During the summer months of the year , six forensic cases one is reported in the present paper , a pig carrion study in the city of Vienna latitude 48 degrees 12'N, longitude 16 degrees 22'E and several liver-baited traps north of Vienna, yielded large numbers of maggots of the blowfly Chrysomya albiceps Wiedemann Diptera: Calliphoridae. Apart from some records from France, reports of C. Our findings provided an opportunity to derive developmental schedules for C. The minimal duration of development from oviposition to adult was inversely related to temperature, ranging from 8.
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Rearing of L. For C. Addition of C. Neither egg density nor temperature has a significant effect on the sex ratio of the resulting adults. It seems that the interaction between these species is a highly asymmetric case of competition.
Competition in nature is difficult to detect and defining of competition is not straightforward Paul, The natural history of carrion flies is thought to include intense competition for larval food Suenaga, a, b; Beaver, , ; Cornaby, ; Baxter and Morrison, ; So and Dugeon, ; Wells and Greenberg, a, b.
Almost every aspect of their breeding biology suggests strong selection for rapid location and consumption of this patchy and empheral resource Beaver, ; Hanski, Intra- and inter-specific larval competition for food result in larval mortality, reduction in size and weight of individual larvae and pupae and undersized adults with less fecundity and short life Ullyett, ; Putman, ; Williams and Richardson, ; Shahein, ; Goodbrod and Goff, ; Omar, ; Reis et al. The degree to which blowflies species suffer loss of population from the effects of intra and interspecific competition on a carcass is determined by their inherent growth characteristics and by the degree to which they are adapted to withstand the adverse conditions engendered by overcrowding of the larval populations on the available food supply Ullyett, Intra- and inter-specific competition in two species of calliphorids; the common green bottle blow fly Lucilia sericata and the African hairy maggot blow fly Chrysomya albiceps can be easily cultured and studied in detail under laboratory conditions.
The blow fly L. It is a Holarctic species distributed over the warmer regions of the temperate zone Hall and Wall, and now the dominant species in urban and suburban districts of Australia and Africa Zumpt, ; Wall et al. Chrysomya albiceps is a hemisynathropic species, which prefers high temperature s and humidity Greenberg and Povolny, In field carrion studies, in Egypt, Tantawi et al. While in summer, little or no breeding in carrion occurred when the adult population was most abundant.
This behavior displayed by L. Therefore, it was found necessary to explore this aspect by a series of laboratory experiments. Maintenance of laboratory fly colonies: Larvae and adults of the two species were collected from exposed rabbit carcasses at Moharrem Bey District, Alexandria, Egypt. Larvae and adults were identified to species after Tantawi and El-Kady Adults were supplied with water, granulated sucrose and powdered milk. Experimental procedures: Gravid females of L.
This provided a dark and moist environment preferred by female flies for oviposition. Eggs were collected within 30 min of oviposition, so that they would be the same age. Clumps of eggs were separated by a gentle shaking for 10 min in a tube of 0. Unseperated eggs, which float unlike the separated eggs and the solution were decanted.
The remaining eggs were rinsed twice by filling the tube with distilled water, which then was decanted when the eggs had settled.
The eggs were poured with a small amount of water onto a paper towel marked with a grid and counted under a dissecting microscope Model 41 THRU A piece of towel with the desired number of eggs was then cut out and placed with the eggs down on the meat of the experimental jar.
Care was taken that the towel did not dry before the eggs were placed in each experimental jar. Containers used in these experiments were 1 L jars.
Each jar filled, in the following order, with about 5 cm height of moistened sawdust, g of minced meat, the desired combination of calliphorid eggs and dry sawdust to within 2 cm of the top. The quantity of meat used in these experiments was selected according to previous experiments of competition conducted by Ullyett and Wells and Greenberg a. To estimate hatching success, a number of leftover eggs at least in hundreds were kept moist in petri dishes next to the jars. Intra-specific competition pure cultures : Three treatments of 40, and eggs of each species were selected.
The quantities of food available per larva for these treatments were 3. Inter-specific competition mixed cultures : Nine combinations of 20, or eggs of L. Development under different temperature regimes: In this study, the minimum duration of total development from egg to adult eclosion of each species at each of the four studied temperature regimes in pure and mixed cultures was recorded.
As the larvae grew the mean temperature within the center of actively feeding maggots was recorded at regular intervals throughout the entire feeding period by inserting the probe of a calibrated mercury thermometer in the core of the maggot mass.
The time range of the adult eclosion was determined from periodical observations at 6 h intervals. This procedure was in triplicates for each egg density at each of the tested temperature regimes. Survivorship criteria of adults: The effect of larval competitionon the resulting adults was studied as follows: adult flies were killed by refrigerating after 12 h of observing the first fly to eclose, sorted by species and counted.
At all tested temperatures, the maggot mass temperature of each species showed a regular pattern of increase as the number of eggs was increased. In cultures of lower egg densities 40 eggs , the differences between the ambient and maggot mass temperature were slight and showed no detectable pattern.
On the other hand, in cultures of higher densities and , strong peaks in temperature were observed. Analysis of data found a significant decrease in the development time of L. Concerning the development time of C.
On the other hand, when the egg density of C. For mixed cultures, no statistically true effect of intra- and inter-specific competition on the survivorship of L. On the other hand, there was a significant decrease in the survivorship of C. Analysis of the data revealed a significant increase in mortality of L. Size: In pure cultures, there was a significant decrease in adult size of both sexes of each species as the initial number of eggs was increased For L. For mixed cultures, the adult size of L.
In contrast, a significant increase in the adult size of C. Development rate: Due to the rapid deterioration of the carrion habitat, the relative success of larvae will depend on how quickly they attain the minimum weight for viable pupation Ullyett, ; Levot et al.
For both species, the development time decreased with increasing the number of eggs was increased. Reduction of the development time as the initial number of eggs was increased has been observed in other dipterans Ullyett, ; Baxter et al. It has been shown in the study by Baxter and Morrison that fly larvae reared in crowded conditions may benefit from the presence of others through elevation of temperature, accumulation of digestive enzymes and physical alterations of the carcasses which will facilitate feeding.
The present study reported excess heat in maggot mass of L. Elevation of maggot mass temperature is common in many carrion flies Marchenko ; Lord et al. The present study adds support to the view of Goodbrod and Goff who mentioned that maggot mass could be another factor for consideration when estimating postmortem intervals PMI , based on maggot development. This result is in accordance to Hutton and Wasti and Furman et al. This elimination could be explained in view of Tantawi et al.
However, in summer, no breeding in carrion occurred when the adult population of L. This behaviour of L.
Larval predation by C. It also found that the development of C. This result contradicts that obtained by Wells and Greenberg a who recorded a prolongation in the development of C. Comparison between pure and mixed cultures indicates that, at all the density level tested, the development of L. We believe that prolongation of C. Thus the feeding larvae of C.
Survivorship: Presented data of single-species cultures indicated that survivorship at each tested temperature decreased as a function of increasing egg densities in both species. This result in accordance with Ullyett, ; Miller, ; Klomp, ; Wasti et al. In contrast, Wells and Greenberg a reported insignificant effect of density on survival of C. Explanations for decreasing survival at higher egg densities have been forward by De Jong, ; Baxter and Morrison ; Hanski ; Lominicki ; Godoy et al.
These authors have emphasized the importance of increasing levels of exploitative competition for limited resources among larvae. In double-species cultures, the high survivorship of C. The greater survival ability of C. Wells and Greenberg a found that the interaction between C. Goodbrod and Goff and Reis et al. They found that the interaction increased the survivorship of the former species and decreased that of the latter species.
Sex ratio: In this study, neither egg density nor temperature has a significant effect on the sex ratio of both species raised in pure and mixed cultures. Similar observation was recorded for C. It is evident from previous studies, that the density levels did not show any remarkable effect on the sex ratio of various dipteran species; M.
Amano attributed this due to the density would affect male and female larvae to the same extent as for pupariation. In contrast, in a similar study, Omar observed that the sex ratio of C. Size: The present results indicated that adult size of both species reduced in higher densities than in lower densities. Declines in adult size in favour of larval survivorship is common in many Diptera colonizing ephemeral habitats such as carrion, dung and decaying fruit; Ullyett, ; Kitaoka, ; Bakker, ; Sullivan and Sokal, ; Manoukas and Tsiropoulos, ; Atkinson, ; Butlin and Day, ; Sigurjonsdottir, Explanation for smaller body size, mediated by competition has already been demonstrated by Sullivan and Sokal So and Dudgeon b reported that reduced food individual ration to Boettcherisca formosensis larvae in crowded cultures produced undersized adults.
Comparison between adult size in pure and mixed cultures shows that, for L. The reverse was true for C. Hence, in terms of a reduction in adult size, the data suggest that L. It was shown here that L. Tantawi et al. Therefore, extinction of L. Subscribe Today. Science Alert. Table 1: Minimal total development times in hours of Lucilia sericata and Chrysomya albiceps raised in pure and mixed cultures of a variety of densities and proportions at different temperature regimes Upper figures for Lucilia sericata , Lower figures for Chrysomya albiceps.
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Rearing of L. For C. Addition of C. Neither egg density nor temperature has a significant effect on the sex ratio of the resulting adults. It seems that the interaction between these species is a highly asymmetric case of competition. Competition in nature is difficult to detect and defining of competition is not straightforward Paul, The natural history of carrion flies is thought to include intense competition for larval food Suenaga, a, b; Beaver, , ; Cornaby, ; Baxter and Morrison, ; So and Dugeon, ; Wells and Greenberg, a, b.
Until recently, the two biologically equivalent blow flies Chrysomya albiceps Wiedemann and Chrysomya rufifacies Macquart had disjunct distributions outside the Americas; the former was Palaearctic, the latter Australasian and Oriental. The two species are now spreading throughout the Americas and coexist in Argentina. The predatory "hairy" larvae of both species are difficult to separate, which could result in taxonomic errors. New diagnostic characters are presented to differentiate the third instars of the two species.
Chrysomya albiceps is a species belonging to the blow fly family, Calliphoridae. Chrysomya albiceps is considered conspecific with Chrysomya rufifacies by some authorities. The two species have a similar biology and the morphological differences are slight prostigmatic  bristle present in C. There are minor differences in larval morphology. The taxonomy of C.