scholarly journals Insect rearing protocols in forensic entomology: Benefits from collective rearing of larvae in a carrion beetle Necrodes littoralis L. (Silphidae)

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260680
Author(s):  
Joanna Gruszka ◽  
Szymon Matuszewski

Forensic entomologists frequently use a developmental method to estimate a post-mortem interval (PMI). Such estimates are based usually on the blow fly larvae or puparia. Data on their development is obtained by rearing them in colonies. In the case of beetles, which can be also useful for PMI estimation, development data is frequently collected by rearing them individually. However, some carrion beetles are gregarious, for instance, Necrodes littoralis (Linnaeus, 1758) (Silphidae). We compared mortality, rate of development and body size of emerged adult beetles reared individually and in aggregations. Mortality was much higher for beetles reared individually, particularly at low temperatures. The rearing protocol affected the time of immature development and the size of adult insects. Individually reared specimens developed much longer at 16°C, whereas at 20°C and 26°C development times of individually reared beetles were slightly shorter. Significant differences in the body size were observed only at 16°C; beetles that developed in aggregations were larger at this temperature. These findings demonstrate that aggregating is particularly beneficial for larvae of N. littoralis at low temperatures, where it largely reduces mortality and facilitates growth. Moreover, these results indicate that in forensic entomology the protocol of individual rearing is unsuitable for gregarious beetles, as it produces reference developmental data of low quality.

Author(s):  
Dian-Xing Feng ◽  
Jing Wu ◽  
Da-Peng Sun

Abstract Dohrniphora cornuta (Bigot) is a forensically important phorid fly indoors and in burial environments. The determination of a minimum postmortem interval (PMImin) often relies on the determination of the age of the immatures. Although the larval development data of D. cornuta under different temperatures has been established, the intrapuparial stage which lasts for about half of the total immature development is scarce. In this study, we investigated the key morphological changes during intrapuparial development at constant temperatures (15, 18, 21, 24, 27, 30, 33, and 36°C), with an aim to estimate the intrapuparial age of D. cornuta. Puparia were sampled at 12-h (24, 27, 30, and 33°C), 24-h (18 and 21°C), and 48-h (15°C) intervals. The morphological developments within the puparium were analyzed using a stereomicroscope after the puparium was removed. The average minimum duration of intrapuparial stage was inversely related to temperature, ranging from 184.79 ± 3.00 h at 30°C to 1102.86 ± 25.55 h at 15°C for female, and 197.40 ± 4.12 h at 30°C to 1175.33 ± 18.55 h at 15°C for male. It did not develop at 36°C. Some morphological traits that changed during development within the puparium could be used as age markers. According to these changes, the intrapuparial stage of D. cornuta was divided into nine stages which could be used for both sexes. This study provides relatively systematic development data of D. cornuta intrapuparial for the estimation of PMImin in forensic entomology.


Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 314
Author(s):  
Szymon Matuszewski

During death investigations insects are used mostly to estimate the post-mortem interval (PMI). These estimates are only as good as they are close to the true PMI. Therefore, the major challenge for forensic entomology is to reduce the estimation inaccuracy. Here, I review literature in this field to identify research areas that may contribute to the increase in the accuracy of PMI estimation. I conclude that research on the development and succession of carrion insects, thermogenesis in aggregations of their larvae and error rates of the PMI estimation protocols should be prioritized. Challenges of educational and promotional nature are discussed as well, particularly in relation to the collection of insect evidence.


Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 152
Author(s):  
Jens Amendt ◽  
Valentina Bugelli ◽  
Victoria Bernhardt

The estimation of the minimum time since death is one of the main applications of forensic entomology. This can be done by calculating the age of the immature stage of necrophagous flies developing on the corpse, which is confined to approximately 2–4 weeks, depending on temperature and species of the first colonizing wave of flies. Adding the age of the adult flies developed on the dead body could extend this time frame up to several weeks when the body is in a building or closed premise. However, the techniques for accurately estimating the age of adult flies are still in their beginning stages or not sufficiently validated. Here we review the current state of the art of analysing the aging of flies by evaluating the ovarian development, the amount of pteridine in the eyes, the degree of wing damage, the modification of their cuticular hydrocarbon patterns, and the increasing number of growth layers in the cuticula. New approaches, including the use of age specific molecular profiles based on the levels of gene and protein expression and the application of near infrared spectroscopy, are introduced, and the forensic relevance of these methods is discussed.


Parasitology ◽  
1938 ◽  
Vol 30 (3) ◽  
pp. 392-402 ◽  
Author(s):  
Kenneth Mellanby

1. Diapause inLucilia sericatais caused by unfavourable conditions during the larval or prepupal period.2. Diapausing prepupae usually contain a higher proportion of dry matter than do normal individuals.3. Diapause occurs because the corpus allatum (Weismann's ring) is not producing the necessary hormone.4. Diapause is ended when prepupae are removed from sand to empty tubes. Probably the corpus allatum is stimulated by a nervous reaction; the reaction is not due to an increase in the rate of metabolism.5. Low temperatures (5° C.) do not affect the hormone, but high ones (35–37° C.) destroy it.6. Prepupae ofLucilia sericatahave salivary glands which are dilated to nearly a quarter the body size. The contents serve as a store of water during diapause.7. Diapausing prepupae after desiccation drink water and return to their original body weight. The water increases the volume of blood in circulation, and the blood controls the size of the adult produced.8. Diapause in nature enables the species to survive unfavourable conditions.


2017 ◽  
Vol 25 (2) ◽  
pp. 161
Author(s):  
Sławomir Mitrus ◽  
Bartłomiej Najbar ◽  
Adam Kotowicz ◽  
Anna Najbar
Keyword(s):  
The Body ◽  

Author(s):  
Adrian Marciszak ◽  
Yuriy Semenov ◽  
Piotr Portnicki ◽  
Tamara Derkach

AbstractCranial material ofPachycrocuta brevirostrisfrom the late Early Pleistocene site of Nogaisk is the first record of this species in Ukraine. This large hyena was a representative of the Tamanian faunal complex and a single specialised scavenger in these faunas. The revisited European records list ofP.brevirostrisdocumented the presence of this species in 101 sites, dated in the range of 3.5–0.4 Ma. This species first disappeared in Africa, survived in Europe until ca. 0.8–0.7 Ma, and its last, relict occurrence was known from south-eastern Asia. The main reason of extinction ofP.brevirostrisprobably was the competition withCrocuta crocuta. The cave hyena was smaller, but its teeth were proportionally larger to the body size, better adapted to crushing bones and slicing meat, and could also hunt united in larger groups.


Hydrobiologia ◽  
2021 ◽  
Author(s):  
Rungtip Wonglersak ◽  
Phillip B. Fenberg ◽  
Peter G. Langdon ◽  
Stephen J. Brooks ◽  
Benjamin W. Price

AbstractChironomids are a useful group for investigating body size responses to warming due to their high local abundance and sensitivity to environmental change. We collected specimens of six species of chironomids every 2 weeks over a 2-year period (2017–2018) from mesocosm experiments using five ponds at ambient temperature and five ponds at 4°C higher than ambient temperature. We investigated (1) wing length responses to temperature within species and between sexes using a regression analysis, (2) interspecific body size responses to test whether the body size of species influences sensitivity to warming, and (3) the correlation between emergence date and wing length. We found a significantly shorter wing length with increasing temperature in both sexes of Procladius crassinervis and Tanytarsus nemorosus, in males of Polypedilum sordens, but no significant relationship in the other three species studied. The average body size of a species affects the magnitude of the temperature-size responses in both sexes, with larger species shrinking disproportionately more with increasing temperature. There was a significant decline in wing length with emergence date across most species studied (excluding Polypedilum nubeculosum and P. sordens), indicating that individuals emerging later in the season tend to be smaller.


Author(s):  
Kent M. Daane ◽  
Xingeng Wang ◽  
Brian N. Hogg ◽  
Antonio Biondi

AbstractAsobara japonica (Hymenoptera: Braconidae), Ganaspis brasiliensis and Leptopilina japonica (Hymenoptera: Figitidae) are Asian larval parasitoids of spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae). This study evaluated these parasitoids’ capacity to attack and develop from 24 non-target drosophilid species. Results showed that all three parasitoids were able to parasitize host larvae of multiple non-target species in artificial diet; A. japonica developed from 19 tested host species, regardless of the phylogenetic position of the host species, L. japonica developed from 11 tested species; and G. brasiliensis developed from only four of the exposed species. Success rate of parasitism (i.e., the probability that an adult wasp successfully emerged from a parasitized host) by the two figitid parasitoids was low in hosts other than the three species in the melanogaster group (D. melanogaster, D. simulans, and D. suzukii). The failure of the figitids to develop in most of the tested host species appears to correspond with more frequent encapsulation of the parasitoids by the hosts. The results indicate that G. brasiliensis is the most host specific to D. suzukii, L. japonica attacks mainly species in the melanogaster group and A. japonica is a generalist, at least physiologically. Overall, the developmental time of the parasitoids increased with the host’s developmental time. The body size of female A. japonica (as a model species) was positively related to host size, and mature egg load of female wasps increased with female body size. We discuss the use of these parasitoids for classical biological control of D. suzukii.


2011 ◽  
Vol 76 (3) ◽  
pp. 403-428 ◽  
Author(s):  
Jack M. Broughton ◽  
Michael D. Cannon ◽  
Frank E. Bayham ◽  
David A. Byers

The use of body size as an index of prey rank in zooarchaeology has fostered a widely applied approach to understanding variability in foraging efficiency. This approach has, however, been critiqued—most recently by the suggestion that large prey have high probabilities of failed pursuits. Here, we clarify the logic and history of using body size as a measure of prey rank and summarize empirical data on the body size-return rate relationship. With few exceptions, these data document strong positive relationships between prey size and return rate. We then illustrate, with studies from the Great Basin, the utility of body size-based abundance indices (e.g., the Artiodactyl Index) when used as one component of multidimensional analyses of prehistoric diet breadth. We use foraging theory to derive predictions about Holocene variability in diet breadth and test those predictions using the Artiodactyl Index and over a dozen other archaeological indices. The results indicate close fits between the predictions and the data and thus support the use of body size-based abundance indices as measures of foraging efficiency. These conclusions have implications for reconstructions of Holocene trends in large game hunting in western North America and for zooarchaeological applications of foraging theory in general.


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