Angel Alonso Romero-López

Sensory Organs in the Antennae of Phyllophaga obsoleta (Coleoptera: Melolonthidae)

Abstract The antennal flagellum of the melolontid beetle Phyllophaga obsoleta Blanchard consists of three terminal plates of lamellae: proximal, middle, and distal. Six types of sensilla were identified on the internal and external surfaces of lamellae from both sexes: placodea (PLAS), basiconica (BAS), coeloconica (COS), auricilica (AUS), chaetica (CHS), and trichodea (TRS). The first four types have been considered as chemoreceptor sensilla and the last two as mechanoreceptor sensilla. The sensilla from the internal and external surfaces of each of three lamellae present in the antennal club from both sexes were mapped by scanning electron microscopy. PLAS were abundant and followed a uniform pattern of distribution on both internal and external surfaces of lamellae from both sexes. Males antennae present a higher number of PLAS in comparison with females antennae. BAS are more abundant in males than in females and follow a more aggregated distribution than PLAS. AUS were included within the BAS group. COS are scarce and only observed on the internal surfaces of all lamellae. TRS and CHS are only present on the periphery of the lamellae. Most sensillar types identified were more abundant in males than in females. The higher number of PLAS observed in males lamellae compared with females lamellae suggests that these sensilla may be involved in sex pheromone reception.

Sexual dimorphism in antennal receptors of Phyllophaga ravida Blanchard (Coleoptera: Scarabaeoidea: Melolonthidae)

The external morphology of sensilla on the antennae of males and females of Phyllophaga ravida Blanchard is described using scanning electron microscopy. Sexual dimorphism in body and antennal dimensions and in antennal receptor types was found. The females body is slightly larger than the males, although male antennal lamellae are longer than in females. Sixteen types of sensilla were identified on the proximal and distal surfaces of lamellae from both sexes, most of them in males: three types of placodea sensilla, four types of auricilica sensilla, five types of basiconica sensilla, and four types of coeloconica sensilla. Also, two types of mechanoreceptor sensilla were present on the lamellae periphery. Furthermore, males had larger placodea, auricilica and some types of basiconica sensilla.

La “Gallina Ciega” (Coleoptera: Scarabaeoidea: Melolonthidae) Vista Como Un “Ingeniero del Suelo”

Abstract. An updated review has been made on the potential of “white grubs” as beneficial insects for increasing soil fertility. Historically white grubs have been considered economic pests because they cause damage in diverse agricultural crops. However, many species of white grubs also consume plant residues in the decaying process. According to the written literature, white grubs may promote fertility in agricultural soils mainly through decomposition of organic matter, rendering humic substances in a similar way as earthworms do. Main activities in which white grubs are considered as soil engineers that may increase soil fertility are that: 1) white grubs may act as earthworms because they may positively affect soil physical functions through increasing soil pore space and improve drainage and aeration; 2) white grubs may affect soil chemical functions either by nutrient immobilization, nutrient distribution, mineralization and/or humification in a dynamic way acting like biological facilitators, and 3) white grubs may stimulate soil biological activities by increasing microbiological decomposition of organic matter and regulating soil biotic composition and exporting aboveground soil nutrients contained in the adult beetle. All of these activities may give us a different vision of the problem caused by white grub when it is regarded as a soil engineer and may inspire possible solutions for their management.

Tissues Involved in Sex Pheromone Production in Phyllophaga obsoleta (Coleoptera: Scarabaeoidea: Melolonthidae)

ABSTRACT Females of Phyllophaga obsoleta (Blanchard) (Coleoptera: 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, Golgi 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.

Anatomía del Aparato Reproductor de Macrodactylus mexicanus (Coleoptera: Scarabaeoidea: Melolonthidae) y su Posible Participación en su Comunicación Química Sexual

Resumen. Se describe la anatomía del aparato reproductor de hembras y machos de Macrodactylus mexicanus (Burmeister), complementándose con un estudio histológico de las glándulas accesorias (tipo I y tipo II) y la cámara genital de las hembras, para buscar evidencias sobre la participación de ambas estructuras en la producción de atrayentes químicos. El aparato reproductor de ambos sexos de M. mexicanus es similar en la morfología y organización de estructuras y órganos al de otros integrantes de la familia Melolonthidae. El epitelio glandular de las glándulas accesorias tipo I es pluriestratificado; las células secretoras basales son cúbicas y tienen poco citoplasma; las células secretoras de las subsecuentes capas son redondas y pueden ser de un tamaño grande o pequeño y tener abundantes o escasas secreciones. En el caso de las glándulas accesorias tipo II, poseen células secretoras basales redondeadas; el epitelio glandular también es pluriestratificado, sus células secretoras son alargadas y tienen abundantes secreciones. La cámara genital presenta una capa de células cúbicas y una capa cuticular delgada y continua; algunos oenocitos fueron encontrados. En conclusión, se observó que los dos pares de glándulas accesorias (tipo I y II) presentan características tanto anatómicas como histológicas que indican que podrían estar involucradas en la producción de atrayentes químicos. Asimismo, la cámara genital destaca por presentar oenocitos, los cuales posiblemente estén involucrados en la síntesis de precursores de atrayentes.

Sexual Dimorphism in Antennae of Mexican Species of Phyllophaga (Coleoptera: Scarabaeoidea: Melolonthidae)

© 2013 Romero-Lopez and Moron, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Sexual Dimorphism in Antennae of Mexican Species of Phyllophaga (Coleoptera: Scarabaeoidea: Melolonthidae)

EFFECT OF A MERIDIC DIET ON THE LARVAL DEVELOPMENT OF PHYLLOPHAGA OBSOLETA (COLEOPTERA: MELOLONTHIDAE).

Abstract. Phyllophaga obsoleta Blanchard is a key pest in Mexican agriculture. Its chemical communication dynamics are partially known. A system of monitoring based on sex pheromones helps reduce the amount of damage it can cause as “white grubs.” To identify the sex pheromone requires many individuals, especially virgin females. Meridic diet and check diet were used to rear larvae. Both substrates were supplied with food for first- and second-instar larvae of P. obsoleta. The effect of each diet on larval survival, weight, and instar transition was evaluated. On Day 175, the meridic diet resulted in more larval weight gain and faster development into third instars than did the check diet. The meridic diet is effective for rearing P. obsoleta in a laboratory.