Introduced plants as novel Anthropocene habitats for insects

Major environmental changes in the history of life on Earth have given rise to novel habitats, which gradually accumulate species. Human‐induced change is no exception, yet the rules governing species accumulation in anthropogenic habitats are not fully developed. Here we propose that nonnative plants introduced to Great Britain may function as analogues of novel anthropogenic habitats for insects and mites, analysing a combination of local‐scale experimental plot data and geographic‐scale data contained within the Great Britain Database of Insects and their Food Plants. We find that novel plant habitats accumulate the greatest diversity of insect taxa when they are widespread and show some resemblance to plant habitats which have been present historically (based on the relatedness between native and nonnative plant species), with insect generalists colonizing from a wider range of sources. Despite reduced per‐plant diversity, nonnative plants can support distinctive insect communities, sometimes including insect taxa that are otherwise rare or absent. Thus, novel plant habitats may contribute to, and potentially maintain, broader‐scale (assemblage) diversity in regions that contain mixtures of long‐standing and novel plant habitats.     

Priority effects on the life‐history traits of two carrion blow fly (Diptera,Calliphoridae) species

1. Third instars of the invasive blow fly Chrysomya rufifacies are facultative predators on larvae of the native blow fly Cochliomyia macellaria. 2. The effects of priority arrival time on the survivorship and fitness of C. rufifacies and C. macellaria were investigated in laboratory experiments. 3. Cochliomyia macellaria colonising a resource within 1–2 days after C. rufifacies resulted in a 20–70% reduction in survivorship, pupal weight and fecundity compared with those colonising a resource more than 2 days before or after C. rufifacies. Inversely, C. rufifacies exhibited a 50% increase in survivorship and fecundity when closely (～2 days) associated temporally on the resource with C. macellaria and was negatively affected by disparate arrival. 4. These results demonstrate that arrival sequence significantly affects the fitness of both C. rufifacies and C. macellaria. Early colonisation may allow C. macellaria to persist in a community, while there are fitness benefits for C. rufifacies colonising after C. macellaria. 5. The 60% reduction in C. macellaria survivorship when in close temporal association with C. rufifacies may act as an agent of selection for C. macellaria to colonise a resource early and develop quickly to avoid predation on resources colonised by C. rufifacies. 6. Selection for such traits may explain how C. macellaria is able to persist despite intraguild predation by this invasive species. In contrast, the 50% increase in survivorship and fecundity exhibited by C. rufifacies when arriving after C. macellaria may select for C. rufifacies to delay colonisation.     

双向凝胶电泳图谱用于常见尸食性蝇类初孵幼虫的鉴别

双向凝胶电泳分析技术已在生物科学各领域被广泛应用,蛋白质组作图的意义已经日益显现。通过对4种常见尸食性蝇类初孵幼虫蛋白质组双向凝胶电泳和图象分析,发现各种类间双向凝胶电泳图谱差异显著,并对相应的等电点和相对分子量进行聚类和判别分析,结果表明,建立合适的尸食性蝇类初孵幼虫的双向凝胶电泳图谱可用于鉴别形态学极易混淆的昆虫种类。图4参17     

Larval growth rates of the blowfly, Calliphora vicina, over a range of temperatures

Blowfly larvae (Diptera: Calliphoridae) fulfil an important ecological function in the decomposition of animal remains. They are also used extensively in forensic entomology, predominantly to establish a minimum time since death, or a minimum post-mortem interval, using the larval length as a 'biological clock'. This study examined the larval growth rate of a forensically important fly species, Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) at temperatures of between 4 degrees C and 30 degrees C, under controlled laboratory conditions. The laboratory flies had been trapped initially in London, U.K. The minimum developmental temperature was estimated to be 1 degrees C and 4700 accumulated degree hours (ADH) were required for development from egg hatch to the point of pupariation. Lines fitted to the laboratory larval growth data were found to adequately explain the growth of larvae in the field. The nature of variation in growth rates from geographically isolated populations is discussed.     

Host location and behavioural response patterns of the parasitoid,Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae), to host and host‐habitat odours

Abstract 1. To overcome the challenge of host location in patchy and complex environments, many parasitoids exploit host‐habitat derived odour cues. This study investigated the role of odour cues used during host location by the generalist parasitoid, Tachinaephagus zealandicus, a common parasitoid of Dipteran larvae found in association with decomposing carrion. 2. A Y‐tube olfactometer was used to test aspects of host searching behaviour of T. zealandicus females under different choice scenarios: combinations of host–liver complex, eaten liver, unwashed host larvae, washed host larvae, liver in six stages of decay, and control (no odour). 3. T. zealandicus females demonstrated an innate response to, and preference for, odours arising from liver substrates following interaction with the host. However, this was dependent on the stage of meat decay. Females were not attracted to liver that had never been in contact with a host, regardless of the stage of decay. There were discernible differences in parasitoid movement and behaviour under different choice scenarios. The absence of odour stimulus elicited limited movement about the olfactometer. In the presence of any odour stimuli, females were more active within the olfactometer, and when presented with two odour options T. zealandicus females demonstrate a heightened investigation response, moving across all regions of the olfactometer. 4. Knowledge of the cues that mediate host location for T. zealandicus can contribute to fields such as forensic entomology, where the presence of parasitoids on decomposing remains can be used to estimate time since death.     

Rates of development of Hydrotaea rostrata under summer and winter (cyclic and constant) temperature regimes

The black carrion fly Hydrotaea rostrata Robineau-Desvoidy (Diptera: Muscidae) is a muscid, which occurs on approximately one-third of decomposing human corpses involved in homicide cases in south-western Australia. Work to date on its development rates is scant with only one published source available. The current study measured the precise developmental rates of this species using high repetition and sampling rates. A comparison was made of the developmental rates between constant and cyclic temperatures in winter and summer temperature regimes in south-western Australia. Developmental times for 90% of first stage larvae to emerge as adult flies are: summer constant, 21.6days, summer cyclic, 23.5 days, winter constant 64.5days and winter cyclic, 48.3 days. These data will allow forensic entomologists to make more accurate determinations of post-mortem intervals in cases where H. rostrata life history stages are present.     

Molecular identification of forensically important beetles in Saudi Arabia based on mitochondrial 16 s rRNA gene

Forensic science uses scientific methods to help the scientists who study evidence to assist in the solving of crimes. Coleoptera is the most diverse and speciose group of insects that have an important role in many scientific fields especially forensic entomology. In addition, it is difficult to morphologically identify and discriminate between them. In the present study, the molecular analysis using mitochondrial DNA information was conducted to swiftly and accurately identify the recovered Coleoptera species. A molecular identification method involving a 221‐bp segment of the 16 s ribosomal RNA (16 s rRNA) gene from three beetle species, collected from a rabbit carcass, was evaluated. The analysis with maximum likelihood method recovered a generally well supported phylogeny, with most currently accepted taxa and species groups as monophyletic. These results will be instrumental for the implementation of the Saudian database of forensically relevant beetles.     

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.     

Accumulation and excretion of morphine by Calliphora stygia, an Australian blow fly species of forensic importance

This study examined the ability of the forensically important blow fly, Calliphora stygia to actively excrete morphine, thereby maintaining a low morphine level within its body when fed on a diet containing morphine at low (7 pmol g⁻¹) and high (17.5 pmol g⁻¹) concentrations. Morphine was accumulated within the bodies of maggots (≈70% within the tissues) at concentrations which were lower than that of the meat (3-24%). The morphine content of the initial developing stages (second and third instar maggots) maintained on the high morphine diet was higher than those on the low morphine diet. Morphine was cleared from the body with negatively exponential kinetics (High morphine group: Morphine (pmol g⁻¹ wet weight) = 8425e^−0.014t. Low morphine group: Morphine (pmol g⁻¹ wet weight) = 2180e^−0.010t). Clearance constants for morphine by animals in both groups were similar and thus both groups had a similar ability to excrete morphine. The Malpighian tubules of maggots were able to actively secrete morphine using a transport mechanism that transports small type II organic cations, such as morphine and quinine. The rate of morphine secretion by the Malpighian tubules could explain the clearance of the drug by the maggots. As the morphine was transported across the Malpighian tubules cells, a significant proportion was metabolised into a compound that is yet to be fully characterised.     

Molecular phylogeny of the blowfly genus Chrysomya

Chrysomya Robineau-Desvoidy (Diptera: Calliphoridae) is a genus of blowfly commonly observed in tropical and subtropical countries of the Old World. Species in this genus are vectors of bacteria, protozoans and helminths, cause myiasis, are predators of other carrion insects, and are important forensic indicators. Hypotheses concerning the evolution of sex determination, larval anatomy and genome size in Chrysomya have been difficult to evaluate because a robust phylogeny of the genus was lacking. Similarly, the monophyly of subgenera was uncertain. The phylogeny of Chrysomya spp. was reconstructed based on 2386 bp of combined mitochondrial cytochrome oxidase subunit I (COI) and nuclear carbamoylphosphate synthetase (CPS) genes. Maximum parsimony (MP), maximum likelihood (ML) and Bayesian analysis (BA) differed only slightly in the resulting tree topology. Chrysomya was monophyletic. Monogenic reproduction is almost certainly derived rather than, as has been suggested, primitive within the genus, and tuberculate larvae probably evolved twice. Genome size is more likely to have decreased over evolutionary time rather than, as has been suggested, increased within the genus, but its correlation with developmental time was not observed. The subgenera Microcalliphora, Eucompsomyia and Achoetandrus were recovered as monophyletic.