Abstract Avocado is one of the most demanded fruits worldwide. Comparative studies on the morphology and genetics of avocado have pointed out similarities and differences between different cultivars. Plant volatile compounds may facilitate cultivar differentiation. The volatile composition of leaves, flowers and fruit mesocarp of different cultivars has been reported, but the volatile chemical composition of immature fruits is unknown. This information may be relevant for studies on the chemical ecology of seed boring insects. Therefore, in this work the volatile chemical composition of three avocado cultivars was compared. A total of 31 compounds in developing fruits of Mexican, Fuerte and Hass avocado cultivars were identified by gas chromatography (GC) coupled to mass spectrometry (MS). Of these compounds, α-copaene, β-copaene and β-caryophyllene are among the most abundant in the extracts of the three avocado cultivars. Estragole, which has a characteristic aniseed aroma, was the most abundant compound in the Mexican cultivar (62.61%), while in Fuerte it was found in traces and in Hass it was not detected. The volatile profile of the Mexican cultivar was different from that of the Fuerte and Hass cultivars.

Abstract Mexico is the world’s leading producer of ‘Hass’ avocado and the Antillean race avocado is grown in the south of the country. Avocado plant flowers produce a great variety of volatile compounds, which act as chemical signals to attract herbivores and pollinating insects, in addition to providing information for taxonomic purposes. The research aim was to identify and compare the floral volatiles between the ‘Hass’ and Antillean race avocado. Floral volatiles were captured by solid-phase microextraction, and identification was made by gas chromatography coupled to mass spectrometry (GC-MS). Thirty-five compounds were identified as constituents of the flower aromas; most were monoterpenes and sesquiterpenes. α-Pinene, sabinene, β-pinene, (E)-linalool oxide, benzyl nitrile, lavandulol, methyl salicylate, α-copaene, β-gurjunene and γ-muurolene were only found in ‘Hass’ avocado flowers. The differences can help classify the two types of avocados analyzed into different races. Eventually, this information could be used to find out if these volatile compounds influence the interactions of avocado with its pollinating insects and herbivores.

Resumen México es el principal productor a nivel mundial de aguacate ‘Hass’, y en el sur del país se cultiva aguacate de la raza Antillana. Las flores de las plantas de aguacate producen una gran variedad de compuestos volátiles, los cuales actúan como señales químicas para atraer herbívoros e insectos polinizadores, además de proporcionar información para fines taxonómicos. El objetivo de este trabajo fue identificar y comparar los volátiles florales entre el aguacate ‘Hass’ y el de raza Antillana. La captura de los volátiles de las flores se realizó por microextracción en fase sólida, y la identificación se realizó por cromatografía de gases acoplado a espectrometría de masas (CG-EM). Se identificaron 35 compuestos como constituyentes de los aromas florales; la mayoría fueron monoterpenos y sesquiterpenos. α-Pineno, sabineno, β-pineno, (E)-oxido de linalool, nitrilo de bencilo, lavandulol, salicilato de metilo, α-copaeno, β-gurjuneno y γ- muuroleno se encontraron únicamente en las flores de aguacate ‘Hass’. Las diferencias pueden ayudar a clasificar en diferentes razas los dos tipos de aguacates analizados. Eventualmente, esta información se podría utilizar para conocer si estos compuestos volátiles influyen en las interacciones del aguacate con sus herbívoros e insectos polinizadores.

ABSTRACT We studied the volatile composition and sexual morphs of Nephelium lappaceum flowers from two orchards, and investigated the choice behavior of the honey bee, Apis mellifera toward the floral extracts from both locations. Our results showed significant differences in chemical composition and sexual morphs; only the hermaphrodite flowers from the Herradero orchard produced limonene and α-pinene and had longer peduncle and sepal than flowers from the Metapa orchard; on the other hand, the hermaphrodite flowers from the Metapa orchard had longer gynoecium. In the behavioral experiment the extracts from the Herradero orchard seemed to give A. mellifera foragers better cues for orientation to food sources, perhaps due to the presence of limonene and α-pinene, which are absent in the samples from Metapa. Such differences in both orchards could affect pollinator attraction and ultimately seed set and productivity.

Abstract: Jatropha curcas flowers from two localities in the Soconusco region, southern Mexico, were chemical and morphometrically analyzed: Camino a la Pita (CP) and Manuel Lazos (ML). Our results showed significant differences in floral volatile composition and flower morphology. A total of 30 compounds were identified; (E)-β-ocimene was the main compound in all flowers, followed by dendrolasin, (Z, E)-α-farnesene, linalool, and (3Z)-hexenyl benzoate. (Z, E)-α-farnesene was the first discriminant compound between flower sex and locations, followed by (3Z)-hexenyl benzoate, (cis)-β-elemenone and linalool based on the Gini index. Morphometrically, there were significant differences between study sites, where CP female flowers were smaller in sepal, petal length and gynoecium height. These phenotypic variations could be the consequence of the high genetic differentiation driven for the environmental conditions where these populations are grown.

Resumen: En este estudio se analizaron química y morfométricamente flores de Jatropha curcas de dos localidades de la región Soconusco, del sur de México: Camino a la Pita (CP) y Manuel Lazos (ML). Nuestros resultados muestran diferencias significativas en la composición de volátiles florales y morfológicos. Se identificaron un total de 30 compuestos; (E)-β-ocimeno fue el principal compuesto en todas las flores, seguido por dendrolasin, (Z, E)-α-farneseno, linalol y (3Z)-benzoato de hexenilo. El compuesto que discriminó ambos sexos de flores y sitios de estudio fue el (Z, E)-α-farneseno, seguido por (3Z)-benzoato de hexenilo, (cis)-β-elemenona y linalol, basado en el índice de Gini. Asimismo, morfométricamente se observaron diferencias significativas entre ambas localidades; las flores femeninas de CP fueron más pequeñas en el tamaño del sépalo, pétalo y gineceo. Estas variaciones fenotípicas pueden ser consecuencia de la alta diferenciación genética debida a las condiciones ambientales donde estas plantas se encuentran.

Este estudio tuvo como objetivo determinar la riqueza y la abundancia de abejas (Hymenoptera, Apoidea) en huertas de naranja y limón en floración en Yucatán, México. Se colectaron ocho especies de abejas; el 98% de los especímenes correspondió a Apis mellifera, y el 2% restante a abejas nativas. Estos hallazgos se discuten con base en la ecología de las abejas nativas y en estudios previos en la misma área de estudio.

Extratos florais de Citrus no comportamento de forrageamento da abelha sem ferrão Scaptotrigona pectoralis (Dalla Torre). As abelhas sem ferrão têm um papel importante na polinização de muitas espécies de plantas nativas e plantas cultivadas em regiões tropicais. Pouco se sabe, no entanto, sobre a interação entre as fragrâncias florais e comportamento de forrageamento de espécies de meliponíneos. Assim, investigou-se a composição química dos extratos de cítricos florais (limão e laranja) e seus efeitos sobre o comportamento de forrageamento da abelha sem ferrão Scaptotrigona pectoralis. Nós descobrimos que cada tipo de flor tem a sua própria composição específica de mistura de compostos: limoneno (62,9%), e farnesol (26,5%) para flores de limão, (E)-nerolidol (20,8%), e linalol (12,7%) para flores de laranja. Nos experimentos de forrageamento, as operárias de S. pectoralis foram capazes de utilizar os extratos de flores para se orientarem até a fonte de alimento, não sendo atrapalhadas por placas com iscas apenas de hexano. No entanto, os extratos de flores de laranja foram aparentemente mais atraentes para essas abelhas operárias, talvez por causa da mistura particular do extrato. Nossos resultados revelam que essas fragrâncias são muito atraentes para S. pectoralis, assim pode-se inferir que dentro de pomares cítricos poderiam ser visitantes importantes na área de estudo; no entanto a destruição do habitat, o uso excessivo de pesticidas e a substituição competitiva por abelhas Apis poderia por em risco suas populações e, assim, os serviços ecológicos que prestam para nós.

Effect of Citrus floral extracts on the foraging behavior of the stingless bee Scaptotrigona pectoralis (Dalla Torre). Stingless bees have an important role as pollinators of many wild and cultivated plant species in tropical regions. Little is known, however, about the interaction between floral fragrances and the foraging behavior of meliponine species. Thus we investigated the chemical composition of the extracts of citric (lemon and orange) flowers and their effects on the foraging behavior of the stingless bee Scaptotrigona pectoralis. We found that each type of flower has its own specific blend of major compounds: limonene (62.9%) for lemon flowers, and farnesol (26.5%), (E)-nerolidol (20.8%), and linalool (12.7%) for orange flowers. In the foraging experiments the S. pectoralis workers were able to use the flower extracts to orient to the food source, overlooking plates baited with hexane only. However, orange flower extracts were seemingly more attractive to these worker bees, maybe because of the particular blend present in it. Our results reveal that these fragrances are very attractive to S. pectoralis, so we can infer that within citric orchards they could be important visitors in the study area; however habitat destruction, overuse of pesticides and the competitive override by managed honeybees might have put at risk their populations and thus the ecological services they provide to us.

Plants use visual and olfactory cues to attract pollinators and to allow them to detect the presence of flowers, which most of them are insects. Some plants have evolved with their pollinators, based on the olfactory messages, which make them unique for their specific pollinators. These mechanisms have evolved in certain plants in relation to their pollinators, and there are also inter and intra-specific variation in fragrance cues which show specific chemical profile for each plant species, so insects attracted are specific to them. Most of the floral scents are organic compounds identified with techniques and methodologies which become more specific and efficient along the time. The application of floral scent could be used as a tool in pollination and pest management. In these studies, insect interaction with floral scent is reviewed and specificity of plant-pollinator, additionally the method of analysis, some patterns and trends in these interactions, the application and its importance are examined.

Las plantas emplean diversas señales visuales y olfativas con la finalidad de atraer a los polinizadores que en su mayoría son insectos. Algunas plantas han desarrollado mecanismos, basándose en mensajes olfativos que los hacen únicos para sus polinizadores específicos. Estos mecanismos, así como las variaciones intra- e interespecíficas en el perfil de los aromas florales han evolucionado para determinadas especies. Los aromas florales son un conjunto de compuestos volátiles orgánicos y para su estudio hay varios métodos que requieren de técnicas que cada vez son más eficientes. El uso de estos aromas podría ser una opción en determinados sistemas de polinización, utilizándolos como atrayente de polinizadores o de depredadores y/o herbívoro para incrementar la producción y disminuir los daños por plagas. En este trabajo se revisan las distintas interacciones de los insectos y los aromas florales, los sistemas específicos planta-polinizador, los métodos de análisis, así como algunos patrones o tendencias de estas interacciones y su aplicación e importancia.

In this paper colored traps were evaluated to capture thrips in mango cv. Ataulfo trees in Soconusco, Chiapas, Mexico. Sticky traps were compared in different colors: blue, yellow and violet. It was placed a trap of each color per tree and they were evaluated in five trees. The results showed that significantly more thrips were caught in violet traps.

En este trabajo se evaluaron trampas de colores para capturar trips en árboles de mango cv. Ataulfo en el Soconusco, Chiapas, México. Se compararon trampas pegajosas de color azul, amarillo y violeta. Se colocó una trampa de cada color por árbol y se evaluaron en 5 árboles. Los resultados mostraron que se capturaron significativamente más trips en las trampas de color violeta.

The pirate bug Orius insidiosus (Say) was found for the first time in the inflorescences of mango cultivar Ataúlfo in Soconusco, Chiapas, Mexico.

We compared the biology and sexual behavior between a strain of laboratory with wild phenotype (LFS) and a strain of laboratory with mutant phenotype (LFM) of Anastrepha ludens (Loew), characterized by clear coloration of the body and creamy yellow eyes to determine their potential as genetic marker in the control programmes through the use of the sterile insect technique. The survey results indicated that individuals of the LFM mutant strain not differ significantly from individuals of the LFS strain respect to their fecundity, fertility and survival of immature stages, as well as in the emission of sexual pheromone. This indicates that could be adapted to mass-rearing. However, mating tests indicated that although the LFM insects mated with the insects of field of wild phenotype (CFS), presented some degree of isolation and low percentages of mating of males with both LFS and CFS females, implying that is not recommended the use of the LFM mutant strain as genetic marker in programs that use the sterile insect technique, for the control of the Mexican fruit fly.

Se comparó la biología y el comportamiento sexual entre una cepa de laboratorio con fenotipo silvestre (LFS) con una cepa de laboratorio con fenotipo mutante (LFM) de Anastrepha ludens (Loew), que se caracteriza por una coloración del cuerpo clara y ojos amarillo cremoso, para determinar su potencial como marcador genético en los programas de control mediante el uso de la técnica del insecto estéril. Los resultados del estudio indicaron que los individuos de la cepa mutante LFM no difieren significativamente de los individuos de la cepa LFS respecto a su fecundidad, fertilidad y supervivencia de inmaduros, así como en la emisión de feromona sexual. Esto es indicativo de que podría ser adaptada a las condiciones de cría masiva. Sin embargo, las pruebas de apareamiento indicaron que aunque los insectos LFM copularon con los insectos de campo de fenotipo silvestre (CFS), presentaron cierto grado de aislamiento y bajos porcentajes de apareamiento de los machos tanto con hembras CFS y LFS, lo cual implica que no sea recomendable el uso de la cepa mutante LFM como marcador genético en programas que utilizan la técnica del insecto estéril, para el control de la mosca Mexicana de la fruta.

OBJECTIVE: To determine effects of volatile compounds in homes on the behavioral response of Anopheles albimanus. MATERIAL AND METHODS: The study was conducted in January 2006, in the village of Nueva Independencia village, Suchiate, Chiapas. Volatile compounds were collected inside homes and the extracts were tested on unfed females in a Y-olfactometer. Extracts were analyzed in a gas chromatography-mass spectrometry system (GC-MS). RESULTS: Twenty eight extracts were obtained, twelve presented attraction and two repellency responses. GC-MS analyses of the extracts indicated variation in the volatile compound present in the extracts, but could not associated specific compounds with any particular effect. CONCLUSIONS: Within homes, volatiles presented attraction and repellency responses to An. albimanus. A definate pattern concerning the presence of a characteristic chemical compound and the observed response was not found.

OBJETIVO: Determinar el efecto de los compuestos volátiles en las casas sobre la respuesta conductual del vector del paludismo Anopheles albimanus. MATERIAL Y MÉTODOS: El estudio se realizó en enero de 2006 en el ejido Nueva Independencia, municipio de Suchiate, Chiapas. Se colectaron compuestos volátiles dentro de casas y los extractos se probaron sobre hembras sin alimentar en un olfatómetro en "Y". Los extractos se analizaron mediante cromatografía de gases-espectrometría de masas (CG-EM). RESULTADOS: Se obtuvieron 28 extractos, 12 presentaron respuesta de atracción y dos de repelencia. Los análisis por CG-EM indicaron variación en la presencia de compuestos volátiles y no se vincularon con compuestos específicos indicativos de algún efecto. CONCLUSIONES: Los volátiles en casas presentaron efecto de atracción y repelencia para An. albimanus. No se reconoció un patrón definido en cuanto a la presencia de compuestos químicos característicos y la respuesta obtenida.

OBJECTIVE: To determine effects of volatile compounds in homes on the behavioral response of Anopheles albimanus. MATERIAL AND METHODS: The study was conducted in January 2006, in the village of Nueva Independencia village, Suchiate, Chiapas. Volatile compounds were collected inside homes and the extracts were tested on unfed females in a Y-olfactometer. Extracts were analyzed in a gas chromatography-mass spectrometry system (GC-MS). RESULTS: Twenty eight extracts were obtained, twelve presented attraction and two repellency responses. GC-MS analyses of the extracts indicated variation in the volatile compound present in the extracts, but could not associated specific compounds with any particular effect. CONCLUSIONS: Within homes, volatiles presented attraction and repellency responses to An. albimanus. A definate pattern concerning the presence of a characteristic chemical compound and the observed response was not found.

OBJETIVO: Determinar el efecto de los compuestos volátiles en las casas sobre la respuesta conductual del vector del paludismo Anopheles albimanus. MATERIAL Y MÉTODOS: El estudio se realizó en enero de 2006 en el ejido Nueva Independencia, municipio de Suchiate, Chiapas. Se colectaron compuestos volátiles dentro de casas y los extractos se probaron sobre hembras sin alimentar en un olfatómetro en "Y". Los extractos se analizaron mediante cromatografía de gases-espectrometría de masas (CG-EM). RESULTADOS: Se obtuvieron 28 extractos, 12 presentaron respuesta de atracción y dos de repelencia. Los análisis por CG-EM indicaron variación en la presencia de compuestos volátiles y no se vincularon con compuestos específicos indicativos de algún efecto. CONCLUSIONES: Los volátiles en casas presentaron efecto de atracción y repelencia para An. albimanus. No se reconoció un patrón definido en cuanto a la presencia de compuestos químicos característicos y la respuesta obtenida.

Behavioral and electrophysiological tests were performed to evaluate the responses of workers of the ant Solenopsis geminata (Fabricius) from different size categories to Dufour gland extracts. Morphometric measures based in head widths across eyes were used to determine worker sizes. Trail following response of different worker sizes to Dufour gland extract from workers of different sizes was assessed. For each worker size category olfactory responses to Dufour gland extracts were determined using electroantennography (EAG). Gas chromatography and mass spectrometry (GC-MS) were used to determine the chromatographic profile of Dufour gland secretion for each worker size. Morphometric measures permitted to classify the workers of S. geminata as large, medium and small workers. Medium S. geminata workers displayed a significantly higher behavioral response to Dufour gland extracts produced by medium size workers. Similarly, medium workers showed a significantly higher EAG response to Dufour gland extracts produced by medium sized workers. Chromatographic profile of Dufour gland secretions produced by workers showed that each size category exhibited a characteristic profile of the three main components considered as potential trail pheromone constituents. This work showed that medium workers of S. geminata exhibited a high trail-following behavior as well as a high antennal response to Dufour gland secretion. This and their relative abundance in field foraging areas, suggest that medium-sized workers are specialized in foraging activities.

Se efectuaron pruebas comportamentales y electrofisiológicas para evaluar las respuestas de obreras de Solenopsis geminata (Fabricius) de diferentes tamaños a extractos de la glándula de Dufour. Se usaron medidas del ancho de la cabeza para determinar el tamaño de las obreras. Se evualuó la respuesta de seguimiento de ruta de obreras de diferentes tamaños a extractos de la glándula de Dufour proveniente de obreras de diferentes tamaños. Para cada grupo de obrera de determinado tamaño se le determinó la respuesta olfatoria por medio de electroantenografía (EAG). Se utilizó Cromatografía de Gases acoplada a Espectrometría de Masas (GC-EM) para determinar el perfil cromatográfico de la secreción de la glándula de Dufour para cada grupo de obreras. Las medidas morfométricas permitieron clasificar a las obreras de acuerdo a su tamaño en grandes, medianas y pequeñas. Las obreras medianas de S. geminata exhibieron una respuesta comportamental alta a los extractos glandulares de hormigas medianas. Las obreras medianas mostraron también una alta respuesta antenal a los extractos de obreras medianas. El perfil cromatográfico de la secreción de la glándula de Dufour producida por obreras muestra que cada tamaño exhibió un perfil característico de los tres componentes potenciales como feromona de ruta. Concluimos que las obreras de tamaño mediano exhibieron altas respuestas tanto comportamentales como olfatorias a la secreción de la glándula de Dufour. Lo anterior y el hecho de que sean las más abundantes en el área de forrajeo sugieren que este grupo de obreras está especializado en actividades de forrajeo.

Head space volatiles from flowers, as well as green and ripe mango fruit of cv. Ataulfo from Soconusco, Chiapas, were collected using Solid Phase Microextraction (SPME). Identification of chemical species was carried out by Gas Chromatography-Mass Spectrometry (GC-MS). A complex mixture of monoterpenes and sesquiterpenes was found. 3-carene, α-pinene, myrcene, limonene, terpinolene, β-selinene and the sesquiterpene tentatively identified as germacrene D were the major constituents. This information could be valuable to characterize certain aspects of genetic traits, which in turn will be useful for breeding programs, and to provide assessment of cross pollination techniques.

Los compuestos volátiles emitidos por flores y frutas verdes y maduras de mangos de la variedad Ataulfo del Soconusco, Chiapas fueron colectados por medio de la técnica de Microextracción en Fase Sólida (MEFS). El análisis químico de los volátiles se llevó a cabo por Cromatografía de Gases y Espectrometría de Masas (CG-EM). El análisis mostró que los volátiles del mango están formados por una mezcla principalmente de monoterpenos y sesquiterpenos. 3-careno, α-pineno, mirceno, limoneno, terpinoleno, β-selineno y el sesquiterpeno tentativamente identificado como germacreno D fueron los principales constituyentes. Esta información será de mucha utilidad en los programas de mejoramiento genético de variedades de mango, ofreciendo así confirmación del éxito de las técnicas de polinización cruzada.