Necrophagous Fly Assembly: Evaluation of Species Bait Preference in Field Experiments

The assembly of species that colonize animal organic matter, their relative abundance, and dynamics are affected by the environmental and biogeographical conditions to which these resources are exposed. Baited trap studies are essential for research on the diversity, seasonality, distribution and population dynamics of necrophagous flies. Decomposing baits provide the necessary stimulus for flies to aggregate on them. In this study, three types of bait of animal origin with different organic chemical composition were compared in terms of the diversity, richness, abundance, and species composition of saprophagous flies species that were attracted to them. Bone-meal (BM), cow liver (CL), and rotten chicken viscera (CV) were used as bait to collect flies. In total, 3,387 Calliphoridae, Sarcophagidae, and Muscidae adult flies were collected. The most abundant species were Lucilia ochricornis (Wiedemann 1830), Chrysomya albiceps (Wiedemann 1819) (Diptera: Calliphoridae), Peckia (Sarcodexia) lambens (Wiedemann 1830) (Diptera: Sarcophagidae), and Ophyra capensis (Wiedemann 1818) (Diptera: Muscidae). The type of bait had significant effects on both the total richness (F2,18 = 57.08; P < 0.0001) and the effective number of species (F2,18 = 12.81; P = 0.0003) per trap. The average richness was higher in traps baited with chicken viscera, followed by cow liver and finally by bone-meal. The composition of cow liver and bone meal species constitute subsets of the species collected with chicken viscera, thus using the three baits would not increase the number of species detected. These results indicate that chicken viscera is the most efficient bait for testing or assessing necrophagous fly diversity.

Droppings from captive Coturnix coturnix (Galliformes: Phasianidae) as a fly breeding resource

The aim of this study was to describe the fauna of flies associated with captive Coturnix coturnix (L.) (Galliformes: Phasianidae) droppings. Samples of 150 g of quail droppings were exposed in the quail house for 48 h in plastic containers to promote eventual access of flies, and then placed in emergence traps. The number of adults and species emerging was recorded daily. This procedure was carried out in spring 2008 and spring and autumn 2009. In total, 2,138 adults belonging to Muscidae, Calliphoridae, Piophilidae, Phoridae, Fanniidae, and Milichiidae families were collected. The most numerous family was Muscidae (representing >82% of the total specimens), with Musca domestica L. being the most abundant species followed by Ophyra aenescens (Wiedemann) (both Diptera: Muscidae). Quail breeding should include adequate droppings management policies to avoid potential sanitary issues related to fly production.

Fly emergence from manure of Japanese quail fed thymol- or isoeugenol-supplemented diets

Many problems in poultry production are caused by a combination of interrelated factors such as management, stress, nutrition, and exposure to pathogens. Saprophagous flies that develop in poultry manure are a potential route of pathogen transmission. Besides being a nuisance, defecation and regurgitation of flies soil equipment and structures and can reduce light levels of lighting fixtures. These effects clearly affect management and may contribute to reductions in poultry egg production, health, and welfare. Many essential oils or their main components have bioactive effects such as natural repellents and insecticides, antioxidants, anticholesterolemics, and antimicrobials. This study evaluated if supplementing quail feed with thymol or isoeugenol as functional food could alter the production of flies from manure. Dropping samples deposited by quail fed with a supplementation of 2,000 mg of thymol or isoeugenol per kg of feed or no supplement (control) were collected. Each sample was incubated inside an emergence cage that was inspected daily to collect emerging adult flies. Fewer flies emerged from droppings of quail fed a thymol-supplemented diet (P = 0.01) and there was a tendency to a lower emergence from droppings of isoeugenol-fed quail (P = 0.09). The number of positive containers for Musca domestica was smaller from quail droppings of thymol- (P = 0.02) or isoeugenol- (P = 0.01) supplemented feed than from the control counterparts, suggesting an oviposition repellent effect. Supplementing quail feed with thymol or isoeugenol has an overall moderate effect against flies, reducing M. domestica emergence.

Seasonal composition and temporal succession of necrophagous and predator beetles on pig carrion in central Argentina

Insects are the most important components of the terrestrial fauna associated with carrion because they recycle organic matter back into the ecosystem. They can be classified into four ecological categories comprising: necrophages; parasites and predators of necrophagous species; omnivores, and incidentals. To determine the composition and temporal succession of necrophagous and predator beetles on pig carrion, four experiments, one in each season, were carried out during 2004 in a rural area of Cordoba, central Argentina. Two pigs (Sus scrofa L.), weighing approximately 8 kg each, were used in each of the four experiments. The animals were killed by a sharp blow to the head and immediately placed in an appropriate trap. One pig was placed in the shade and the other in direct sunlight. Beetle fauna were collected daily during the first 4 weeks and thereafter every 2 or 3 days. Five stages of decomposition were observed and a total of 1586 adults and 4309 immatures of Coleoptera belonging to the Staphylinidae, Nitidulidae, Cleridae, Dermestidae, Histeridae, Anthicidae and Trogidae families were collected during the four experiments. The necrophagous community was represented by Dermestes maculates (De Geer), nitidulid species and members of the Trox genus. Staphylinidae, Cleridae and Histeridae species were considered to be the main predators of the necrophagous species.

Environmental conditions influence allometric patterns in the blow fly, Chrysomya albiceps

The objective of this research was to study variations in allometry of body characters in females and males of two populations of blow flies, Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae), under different environmental conditions to establish patterns of morphological variation. Body size of both males and females in the experimental population was significantly higher than in the individuals of the natural population, indicating an important influence of food on body size. All genitalic and non-genitalic characters in males and females of the two populations showed a trend towards negative allometry rather than isometry. Allometric patterns were modified in both sexes and between populations. The data show generally larger allometric slopes in females than in males. We confirmed that the environmental conditions have an important effect on allometric patterns and body size.

Decomposition and dipteran succession in pig carrion in central Argentina: ecological aspects and their importance in forensic science

Data on the insect species associated with corpse decomposition are particularly important for estimation of the post-mortem interval (PMI) in forensic science because the PMI is based on the lifecycle and behaviour of necrophagous insects, among other measures. To determine the dipteran succession on pig carrion, four experiments, one in each season, were carried out during 2004 in a rural area of Córdoba, central Argentina. Two pigs (Sus scrofa L.) were used in each of the four experiments. At each time-point one pig was placed in the shade and the other under direct sunlight. Insects were collected daily during the first 4 weeks and thereafter every 2 or 3 days. Five stages of decomposition were observed and a total of 24 710 adult specimens were collected, belonging to the following eight families of Diptera: Calliphoridae; Muscidae; Sarcophagidae; Phoridae; Piophilidae; Fanniidae; Sphaeroceridae, and Anthomyiidae. All Calliphoridae collected in this study were considered to be of potential forensic importance because of their necrophagous behaviour and because their immature stages use carrion as a food source. Other species, such as Musca domestica L. and Ophyra aenescens (Wiedemann), were also considered to represent potential forensic indicators.