Ceratitis capitata, also known as the Mediterranean fruit fly, is a notorious pest of fruits and vegetables worldwide. The current expansion of its geographic distribution is limited by the cooler ...temperate areas of the Northern Hemisphere, which points to a more comprehensive investigation of its thermal biology considering its high invasion capacity. Cold tolerance in adults has been studied thoroughly but the impact of extremely low temperatures on the immature stages remains unexplored. We estimated the acute cold stress response of three geographically divergent populations (two from Greece and one from Croatia). Overall, the populations exhibited different responses to acute cold stress depending on the developmental stage. The northernmost population was the most cold-susceptible at the egg stage, whereas in the southernmost population it was at the larval and pupal stage. The geographically intermediate population was the most cold-tolerant regardless of the developmental stage. The egg stage was the most cold-tolerant, followed by pupae and larvae. Our findings broaden the existing knowledge on cold tolerance of C. capitata and can be used for the development of population and invasion dynamics models. Cold tolerance of adult medflies has been extensively studied but the effect of subfreezing temperatures on the immature stages remains poorly investigated, especially as far as different populations are regarded. In this study, we estimated the acute cold stress response of three geographically divergent Mediterranean fruit fly populations originating from Greece (Crete, Volos) and Croatia (Dubrovnik) by exposing immature stages (eggs, larvae, pupae) to subfreezing temperatures. We first determined the LTsub.50 for each immature stage following one hour of exposure to different temperatures. Then eggs, larvae and pupae of the different populations were exposed to their respective LTsub.50 for one hour (LTsub.50 = −11 °C, LTsub.50 = −4.4 °C, LTsub.50 = −5 °C for eggs, larvae and pupae, respectively). Our results demonstrate that populations responded differently depending on their developmental stage. The population of Dubrovnik was the most cold-susceptible at the egg stage, whereas in that of Crete it was at the larval and pupal stage. The population of Volos was the most cold-tolerant at all developmental stages. The egg stage was the most cold-tolerant, followed by pupae and finally the 3rd instar wandering larvae. This study contributes towards understanding the cold stress response of this serious pest and provides data for important parameters that determine its successful establishment to unfavorable environments with an emphasis on range expansion to the northern, more temperate regions of Europe.
Ceratitis capitata is a globally destructive pest distributed mainly in the Mediterranean, African, and South American regions that causes significant economic losses. In this study, we adjusted the ...biological parameters of C. capitata and used the CLIMEX model to predict its potential geographical distribution under current and future conditions. Under the current climatic conditions, southern Asia, southern Oceania, southern North America, southern and central South America, and mainly southern and central Africa are highly favorable habitats. Owing to changes in temperature under future climatic conditions, the area of geographical distribution is projected to decrease and shift to higher latitudes. The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), which is native to tropical Africa, has invaded more than 100 countries and constitutes a risk to the citrus sector. Studying its potential geographical distribution (PGD) in the context of global climate change is important for prevention and control efforts worldwide. Therefore, we used the CLIMEX model to project and assess the risk of global invasion by C. capitata under current (1981–2010) and future (2040–2059) climates. In the prevailing climatic conditions, the area of PGD for C. capitata was approximately 664.8 × 10sup.5 kmsup.2 and was concentrated in South America, southern Africa, southern North America, eastern Asia, and southern Europe. Under future climate conditions, the area of PGD for C. capitata is projected to decrease to approximately 544.1 × 10sup.5 kmsup.2 and shift to higher latitudes. Cold stress was shown to affect distribution at high latitudes, and heat stress was the main factor affecting distribution under current and future climates. According to the predicted results, countries with highly suitable habitats for C. capitata that have not yet been invaded, such as China, Myanmar, and Vietnam, must strengthen quarantine measures to prevent the introduction of this pest.
The development of polymerase chain reaction (PCR) markers to identify the Y chromosome of Ceratitis capitata Wiedemann has permitted the detection of sperm transferred to females during mating. ...However, a molecular technique to quantify the sperm transferred has not yet become available. The current method to quantify the amount of sperm has been the direct counting of sperm heads. Thus, the purpose of this research was to develop and validate an accurate molecular method of diagnosis based on the application of an absolute quantitative real-time PCR, which allows the assessment of the quantity of sperm stored in the spermathecae. For this, Y-spec!f!c sequences were used to re-design and test distinct sperm markers. From the amplification product of samples detected as strong positives in conventional PCR, a cloning process of the target sequence was carried out to build the required standard curve. A series of known dilutions of this standard material was prepared for the absolute quantification process. A Roche Lightcycler 480 Real-Time PCR System and SYBRGreen fluorescent dye were used to quantify the sperm contained in the spermathecae of 4-d-old mated females and virgins. Wild-type and Vienna-8 strain sterile males were used to quantify the sperm transferred at four mating durations (10, 30, 60, and 90 min) under laboratory conditions. To validate the reported quantitative method, our results were compared by counting sperm heads under a fluorescent microscope using the same experimental design. In addition, DNA samples were also evaluated and compared by conventional PCR. Key words: Mediterranean fruit fly, tephritidae, sperm transfer, quantification, molecular technique
The Mediterranean fruit fly (medfly), Ceratitis capitata, is a pest of worldwide substantial economic importance, as well as a Tephritidae model for sterile insect technique (SIT) applications. The ...latter is partially due to the development and utilization of genetic sexing strains (GSS) for this species, such as the Vienna 8 strain, which is currently used in mass rearing facilities worldwide. Improving the performance of such a strain both in mass rearing facilities and in the field could significantly enhance the efficacy of SIT and reduce operational costs. Recent studies have suggested that the manipulation of gut symbionts can have a significant positive effect on the overall fitness of insect strains. We used culture-based approaches to isolate and characterize gut-associated bacterial species of the Vienna 8 strain under mass rearing conditions. We also exploited one of the isolated bacterial species, Enterobacter sp., as dietary supplement (probiotic) to the larval diet, and we assessed its effects on fitness parameters under the standard operating procedures used in SIT operational programs. Probiotic application of Enterobacter sp. resulted in improvement of both pupal and adult productivity, as well as reduced rearing duration, particularly for males, without affecting pupal weight, sex ratio, male mating competitiveness, flight ability and longevity under starvation.
Microorganisms are acknowledged for their role in shaping insects' evolution, life history and ecology. Previous studies have shown that microbial communities harbored within insects vary through ...ontogenetic development and among insects feeding on different host-plant species. In this study, we characterized the bacterial microbiota of the highly polyphagous Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), at different instars and when feeding on different host-plant species. Our results show that the bacterial microbiota hosted within the Mediterranean fruit fly differs among instars and host-plant species. Most of the bacteria harbored by the Mediterranean fruit fly belong to the phylum Proteobacteria, including genera of Alphaproteobacteria such as Acetobacter and Gluconobacter; Betaprotobacteria such as Burkholderia and Gammaproteobacteria such as Pseudomonas.
Coptera haywardi(Ogloblin) is a pupal endoparasitoid of tephritid flies with great potential as a biological control agent worldwide as it does not attack other Diptera.To reach its full potential, ...its mass rearing needs to be enhanced lowering costs. Here, we focused on the use of irradiated pupae of Ceratitis capitata (Wiedemann) stemming from the temperature-sensitive lethal (tsl) Vienna-8 genetic sexing strain (= Cc.sub.Vienna-8), which is mass-produced in the San Juan Medfly and Parasitoid Mass Rearing Facility in Argentina. Exposure of 1- to 2-d-old Cc.sub.Vienna-8 pupae irradiated at 90 Gy to 6- to 8-d-old C. haywardi females at a 10:1 host/parasitoid ratio for 24 h turned out to be highly successful for the rearing of this parasitoid. High radiation doses (90-100 Gy) did not adversely influence fitness parameters of C. haywardi offspring F1, namely lifetime reproductive rates, adult life expectancy, and survival time. Demographic parameters in C. haywardi F1 from irradiated Cc.sub.Vienna-8 young pupae were improved compared to those values recorded from parasitoid originated from nonirradiated Cc.sub.Vienna-8 pupae.These findings will help to enhance parasitoid mass rearing for augmentative releases against medfly in Argentinean fruit-producing regions. Key words: biological control, pupal parasitoid mass rearing, radiation, temperature-sensitive lethal mutation
The host status of sweet granadilla (Passifflora ligularis Juss.) to Ceratitis capitata (Wiedemann) and Anastrepha fraterculus (Wiedemann) in Peru was determined. Experiments were conducted in Pasco ...(Peru) in four different orchards, over 2 yr (2016 and 2017), two orchards per year. Choice (granadilla plus natural host) and no-choice foraging behavior trials were conducted using sleeves under field conditions, and forced infestation was examined in laboratory cages, with five females per fruit.The development time of C. capitata was determined, and the oviposition behavior of C. capitata and A. fraterculus was examined. Three fruit maturity stages of intact (n = 1,320) and punctured (n = 1,320) granadilla fruits were examined. Adult C. capitata (n = 4,418) and A. fraterculus (n = 2,484) were trapped in the orchards, and commercial granadilla fruits (n = 1,940) sampled and dissected. Fruit fly infestation was not found in any intact granadilla fruits. Larvae and pupae were found inside punctured granadilla only in fruits broken after 20 d, and adults only emerged when those pupae were removed from the fruit. Ceratitis capitata development time was longer in punctured granadilla than that in host fruit. In the oviposition test, A. fraterculus and C. capitata did not lay eggs in intact granadilla, and C. capitata laid eggs in punctured fruits but larvae were not found. Because of the resistance mechanisms of the pericarp, commercial fruits of Passiflora ligularis are not a natural host of C. capitata and A. fraterculus in Peru. Key words: Granadilla, Anastrepha, Ceratitis, Tephritidae, host status
In radar entomology, one primary challenge is detecting small species (smaller than 5 cm) since these tiny insects reflect radiation that can be poorly observable and, therefore, difficult to ...interpret. After a literature search on radar entomology, this research found few works where it has been possible to sense insects with dimensions smaller than 5 cm using radars. This paper describes different methodologies to detect Mediterranean fruit flies with 5–6 mm sizes using a pulsed W-band radar and presents the experimental results that validate the procedures. The article’s main contribution is the successful detection of Mediterranean fruit flies employing the shadow effect on the backscattered radar signal, achieving an 11% difference in received power when flies are present. So far, according to the information available and the literature search, this work is the first to detect small insects less than 1 cm long using a pulsed radar in W-Band. The results show that the proposed shadow effect is a viable alternative to the current sensors used in smart traps, as it allows not only detection but also counting the number of insects in the trap.
Detection of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), relies heavily on traps baited with trimedlure, a male-specific attractant. Originally used ...as a liquid, trimedlure is now dispensed from solid polymeric plugs (2 g active ingredient) that reduce volatilization and increase the effective longevity of the lure. Even so, plugs are attractive over a relatively short interval, and guidelines suggest that trimedlure plugs be replaced every 6 wk. The present study had 2 goals. First, at periodic intervals up to 10 or 12 wk, we evaluated the performance of plugs containing 4 g of trimedlure (i.e., twice the standard amount) to determine whether the increased loading resulted in an increased period of effective attractiveness. Second, we examined the relationship between trap captures and temporal changes in the residual amount and release rate of trimedlure. In 2 of the 3 field trials conducted in Hawaii and Florida, 4 g plugs weathered for as long as 8 wk, but not for 10 or 12 wk, performed as well as fresh liquid trimedlure applied to cotton wicks. In the other trial, plugs weathered for as long as 12 wk were as effective as fresh liquid. Chemical analyses revealed that the plugs were effective until the residual amount of trimedlure decreased below approximately 1.4 g and the release rate dropped below approximately 2.0 mg per h. The potential usefulness of 4 g trimedlure plugs in large-scale detection programs is discussed considering these findings.
The Mediterranean fruit fly (Medfly) is one of the world's most economically damaging pests. It displays highly seasonal population dynamics, and the environmental conditions suitable for its ...abundance are not constant throughout the year in most places. An extensive literature search was performed to obtain the most comprehensive data on the historical and contemporary spatio-temporal occurrence of the pest globally. The database constructed contained 2328 unique geo-located entries on Medfly detection sites from 43 countries and nearly 500 unique localities, as well as information on hosts, life stages and capture method. Of these, 125 localities had information on the month when Medfly was recorded and these data were complemented by additional material found in comprehensive databases available online. Records from 1980 until present were used for medfly environmental niche modeling. Maximum Entropy Algorithm (MaxEnt) and a set of seasonally varying environmental covariates were used to predict the fundamental niche of the Medfly on a global scale. Three seasonal maps were also produced: January-April, May-August and September-December. Models performed significantly better than random achieving high accuracy scores, indicating a good discrimination of suitable versus unsuitable areas for the presence of the species.
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