Insect Succession Patterns Research Articles

Patterns of insect succession and decomposition on rabbit carcasses over the summer and winter seasons

Patterns of insect succession and decomposition on rabbit carcasses over the summer and winter seasons

Decomposition and insect succession of pig cadavers in tents versus outdoors – A preliminary study

The pattern of insect succession and the species composition on cadavers can be influenced by several parameters, one of which is concealment. It has been previously shown for cadavers inside containers (e.g. suitcases or vehicles) or various indoor situations, that concealment can lead to a delayed arrival, altered species composition and decreased number of taxa present at the cadaver. As no data is yet available for the specific environment of tents on these processes, we placed five pig cadavers inside closed two-person tents during the summer of 2021 in a mixed forest in Germany. Five control cadavers were freely accessible for insects. To minimize disturbances, tents were only opened every fifth day over a period of 25 days for estimating the temperature profiles, insect diversity and quantification of the cadavers’ decomposition using the total body score (TBS).The temperature inside the tents was only slightly elevated compared to the ambient temperature during the study. Although the tents prevented direct access of adult flies and beetles, the cadavers were colonized because the flies oviposited on the zippers and fly screens of the inner tents. However, the resulting infestation of the cadavers by fly larvae was reduced and delayed, compared to the exposed cadavers. The dominant fly species on both the tent and exposed cadavers was the blow fly Lucilia caesar. Open cadavers showed the expected decomposition patterns with large larval masses. 25 days after placement, only bones and hair remained from the exposed pigs (TBS = 32), while most of the tissue of the cadavers inside the tents was still present (TBS = 22.5) and post feeding larvae were not able to leave the tents. Regarding the attraction of beetles to both treatments, open cadavers were predominately colonized by the silphid Oiceoptoma thoracicum, while the silphid Necrodes littoralis was the most dominant species in the pitfall traps surrounding the tents. Considering the prolonged pre-appearance interval of fly larvae colonizing the cadavers inside tents, the entomological evidence of forensic cases dealing with concealed bodies should be handled with caution, since the post mortem interval might be significantly underestimated.

Succession patterns of sarcosaprophagous insects on pig carcasses in different months in Yangtze River Delta, China

The Yangtze River Delta is one of the most economically developed regions in China, and many cases in the area require an estimation of the postmortem interval each year. This article reports forensic entomological research conducted in this region in different months. A total of 18 domestic pigs were used to study carcass decomposition, species composition, development events, and succession patterns of insects in different months from 2015 to 2021. A total of 53 arthropod species were identified, of which 38, 40, 41, and 25 were observed in April, June, September, and November, respectively. We demonstrated that insects vary in number and species from month to month, and the same species vary in number among the different months. Larvae of Calliphoridae mainly drove the decomposition of carcasses, and the decomposition rate of carcasses varied over the months. Particularly, the decomposition rate was highest in June and September, slower in April, and slowest in November. The predominant species on the carcasses also varied from month to month; Calliphora grahami Aldrich, Chrysomya pinguis (Walker), Lucilia sericata (Meigen) (Diptera: Calliphoridae), and Hydrotaea spinigera Stein (Diptera: Muscidae) were most predominant in April; Chrysomya megacephala (F.) and Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae) were most predominant in June and September; and Ca. grahami was most predominant in November. In addition, the seven dominant insect species displayed four developmental events, which could be used to determine minimum postmortem interval, including adult arrival (T1), larvae wandering (T2), pupation (T3), and eclosion (T4) time on the carcasses. Insect succession patterns on carcasses also varied across months. For example, Ch. megacephala appeared later in the composition stages and was not numerically dominant in April but appeared earlier and was dominant in June and September. The results of this study guide the use of insect evidence in different months in the Yangtze River Delta region of China for estimating the postmortem interval of carcasses.

Dynamics of insects, microorganisms and muscle mRNA on pig carcasses and their significances in estimating PMI

The accurate estimate of the postmortem interval (PMI) is of vital significance in the investigation of homicide cases. In this study, three pig carcasses were placed in the field to study the pattern of insect succession, the change of microorganisms and the degradation of muscle tissue RNA during the decomposition process. The results showed that insects could quickly colonize the carcasses and still exist on them until the end of the experiment (41 days). Their development and succession patterns are useful indicators for PMI estimation. The diversity of rectal microorganisms decreased with the decomposition time. In different decomposition periods, significant differences in the rectal and soil microbial composition and relative abundance were found, which could be used to estimate the PMI with an accuracy of 3–4 days. The RNA of muscle tissue was found to have a time-dependent relationship with the PMI. Ppia and Gapdh showed a linear upward trend within 10 h after the death, followed by a gradual downward trend from 10 to 240 h. The expression of β-actin gene showed a gradual downward trend during 0–240 h. This is the first study in China to analyze the changes of insects, muscle RNA and microorganisms on pig carcasses in the same natural environment, which provide basic data for the PMI estimation.

Effects of ante-mortem use of methadone on insect succession patterns

BackgroundEvaluation of insect succession patterns is a scientific method to estimate the time elapsed since death. Several studies have shown that ante-mortem intake of opioids affect maggot growth rate. However, there are few published data that investigate the effect of ante-mortem opioid use on insect succession patterns.Therefore, the main purpose of this research was to investigate the effect of methadone on the succession patterns of insects on rabbit carcasses during the spring and winter of 2019. In the present study, the H-null hypothesis represents the dissimilarity between the successional waves of species from testing and control carcasses (H0: P: 0).ResultsDuring this study, 15 and 13 insect species were collected from carcasses during the spring and winter, respectively. The most dominant species during the both seasons were Chrysomya albiceps and Calliphora vicina. These two species preferred to lay eggs on the control carcasses earlier than the treated carcasses. Lucilia cuprina was observed only from the remains of untreated carcasses, while Saprinus chalcites and Necrobia rufipes were recorded only from the remains of treated rabbits. Samples indicate that 11.8% of the insects were members of the Coleoptera. Permutation analyzes based on the Mantel test were 0.647 ± 0.16 (P = 0.009) and 0.693 ± 0.16 (P = 0.003) for the similarity of the species between treated and untreated carcasses in the spring and winter, respectively. Permutation analyzes for the two most dominant fly species (Ch. albiceps and C. vicina) between the treated and untreated carcasses in the spring and winter were 0.515 ± 0.15 (P = 0.05) and 0.491 ± 0.14 (P = 0.09), respectively.ConclusionThe results revealed that the overall pattern of insect succession was similar between the treated and untreated rabbit carcasses. However, the patterns of succession of Chrysomya albiceps and Calliphora vicina differed slightly between treated and untreated carcasses, and this could have an effect on the PMI min estimate.

A Preliminary Investigation of Insect Succession Patterns on Decomposing Carrion on Rottnest Island (WA)

Introduction: Pivotal component of medico-legal investigations is the determination of time since death, or (minimum) postmortem interval, (min) PMI. Forensic entomology can provide reliable estimates of (min) PMI using carrion insect species. Carrion insect arrival and departure occurs in predictable and sequential waves, however, successions may vary depending on geographical location and environmental conditions. Hence, it is crucial to refer to insect succession data of the same region where the death scene occurs. A current gap in forensic entomology research is on carrion-breeding species and succession on decomposition remains/carrions on small islands. Rottnest Island is located off the south-west coast of Perth. The aim of this study was to establish baseline data of carrion insect fauna present on this island, and to provide entomological evidence that may aid in any future investigations on the island. Methods: A list of the insect taxa associated with two decomposing swine hindquarters during the summer season was compiled over a 15-day study period and compared with published mainland data obtained during the same period of the year. Results: Ten insect taxa representing four families were collected and identified in association with the decomposing carrion. The first wave of colonising Diptera species included Calliphoridae species and Sarcophagidae species. The second wave of Diptera comprised Muscidae species, in addition to beetles. Furthermore, ants and spiders were noted throughout the trial. Conclusions: Comparing the results on Rottnest Island with currently available data from mainland WA, showed that the composition of insect speciesand the patterns of succession were similar.

Consistency of seasonal patterns of insect succession on pig cadavers at Yeongdo Island in Busan, Korea

AbstractCadaver insects cause dead bodies to break down in ecological processes. Still, the knowledge has been accumulated slowly about the structure and role of the insect assemblages attending to death scenes. This study analysed the successional patterns of insects on pig cadavers in the spring, summer, and autumn from 2016 to 2019 at Yeongdo Island, Busan, South Korea. A sum of 71 insect species belonging to four orders and 21 families were sampled. Predominant insects were largely Diptera and Coleoptera. The majority of the flies were the calliphorids as Chrysomya pinguis (Walker) and Lucilia porphyrina (Walker). The most common beetles were Creophilus maxillosus (L.), Omosita japonica (Reitter), and Staphylinidae sp. regardless of seasons. Occurrence matrices were made from the successional patterns of insect species during 42 sampling intervals in the spring, 38 sampling intervals in the summer, and 26 sampling intervals in the autumn. Permutation analyses of the occurrence matrices showed that the patterns of succession were similar between spring 2016 and 2017 (P = 0.019), between summer 2016 and 2017 (P = 0.003), and between autumn 2016 and 2019 (P = 0.002). The result shows that there are clear patterns in succession between seasons, and provides the reference data to presume the death time, at least in the southeast part of South Korea.

Seasonal Impact of Heroin on Rabbit Carcass Decomposition and Insect Succession.

This study investigates the succession of insects and the length of the decomposition of rabbit carcasses injected with heroin. In total, 24 rabbits (2-2.5 kg, Oryctolagus cuniculus domesticus L.) were used in the study. Twelve carcasses were exposed to insect activity in winter (January and February) and 12 in summer (July and August) in Riyadh, Saudi Arabia. Three replicate experiments were conducted in each season. For each experiment, three rabbits were injected with varying doses of heroin, and the fourth rabbit was used as a control, being injected only with saline solution. Insects belonging to the order Diptera, Coleoptera, and Hymenoptera were attracted to the carcasses. In both of the investigated seasons, heroin appeared to delay the decomposition process but did not have a significant impact on the number of insects. In general, the number of flies in both seasons was substantially higher than that of beetles and ants. During the summer, flies were more attracted to treated carcasses with a higher dose of heroin. Some flies such as Musca domestica L. (Diptera: Muscidae) and Chrysomya albiceps Wiedemann (Diptera: Calliphoridae) and some beetles such as Pimelia boyeri Solier (Coleoptera: Tenebrionidae) were represented on the carcasses by different developmental instars (larvae, pupae, and adults). Overall, heroin has not potential effects on the insect succession patterns of insect, however, influences the decomposition of rabbit carcasses. These findings are important while using insects in medicolegal investigation, since heroin is one of the common poisons used as an addictive agent.

Impacts of antemortem ingestion of alcoholic beverages on insect successional patterns.

This paper studies the impacts of antemortem ingestion of alcoholic beverages by the domestic rabbit, Oryctolagus cuniculus L., on postmortem successional patterns of insects during winter and summer 2018 in Riyadh, Saudi Arabia. Insect samples were collected from the carcasses of rabbits fed alcoholic beverages as well as untreated rabbits for 15 days postmortem during two successional studies in each season. The results showed that, during both seasons, the decomposition process for the carcasses of rabbits fed alcoholic beverages antemortem was one to two days longer. The results also showed, however, that alcoholic beverages did not affect insect succession patterns in either season. In fact, the number of insects appeared to be influenced by the ambient temperature during the two seasons, with 4415 insects in the winter compared to 1033 insects in the summer. In total, 30 insect taxa were collected during the winter study from the carcasses of rabbits fed alcoholic beverages antemortem; while 26 of these same taxa were collected from the carcasses of the untreated rabbits. Among the treated rabbits, those fed 25 ml alcoholic beverages treated attracted the highest number of insect taxa (24 taxa). In the summer study, 21 insect taxa were collected in total, 19 from the carcasses of the alcohol-treated rabbits and 13 from untreated rabbits. Among the treated rabbits, those fed 50 ml alcoholic beverages attracted the highest number of insect taxa (14 taxa). These results contribute to the understanding of the factors affecting the use of insects in medical investigations, given that alcoholic beverages are a common addictive agent.

Variation in decomposition stages and carrion insect succession in a dry tropical climate and its effect on estimating postmortem interval

Insects have an important role in minimum postmortem interval (PMImin) estimation. An accurate PMImin estimation relies on a comprehensive study of the development and succession of local carrion insects. No published research on carrion insect succession exists for tropical north Queensland. To address this, we aimed to obtain preliminary observational data concerning the rate of decomposition and insect succession on pig carcasses in Townsville and compare these with other regions of Australia and overseas. Adult insects were collected daily from three pig carcasses for 30 d during summer and identified to family level. Observations of decomposition rate were made each day and progression through the stages of decomposition were recorded. Adult insects were identified to family and their presence/absence used as a proxy for arrival at/departure from the remains, respectively. These preliminary data highlight several interesting trends that may be informative for forensic PMImin estimation. Decomposition was rapid: all carcasses were at the dry/remains stage by Day 5, which was substantially quicker than all other regions in the comparison. Differences were also observed in the presence/absence of insect families and their arrival and departure times. Given the rapid progression through early decomposition, we argue that later-arriving coleopteran taxa may be more forensically informative in tropical Australia, in contrast with temperate regions where Diptera appear most useful. This research contributes preliminary observational data to understanding insect succession patterns in tropical Australia and demonstrates the critical need for comprehensive local succession data for each climatic region of Australia to enable accurate PMImin estimation. These data will inform future research targeted at gaining a more comprehensive understanding of insect succession in the Australian tropics. Key points: We obtained preliminary observational data concerning the rate of decomposition and insect succession on pig carcasses in tropical Australia. Decomposition was rapid: all carcasses were at the dry/remains stage by Day 5. Coleopteran taxa may be more forensically informative in tropical Australia than dipterans.

The Effect of Suitcase Concealment on Insect Colonization: A Pilot Study in Western Australia

Decomposition is a complex and continuous process that involves the breakdown of soft tissues following a death event. This is often mediated by the action of micro- and macro-fauna, especially necrophagous insects belonging to the Orders Diptera and Coleoptera. Access to the cadaver is a major prerequisite for decomposition to proceed. However, a cadaver maybe concealed to avoid an easy discovery by the authorities. The present field study investigated the decomposition process of a carcass placed in a suitcase in Western Australia. A total of six pig carcasses (Sus scrofa L.) were used as a substitute for human cadavers. Five pigs were singularly placed in identical zip suitcases made of fabric and a sixth pig being fully exposed (control pig). As expected, the study showed that the rate of decomposition differed between the control pig and concealed pigs. The rate of decomposition of the control pig followed the typical pattern, in terms of stages of decomposition, and revealed the insect species involved in the process. Pigs inside the suitcases exhibited the characteristics of wet decomposition. This occurred despite no significant differences between the ambient temperature and the temperature inside the suitcases. However, the relative humidity inside of the suitcases was found to be statistically different and the pattern of insect succession varied between the concealed carcasses and the control pig. Carcass attendance by blow flies at the control occurred within minutes of positioning, and oviposition occurred within the first day. In contrast, blow flies were not observed visiting the suitcases until the next day, with oviposition on the external part of the suitcases not recorded until day 9 and inside the suitcases after day 14. The insect species also varied between those found inside the suitcases and on the control, with families Phoridae (scuttle flies) and Fanniidae (lesser house flies) being the most prevalent species inside the suitcases. This pilot study represents the first attempt in Australia to research decomposition of remains inside a suitcase.

Insect succession pattern on decomposing pig carcasses in Tasmania: a summer study'

Insect succession has been studied around the world using the predictable and mostly sequential arrival pattern of different insect species that are attracted to a decomposing carcass. In cases of suspicious death of humans and animals, carrion insects may be used to assist in crime scene reconstruction. The present research represents the first study in forensic entomology to be undertaken in Tasmania, investigating insect succession patterns on decomposing pig carcasses and providing a preliminary database of forensically important insects. Six pig carcasses were placed in two contrasting locations (rural and urban) in northern Tasmania. Insect successional waves were recorded over a 40-day study during the austral summer season. Results showed that decomposition rates and insect assemblages varied between each location. Eleven insect taxa, representing nine families, were identified in association with the decomposition of the pig carcasses at both localities. Blowflies present on the pig carcasses throughout the decomposition process were Calliphora stygia Malloch (Diptera: Calliphoridae) at both sites and Lucilia sericata (Meigen) at the urban site only. These preliminary results will provide useful information in any future casework involving human remains and associated insect material in Tasmania.

Insect succession on remains of human and animals in Shenzhen, China

Most forensic entomological succession studies have been carried out using pig or rabbit carcasses; however, there have been few studies on the differences between insect succession patterns on human cadavers and on animal carcasses. In order to clarify the differences between decomposition and insect succession patterns of human cadavers and animal carcasses, one 49.5kg human cadaver, two large pig carcasses (45 and 48kg), two small pig carcasses (23 and 25kg) and two rabbit carcasses (both 1.75kg) were placed in the same field conditions in Shenzhen, China for a comparative study on August, 2013. The results indicated that: (1) The duration from fresh to skeletonization is in order of human cadaver>large pig carcasses>small pig carcasses>rabbit carcasses; (2) insect assemblages (including developmental stages) are more complex on larger carcasses, in order of human cadaver=large pig carcasses>small pig carcasses>rabbit carcasses; (3) the developmental rates of the same forensically important fly species on all carcasses are consistent; (4) all identified species of Calliphoridae can complete development of one generation on human cadaver, and both large and small pig carcasses, while on rabbit carcasses, only a subset of the Calliphoridae species can finish development of one generation; (5) beetles can generate offspring on human cadaver, and both large and small pig carcasses, while they do not generate offspring on rabbit carcasses. This study provides useful comparative data for decomposition and insect succession pattern of human cadaver with animal carcasses.

Evaluating the utility of hexapod species for calculating a confidence interval about a succession based postmortem interval estimate

Carrion insect succession patterns have long been used to estimate the postmortem interval (PMI) during a death investigation. However, no published carrion succession study included sufficient replication to calculate a confidence interval about a PMI estimate based on occurrence data. We exposed 53 pig carcasses (16±2.5 kg), near the likely minimum needed for such statistical analysis, at a site in north-central Indiana, USA, over three consecutive summer seasons. Insects and Collembola were sampled daily from each carcass for a total of 14 days, by this time each was skeletonized. The criteria for judging a life stage of a given species to be potentially useful for succession-based PMI estimation were (1) nonreoccurrence (observed during a single period of presence on a corpse), and (2) found in a sufficiently large proportion of carcasses to support a PMI confidence interval. For this data set that proportion threshold is 45/53.Of the 266 species collected and identified, none was nonreoccuring in that each showed at least a gap of one day on a single carcass. If the definition of nonreoccurrence is relaxed to include such a single one-day gap the larval forms of Necrophilaamericana, Fanniascalaris, Cochliomyia macellaria, Phormiaregina, and Luciliaillustris satisfied these two criteria. Adults of Creophilus maxillosus, Necrobiaruficollis, and Necrodessurinamensis were common and showed only a few, single-day gaps in occurrence.C.maxillosus, P.regina, and L.illustris displayed exceptional forensic utility in that they were observed on every carcass. Although these observations were made at a single site during one season of the year, the species we found to be useful have large geographic ranges. We suggest that future carrion insect succession research focus only on a limited set of species with high potential forensic utility so as to reduce sample effort per carcass and thereby enable increased experimental replication.

Insect succession associated with corpse's decomposition of the guinea pig Cavia porcellus in Benha city, Egypt

Eleven domestic guinea pig corpses were employed as models for studying decomposition and insect succession in Benha city, Egypt, from April 2009 to March 2010. Ambient temperature, faunistic succession over time, and the rate of decay in different seasons were all compared. Results indicated that ambient temperature is the chief factor determining the seasonal variations in decay rate. The diversity of insect community increased as the state of decomposition advances. Members of Dermistidae and Forrmicidae were the first coleopteran and hymenopteran colonizers in all seasons. Sarcophaga, Wholfortia and Chrysomya was observed in spring and summer. Meanwhile, species of Wholfortia were absent in winter and Crysomya species were absent in fall. Patterns of insect succession occurred in a predictable sequence that varied across different seasons. The rate of corpse's decomposition was faster in summer and autumn as compared to spring and winter

Insects Breeding in Pig Carrion in Two Environments of a Rural Area of the State of Minas Gerais, Brazil

The main objective of this study was to identify potential forensic indicators in the insect fauna associated with pig carrion and the pattern of insect succession during the decomposition process in two environments of a rural area in Uberlândia, State of Minas Gerais, Brazil. The study was conducted at two locations: in a pasture and in a fragment of a semi-deciduous forest (vegetation profile of the Cerrado biome) in two different seasons (rainy and dry) of 2010. The decomposition process was more rapid in the rainy season. More than 32,000 insects belonging to 17 species of 6 families of Diptera and 2 species of Coleoptera bred in the carcasses. The majority of Diptera bred in the first three stages of decomposition. However, Phoridae and Coleoptera bred mainly in the last two stages. The insects bred more abundantly in the pasture and in the humid season. The exceptions were the Fanniidae (Diptera), which bred more abundantly in the forest and the Dermestidae and Cleridae (Coleoptera), which did not demonstrate any preference in terms of environments and were more abundant in the dry season, respectively. Species such as Chrysomya albiceps (Wiedemann), Peckia (Patonella) intermutans (Walker), Necrobia rufipes (De Geer), and Dermestes maculatus (De Geer) may be potential indicators of post-mortem interval. Hemilucilia segmentaria (Fabricius) and Ophyra aenescens (Wiedemann) may be indicators of localization of the natural environment, while Musca domestica Linnaeus may be an indicator of the anthropic environment. The study thus presented many species of potential forensic indicators in rural areas of this region.

Decomposition and insect succession of clothed and unclothed carcasses in Western Australia

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.

The bodies of two missing children in an enclosed underground environment

Two young children, respectively 11 and 13 years old, originally from a small town of Southern Italy, were missing on 5 June 2006 (06:30 p.m.). Soon after their disappearance, the search for the missing children began. Broadcasters promptly transmitted a description of the missing children, pushing the entire community to assist in the search and safe recovery of the children. However, every effort was in vain, and the search went on for more than 1 year. During the missing-child search, the investigators collected enough evidence against the father, who was arrested 17 months after the children's disappearance. He was indicted for kidnapping, homicide and concealment of the two bodies. He never confessed to the crimes and claimed to be innocent. Three months after the conviction, a fireman found the two corpses in a subterranean, dry cistern next to a well over 20 m deep. The bodies were well preserved, almost mummified, with only few body-parts skeletonised. Based on dental records, they were identified as those of the two children, who had gone missing 1.5 years before. Signs of a very low insect activity were present, reasonably consistent with a rapid skin dehydration. The autopsy showed no signs of defence injuries or ligature consistent with strangulation or captivation, except for fractures of the axial skeleton at a number of points consistent with a fall from a low-medium height. The body of the elder brother presented major injuries with signs of recent haemorrhages and gut content analysis consistent with the last meal, which provided enough evidence to ascertain a very short survival time. The younger child showed minor injuries, signs of old haemorrhages and gastric- and intestine-emptying time consistent with a longer survival time of approximately 3-4 days, spent alone in the dark and cold cistern. A long post-mortem interval (PMI) of approximately 20 months was estimated, mainly from the pattern of insect succession. Based on such physical evidence, on 4 March 2008, 4 months after conviction and 40 days after the recovery of the two bodies, the father was finally released from prison and exonerated from previous indictment of homicide.

Patterns of saproxylic beetle succession in loblolly pine

Patterns of insect succession in dead wood remain unclear, particularly beyond the first several years of decay. In the present study, saproxylic beetles were sampled from loblolly pine (Pinus taeda L.) logs aged between 1 month and 9 years old using both emergence traps attached to logs in the field and rearing bags in the laboratory. Species richness peaked within the first year as a result of a diverse assemblage of bark beetles, wood‐borers and predators associated with young logs. After the phloem phase, there were no significant differences in species richness among decay classes. Beetle communities differed significantly among decay classes, with 25 and seven species being significantly associated with young and old logs, respectively.

Annual and seasonal patterns of insect succession on decomposing remains at two locations in Western Australia

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.