Social wasps (Vespidae: Polistinae) on carcasses of Rattus norvegicus (Mammalia: Muridae) in the Central Amazonia,Brazil: possible forensic implications

We evaluated the occurrence of social wasps in the decomposition process in tropical rainforest in central Amazonia (Ducke Reserve, Manaus, Brazil), using cadavers of rats as attractants, exposed in suspended cages. Ten species, in three genera, of social wasps were collected only in the initial stages of decay (fresh and bloated). Five species were collected, mainly in the fresh stage, feeding on flesh: Agelaia angulata, Agelaia constructor, Agelaia fulvofasciata, Agelaia pallipes and Angiopolybia pallens. Five species were collected, mainly in the bloated stage, feeding on flesh and eggs and first instar larvae of dipteran: Agelaia testacea, Angiopolybia obidensis, Apoica arborea, Apoica pallens and Apoica thoracica. Due to the aspect of the injuries caused by the wasps to the carcass, they may be mistaken as skin ulcers, burns or abrasions, which may mislead a forensic investigation.     

北美法医昆虫学年会及其论文简介

北美法医昆虫学第1,2届年会于2003年8月7～9日和2004年7月21～24日分别在美国内华达州拉斯维加斯和加利福尼亚州戴维斯召开,大会论文涉及到了案例分析、分类鉴定、教学、死后间隔时间推断和死亡原因查找等诸多方面。文章介绍了北美法医昆虫学年会,并对北美法医昆虫学第1,2届年会论文的相关内容进行总结分析。     

巴西东南部夏、冬季吹蝇幼虫的食后扩散

估计死亡和案发之间的最短时间是法医昆虫学的重要目标之一。在估计死亡时间时,研究吹蝇扩散至关重要。如果低估了最早扩散的幼虫距离和深度就可能低估死亡的时间。因此,掌握影响吹蝇幼虫扩散的有关因素,包括竞争、同类相食、在食源上的聚集密度、光周期、温湿度等以及潜入习性,进而推测吹蝇幼虫在尸体附近或远离尸体化蛹等都会影响估计死亡时间的准确性。本研究分析了从2006年夏季至2007年冬季在巴西南部自然状态下吹蝇食后的扩散。除趋光性外,扩散距离在季节上的不同(夏季3·1 m对应冬季的1·2 m)是由于环境条件起了重要作用。在用屠宰动物模拟实验时显示,吹蝇幼虫在低温低湿环境下扩散的时间滞后,扩散的距离也缩短。本研究表明温度(也许包括湿度)影响吹蝇幼虫的扩散,环境条件也决定吹蝇何时开始扩散。     

Characterization of the complete mitochondrial genome of Hydrotaea spinigera (Diptera: Muscidae) with phylogenetic implications

Hydrotaea spinigera Stein is a muscid species with high forensic importance. To further supplement the genome-level features of related species, the complete mitochondrial genome of H. spinigera is amplified, sequenced, annotated, analyzed, and compared with 13 other species of the family Muscidae. This mitogenome is 15,517?bp in length, with a standard set of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and a typical non-coding control region. The gene organization, base composition, and secondary structures of tRNA genes of this mitogenome are similar to other dipteran species. Phylogenetic analyses based on all the mitochondrial PCGs and rRNA genes for 14 muscid and one outgroup taxa are performed using Bayesian inference (BI) and maximum likelihood (ML) analysis. The inferred trees indicate that the Muscidae, the subfamily Muscinae, and the tribes Azeliini and Reinwardtiini are monophyletic, whereas the monophyly of the subfamily Azeliinae and the tribe Muscini is not supported.     

The contribution of abiotic processes to buried litter decomposition in the northern Chihuahuan desert

Summary Creosobebush (Larrea tridentata) fine litter was treated with either the general biocide HgCl₂ and CuSO₄ or water (controls) and buried 5 cm beneath the soil surface in the northern Chihuahuan Desert. The treated litter showed significantly less mass loss than controls during the three month summer-autumn field study; controls lost about 20% of the original mass while treated litter lost less than 2%. In addition, the total nitrogen content of the control litter increased from an initial concentration of about 14.08 g kg^-1 to 17.62 g kg^-1 dry weight by the end of the study, while treated litter nitrogen content decreased to 13.30 g kg^-1. Results suggest abiotic processes other than leaching have little effect on the decomposition of buried litter in this environment.     

Utility of GenBank and the Barcode of Life Data Systems (BOLD) for the identification of forensically important Diptera from Belgium and France

Fly larvae living on dead corpses can be used to estimate post-mortem intervals. The identification of these flies is decisive in forensic casework and can be facilitated by using DNA barcodes provided that a representative and comprehensive reference library of DNA barcodes is available.We constructed a local (Belgium and France) reference library of 85 sequences of the COI DNA barcode fragment (mitochondrial cytochrome c oxidase subunit I gene), from 16 fly species of forensic interest (Calliphoridae, Muscidae, Fanniidae). This library was then used to evaluate the ability of two public libraries (GenBank and the Barcode of Life Data Systems – BOLD) to identify specimens from Belgian and French forensic cases. The public libraries indeed allow a correct identification of most specimens. Yet, some of the identifications remain ambiguous and some forensically important fly species are not, or insufficiently, represented in the reference libraries. Several search options offered by GenBank and BOLD can be used to further improve the identifications obtained from both libraries using DNA barcodes.     

Effect of body length and temperature on the crawling speed of Protophormia terraenovae larvae (Robineau-Desvoidy) (Diptera Calliphoridae)

This work investigates variation in the crawling speed of Protophormia terraenovae larvae (Robineau-Desvoidy) (Diptera Calliphoridae) as a function of body length and ambient temperature. A video-tracking system was used to follow the movement of larvae in an experimental arena, and to estimate their average crawling speed. Recordings were carried out at various temperatures using larvae of different developmental stages. As temperature increased, the larvae crawled at a faster speed. Furthermore, speed increased as a function of body length. We present a general allometric relationship to express the average crawling speed of larvae as a combined function of temperature and body length, expressed in the following equation: speed (cm/min)=5.45 x log[length (mm)]+0.66 x temperature (degrees C)-12.8. These results are particularly useful in forensic entomology for estimating the time that elapsed following the larva's departure from the corpse. This information can provide more accuracy for post-mortem interval estimations and a better comprehension of larvae behaviour and displacement.     

贵州省尸食性蝇类的种类和分布

2000～2002年在贵州不同地区和不同海拔高度,设置采样点12个,在每个季度中间月份的中旬日用诱饵法采集一次尸食性蝇类标本,分析了贵州地区与尸体有关的蝇类及其分布。采集到的尸食性蝇类经鉴定隶属于5科15属25种,其中12种是在贵州首次发现,文中列出了尸食性蝇类名录,分析了它们在贵州的地理分布和季节变化,丰富了昆虫学和法医昆虫学的内容,为法医学推测死者的死亡时间提供了参考依据。