult spiders; however, patterns between spider abundance and habitat variables were similar for both adults and juveniles. Laboratory experiments showed that O. navus preferred to build webs on wooden substrates, and pitted limestone walls. These findings indicate that O. navus may be vulnerable to desiccation and/or thermal stress, and thus survives better on sheltered walls.

Abstract: A 2-yr survey of hymenopteran parasitoids associated with carrion-breeding flies was conducted to establish the parasitoid species of potential forensic significance in Western Australia. Host associations, seasonality, and rates of parasitism in the field were examined to assess the value of the identified parasitoids as forensic indicators of time since death. Four species of parasitoid emerged from dipteran specimens collected from carcasses: Tachinaephagus zealandicus Ashmead (Encryptidae), Nasonia vitripennis Walker (Pteromalidae), Spilomicrus sp. (Diapriidae), and Aphaereta sp. (Braconidae). Overall parasitism of carrion-breeding flies was 11.8%. T. zealandicus and N. vitripennis were the predominant species, accounting for 86.3 and 11.5% of parasitism observed, respectively. In contrast, Aphaereta sp. and Spilomicrus sp. were intermittently collected from carcasses throughout the study and the parasitism rates of both species were low (< or = 3.0%). Our findings provide forensically important biological and behavioral data of parasitoid-host interactions within carcass environments. The cosmopolitan parasitoids T. zealandicus and N. vitripennis have the greatest potential as indicators of time since death in forensic investigations based on their broad host ranges, rates of parasitism, and seasonal prevalence. In combination, these two species are present throughout the year and they parasitized nearly all of the dipteran species that colonize carcasses. Because both are cosmopolitan species, the data presented here are applicable to regions experiencing a similar Mediterranean climate. This work reports the first incidence of T. zealandicus and N. vitripennis parasitizing the dipteran species Calliphora albifrontalis Malloch (Calliphoridae), Calliphora dubia Macquart (Calliphoridae), and Hydrotaea rostrata Robineau-Desvoidy (Muscidae).

Abstract: Prior to the work of Cable and Hopp (J. Parasit. 40(6): 674.680, 1954) Neoechinorhynchus emydis (L e i d y, 1851) was the only recognized species of Acanthocephala in North American turtles. To date, a total of five species have been described. Of these, two species (Neoechinorbynchus pseudemydis Cable and Hopp, 1954, and N. emyditoides Fisher, 1960) were recovered from six of 12 Louisiana turtles (Pseudemys scripta elegans (Wied)) examined by Fisher (J. Parasit. 46(2): 257-266, 1960). He (1960) also found N. chrysemydis Cable and Hopp, 1954 in Pseudemys scripta subsp. The data pt .sented are results of studies conducted between the spring of 1965 and the summer of 1966. Seventynine turtles (48 female and 31 males) encompassing seven species (47 Pseudemys scripta elegans (Wied), three P. floridana hoyi (Holbrook), eight Chelydra serpentina serpentina (L.), eight Kinosternon subrubrum hippocrepis Gray, seven Terrapene carolina carolina (L.), five T. c. triunguis (Agassiz) and one Trionyx muticus (LeSueur) collected from Baton Rouge and vicinity were examined. This investigation revealed the presence of three species of Acanthocephala (Neoechinorhynchus pseudemydis, N. emyditoides, and N. chrysemydis) in Louisiana turtles and confirms Fisher’s (1960) work. Of the seven species of turtles examined, only P. s. e!egans (25 16 females and 9 males) and P. floridana hoyi (2 females) were positive with infection. Three of the 25 P. s. e!egans had mixed infection comprising three species of Neoechinorhynchus while seven had two species respectively. P. f!oridana hoyi represents a host record for N. chrysemydis;

Abstract: Forensic entomology is the science of collecting and analysing insect evidence to aid in forensic investigations. Its main application is in the determination of the minimum time since death in cases of suspicious death, either by estimating the age of the oldest necrophagous insects that developed on the corpse, or by analysing the insect species composition on the corpse. In addition, toxicological and molecular examinations of these insects may help reveal the cause of death or even the identity of a victim, by associating a larva with its last meal, for example, in cases where insect evidence is left at a scene after human remains have been deliberately removed. Some fly species can develop not only on corpses but on living bodies too, causing myiasis. Analysis of larvae in such cases can demonstrate the period of neglect of humans or animals. Without the appropriate professional collection of insect evidence, an accurate and convincing presentation of such evidence in court will be hampered or even impossible. The present paper describes the principles and methods of forensic entomology and the optimal techniques for collecting insect evidence.

Abstract: The National Research Council issued a report in 2009 that heavily criticized the forensic sciences. The report made several recommendations that if addressed would allow the forensic sciences to develop a stronger scientific foundation. We suggest a roadmap for decomposition ecology and forensic entomology hinging on a framework built on basic research concepts in ecology, evolution, and genetics. Unifying both basic and applied research fields under a common umbrella of terminology and structure would facilitate communication in the field and the production of scientific results. It would also help to identify novel research areas leading to a better understanding of principal underpinnings governing ecosystem structure, function, and evolution while increasing the accuracy of and ability to interpret entomological evidence collected from crime scenes. By following the proposed roadmap, a bridge can be built between basic and applied decomposition ecology research, culminating in science that could withstand the rigors of emerging legal and cultural expectations.

Abstract: How does nature work in our human-created city, suburb, and exurb/peri-urb? Indeed how is ecology - including its urban water, soil, air, plant, and animal foundations - spatially entwined with this great human enterprise? And how can we improve urban areas for both nature and people? Urban Ecology: Science of Cities explores the entire urban area: from streets, lawns, and parks to riversides, sewer systems, and industrial sites. The book presents models, patterns, and examples from hundreds of cities worldwide. Numerous illustrations enrich the presentation. Cities are analyzed, not as ecologically bad or good, but as places with concentrated rather than dispersed people. Urban ecology principles, traditionally adapted from natural-area ecology, now increasingly emerge from the distinctive features of cities. Spatial patterns and flows, linking organisms, built structures, and the physical environment highlight a treasure chest of useful principles. This pioneering interdisciplinary book opens up frontiers of insight, as a valuable source and text for undergraduates, graduates, researchers, professionals, and others with a thirst for solutions to growing urban problems.

Abstract: The succession of insects on pig carrion was monitored in spring, summer and autumn, in three forest types and 2 years in Western Poland (Central Europe). In most forensically useful taxa, significant differences between seasons, forests and years in time of appearance on carrion were found. The lowest values of appearance time were recorded in summer and the highest in spring. In alder forest insects appeared on carcasses significantly earlier than in pine-oak forest and hornbeam-oak forest. In summer periods of insect presence on carrion were significantly shorter than in spring and autumn. In most taxa no significant effect of forest type or year on length of the presence period was found. In all seasons assemblages of adult taxa were clearly more aggregated than assemblages of larval taxa. Sequence of insects’ appearance on carcasses was very similar in different seasons, forests and years. General seasonal models of insect succession on carrion are proposed for forests of Central Europe. Data on appearance time and length of the presence period in particular seasons, forests and years are presented for forensically useful taxa. Implications for methods of PMI estimation (particularly the succession-based method) are discussed.