Experimental study of Lucilia sericata (Diptera Calliphoridae) larval development on rat cadavers: Effects of climate and chemical contamination
Introduction
Forensic entomology estimates the time of death by colonization of the corpse with necrophagous insects. However, cadaver accessibility [1], weather conditions [2], [3] and chemical contamination [4], [5] affect the insect pre-appearance interval (PAI), i.e., the time elapsed between death and the colonization by necrophagous insects [6]. Marchenko [7] showed that gas, paint or a lubricant disrupted the arrival and the larval development of Calliphorid flies. In a 2009 study, Charabidze et al. [4] demonstrated that household products delayed the appearance of flies on a corpse. Using an olfactometer (controlled conditions), the authors showed that an insecticide, unleaded gasoline, hydrochloric acid and patchouli perfume strongly repelled adult flies. Furthermore, field experiments showed that rat cadavers covered with spilled hydrochloric acid, unleaded gasoline or patchouli perfume delayed PAI by up to 60 h. In a recent study, we showed that some household products mixed with beef liver rearing substrate also affected larval development [8]. Patchouli perfume, caustic soda, an insecticide, hydrochloric acid, mosquito repellent and unleaded gasoline increased the larval mortality rate and the larval development time (minimum, maximum and median times) and decreased the size of adults. Additionally, these effects were correlated with the quantities of household products mixed into the meat. Nevertheless, this study was performed under laboratory conditions, and the likely effects of climate was not considered. Using various field experiments, Marchenko [7] demonstrated that weather conditions affected the diffusion or evaporation of contaminants (paint and gasoline) spilled on a corpse and changed the effects on larval development. Moreover, rain increased gasoline diffusion into flesh, and thus altered the effects of this chemical on necrophagous insects.
The present study was performed under laboratory conditions and focused on the effects of rain on the development of necrophagous larvae. The experimental design, based on the study of Aubernon et al. [8], followed larvae development on rat cadavers, treated with various household products, under dry or rain conditions. The survival rate and the development time of the larvae and the size of adults were used to assess the effects of rainfall on chemicals and subsequent necrophagous larval development. The relevance of the results for forensic entomology analysis is discussed, particularly for the estimation of the Post Mortem Interval (PMI).
Section snippets
Insect rearing
The experiments were performed with Lucilia sericata (Meigen), (Diptera: Calliphoridae), which were obtained from rearing colonies (Lille, France). The adult flies were raised according to Aubernon et al. [8]. To trigger egg-laying, 25 ± 5 g of minced beef liver was placed in an insectarium. The presence of eggs was checked for hourly, giving an oviposition time known within ±30 min. The eggs were placed on minced beef liver in a climate chamber (SANYO MIR, 554) at 25 ± 0.1 °C.
Experiment rearing media
The study was performed
Dry condition
Under dry condition, gasoline killed all the larvae. Only the larvae exposed to bleach had a survival rate similar to that of the larvae in the control (z test: bleach, p = 0.144; other substances, p < 0.0001) (Fig. 1). The survival rate for larvae was greater than 60% for bleach and mosquito repellent, but for the other substances, it was less than 20%. The survival rates of the pupae were significantly decreased by perfume, mosquito repellent and insecticide (z test: perfume, p = 0.011; mosquito
Discussion
This research was designed to investigate the effects of common household products and climatic conditions on the development of necrophagous larvae on rat cadavers. In the current study, the effects of tested household products on necrophagous larvae are different to those reported in Aubernon et al. [8]. In this former study, the authors observed no survival for larvae reared on beef liver mixed with gasoline, insecticide and caustic soda. On the contrary, our results show a 10% larval
Conclusion
According to our results and those of former studies by Charabidze et al. [4] and Aubernon et al. [8], we demonstrated the possible impacts of household products on forensic entomology analysis. First, insects survived on cadavers spilled with household chemicals. Secondly, climatic conditions impacted insect development and, particularly, survival rates. Third, development times were only slightly impacted. Finally, the household products affected the size of adults, and thus likely affected
References (15)
- et al.
Repellent effect of some household products on fly attraction to cadavers
Forensic Sci. Int.
(2009) - et al.
Effects of methamphetamine and its primary human metabolite, p-hydroxymethamphetamine, on the development of the Australian blowfly Calliphorastygia
Forensic Sci. Int.
(2014) Estimating the pre-appearance interval from temperature in Necrodes littoralis L. (Coleoptera: Silphidae)
Forensic Sci. Int.
(2011)- et al.
Effect of temperature on Lucilia sericata (Diptera: Calliphoridae) development with special reference to isomegalen and isomorphen-diagram
Forensic Sci. Int.
(2001) - et al.
The effects of larval crowding and food type on the size and development of the blowfly, Calliphora vomitoria
Forensic Sci. Int.
(2006) - et al.
Is rain or snow a more efficient scavenger of organic chemicals?
Atmos. Environ.
(2004) Rainfall and temperature effects on the decomposition rate of exposed neonatal remains
Sci. Justice
(2004)
Cited by (13)
Effects of antibiotics ceftriaxone and levofloxacin on the growth of Calliphora vomitoria L. (Diptera: Calliphoridae) and effects on the determination of the post-mortem interval
2021, Journal of Forensic and Legal MedicineCitation Excerpt :There is a vast amount of data on the influence of toxic substances on the development of insects. In forensic entomotoxicology, insects are typically used as indicators to determine whether toxins were present in a body at the time of death, where a variety of toxins, mainly drugs, household products or pollutants, including their pharmacokinetics, have been studied.9,26–31 Studies revealed that methamphetamine increased development time and mortality rate of Calliphora vomitoria and that α- and β- Endosulfan did not affect the maggot development in a significant way.26,27
Effect of dimethoate on the developmental rate of forensic importance Calliphoridae flies
2021, Saudi Journal of Biological SciencesCitation Excerpt :Low concentrations decreases the survival rate while high concentrations have proved to be lethal. Some chemicals such as perfume and bleach barely alters the growth rate (Aubernon et al., 2015a; Aubernon et al., 2015b) and 2015a) or size of adult flies. Numerous studies have also indicated that various drugs and other toxic compounds can alter the developmental rate of maggot and interfere with estimations of postmortem intervals (Bourel et al., 1999; Bourel et al., 2001; Goff and Lord, 2001; Goff et al., 1992).
Effects of antibiotics ceftriaxone and levofloxacin on the growth of Lucilia sericata (Diptera: Calliphoridae)
2023, Medical and Veterinary EntomologyFORENSIC ENTOMOLOGY IN DEATH INVESTIGATIONS
2023, The Routledge International Handbook of Homicide InvestigationThe effects of hydrated lime and bleach on carrion decomposition and associated insect succession
2023, Australian Journal of Forensic SciencesEffects of Pesticides Use (Glyphosate & Paraquat) on Biological Nitrogen Fixation
2021, Water, Air, and Soil Pollution