The tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae) is a devastating pest of cultivated tomato Solanum lycopersicum throughout South and Central America and Europe. We aimed to characterize the behavioral mechanisms and the chemical cues involved in host selection of T. absoluta females by chemical analysis of tomato leaf volatiles, wind tunnel attraction assays, and oviposition bioassays. Tomato leaf odor elicited in mated females upwind orientation flight followed by landing as well as egg-laying, demonstrating the essential role of plant volatiles in T. absoluta host-finding behavior. In wind tunnel and oviposition choice experiments, T. absoluta females significantly preferred tomato S. lycopersicum over wild tomato Solanum habrochaites, which is resistant to larval feeding. This indicates that leaf volatiles provide information on the suitability of plants as larval hosts. Mated females also discriminated three cultivars of S. lycopersicum according to their volatile profiles. Headspace collections from leaves of these three cultivars contained large amounts of β-phellandrene, followed by limonene, 2-carene, and (E)-β-caryophyllene, which together accounted for more than 70% of tomato foliage headspace. Most leaf volatiles were released by all three cultivars, but they showed significant differences with respect to the presence of a few minor compounds and blend proportion. This is an initial study of the volatile signatures that mediate attraction and oviposition of tomato leafminer T. absoluta in response to its main host, tomato.

The aim of this work was to evaluate the carotenoid content and genetic variability of banana accessions from the Musa germplasm collection held at Embrapa Cassava and Tropical Fruits, Brazil. Forty-two samples were analyzed, including 21 diploids, 19 triploids and two tetraploids. The carotenoid content was analyzed spectrophotometrically and genetic variability was estimated using 653 DArT markers. The average carotenoid content was 4.73 μg.g -1 , and ranged from 1.06 μg.g -1 for the triploid Nanica (Cavendish group) to 19.24 μg.g -1 for the triploid Saney. The diploids Modok Gier and NBA-14 and the triploid Saney had a carotenoid content that was, respectively, 7-fold, 6-fold and 9-fold greater than that of cultivars from the Cavendish group (2.19 μg.g -1). The mean similarity among the 42 accessions was 0.63 (range: 0.24 to 1.00). DArT analysis revealed extensive genetic variability in accessions from the Embrapa Musa germplasm bank.

Why is the ground brown, when detritivores and decomposers have the numbers and ability to speed up the turnover of dark-coloured soil organic carbon? We consider this soil analogue to the 'green world' hypothesis measuring in the field how fast termites occupied cellulosic baits of varying quantity and quality and how predation risks by ants affect such encounters. Single baits with ants were occupied by termites later than triple baits without ants, implying that termites may spend longer searching for suitable food than feeding on it, thereby delaying decomposition rates of both chosen and neglected items. Because termites' feeding speeds up dissimilation of polymers by decomposers, such results may imply that bottom-up and top-down forces, ultimately, impair carbon processing and release from soil. We argue that the ground is brown partly because of delays imposed upon termites' use of resources by bottom-up and top-down forces.

Resumo -O objetivo deste trabalho foi estimar a divergência genética entre 38 diplóides de banana do programa de melhoramento da Embrapa Mandioca e Fruticultura Tropical, incluindo genótipos melhorados, cultivados e selvagens, por meio de 15 marcadores microssatélites ou SSR. As similaridades genéticas, com base no coefi ciente de Jaccard, foram utilizadas para fazer o agrupamento dos genótipos pelo método UPGMA. O número de alelos obtidos foi 113, com média de 7,53 alelos por iniciador. A similaridade genética média foi de 0,22, e variou de 0,028 a 0,48, o que indica existência de variabilidade genética entre os genótipos. A análise de grupos, com base no polimorfi smo de microssatélites, não pôde separar completamente os híbridos melhorados, cultivados e selvagens. Alguns diplóides agruparam-se com base em sua origem geográfi ca, entre eles Musa ornata e IAC-1, e Tjau Lagada e Lidi, enquanto que, em outros, nenhuma relação foi estabelecida. Houve tendência de agrupamento entre os diplóides aparentados, como: SH3263 e 8694-20, 4279-01 e 9179-03, 1304-06 e 5854-03, 86B79-10 e 7341-03, 86B79-12 e 0337-02, e 9194-04 e 4154-08.Termos para indexação: Musa, diplóides, divergência genética, híbridos, marcadores moleculares. Genetic variability estimated in banana diploids through microsatellite markersAbstract -The objective of this work was to estimate the genetic diversity between 38 banana diploids from the banana breeding program of Embrapa Mandioca e Fruticultura Tropical (Embrapa Cassava and Tropical Fruits), including improved hybrids, cultivated and wild species, using fi fteen SSR markers. Genetic similarities were utilized to cluster genotypes through UPGMA, based on Jaccard coeffi cient. The average number of alleles per primer was 7.53, with a total of 113 alleles identifi ed. The average similarity was 0.22, and ranged from 0.028 to 0.48, indicating the existence of genetic variability between genotypes. The clustering analysis based on microsatellite polymorphism could not completely separate improved hybrids, cultivated and wild species. Some diploids grouped according to their geographic origins, among which Musa ornata and IAC-1, and Tjau Lagada and Lidi, while in others no relation was established. There was a trend of clustering among related diploids as: SH3263 and 8694-20; 4279-01 and 9179-03; 1304-06 and 5854-03; 86B79-10 and 7341-03; 86B79-12 and 0337-02; and 9194-04 and 4154-08.

Resumo -O objetivo deste trabalho foi estimar a variabilidade genética em dois ciclos de seleção recorrente do maracujazeiro-amarelo (Passiflora edulis) e avaliar o impacto da seleção nas progênies selecionadas via alterações nas frequências alélicas, detectadas com uso de marcadores microssatélites. Genetic diversity in recurrent selection of yellow passion fruit detected by microsatellites markersAbstract -The objective of this work was to estimate the genetic variability in two recurrent selection cycles of the yellow passion flower (Passiflora edulis), and to evaluate the impact of selection on the progenies selected via changes in allele frequency, detected by microsatellite markers. Twenty-three microsatellites were used for genotyping 66 full-siblings. Allele frequency, expected (H e ) and observed (H o ) heterozygosity, polymorphic information content (PIC) and inbreeding coefficient (f) were estimated. Thirty-two alleles were found in these populations, of which only two were lost during selection. The average number of alleles per locus was 2.46 in the first cycle, and 2.30 in the second. The differences in allele frequencies in the two cycles were not significant. The mean H e in the first cycle was 0.20 per locus, slightly higher than H o (0.15). In the second selection cycle, the mean value of H o was lower than of H e , with an average of 0.12. The mean values of f increased in the second selection cycle, from 0.26 to 0.32. Most of the loci showed negative values of f, which suggests high levels of heterozygosity. The mean value of PIC decreased from 0.18 to 0.16 in the second cycle. There were small losses of variability and changes in allele frequencies; however, these variations can be considered normal when selection is practiced.

RESUMO-O objetivo do trabalho foi verificar a divergência genética entre 25 genótipos de mangaba da região de Iramaia-Chapada Diamantina-Bahia, utilizando os marcadores morfológicos e os marcadores RAPD. As seguintes aferições foram realizadas nos frutos maduros: diâmetro longitudinal (DL) e transversal (DT), massas do fruto (MF), da semente (MS) e da polpa (MP), rendimento de polpa (%P) e a contagem do número de sementes (NS). Os caracteres químicos avaliados no fruto maduro foram: pH, acidez (Ac), sólidos solúveis totais (SST), ácido ascórbico (AA), açúcar total (ACT) açúcar redutor (ACR), açúcar não redutor (ACNR) e relação sólidos solúveis totais: acidez (SST/Ac). MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF MANGABA GENOTYPESABSTRACT-The objective was to assess the genetic diversity among 25 Mangaba genotypes in the Iramaia-Chapada Diamantina region, Bahia, using morphological markers and RAPD markers. The following measurements were performed in mature fruits: longitudinal (LD) and transverse (TD) diameter, fruit (FM), seed (SM) and the pulp (PM) mass, pulp yield (% P) and the count seed number (SN). The chemical characters were evaluated in mature fruit: pH, acidity (Ac), total soluble solids (TSS), ascorbic acid (AA), total sugar (TS) reducing sugar (RS), non-reducing sugar (NRS) and total soluble solids /acidity (TSS/Ac). For amplification were tested 51 random primers. ). Eight random primers were selected for having more intense bands and six (OPA 08, OPB 12, OPB 19, OPH 15, OPH 18, OPH 19) were sufficient to generate 28 polymorphic bands. Among the morphological markers, FM and PM were the most effectively contributed to divergence. The formation of six and seven groups for molecular markers and morphological, respectively, indicated the presence of genetic variability in the population. .

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A well known case of ineffective natural biological control: the puzzling coexistence of the coffee leaf miner, Leucoptera coffeellum (Guérin-Mèneville), and its natural enemies was analyzed. Despite being a suitable prey to eight parasitoid species and three wasp species, all occurring simultaneously, the coffee leaf miner too often presents populations far above the damaging level for the coffee plantation. It is demonstrated that predatory wasps and parasitoids interact negatively, possibly because predatory wasps kill parasitized miner's larvae. In doing so, predatory wasps indirectly kill parasitoids, thereby impairing the efficacy of the natural biological control. It is warned that biological control programs should be based on knowledge of food web interactions, rather than simply on strategies involving introduction of exotic natural enemies.