Scavenger-induced scattering of wild boar carcasses over large distances and its implications for disease management.

Vertebrate scavengers provide essential ecosystem services such as accelerating carrion decomposition by consuming carcasses, exposing tissues to microbial and invertebrate decomposers, and recycling nutrients back into the ecosystem. Some scavengers do not consume carcasses on site but rather scatter their remains in the surroundings, which might have important implications for nutrient transport, forensic investigations and the spread of diseases such as African Swine Fever. However, only a few studies have investigated and measured the scatter distances. Using wild boar (Sus scrofa) carcasses and limbs, we monitored scavenging behavior and measured scatter distances of mammals. We placed 20 carcasses (up to 25 kg) and 21 separate limbs equipped with very high frequency (VHF) transmitters and monitored scavenger activity using camera traps in a mountainous region in southeast Germany. Except for one carcass, all other carcasses and limbs were scattered. We measured 72 scatter distances (of 89 scattering events; mean = 232 m, maximum = 1250 m), of which 75% were dispersed up to 407 m. Scavengers moved scattered pieces into denser vegetation compared to the half-open vegetation at provisioning sites. Red foxes (Vulpes vulpes) were the most common scavenger species, contributing to 72 scattering events (58 measured scatter distances). Our results provide evidence of scatter distances farther than previously assumed and have far-reaching implications for disease management or forensic investigations, as the broader surroundings of carcasses must be included in search efforts to remove infectious material or relevant body parts for forensic analysis.

Linking bacteria, volatiles and insects on carrion: the role of temporal and spatial factors regulating inter-kingdom communication via volatiles.

Multi-kingdom community complexity and the chemically mediated dynamics between bacteria and insects have recently received increased attention in carrion research. However, the strength of these inter-kingdom interactions and the factors that regulate them are poorly studied. We used 75 piglet cadavers across three forest regions to survey the relationship between three actors (epinecrotic bacteria, volatile organic compounds (VOCs) and flies) during the first 4 days of decomposition and the factors that regulate this interdependence. The results showed a dynamic bacterial change during decomposition (temperature-time index) and across the forest management gradient, but not between regions. Similarly, VOC emission was dynamic across a temperature-time index and the forest management gradient but did not differ between regions. However, fly occurrence was dynamic across both space and time. The strong interdependence between the three actors was mainly regulated by the temperature-time index and the study regions, thereby revealing regulation at temporal and spatial scales. Additionally, the actor interdependence was stable across a gradient of forest management intensity. By combining different actors of decomposition, we have expanded our knowledge of the holistic mechanisms regulating carrion community dynamics and inter-kingdom interactions, an important precondition for better describing food web dynamics and entire ecosystem functions.

DNA Barcoding in Forensic Entomology - Establishing a DNA Reference Library of Potentially Forensic Relevant Arthropod Species.

Throughout the years, DNA barcoding has gained in importance in forensic entomology as it leads to fast and reliable species determination. High-quality results, however, can only be achieved with a comprehensive DNA barcode reference database at hand. In collaboration with the Bavarian State Criminal Police Office, we have initiated at the Bavarian State Collection of Zoology the establishment of a reference library containing arthropods of potential forensic relevance to be used for DNA barcoding applications. CO1-5P' DNA barcode sequences of hundreds of arthropods were obtained via DNA extraction, PCR and Sanger Sequencing, leading to the establishment of a database containing 502 high-quality sequences which provide coverage for 88 arthropod species. Furthermore, we demonstrate an application example of this library using it as a backbone to a high throughput sequencing analysis of arthropod bulk samples collected from human corpses, which enabled the identification of 31 different arthropod Barcode Index Numbers.

Helicopter thermal imaging for detecting insect infested cadavers.

One of the most common techniques applied for searching living and even dead persons is the FLIR (Forward Looking Infrared) system fixed on an aircraft like e.g. a helicopter, visualizing the thermal patterns emitted from objects in the long-infrared spectrum. However, as body temperature cools down to ambient values within approximately 24h after death, it is common sense that searching for deceased persons can be just applied the first day post-mortem. We postulated that the insect larval masses on a decomposing body generate a heat which can be considerably higher than ambient temperatures for a period of several weeks and that such heat signatures might be used for locating insect infested human remains. We examined the thermal history of two 70 and 90kg heavy pig cadavers for 21days in May and June 2014 in Germany. Adult and immature insects on the carcasses were sampled daily. Temperatures were measured on and inside the cadavers, in selected maggot masses and at the surroundings. Thermal imaging from a helicopter using the FLIR system was performed at three different altitudes up to 1500ft. during seven day-flights and one night-flight. Insect colonization was dominated by blow flies (Diptera: Calliphoridae) which occurred almost immediately after placement of the cadavers. Larvae were noted first on day 2 and infestation of both cadavers was enormous with several thousand larvae each. After day 14 a first wave of post-feeding larvae left the carcasses for pupation. Body temperature of both cadavers ranged between 15°C and 35°C during the first two weeks of the experiment, while body surface temperatures peaked at about 45°C. Maggot masses temperatures reached values up to almost 25°C above ambient temperature. Detection of both cadavers by thermal imaging was possible on seven of the eight helicopter flights until day 21.

Molecular identification and phylogenetic analysis of the forensically important family Piophilidae (Diptera) from different European locations.

Species identification plays an important role in forensic entomology and is mandatory for an accurate calculation of the minimum post-mortem interval. Many important Diptera and Coleoptera taxa of the cadaver community can already be identified by common barcoding approaches, i.e., by sequencing a 658bp region in the mitochondrial cytochrome c oxidase subunit I (coI) gene. Nevertheless, there is still a lack of reference barcodes for species, in particular, that can be found on cadavers at later decomposition stages. Flies of the family Piophilidae illustrate this gap of knowledge perfectly. Due to the fact that a reliable morphological identification key for the immature stages of this flies is still missing and the immature stages of many piophilids cannot be assigned to a certain species, there is need for additional tools to identify forensically relevant taxa. We collected adult piophilid specimens at 10 locations in five European countries: Spain (n=3 locations), Germany (n=3), Portugal (n=2), Poland (n=1) and Switzerland (n=1). Apart from the coI barcoding region, we additionally analyzed a 398bp long region of the nuclear elongation factor 1 alpha (ef1a) and subsequently established the molecular identifier for nine piophilid species. In addition, we present the molecular phylogeny of the examined taxa.

Modifications of the falciform process in the eye of beloniformes (Teleostei: Atherinomorpha): evolution of a curtain-like septum in the eye.

In order to comparatively analyze curtain-like septa in the eyes of visually orientated "close-to-surface-predators" among atherinomorph teleosts, we examined the eyes of 24 atherinomorph species under a binocular microscope with regard to the falciform process and related structures in the vitreous cavity. Additionally, falciform process samples were analyzed by transmission electron microscopy. All the studied representatives of the Cyprinodontiformes and Atheriniformes, and of one of the beloniform suborder, Adrianichthyioidei, possess a "typical" processus falciformis. In the eyes of the representatives of the other beloniform suborder, Belonoidei, however, pigmented structures that originate in the region of the optic disc and protrude into the vitreous cavity were noted. In the Hemiramphidae (halfbeaks) and Exocoetidae (flying fishes) these pigmented structures have a more cone-like shape, whereas in the Belonidae (needlefishes) and Scomberesocidae (sauries) horizontally oriented heavily pigmented curtain-like septa occur that divide the vitreous cavity dorsoventrally. It is suggested that the "typical" processus falciformis represents a plesiomorphic feature within the Atherinomorpha, whereas the pigmented modifications of the falciform process must be seen as a synapomorphic character state of the Belonoidei. The curtain-like septum of the Belonidae and Scomberesocidae might have evolved from the cone-like structures that are found in the Exocoetoidea. The functional significance of the pigmented structures in the eye is as yet not clear, except for the curtain-like septum found in Belonidae. It might play a role in visual orientation near the water surface at Snell's window.

Regional variations in the outer retina of atherinomorpha (Beloniformes, Atheriniformes, Cyprinodontiformes: Teleostei): photoreceptors, cone patterns, and cone densities.

The outer retinae of adults of 13 atherinomorph species, representing nine different families, were examined by both light and electron microscopy. The retinae were investigated with respect to photoreceptor types, cone densities, and cone patterns. All data were composed to eye maps. This procedure allows an interspecific comparison of the regional differences within the outer retina among these shallow-water fish. Furthermore, for a more detailed pattern analysis nitro-blue tetrazolium chloride- (NBT)-stainings in the retina of Melanotaenia maccullochi are presented. Apart from rods, eight morphologically different cone types could be identified: short, intermediate, and long single cones, double cones (equal and unequal), triple cones (triangular and linear), and in Ameca splendens one quadruple cone. Dimensions and occurrence of photoreceptors vary among the respective species and within the retinal regions. In the light-adapted state, the cones are arranged in highly ordered mosaics. Five different cone tessellation types were found: row patterns, twisted row patterns, square patterns, pentagonal patterns, and, exclusively in Belone belone, a hexagonal pattern. In Melanotaenia maccullochi the different spectral photoreceptor classes correspond well with the distribution of morphological photoreceptor classes within the mosaic. Double cone density maxima together with a highly ordered cone arrangement usually occur in the nasal and/or ventral to ventrotemporal retina. In most of the species that were examined these high-density regions are presumed to process visual stimuli from the assumed main directions of vision, which mainly depend on feeding behavior and predator pressure. Our findings are discussed with respect to the variable behavioral and visual ecology and phylogeny of the respective species.