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Females of Phyllophaga obsoleta (Blanchard) (Coleóptera: Scarabaeoidea: Melolonthidae) perform "sexual calling" with their protractile genital chamber (PGC) exposed to release substances that attract males. Histological aspects of the PGC and accessory glands ( AGs) of P. obsoleta females were studied. Studies with light microscope and transmission electron microscope revealed exocrine tissue in the posterior section of the PGC, where it might be producing the attractants. This epithelial gland is formed by a basement membrane, a hypodermis for substance production, secretion, and transport (cells, nucleus, mitochondria, endoplasmic reticulum, Colgi complex, and presence of folds in the plasma membrane), as well as evidence of the substance to be secreted to the outside (connecting cuticular pores to plasma membrane). Histological similarities between AG types I and II were observed, although only the PGC had properties of class I cells. These results suggest that the posterior section of the P. obsoleta PGC is involved in sex pheromone production.

A BSTRACTAntennal morphology and funicular sensilla of male and female papaya fruit fly, Toxotrypana curvicauda Gerstaecker, were studied with light microscopy and scanning electron microscopy. Antennae were 3-segmented, consisting of a scape, a pedicel, a flagellum or funiculus that bears the arista. Antennal segments of males showed a trend toward slightly greater dimensions than those of females, but the differences were not significant. Numerous microtrichia as well as trichoid, basiconic, clavate, and styloconic sensilla were observed on the funiculus, and the sensillar characteristics were similar to those reported for other tephritid species. Males and females did not differ in total number or type of sensilla found on the funiculus, but trichoid and clavate sensilla were significantly larger in females. This difference may be related to female chemoreception of male-emitted sex pheromone and of host plant volatiles.

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Adults of the papaya fruit fly, Toxotrypana curvicauda Gerstaecker, living in wild vegetation in Yautepec, Morelos, Mexico, were captured using McPhail traps baited with pineapple juice or brown sugar. Maximum capture peaks occurred during August and November in the afternoon. Baits were most effective when aged over a 4-d period. Traps baited with brown sugar captured the highest number of adults, and both baits were more attractive to females than males. Potential use of these baits for pest management and research is discussed, considering that this is the first report of pineapple juice being attractive to the papaya fruit fly.

Las hembras de Phyllophaga obsoleta (Blanchard) (Coleoptera: Melolonthidae), una de las especies de mayor importancia agrícola en México, presentan un “llamado sexual” en el cual exponen una estructura en forma de bolsa del ápice abdominal y provocan la atracción de los machos. El contenido de esta estructura se ha extraído en estudios previos con diferentes disolventes y se ha confirmado su actividad biológica mediante bioensayos con túnel de viento y electroantenografía. Sin embargo, las características morfológicas de esta “bolsa” no han sido estudiadas. Por ello, en el presente trabajo se caracterizó morfológicamente los terminalia del abdomen femenino de P. obsoleta y se estudió el mecanismo de protrusión-retracción de la estructura en forma de bolsa. Se realizaron disecciones longitudinales de los terminalia del abdomen de hembras para su análisis con microscopía estereoscópica. Se encontró que la “bolsa” es la cámara genital protráctil (CGP), propia de las hembras de Melolonthidae y que se encuentra flanqueada por músculos esterno-saculares laterales y esternosaculares ventrales, así como de membranas intersegmentales VIII y IX. Músculos y membranas podrían estar involucrados en los procesos de protrusión y retracción de la CGP.

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