Competitive strategies between Anastrepha fraterculus and Anastrepha obliqua (Diptera: Tephritidae) regulating the use of host fruits

Interspecific competition between individuals of different species can result in reductions in their fecundity, growth or survival, reflecting differential exploitation of resources that become intensified due to spatial co-occurrence, ecological similarity and increased population densities. As two species cannot occupy the same niche, coexistence is only possible if the available resources are used in non-overlapping manners such as niche partitioning or the use of refuges. Among agricultural insect pests, such as fruit flies of the family Tephritidae, competitive interactions can result in competitive displacement, host changes, or the expansion or restriction of the numbers of hosts utilized that can have negative consequences for human agricultural activities. We evaluated the competitive interactions between two fruit fly species of the genus Anastrepha, Anastrepha obliqua (Macquart, 1835) and Anastrepha fraterculus (Wiedmann, 1830), on their respective preferred hosts (mangoes and guava). Experiments of larval competition and competition for ovipositioning sites by adult females were performed to compare the parameters of larval development time, numbers of pupae and emerged adults and numbers of ovipositions in the presence or absence of interspecific competition. We observed that the interactions between those species were asymmetrical and hierarchical, and our results suggest a competitive displacement of A. fraterculus by A. obliqua when those two species are present on the same fruit, whether mangoes or guavas.     

Effects of different protein concentrations on longevity and feeding behavior of two adult populations of Ceratitis capitata Wiedemann (Diptera: Tephritidae)

The effects of protein intake on two adult male and female populations of Ceratitis capitata Wiedemann were assessed. One population consisted of flies reared for twenty years in the laboratory (Lab-pop); the other population consisted both of flies reared in the laboratory for approximately fifteen years and of the periodically introduced wild flies (Hybrid-pop). Three diets were tested: a no-yeast diet and two diets containing yeast (protein source) at the concentrations 6.5 g or 1.5 g per 100 ml diet. The parameters analyzed were: adult longevity, diet intake with and without yeast, and discrimination threshold for yeast. Protein intake increased Lab-pop adult longevity and did not affect longevity of the Hybrid-pop. Longevity in each population was similar for males and females fed on the same diet. Food behavior were similar for male and female adults of both populations; all preferred diets containing protein (yeast). Males and females in both populations ingested similar amounts of each diet. The discrimination threshold for yeast was similar for all males (0.5 g yeast/100 ml diet); Lab-pop females were able to detect the presence of smaller quantities of yeast in their diet, thus having a higher discrimination capacity (0.4 g/100 ml diet) as compared to the Hybrid-pop females (0.6 g/ 100 ml diet).     

Statistical modeling of biomedical corpora: mining the Caenorhabditis Genetic Center Bibliography for genes related to life span

Background  

The statistical modeling of biomedical corpora could yield integrated, coarse-to-fine views of biological phenomena that complement discoveries made from analysis of molecular sequence and profiling data. Here, the potential of such modeling is demonstrated by examining the 5,225 free-text items in the Caenorhabditis Genetic Center (CGC) Bibliography using techniques from statistical information retrieval. Items in the CGC biomedical text corpus were modeled using the Latent Dirichlet Allocation (LDA) model. LDA is a hierarchical Bayesian model which represents a document as a random mixture over latent topics; each topic is characterized by a distribution over words.     

Influence of Female Age on Variation of Mate Choice Behavior in Mediterranean Fruit Fly (Diptera: Tephritidae)

In spite of the fact that studies concerning the mate choice by females have largely been based on the idea of the unanimity of the preference for certain male characteristics, variations in this behavior have been reported. Considering this aspect, we studied the influence of female age on mate choice and on the acceptance of courting by males of different ages in lab-reared medflies. The effects of the age of both sexes on the total courtship duration and on the behavioral units performed by males were also examined. Our results demonstrated that: (1) 4 to 12 day-old females prefer younger males; (2) 20 day-old females were less selective; (3) the acceptance of courting was not influenced by male age neither by the duration of behavioral units of courtship; (4) only the duration of continuous wing vibration was affected by the age of both sexes.     

Estimating the rate of evolution of the rate of molecular evolution

A simple model for the evolution of the rate of molecular evolution is presented. With a Bayesian approach, this model can serve as the basis for estimating dates of important evolutionary events even in the absence of the assumption of constant rates among evolutionary lineages. The method can be used in conjunction with any of the widely used models for nucleotide substitution or amino acid replacement. It is illustrated by analyzing a data set of rbcL protein sequences.      

Evaluation of a candidate International Standard for Meningococcal Group C polysaccharide

Meningococcal group C (MenC) plain polysaccharide (PS) and conjugate vaccines are primarily evaluated by physicochemical methods to ensure that batches are consistently manufactured. As different assays are employed to quantify the MenC PS content of final formulations and bulk intermediaries, there is a need for an International MenC PS Standard to calibrate internal references used in the different laboratories. Twelve laboratories from nine different countries participated in a collaborative study to determine the MenC PS content of a candidate International Standard MenC PS preparation (08/214) and to assess its suitability. On the basis of the results from this study the candidate standard 08/214 was established as an International Standard for the quantification of MenC PS content in vaccines and components. It has a content of 1.192 ± 0.192 mg MenC PS/ampoule (expanded uncertainty with coverage factor of k = 2.365 corresponding to a 95% level of confidence), as determined by the resorcinol assays carried out by eight of the participating laboratories. The standard is available from The National Institute of Biological Standards and Control who act as guardians and distributors of the material under the auspices of WHO.     

Relevance of Male Size to Female Mate Choice in Ceratitis capitata (Diptera: Tephritidae): Investigations with Wild and Laboratory-Reared Flies

We examined the influence of male size on the mating success of both wild and laboratory populations of the Mediterranean fruit fly (medfly) Ceratitis capitata. Laboratory females selected larger males even when smaller males were present in large proportions (5:1), although this phenomenon did not occur when the proportion was extended to 10:1. Wild females were observed to prefer wild males over laboratory-reared ones independent of their respective sizes, and wild males of different sizes were found to transfer similar quantities of sperm to the spermathecae of the females.     

Ensemble attribute profile clustering: discovering and characterizing groups of genes with similar patterns of biological features

Background  

Ensemble attribute profile clustering is a novel, text-based strategy for analyzing a user-defined list of genes and/or proteins. The strategy exploits annotation data present in gene-centered corpora and utilizes ideas from statistical information retrieval to discover and characterize properties shared by subsets of the list. The practical utility of this method is demonstrated by employing it in a retrospective study of two non-overlapping sets of genes defined by a published investigation as markers for normal human breast luminal epithelial cells and myoepithelial cells.     

Courtship in Two Morphotypes of the <Emphasis Type="Italic">Anastrepha fraterculus</Emphasis> (Diptera: Tephritidae) Cryptic Species Complex and their Implications for Understanding Mate Recognition

Ritualized courtship behaviors are used to recognize potential mates and behavioral patterns are inevitably different among populations that demonstrate reproductive incompatibility. We characterized and compared the courtship behaviors of two morphotypes of the cryptic species complex Anastrepha fraterculus: Brazil-1 morphotype and Brazil-3 morphotype. Courtship behaviors were filmed to analyze the behavioral sequences of these two morphotypes during homotypic crossings. The behavioral units Alignment (AL) and Abdominal movements (AB and AB-call) were newly recognized in the courtship ethogram of Anastrepha fraterculus males. The two morphotypes show distinct behavioral sequences leading up to copulation. Some behaviors were repeated frequently during the courtship process, while others were more restricted to the final moments of courtship. The three behavioral units that contributed most to copulation success were Contact, Alignment, and Arrowhead 1 in the Brazil-1 morphotype and Alignment, Arrowhead 1, and Fanning in the Brazil-3 morphotype. Some behavioral routines differed across the two morphotypes. Significant differences were also noted between the frequencies of the behavioral units displayed during courtship in the two morphotypes. The relationships between the pre-zygotic incompatibilities of the Brazil-1 and Brazil-3 morphotypes and the differences between the courtship behaviors of their males are discussed. Our results indicate that behavioral isolation is involved in the process of pre-zygotic reproductive isolation of Brazil-1 and Brazil-3 morphotypes.     

Sexual behaviour of Anastrepha obliqua (Macquart) (Diptera: Tephritidae): Do laboratory domestication conditions influence male courtship behaviour?

We analysed the influence of laboratory domestication, under relaxed conditions, on the courtship behaviour of the fruit fly species Anastrepha obliqua, an important agricultural pest. We compared the temporal patterns of pheromone emission (Calling behaviour) and the frequencies and sequences of the courtship behavioural units of males of a laboratory lineage and a wild lineage. Our results indicated similarities in the temporal behavioural patterns of calling, the durations of their behavioural sequences, the final sequences of courtships resulting in copulation, of wild and laboratory males. Differences, however, were observed between the two populations in terms of the frequencies of the behavioural units executed and the initial sequence of courtship. Differences were noted in the presence or absence of some behavioural units within the courtship behavioural repertoires of the laboratory-reared and wild. The wild males did not show units such as Alignment, Contact, Fighting and Marking Leaf that were observed in the laboratory males' courtship behaviour under laboratory conditions; on the other hand, laboratory males did not show the Abdominal movements and Oscillation observed in the courtship behaviour of wild males. The rearing of A. obliqua males under relaxed conditions in the laboratory provides an environment adequate for the preservation of behavioural characteristics relevant to the successful mating, such as Movement, Arrowhead 1, and Attempt, and in temporal patterns of pheromone emission.