Sensory and physicochemical analysis of honeys of nine stingless bee species of Mexico and Guatemala

Honeys produced by species other than Apis mellifera are little known. The objective of this study was to carry out sensory and physicochemical analyses of 62 samples to characterize honeys from nine species of stingless bees from Mexico and Guatemala. Analyses were performed at the sensory level and at the physicochemical level. Qualitative and quantitative data were studied using the multivariate non-metric multidimensional scaling (NMDS) statistical technique, with the Gower metric. According to the stress value (p > 0.2), the most significant parameters were at the sensory level, for visual evaluation, physical state, color, and appearance; for olfactory-taste evaluation, elemental sweet and acid tastes; for tactile evaluation, consistency, and crystallization, and for physicochemical evaluation, pH, electrical conductivity and reducing sugars. Data analysis showed that Melipona beecheii honeys formed a defined group, with similar sensory characteristics and physicochemical values, even taking into account their place of origin. Frieseomelitta nigra honeys also showed significant differences with the other honeys analyzed. Our work suggests that the entomological origin is the main factor that determines the characteristics of honey, and that the floral origin is the secondary factor, a hypothesis that should be verified in future works.

Does body size influence mating success? A morphometric study of two Anastrepha (Diptera: Tephritidae) fruit fly species

Male mating success depends on various traits and factors, and correctly identifying these traits can be key in the context of pest management. For tephritid pests, controlled through the sterile insect technique (SIT) traits, such as male size, can be manipulated through mass-rearing procedures. Thus, it is particularly important to understand whether male size can favor mating success. Here, we evaluated mating success of males of different sizes in Anastrepha ludens and Anastrepha obliqua, two species controlled through SIT. For both species, a morphometric analysis was performed of mated and unmated mass-reared and wild males in field cages. In both A. ludens and A. obliqua, wild females did not discriminate their mates based on male size and mated more frequently with wild males regardless of size. For mass-reared males, we found no evidence of an advantage of the large males compared to small males in mating success. However, we did find differences between the morphometric traits of mass-reared and wild males. In A. ludens, traits associated to mating success were Face Width (FW), Head Width (HW), Thorax Length (TL) and Wing Length (WL), and for A. obliqua were FW, HW, WL and WW (Wing Width). Overall, FW and TL were more consistent predictors of mating success. In conclusion, female choice seems to suggest multivariate selection, confirming that overall body size (expressed as pupal diameter, which is highly correlated with weight) is not a decisive factor in male mating success in these two species. However, morphological traits such as FW, HW, TL, WL and WW may be relevant in mating preference of wild female.

Brevipalpus mites associated with coffee plants (Coffea arabica and C. canephora) in Chiapas, Mexico

Tenuipalpid mites of the genus Brevipalpus are of significant economic and quarantine importance in agriculture. They can damage and vector phytopathogenic viruses in coffee plantations and other crops. In this study, we focused on: identification of the Brevipalpus species, assessment of the spread of Brevipalpus-associated viruses (CoRSV, CiLV-N, CiLVC and CiLVC2), and mite population fluctuations over the course of 1 year. The study was conducted in coffee plantations in Soconusco, a coffee-producing region in Chiapas, Mexico. The collected mites of the Brevipalpus phoenicis sensu lato species complex (635) were identified as Brevipalpus papayensis (80.2%) and B. yothersi (19.8%) based on morphological and molecular characteristics. Their population abundance was low and there were no indications for virosis. The highest mite abundance was recorded in August-September and the lowest in February-March. An interaction was observed between mite abundance and coffee species in open-growth and shaded cultivation at various altitudes. Brevipalpus papayensis was most abundant in Coffea arabica var. Bourbon, in shaded (80%) growing conditions at an altitude of 1300 m above sea level. In C. canephora (in open-growth cultivation conditions at low altitude), B. yothersi was more abundant than in C. arabica, and as abundant as B. papayensis. We are of the opinion that, at this moment, B. papayensis and B. yothersi do not present risks to the production of coffee for the studied plantations. However, as the coffee-producing regions of Mexico are ecologically diverse, it will be important to continue examining the status of Brevipalpus mite populations in other regions in Mexico.

Assessment of Aedes aegypti (Diptera: Culicidae) Males Flight Ability for SIT Application: Effect of Device Design, Duration of Test, and Male Age

The Sterile Insect Technique (SIT) is a pest control method where large numbers of sterile males are released to induce sterility in wild populations. Since a successful SIT application depends on the released sterile males being competitive with wild males, standard quality control tests are a necessary component of any SIT program. Flight ability (ability to fly out from a device) is a reliable indicator of insect quality. Based on previous studies, we developed four new tubular devices constructed with locally available materials to explore their potential as flight test devices for Aedes aegypti (L.) mass-reared males. Males were allowed to fly upwards through a vertical tube, the ones that flew out were considered successful. The effect of male age (0 to 21 d old), test time interval (30 min to 24 h), and the design of the device (40 and 80 cm height and 2 and 3.5 cm diameter) were evaluated. Our devices determined differences in the flight ability of Ae. aegypti males of different ages. During the first minutes, more old males escaped than young males in three out of four types of devices. However, young males reached higher rates of escape in all cases after 24 h. For standard quality control tests, we recommend testing 2- to 3-d-old sexually mature males in the high and narrow device (80 × 2 cm). Further observations for time intervals between 1 and 5 h might be performed to decide the shortest and more representative interval to use.

Interaction Between Beauveria bassiana (Hypocreales: Cordycipitaceae) and Coptera haywardi (Hymenoptera: Diapriidae) for the Management of Anastrepha obliqua (Diptera: Tephritidae)

The interaction between the entomopathogenic fungus Beauveria bassiana (Balsamo) and the parasitoid Coptera haywardi (Oglobin), as potential biological control agents for Anastrepha obliqua (Macquart) fruit flies, was evaluated under laboratory and semi-protected field cage conditions. The effects of the parasitoids and fungus were individually and jointly assessed in Plexiglas cages. Application of B. bassiana dry conidia to soil produced 40% mortality in A. obliqua adults. However, mortality was lower (21.2%) on evaluation under field cage conditions. According to the multiple decrement life table analysis, the probability of death of A. obliqua was 88% when C. haywardi parasitoids and B. bassiana conidia were used in conjunction, 89% when only C. haywardi parasitoids were released and 23% when only B. bassiana conidia were applied. These results demonstrate that no synergistic, additive or antagonistic interaction took place with the simultaneous use of these natural enemies, since the presence of B. bassiana had no effect on the C. haywardi parasitism. These results indicate that the parasitoid is a better natural enemy for the control of A. obliqua, and show that, although the two biological control agents can be used simultaneously, their joint application will not produce increased control.

Does Beauveria bassiana (Hypocreales: Cordycipitaceae) Affect the Survival and Fecundity of the Parasitoid Coptera haywardi (Hymenoptera: Diapriidae)?

The effect of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin on the development of immature stages, and survival and fecundity of Coptera haywardi (Oglobin) adults was studied under laboratory conditions. The fungus was applied as dry conidia on parasitized pupae of Anastrepha obliqua (Macquart) (Diptera: Tephritidae) and on parasitoid adults of two different age groups (1- to 4-d-old, and 5- to 10-d-old). The fungus caused no negative effects on the development of the immature stages, since there were no differences on the emergence of adults compared with the untreated control. Adults were susceptible to the fungus on both sexes and age groups. Males showed shorter lifespan than females, even in untreated individuals. Despite the increased adult mortality produced by the fungus there was no effect on fecundity during first 18 d of adult life, as the net fecundity was 26.7 and 26.3 parasitoids per female treated and untreated, respectively. Our results suggest that, given the low susceptibility of parasitized pupae and the no effect on fecundity during the first 18 d of adult life, it is possible to develop management strategies using these two natural enemies in the biological control against A. obliqua.

Agaricus bisporus production on substrates pasteurized by self-heating

The aim of this work was to determine if the self-heating pasteurization procedure is technically applicable to the cultivation of Agaricus bisporus. Firstly the substrates alone (corncob, Pangola grass and a mixture of both ingredients with wood shavings) were tested. Two supplementation trials were then undertaken using soybean, wheat bran, sheep manure, sesame seed, black bean and chia. Highest production values (BE = 176.3% and Y = 26.6 kg/m²) were obtained using a 9% supplement, with a formula consisting of 25% each of soybean, black bean, wheat bran and chia, added at spawning and at casing. These results were comparable to those obtained with the Phase II compost traditionally used for A. bisporus cultivation.

Laboratory Evaluation of Two Commercial Abamectin-Based Insecticides Against Anastrepha ludens (Diptera: Tephritidae): Lethal and Sublethal Effects

Toxic environmental effects of most insecticides have led to a search for bio-organic insecticides. In this study, we tested the effects of lethal and sublethal exposure to two abamectin-based insecticides (VOLIAM TARGO and LUQ-THOR) on survival, mating, and oviposition of the tephritid Anastrepha ludens (Loew). Different doses of insecticides (0.001-2.00% of the commercial products) were offered mixed with the phagostimulant bait Captor commonly used in spraying and in trapping activities for the control of flies. Both insecticides exhibited 90% killing effectiveness (Abbott index) when offered in doses between 0.02 to 2.00%. The LC50 obtained from the bioassay at 72 h after treatment was 0.003% of commercial product for TARGO and 0.008% for LUQ-THOR. Sublethal exposures to insecticides (0.003%; LC50 for TARGO and LC30 for LUQ-THOR) caused a reduction in oviposition but not in mating parameters, indicating that females were more susceptible than males to reduced doses of insecticide. The mean amount of eggs deposited 5 d after feeding on the insecticide-bait mixtures was reduced up to a third compared with the amount of eggs deposited by untreated females. Both insecticides are promising bio-organic alternatives to malathion in bait control programs against A. ludens.

Sexual behavior and male volatile compounds in wild and mass-reared strains of the Mexican fruit fly Anastrepha ludens (Diptera: Tephritidae) held under different colony management regimes

We compared the calling and mating behavior and volatile release of wild males Anastrepha ludens (Loew) with males from 4 mass-reared strains: (i) a standard mass-reared colony (control), (ii) a genetic sexing strain (Tap-7), (iii) a colony started from males selected on their survival and mating competitiveness abilities (selected), and (iv) a hybrid colony started by crossing wild males with control females. Selected and wild males were more competitive, achieving more matings under field cage conditions. Mass-reared strains showed higher percentages of pheromone calling males under field conditions except for Tap-7 males, which showed the highest percentages of pheromone calling males under laboratory cage conditions. For mature males of all strains, field-cage calling behavior increased during the last hour before sunset, with almost a 2 fold increase exhibited by wild males during the last half hour. The highest peak mating activity of the 4 mass-reared strains occurred 30 min earlier than for wild males. By means of solid phase microextraction (SPME) plus gas chromatography-mass spectrometry (GC-MS), the composition of volatiles released by males was analyzed and quantified. Wild males emitted significantly less amounts of (E,E)-α-farnesene but emitted significantly more amounts of (E,E)-suspensolide as they aged than mass-reared males. Within the 4 mass-reared strains, Tap-7 released significantly more amounts of (E,E)-α-farnesene and hybrid more of (E,E)-suspensolide. Differences in chemical composition could be explained by the intrinsic characteristics of the strains and the colony management regimes. Characterization of calling behavior and age changes of volatile composition between wild and mass-reared strains could explain the differences in mating competitiveness and may be useful for optimizing the sterile insect technique in A. ludens.

Predation of Anastrepha ludens (Diptera: Tephritidae) by Norops serranoi (Reptilia: Polychrotidae): functional response and evasion ability

The Mexican fruit fly, Anastrepha ludens (Loew), is one of the 10 worldwide more important fruit crop pests. Orchards of southeastern Chiapas also shelter the tree-dwelling lizard Norops serranoi (Köhler), which likely prey upon these flies. In standard laboratory conditions, we determined the functional response of four male and four female lizards on mass-reared fruit flies. We used a general logistic analysis of proportion of killed prey versus available prey to determine the shape of the functional response. Male lizards showed a type II functional response, while females showed a type III functional response. For the highest fruit fly densities, female lizards caught significantly more fruit flies than males did. The predator evasion ability and the survival of mass-reared and wild fruit flies were compared. Wild fruit flies evaded more male lizard attacks than mass-reared flies. However, when female lizards attacked, there was no significant difference between strains. Fruit flies survival was higher with male than with female lizards, but it did not depend on fruit fly strains. This is the first report of a vertebrate preying on the Mexican fruit fly, demonstrating that female lizards impose a higher predation pressure and are more efficient at capturing wild fruit flies than males. We discuss the implications of our results on mass-rearing and quality control of sterile flies.

Population structure of Oncidium poikilostalix (Orchidaceae), in coffee plantations in Soconusco, Chiapas, México

Se estudió la estructura poblacional de la orquídea epífita Oncidium poikilostalix (Kraenzl.) M.W. Chase & N.H. Williams (Orchidaceae), nuevo reporte para México en 2008, en la región del Soconusco, Estado de Chiapas, al sureste del país. Crece en plantaciones de café de sombra en dos comunidades rurales, Fracción Montecristo (FM) y Benito Juárez El Plan (BJ). En 2008-2009, se determinaron las características de estas plantaciones de café, y la distribución de los distintos estadíos de vida (plántulas, juveniles, adultos) de esta orquídea, en los dos forofitos encontrados: plantas de café (Coffea arabica L.) y árboles de sombra (Inga micheliana Harms.). Se utilizó Análisis de Componentes Principales y Análisis Discriminante, para comparar todas las variables evaluadas. Hubo 1.123 individuos (82,63%) de O. poikilostalix en FM y 236 (17,37%) en BJ. De ellos, creciendo sobre cafetos, 1.060 individuos (94,4%) en FM y 214 (91,06%) en BJ, el resto ocupando árboles de sombra (I. micheliana). A pesar de mostrar las características de una epífita de ramilla, el mayor número de ejemplares de O. poikilostalix se contabilizó en los cafetos, en el micrositio ramas, con 703 individuos (55,18%) y en el tronco, en los árboles de sombra, con 78 individuos (91,76%). Más de un tercio de la población fueron individuos juveniles (504 individuos, 37,09%). Oncidium poikilostalix probablemente entró a México desde Guatemala y parece ser una planta vigorosa, que se está adaptando con éxito a sus nuevos sitios de ocupación. 

Effect of cold storage on larval and adult Anastrepha ludens (Diptera: Tephritidae) viability in commercially ripe, artificially infested Persea americana 'Hass'

Commercially ripe 'Hass' avocados, Persea americana Mill, artificially exposed to wild Anastrepha ludens (Loew) (Diptera: Tephritidae) females 24 h after harvest were placed in a cold storage facility to determine the effect of low temperature on larval survival and adult viability. Fruit were left for 3, 6, 9, and 12 d in a cold room at 5 degrees C followed by a 20-25-d period at ambient temperature to allow for larval development and pupation. Hass avocados and grapefruit, Citrus paradisi Macfadyen, maintained at ambient temperature served as controls. Overall, only 0.23% of the Hass avocados and 19.30% of the grapefruit were infested. The number of infested fruit increased with decreasing exposure time to cold. Puparia from cold-treated Hass avocados were significantly smaller than those stemming from cold-treated grapefruit. Hass avocados exposed for 12 d to 5 degrees C yielded no puparia, and those exposed for 6 and 9 d yielded 22 and two puparia, respectively, but no adults. Although Hass avocados exposed to cold temperature for 3 d yielded adults that reached sexual maturity (N = 16), females laid inviable eggs. Grapefruit exposed to cold for 12 d yielded normal-sized puparia (but no adults), whereas those exposed over 9 d yielded females able to lay viable eggs. We conclude that exposing fruit to cold storage after packing and during transport represents an effective risk-mitigating procedure in the highly improbable event that a gravid A. ludens female might lay eggs in a commercially ripe Hass avocado that had been left unprotected in a packinghouse.

Chemical cues from the coffee berry borer influence the locomotory behaviour of its bethylid parasitoids

Cephalonomia stephanoderis and Prorops nasuta are two bethylid wasps released into several Latin American countries for classical biological control of coffee berry borer, Hypothenemus hampei, the most serious insect pest of coffee worldwide. Recent studies on the host location behaviour of these parasitoids have shown that females of both species are attracted to volatile compounds released by immature stages and dust and frass of H. hampei. In this study, we investigated the role of the contact chemicals present in dust and frass of H. hampei on the behaviour of P. nasuta and C. stephanoderis females. Parasitoids remained longer on patches treated with methanol extracts than on acetone and hexane extracts. Females spent more time on the patch treated with the methanol extract of dust and frass than on the patches treated with the methanol extract of dry coffee and methanol control. The concentration of the methanol extracts from dust and frass influenced the locomotory activity of parasitoids of both species. The time that females spent in the patch tended to increase as the concentration of the methanol extracts increased. A further experiment aimed to identify other behavioural descriptors and gain a deeper understanding of the mechanisms underlying the response of parasitoids to methanol extracts was performed. Females of both species spent more time, covered more distance, turned more (per unit time and per unit distance), and decreased their speed when they contacted patches treated with methanol extracts in comparison to patches treated with methanol control.

Response of Anastrepha obliqua (Diptera: Tephritidae) to visual and chemical cues under seminatural conditions

The West Indian fruit fly, Anastrepha obliqua (Macquart), is considered one of the most important pests of several fruit crops in Latin America. Studies on the sensorial ecology of A. obliqua may contribute to the improvement of a trapping system for monitoring this fruit fly species. In this study, we investigated the responses of both sexes of A. obliqua to different visual cues and to the combination of visual and chemical cues in field cages tests. Both sexes were more attracted to lime-green, orange, and yellow spheres than to red, black, or white spheres. Flies were more attracted to three-dimensional models than to flat models. A. obliqua was more attracted to 8-, 10-, and 12-cm-diameter spheres than to 4- and 6-cm-diameter spheres. Flies were more attracted to lime-green spheres baited with mombin fruit odor, Spondias mombin L., than to spheres offering either visual or cues alone.

Comparative ecological risks of pesticides used in plantation production of papaya: application of the SYNOPS indicator

Pesticides are used intensively for crop protection in tropical fruit plantations. Assessments of the relative risks posed by pesticides are needed to assist in the development of management plans that minimize ecological impacts. In this study, the risk indicator SYNOPS_2 was used to compare risks to aquatic ecosystems by pesticides commonly used in papaya plantations. Plant interception and spray drift were measured during six applications of three pesticides (chlorothalonil, chloropyrifos, and malathion) using a turbo fan driven sprayer. Plant interception was estimated to be higher (42.6+/-12.7%; p=0.04) in late (8-14 months old) than in early (4 months old) trees (20.1+/-25.3%). Chlorothalonil concentrations of up to 11.0 microg L(-1) were found in water from an adjacent ditch after field application. Concentrations of this pesticide (7.4+/-4.1 microg L(-1)) in runoff water were also significantly (p<0.01) higher than those of malathion (2.4+/-1.9 microg L(-1)) and chlorpyrifos (0.8+/-0.5 microg L(-1)). Good correlation between measured and predicted values (r2=0.56-0.85, p<0.01) showed that SYNOPS_2 is able to describe trends in runoff pollution in papaya plantations. Linear equations were obtained in order to correct numerical disagreement between measured and calculated runoff concentrations. An independent test showed a reasonable agreement between measured chlorothalonil concentrations and the predicted values using the proposed equations. Fifteen pesticides used in papaya cultivation were ranked according to their calculated chronic biological risk index. Pesticides with the highest risk index for non-target organisms were: chlorothalonil for algae, lambda cyahalotrin for Daphnia and fish, and malathion for earthworms. Chlorothalonil was the pesticide with the highest exposure level in water and therefore represents a high risk for aquatic life. Results show that SYNOPS_2 can be used as a pesticide risk indicator on papaya and possibly other tropical fruit plantations.