Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males. However, distinguishing between male sperm competition and active female sperm choice is difficult for species with internal fertilization. Nevertheless, species that store and use sperm of different males in different storing structures and species where females are able to expel all or part of the ejaculates after copulation may be able to bias fertilization.
View Article and Find Full Text PDFThe figitid and the braconid (Hym: Braconidae, Opiinae) are wide-ranging (from Florida, USA to Argentina) fruit fly parasitoids with tropical and subtropical distribution with a wet and temperate climate. In Argentina, both parasitoid species are thought to be restricted to the subtropical rainforests of the northwest and northeast, locally known as 'Yungas' and 'Paranaense' forests, respectively. However, these species recently have been recorded at the Monte and Thistle of the Prepuna eco-region, an arid region of central-western Argentina.
View Article and Find Full Text PDFEndosymbiont-induced cytoplasmic incompatibility (CI) may play an important role in arthropod speciation. However, whether CI consistently becomes associated or coupled with other host-related forms of reproductive isolation (RI) to impede the transfer of endosymbionts between hybridizing populations and further the divergence process remains an open question. Here, we show that varying degrees of pre- and postmating RI exist among allopatric populations of two interbreeding cherry-infesting tephritid fruit flies (Rhagoletis cingulata and R.
View Article and Find Full Text PDFEpisodes of isolation and secondary contact among populations of insects of Nearctic origin during Pleistocene glacial/postglacial climatic cycles had a strong evolutionary influence on the diversity of flies in the genus Rhagoletis in mountainous areas of Mexico. As a series of experiments undertaken to gather support for phylogenetic hypotheses on the origin of three walnut-infesting species in the suavis group, we examined pre- and postzygotic isolation between Rhagoletis completa Cresson, 1929 and R. ramosae Hernández-Ortiz, 1985.
View Article and Find Full Text PDFDevelopment of cost-effective traps and attractants is important for sustainable pest management. In the case of the Medfly, Ceratitis capitata Wiedemann, a worldwide pest of fruit production, recent interest in development of mass trapping strategies and low-cost easy-to-get artisanal traps for resource poor grower use has prompted renewed interest in research on attractants and traps. Additionally, such interest is also rooted on the need for effective female attractants to monitor wild population dynamics under male-only sterile fly releases.
View Article and Find Full Text PDFAn important criterion for understanding speciation is the geographic context of population divergence. Three major modes of allopatric, parapatric, and sympatric speciation define the extent of spatial overlap and gene flow between diverging populations. However, mixed modes of speciation are also possible, whereby populations experience periods of allopatry, parapatry, and/or sympatry at different times as they diverge.
View Article and Find Full Text PDFAscertaining the causes of adaptive radiation is central to understanding how new species arise and come to vary with their resources. The ecological theory posits adaptive radiation via divergent natural selection associated with novel resource use; an alternative suggests character displacement following speciation in allopatry and then secondary contact of reproductively isolated but ecologically similar species. Discriminating between hypotheses, therefore, requires the establishment of a key role for ecological diversification in initiating speciation versus a secondary role in facilitating co-existence.
View Article and Find Full Text PDFPhytophagous insects synchronize emergence with plant phenology by engaging in dormancy during periods of host scarcity and environmental stress. Regulation of dormancy is achieved through response to seasonal cues. While temperature and photoperiod are important cues in temperate latitudes, seasonal humidity, such as the onset of rains, can be a reliable cue to for synchronization of emergence and affects survival of overwintering insects.
View Article and Find Full Text PDFThe walnut husk fly Rhagoletis completa (Cresson), native to the Midwestern United States and Mexico, is invasive in California and Europe. It is one of the most important pests of walnuts in areas gathering 30% of the world production. Knowledge of life-history regulation is important for the design of management strategies.
View Article and Find Full Text PDFSeminal gifts range from important material donations to items that provide little direct benefit to females. Promiscuous, female silk corn flies Euxesta eluta expel and consume male ejaculates immediately after mating. The evolution and function of this peculiar behavior are currently unknown.
View Article and Find Full Text PDFAmong tephritid fruit flies, hybridization has been found to produce local adaptation and speciation, and in the case of pest species, induce behavioral and ecological alterations that can adversely impact efficient pest management. The fraterculus species group within Anastrepha (Diptera: Tephritidae), is a rapidly radiating aggregate, which includes cryptic species complexes, numerous sister species, and several pest species. Molecular studies have highlighted the possibility of introgression between A.
View Article and Find Full Text PDFA 4-yr study was done to analyze seasonal patterns underlying host plant-fruit fly-parasitoid interactions in a secondary forest in the Argentinean Yunga and its importance for the implementation of conservation and augmentative biological control. Larval-pupal hymenopteran parasitoids associated with all host plants and fruit fly species were identified and the seasonal occurrence of fruit, infestation levels, parasitism percentage, and relative parasitoid abundance were determined. Three fruit fly species in two genera were found in association with surveyed plants, two of which (Ceratitis capitata (Wiedemann) and Anastrepha fraterculus (Wiedemann)) are of major economic importance.
View Article and Find Full Text PDFMales of the Mediterranean fruit fly (Ceratitis capitata (Wiedemann)) display increased mating competitiveness following exposure to the odor of certain host and nonhost plants, and this phenomenon has been used in the sterile insect technique to boost the mating success of released, sterile males. Here, we aimed to establish whether males of the Mexican fruit fly (Anastrepha ludens (Loew)) gain a mating advantage when exposed to the aroma of two preferred hosts, grapefruit (Citrus paradisi Macfadyen) and bitter orange (Citrus aurantium L.).
View Article and Find Full Text PDFAnastrepha tehuacana, a new species of Tephritidae (Diptera) from Tehuacán, Puebla, Mexico reared from seeds of Euphorbia tehuacana (Brandegee) V.W. Steinm.
View Article and Find Full Text PDFThe North American Plant Protection Organization (NAPPO) is an organization comprising plant protection regulatory officials of the three signatory countries: the United States, Canada, and México. NAPPO develops Regional Standards for Phytosanitary Measures (RSPMs) as well as discussion papers on important issues related to plant protection. The Fruit Panel of NAPPO organized a Technical Assistance Group (TAG) to develop a discussion paper on the status of pest species of Rhagoletis (Diptera: Tephritidae) within the NAPPO countries.
View Article and Find Full Text PDFHerbivore host specialization includes changes in behavior, driven by locally induced adaptations to specific plants. These adaptations often result in sexual isolation that can be gauged through detection of reduced gene flow between host associated populations. Hypothetically, reduced gene flow can be mediated both by differential response to specific plant kairomones and by the influence of larval diet on some adult traits such as pheromone composition.
View Article and Find Full Text PDFBackground: Rapid and reliable identification of quarantine pests is essential for plant inspection services to prevent introduction of invasive species. For insects, this may be a serious problem when dealing with morphologically similar cryptic species complexes and early developmental stages that lack distinctive characters useful for taxonomic identification. DNA based barcoding could solve many of these problems.
View Article and Find Full Text PDFAs an initial step to improve the efficiency of the sterile insect technique applied to eradicate, suppress, and control wild Anastrepha obliqua (Macquart) (Diptera: Tephritidae) in mango producing areas of Mexico, the effect of radiation dose and mass rearing history on male mating performance was examined. Field cage tests in which both male and female laboratory flies were irradiated at different doses (0, 40, and 80 Gy) were released with cohorts of wild flies of both sexes, revealing that both mass rearing history and irradiation affected male mating performance. Laboratory males were accepted for copulation by wild females less frequently than wild males.
View Article and Find Full Text PDFFruit flies (Diptera: Tephritidae) are devastating agricultural pests worldwide but studies on their long-term population dynamics are sparse. Our aim was to determine the mechanisms driving long-term population dynamics as a prerequisite for ecologically based areawide pest management. The population density of three pestiferous Anastrepha species [Anastrepha ludens (Loew), Anastrepha obliqua (Macquart), and Anastrepha serpentina (Wiedemann)] was determined in grapefruit (Citrus x paradisi Macfad.
View Article and Find Full Text PDFLife history theory predicts that individuals will allocate resources to different traits so as to maximize overall fitness. Because conditions experienced during early development can have strong downstream effects on adult phenotype and fitness, we investigated how four species of synovigenic, larval-pupal parasitoids that vary sharply in their degree of specialization (niche breadth) and life history (Diachasmimorpha longicaudata, Doryctobracon crawfordi, Opius hirtus and Utetes anastrephae), allocate resources acquired during the larval stage towards adult reproduction. Parasitoid larvae developed in a single host species reared on four different substrates that differed in quality.
View Article and Find Full Text PDFEvidence based medicine has changed the manner in which medicine is practiced and learned. Epidemiological studies, meta-analyses and systematic reviews have been used to create algorithms for the treatment of hyperglycemia in patients with type 2 diabetes. Recently, several randomized controlled trials (i.
View Article and Find Full Text PDFObjective: To estimate the percentage of Mexican adults that may require lipid-lowering treatment according to National Cholesterol Education Program-III guidelines, using data from the National Health and Nutrition Survey 2006 (ENSANut 2006).
Material And Methods: Information was obtained from 4 040 subjects aged 20 to 69 years, studied after a 9 to 12 hours fast.
Results: A cardiovascular risk equivalent was found in 13.
Objective: To describe the prevalence of lipid abnormalities found in the Mexican National Health and Nutrition Survey 2006 (ENSANut 2006).
Material And Methods: Information was obtained from 4 040 subjects aged 20 to 69 years, studied after a 9- to 12-hour fast.
Results: Median lipid concentrations were: cholesterol 198.
An Expert Committee of the American Diabetes Association and the European Association for the Study of Diabetes recommended a move to the use of HbA1c level to diagnose diabetes mellitus. Diagnosis should be made if the A1c level is > or = 6.5%.
View Article and Find Full Text PDFObjective: To report a case of a proinsulin-secreting islet cell adenoma in which the diagnosis was obscured by an ultraspecific insulin assay.
Methods: We describe the case of a 46-year-old woman, who presented with fasting hypoglycemia and appropriately low insulin values.
Results: A prolonged supervised fast produced symptomatic hypoglycemia (20 mg/dL) after only 7 hours.