Dispersal and Predation Behavior in Larvae of <Emphasis Type="Italic">Chrysomya albiceps</Emphasis> and <Emphasis Type="Italic">Chrysomya megacephala</Emphasis> (Diptera: Calliphoridae)

Chrysomya albiceps and Chrysomya megacephala are exotic blowfly species known by producing myiasis in humans and other animals and by transmitting pathogens mechanically. C. albiceps stand out by being a facultative predator of other dipteran larvae. In this paper we investigated the influence of larval predation on the dispersal of larvae of C. albiceps and C. megacephala single and double species for three photophases. An experimental acrylic channel graduated and covered with wood shavings was used to observe the larval dispersal. The results showed that C. albiceps attacks C. megacephala larvae during dispersal and keeps an aggregated pattern close to the release point, in single and double species, independently of the different photophases. Chrysomya megacephala single species exhibited the same pattern, but in double species this was changed to a random distribution.     

Dispersal and Burial Behavior in Larvae of <Emphasis Type="Italic">Chrysomya megacephala</Emphasis> and <Emphasis Type="Italic">Chrysomya albiceps</Emphasis> (Diptera,Calliphoridae)

Blowflies use discrete and ephemeral substrates to feed their larva. After they run out of food, the larvae begin to disperse in order to find adequate places for pupation or additional food sources, a process named post-feeding larval dispersal. Briefly state the aspects and why they are important were studied in a circular arena of 25 cm in diameter and covered with wood shavings to a height of 40 cm allowing post-feeding dispersal from the center of the arena. Larvae of both Chrysomya albiceps and C. megacephala were used in five experiments for each species. For each pupa location, determined as distance from the center, depth, and weight were evaluated. Statistical tests were done to verify the relation between weight, depth and distance for pupation and for larvae of two species shows that the media distance is significantly different for two species and for C. megacephala this distance is greater than the distance for C. albiceps. The depth too is different for each species, as the larvae of C. megacephala buries deeper than C. albiceps. With relation of weight, there is no statistic evidence that have any difference between weights for pupation for each species.     

Foraging behaviour by an intraguild predator blowfly, <Emphasis Type="Italic">Chrysomya albiceps</Emphasis> (Diptera: Calliphoridae)

Optimal foraging theory assumes that predators use different prey types to maximize their rate of energetic gain. Studies focusing on prey preference are important sources of information to understand the foraging dynamics of Chrysomya albiceps. The purpose of this investigation is to determine the influence of larval starvation in C. albiceps on the predation rate of different prey blowfly species and instars under laboratory conditions. Our results suggest that C. albiceps prefers Cochliomyia macellaria larvae to Chrysomya megacephala under non-starvation and starvation conditions. Nevertheless, predators gained more weight consuming C. macellaria. This result suggests that C. albiceps profit more in consuming C. macellaria rather than C. megacephala. The foraging behaviour displayed by C. abiceps on their prey and the consequences for the blowfly community are also discussed.     

Direct and indirect top‐down effects of previous contact with an enemy on the feeding behavior of blowfly larvae

We investigated the addition of a trophic level to a simple food web. Direct and indirect effects caused by the presence of a new species in the food web were quantified by estimating survival and consumption rates on the basal resource. We focused on a blowfly intraguild prey–predator system with various ecological interactions taking place during the larval period. The experiments were designed to set Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) as the intraguild prey and Chrysomya albiceps (Wiedemann) as the intraguild predator and/or cannibal. The generalist pupal parasitoid Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) was introduced into the system during a non‐susceptible life stage of the interacting blowfly species. The cascading parasitoid effects induced behavioral changes in the blowfly larvae, increasing the impact of intraguild predation and cannibalism on blowfly survival. The results suggest that blowfly larvae can change their feeding behavior in response to the presence of a parasitoid.     

Cannibalistic Behavior and Functional Response in Chrysomya albiceps (Diptera: Calliphoridae)

Chrysomya albiceps is a facultative predator and cannibal species during the larval stage. Very little is known about cannibalism and prey size preference, especially in blowflies. The purpose of this investigation was to determine the influence of prey size and larval density on cannibalism by third-instar larvae of C. albiceps under laboratory conditions. Our results indicate that no cannibalism occurs by third-instar larvae on first- and second-instar larvae, but third-instar larvae do eat second-instar larvae. The functional response on second-instar larvae is consistent with Holling type II. The consequences of consuming second-, compared to first- or third-, instar larvae as well as the implications of cannibalism for the population dynamics of C. albiceps are discussed.     

Diversity and Synanthropy of Calliphoridae (Diptera) in the Region of Rio Claro, SP, Brazil

Dipteran blowflies (Calliphoridae) are of great medical and hygienic importance as vectors of pathogens and as parasites of living and dead tissue, and their association with carrion allows their use in forensic entomology. The objective of this study was to determine the synanthropic index of adult Calliphoridae (Diptera) collected in Rio Claro, S?o Paulo. Sampling occurred between September 2009 and August 2010. Traps baited with sardines, beef liver, and minced meat were assessed for five consecutive days per month in three distinct ecological areas representing urban, rural, and forest environments. The most abundant species was Lucilia eximia (Wiedemann), followed by Chrysomya albiceps (Wiedemann) and Chrysomya megacephala (Fabricius). Lucilia eximia was the only species present in all seasons and the only species collected during the winter. The season with the lowest abundance was winter, with 69 (5.5%) specimens, and spring was the season with the greatest number of specimens collected (774?C61.8%). The only species found outside inhabited areas (synanthropic) was Lucilia cuprina (Wiedemann), with a synanthropy index (SI) value of +5.7. The SI values for the other species were negative, showing a preference for uninhabited areas. The rural and urban areas were most similar in terms of species composition as were the beef and sardine baits. Among the baits used, liver attracted the greatest abundance of calliphorids, whereas minced meat attracted the greatest diversity.     

Thermal ecophysiology of seven carrion-feeding blowflies in Southern Africa

A variety of temperature thresholds for larvae, pupae, and adults of seven African species of carrion‐feeding blowflies (Diptera: Calliphoridae) was measured and compared to understand their basic thermal biology and the influence of temperature on their behaviour. Calliphora croceipalpis (Jaennicke) had consistently lower temperature thresholds than all other species tested for all larval (42.9 °C), pupal (16.6 °C), and adult (45.6 °C) stages. Larvae (50.1 °C) and adults (53.4 °C) of Chrysomya marginalis (Robineau‐Desvoidy) had higher upper lethal temperature thresholds than all other species and weighed more than all other species. Pupae and adults of both Chrysomya albiceps (Wiedemann) and Lucilia sericata (Meigen) had similar temperature thresholds, whereas Chrysomya putoria (Wiedemann), Chrysomya chloropyga (Wiedemann), and Chrysomya megacephala (Fabricius) had inconsistent rank temperature thresholds between the larval, pupal, and adult stages. With a few minor exceptions, the nervous activity, muscle activity, and death thresholds in female adult flies responded at higher temperatures than conspecific male flies for all species tested. Similarly, female adult flies weighed consistently more than conspecific male flies for all species tested, except Ca. croceipalpis. These data suggest that there is a phylogenetic component to the thermal biology of blowflies, because Ca. croceipalpis belongs to a primarily Holarctic genus and shows adaptation to that climate even though it inhabits Africa. Comparisons between these temperature thresholds and the distributions of blowfly species present on three rhinoceros carcasses suggest that blowfly larvae with high upper lethal temperature thresholds (particularly C. marginalis) dominate in interspecific competition on the carcass by raising the temperature of the amassed maggots above the thresholds of other carrion‐feeding blowflies, through metabolically generated heat.     

Development of two forensically important blowfly species (Chrysomya megacephala and Chrysomya rufifacies) (Diptera: Calliphoridae) at four temperatures in India

The development of the Oriental latrine fly, Chrysomya megacephala (Fabricius), and hairy maggot blowfly, C. rufifacies (Macquart) (Diptera: Calliphoridae), was studied at four different temperatures (22°C, 25°C, 29°C and 31°C) in order to draw correlations between larval age, body length and body dry weight. The mean larval body length increased steadily from a minimum of 1.4 mm for C. megacephala and 1.8 mm for C. rufifacies to a maximum of 17.4 mm for C. megacephala and 15.9 mm for C. rufifacies at different temperatures. Similarly, the mean dry weight increased steadily from a minimum of 0.0007 g for C. megacephala (second instar) and 0.0008 g for C. rufifacies (second instar) to a maximum of 0.0290 g for C. megacephala and 0.0270 g for C. rufifacies at different temperatures. Entomological evidence is often used to estimate the minimum postmortem interval (mPMI) and both of these species are important from a forensic point of view. Graphs of age of larvae vs. body length and age of larvae vs. dry body weight at different temperatures can be used to estimate the larval age of these two species.     

Effect of Lunar Phases,Tides, and Wind Speed on the Abundance of Diptera Calliphoridae in a Mangrove Swamp

Abiotic factors, such as lunar phases and tides, have a significant effect on insect development. Reproduction and immature development are usually interlinked to these abiotic factors. The tide is at its highest levels at full moon or new moon, hindering the feeding of the immature or causing their drowning. The oviposition by adult females is also compromised on these days because much of the available food is submerged. Another important abiotic factor is the wind, which displaces odoriferous particles in the air. Wind speed and direction are important elements to indicate potential sources of food for insects. I report on the effects of lunar phases, tides, and wind speed on the Calliphoridae fauna in mangrove swamps. The different species collected were identified, and the predominant species in the area were quantified. A total of 1,710 flies were collected over a 1-year period. Six Calliphoridae flies, Chloroprocta idioidea (Robineau-Desvoidy), Chrysomya megacephala (Fabricius), Chrysomya albiceps (Wiedemann), Chrysomya putoria (Wiedemann), Cochliomyia macellaria (Fabricius), and Lucilia eximia (Wiedemann) were collected. Data indicated that lunar phases have a significant effect on the abundance of C. albiceps (r?=?0.39, p?<?0.01), and that the variation of the tides also affected the abundance of C. putoria (r?=?0.40, p?<?0.00), C. macellaria (r?=?0.41, p?<?0.00), and C. idioidea (r?=?0.31, p?<?0.04). The wind speed, however, did not affect these species.     

Ovicidal and Deleterious Effects of Cashew (Anacardium occidentale) Nut Shell Oil and Its Fractions on Musca domestica,Chrysomya megacephala,Anticarsia gemmatalis and Spodoptera frugiperda

In this work, we evaluated the ovicidal activity and the deleterious effects of cashew (Anacardium occidentale) nut shell oil and its fractions on the development of Musca domestica and Chrysomya megacephala, important vectors of several diseases. The insecticidal effects of this plant were also measured on the first and second instar larvae of Anticarsia gemmatalis and Spodoptera frugiperda, soy and maize pests, respectively. The fly eggs and the crop pest insect larvae were exposed to the cashew (Anacardium occidentale) nut shell liquid (CNSL) and its fractions: technical CNSL, anacardic acid, cardanol and cardol. The results show that the cardol fraction, for both species of flies, presented the lowest lethal concentration with LC₅₀ of 80.4 mg/L for M. domestica and 90.2 mg/L for C. megacephala. For the mortality of the larvae of A. gemmatalis and S. frugiperda, the most effective fraction was anacardic acid with LC₅₀ of 295.1 mg/L and 318.4 mg/L, respectively. In all species, the mortality rate of the commercial compounds (cypermethrin 600 mg/L and temephos 2 mg/L) was higher than that of the evaluated compounds. Despite this, the results obtained suggest their potential in field trials, once the fractions of A. occidentale presented high mortality at low lethal concentrations in laboratory conditions, with the possibility of integrated use in the control of disease vectors and agricultural pests, employing ecofriendly compounds.     

Stochastic dynamics in exotic and native blowflies: an analysis combining laboratory experiments and a two-patch metapopulation model

In this study we explored the stochastic population dynamics of three exotic blowfly species, Chrysomya albiceps, Chrysomya megacephala and Chrysomya putoria, and two native species, Cochliomyia macellaria and Lucilia eximia, by combining a density-dependent growth model with a two-patch metapopulation model. Stochastic fecundity, survival and migration were investigated by permitting random variations between predetermined demographic boundary values based on experimental data. Lucilia eximia and Chrysomya albiceps were the species most susceptible to the risk of local extinction. Cochliomyia macellaria, C. megacephala and C. putoria exhibited lower risks of extinction when compared to the other species. The simultaneous analysis of stochastic fecundity and survival revealed an increase in the extinction risk for all species. When stochastic fecundity, survival and migration were simulated together, the coupled populations were synchronized in the five species. These results are discussed, emphasizing biological invasion and interspecific interaction dynamics.     

Temperature adaptation in Chrysomya megacephala and Chrysomya pinguis,two blow fly species of forensic significance

Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) is a common and forensically important blow fly species in the Oriental region. However, in the higher mountain regions and on winter days, its habitats are occupied by a closely related species, Chrysomya pinguis (Walker). The resources that the two species employ to survive are very similar and competition between the species may be one of the factors that trigger differentiation of their behaviors. We conducted experiments to examine how these two closely related species may have adapted to different temperature regimes to avoid competition. Several adult and immature parameters were assessed, such as fecundity, locomotor ability, hatching ratio, larval survivorship, and eclosion ratio. Results indicate that species show specific diapause at high temperature (38 °C), larval survivorship of Ch. megacephala was significantly better than that of Ch. pinguis. Conversely, at low temperature (15 °C), adult locomotor ability was better for Ch. pinguis than for Ch. megacephala. The results indicate that the two species may have evolved different temperature adaptation strategies to avoid competition. In mixed‐species larval rearing experiments, competition between Ch. pinguis and Ch. megacephala was observed: at higher temperature (30 °C), the immature performance index of Ch. megacephala was significantly increased when compared to that in single‐species culture, whereas the index of Ch. pinguis was decreased. These data are consistent with the idea that tolerance for higher temperature conditions would allow larvae of Ch. megacephala to gain a competitive advantage over Ch. pinguis in certain habitats. These results may help to explain their current distribution in the environment and provide more biological information on these forensically important species.     

Untersuchungen über das Verhalten von zwei ostafrikanischen Ameisenarten gegenüber rauberischen Syrphiden

Zusammenfassung Das Verhalten der ostafrikanischen AmeisenartenAcantholepis capensis undPheidole megacephala gegenüber r?uberischen Syrphiden wurde in Kenia durch Beobachtungen und Freilandversuche zu kl?ren versucht. Es zeigte sich, dass es sich beiP. megacephala um eine besonders aggressive Ameise handelt, die lediglich die Gegenwart von Larven der GattungParagus (P. longiventris, P. marshalli undP. borbonicus) in den von ihr besuchten Blattlauskolonien zul?sst. Kommt die Ameise mitParagus-Larven aus Aphidenkolonien mitA. capensis-Besuch in Kontakt, so t?tet sie diese Larven ab. Andererseits verh?lt sichP. megacephala gegenüberParagus-Larven aus Blattlauskolonien mit Besuch durch ihre eigene Art wesentlich weniger feindselig. Larven grosser Syrphidenarten (Allograpta spp.,Betasyrphus spp. undAfrosyrphus varipes) werden von der Ameise regelm?ssig abget?tet und als Beute in die Nester eingetragen. Im Verh?ltnis zwischenP. megacephala undParagus-Arten spielen Geruch, Verhalten und wahrscheinlich auch morphologische Strukturen der Schwebfliegenlarven eine im einzelnen nicht vollst?ndig gekl?rte Rolle. A. capensis verh?lt sich gegenüber Larven von grossen Syrphidenarten bedeutend weniger aggressiv alsP. megacephala. Paragus-Larven werden auch dann, wenn sie aus Blattlauskolonien mitP. megacephala-Besuch stammen, nur schwach angegriffen.P. longiventris-Larven geben, wenn sie vonA. capensis betrillert werden, eine Flüssigkeit ab, die von den Ameisen aufgenommen wird. Demnach bestehen zwischen den beiden Arten Beziehungen, die schon an den Bereich der Trophobiose grenzen. Der indirekte Schaden, den die Ameisen durch ihre Trophobiose-Beziehungen zu Blattl?usen anrichten, wird dadurch teilweise oder ganz ausgeglichen, dass die Syrphideneier und — larven durch die Ameisen einen Schutz vor Parasiten erhalten. Dies gilt besonders fürA. capensis, da die von dieser Ameise besuchten Blattlauskolonien für die meisten aphidophagen Schwebfliegenarten des Hochlandes von Kenia ein wichtiges, vor Parasiten geschütztes Reservoir darstellen.

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Summary The behaviour of the two common East African ant species,A. capensis andP. megacephala, towards various predaceous Syrphids was studied in a number of experiments and by some observations in the Kenya Highlands. P. megacephala proved to be a very aggressive ant. It tolerated only the presence of larvae of the Syrphid genusParagus in aphid colonies.Paragus larvae that originated from aphid colonies fostered byA. capensis were all killed in one experiment. On the other hand,Paragus larvae from aphid colonies attended byP. megacephala were much less aggressively attacked and only exceptionally killed by this ant. Fully grown larvae of large Syrphid species (Allograpta spp.,Betasyrphus spp.,Afrosyrphus varipes) were regularly killed when put into or near aphid colonies fostered byP. megacephala. The relationship betweenP. megacephala and larvae ofParagus spp. is influenced by scent, behaviour and, most probably, morphological structures (such as spines) of the Syrphid larvae. A. capensis, which was considerably less aggressive thanP. megacephalo, tolerated larvae of many Syrphid species in or near colonies of aphids. Larvae ofParagus spp., originating from aphid colonies attended byP. megacephala, were only slightly attacked. The larvae ofP. longiventris sometimes produced a slimy liquid that was taken up byA. capensis. This indicated a closer relationship between this ant andParagus larvae. The indirect damage caused by ants to plants by fostering harmful aphids, is more or less compensated by protection of eggs and larvae of the useful predaceous Syrphids against parasiticDiplazon spp. (Hymenoptera). This mainly applies toA. capensis, as numerous aphid colonies attented by this ant can function as important food reservoirs for many Syrphid species of the Kenya Highlands, especially during periods of high incidence of parasites.

     

Resource competition assays between the African big‐headed ant,Pheidole megacephala (Fabricius) and the invasive Argentine ant,Linepithema humile (Mayr): mechanisms of inter‐specific displacement

1. The spread of Argentine ants, Linepithema humile (Mayr), in introduced areas is mainly through the displacement of native ant species owing to high inter‐specific competition. In South Africa, L. humile has not established in the climatically suitable eastern and northern escarpments dominated by the African big headed ant, Pheidole megacephala (Fabricius), probably owing to local biotic resistance. 2. Inter‐specific aggression, at the individual and colony level, and competition for a shared resource were evaluated in the laboratory. 3. Aggression between the two ant species was very high in all of the assays. Both species suffered similar mortality rates during one‐on‐one aggression assays, however, during symmetrical group confrontations, L. humile workers showed significantly higher mortality rates than P. megacephala workers. During asymmetrical group confrontations both species killed more of the other ant species when they had numeric advantage. Both ant species located the shared resource at the same time; however, once P. megacephala discovered the bait, they displaced L. humile from the bait through high inter‐specific aggression, thereafter dominating the bait for the remainder of the trial. 4. The results demonstrate the potential of P. megacephala to prevent the establishment and survival of incipient L. humile colonies through enhanced resource competition and high inter‐specific aggression. This is the first study to indicate potential biotic resistance to the spread of L. humile in South Africa.     

Direct and indirect interactions between ants (Pheidole megacephala), scales (Coccus viridis) and plants (Pluchea indica)

Summary This study investigated direct and indirect interactions between the ant, Pheidole megacephala (Fabr.), the green scale, Coccus viridis (Green), and the scale's host plant, Pluchea indica (L.). To examine the influence of ants on scales and host plants, scale population densities, scale mortality rates, and plant performance were studied on control host plants with ants and host plants from which ants had been removed. Plants with ants present had significantly greater scale population densities and scale reproductive rates than did plants without ants. Scale mortality from both parasitism and other causes was increased on plants without ants relative to plants with ants. Predator introduction experiments showed that P. megacephala removes predatory coccinellid larvae, even when they are covered with a protective coating. Host plants from which ants had been removed had significantly higher degrees of honeydew accumulation, which resulted in greater colonization by sooty mold and greater rates of leaf death and abscission. Ants also removed herbivorous lepidopteran larvae from plants. Results are discussed in terms of the potential of P. megacephala to exert direct and indirect positive effects on scale populations and an indirect positive effect on Pluchea indica.     

Chrysomya megacephala larvae feeding favourably influences manure microbiome,heavy metal stability and greenhouse gas emissions

Chrysomya megacephala is a saprophagous fly whose larvae can compost manure and yield biomass and bio‐fertilizer simultaneously. However, there are concerns for the safety of the composting system, that is risk of diseases spread by way of manure pathogens, residue of harmful metals and emission of greenhouse gases. Microbiota analysis and heavy metal speciation by European Communities Bureau of Reference were evaluated in raw, C. megacephala‐composted and natural stacked swine manure to survey pathogenic bacterial changes and mobility of lead and cadmium in manure after C. megacephala feeding; the emission rate of CH₄ and N₂O from manure during C. megacephala composting and natural stacking was also measured. C. megacephala composting altered manure microbiota, reduced the risk of pathogenic bacteria and maintained the stability, and microbiota changes might be associated with heavy metal fractions, especially in Pseudomonas and Prevotella. In addition, C. megacephala‐composting significantly reduced the emission rate of CH₄ and N₂O in comparing with natural stacking situation and the first two days should be the crucial period for CH₄ and N₂O emission measurement for manure treatment by C. megacephala. Moreover, OTU26 and Betaproteobacteria were changed after C. megacephala composting which might play a role in emission of CH₄ and N₂O, respectively.     

Temperature‐dependent development of the parasitoid Tachinaephagus zealandicus on five forensically important carrion fly species

The influences of temperature and host species on the development of the forensically important parasitoid Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae) were studied at six constant temperatures in the range of 15–30°C. T. zealandicus completed development successfully between 15°C and 27°C on five species of Calliphoridae, Calliphora albifrontalis Malloch, Calliphora dubia Macquart, Lucilia sericata Meigen, Chrysomya rufifacies Macquart and Chrysomya megacephala Fabricius. No adult parasitoids emerged from any of the host species reared at 30°C. Temperature and host species significantly influenced development time, emergence success and progeny size. Development was significantly longer on Ch. megacephala and Ch. rufifacies at 18–24°C and significantly longer on Ch. rufifacies and C. albifrontalis at 15°C and 27°C. Parasitoid emergence success was greatest at 21°C, declined at the temperature extremes (15°C and 27°C) and was significantly lower on Ch. megacephala and Ch. rufifacies than on the three other host species. Progeny numbers per host pupa were highest at 21–24°C, declined on either side of this temperature range and were significantly lower on L. sericata, Ch. rufifacies and Ch. megacephala than on either C. dubia or C. albifrontalis. An effect of host species on sex ratio was only observed at 27°C, at which a higher proportion of T. zealandicus females emerged from Ch. megacephala and Ch. rufifacies than from the other host species. The thermal requirements for development (developmental thresholds, thermal constant, optimum temperature) of T. zealandicus in each host species were estimated using linear and non‐linear models. Upper and lower developmental thresholds ranged between 29.90°C and 31.73°C, and 9.73°C and 10.08°C, respectively. The optimum temperature for development was estimated at between 25.81°C and 27.05°C. Given the significant effect of host species on development time, the use of parasitoid–host‐specific developmental data in forensic application is recommended.     

Structure and ultrastructure of spermatozoa and spermiogenesis in three species of Lucilia Robineau‐desvoidy, 1830 (Diptera: Calliphoridae)

Morphology of male internal reproductive organs, spermatozoa, and spermiogenesis of the blow‐flies Lucilia cuprina, Lucilia eximia, and Lucilia peruviana is first described here, using light and transmission electron microscopy. Spermiogenesis follows the characteristics described for others insect species. The spermatozoa of L. cuprina are similar to those described for other Brachycera. However, in L. eximia and L. peruviana, some differences were found. In L. cuprina and L. eximia species, the spermatozoa are long and thin, measuring about 211 μm and 146 μm in length, of which the head region measures approximately 19 μm and 17 μm, respectively. A polymorphism was observed in L. cuprina and L. eximia spermatozoa. In all three species, the head includes a monolayered acrosome with electron‐lucent material. The shape of the nucleus, in cross sections, varies from circular to oval with completely condensed chromatin. Implantation of the axoneme was observed in the middle region of the nucleus, known as the “peg” region. In the next region, the beginning of two mitochondrial derivatives of similar diameter and different lengths in L. cuprina and only one in L. eximia and L. peruviana was observed. In the overlap region, the following structures were observed: nucleus, centriolar adjunct, mitochondrial derivatives, and axoneme. The axoneme is of a conventional insectan type with a 9 + 9 + 2 microtubular arrangement. The male internal reproductive tract consists of testis, deferent ducts, a strongly developed seminal vesicle, accessory glands, and ejaculatory duct. These features are consistent with the structural diversity of the dipteran reproductive tract and spermatozoa, comprising an essential tool for understanding the complex variations found in the Diptera. J. Morphol. 2011. © 2011 Wiley Periodicals, Inc.     

Larval Distribution and Behavior of Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae) Relative to Other Species on Florida Black Bear (Carnivora: Ursidae) Decomposing Carcasses

Larval interactions of dipteran species, blow flies in particular, were observed and documented daily over time and location on five black bear carcasses in Gainesville, FL, USA, from June 2002 – September 2004. Cochliomyia macellaria (Fabricius) or Chrysomya megacephala (Fabricius) larvae were collected first, after which Chrysomya rufifacies (Macquart) oviposited on the carcasses in multiple locations (i.e., neck, anus, and exposed flesh) not inhabited already by the other blow fly larvae. Within the first week of decomposition, C. rufifacies larvae grew to ≥12 mm, filling the carcasses with thousands of larvae and replacing the other calliphorid larvae either through successful food source competition or by predation. As a result, C. macellaria and C. megacephala were not collected past their third instar feeding stage. The blow fly species, C. megacephala, C. macellaria, Lucilia caeruleiviridis (Macquart), Phormia regina (Meigen), Lucilia sericata (Meigen), and C. rufifacies, completed two developmental cycles in the 88.5-kg carcass. This phenomenon might serve to complicate or prevent the calculation of an accurate postmortem interval.