Diets for rearing Scyphophorus acupunctatus coleoptera curculionidae

Diets for rearing Scyphophorus acupunctatus coleoptera: curculionidae. The weevil, Scyphophorus acupunctatus Gyllenhall, is a pest of several species of economically important century plants, Agave spp. Aspargales: Asparagaceae, and of Mexican tuberose, Polianthes tuberosa L. Aspargales: Asparagaceae. Larvae feed in the tuberose bulb, and damage 35 to 69% of the crop Camino et al. 2002. In the field, Hernandez 2003 observed that S. acupunctatus larvae feeding on  tuberose bulbs form a series of galleries or tunnels and complete their  development within a cocoon from which the adult emerges. Copulation is carried out among the bulbs, where the female lays her eggs. Due to the economic importance of S. acupunctatus, the scarcity of information on its biology, and the urgent need to accelerate both basic  and applied research, it is essential to develop meridic diets for  immature stages as alternatives to the natural diet. Meridic diets for insects confer a basic advantage over the seasonally available natural nourishment, since they make possible  continuous rearing to support laboratory bioassays for the study of  their ecology, physiology, and behavior Singh 1983. Contamination of rearing media by microorganisms is a major issue that must be resolved  when attempting to develop an artificial diet adequate for rearing an  insect culture under laboratory conditions. To this end, antimicrobial agents are used, such as formaldehyde, methyl Phydroxybenzoate, sorbic  acid, and certain antibiotics such as penicillin, streptomycin, and  aureomycin Singh 1976. These constituents are not always innocuous, because they can be directly toxic to insects, and because they can  affect essential microbial symbionts Dunkel et al. 1982. A compound's safety level can be defined as the concentration that  does not reduce the yield of pupae and that does not prolong the period  of larval development more than 25% of the control Singh & House  1970. Above this safety level, antimicrobial agents produce toxic effects in proportion to the concentration utilized; and the most  frequent toxic effects are reduction of the insect's size,  prolongation of the larval period, and the increase in mortality of the  larval and pupal stages Bass & Barnes 1969; Singh & House 1970;  Dunkel& Read 1991. The purpose of this study was to develop a meridic diet for mass rearing of S. acupunctatus in the laboratory that would supply the  nutritional requirements of development, fecundity, and fertility of the  insect; and that could facilitate the reliable production of larval  stages needed to conduct studies of their biology, and behavior; and to  obtain other information basic to achieving effective management of this  pest. In a tuberose plantation located in the Emiliano Zapata municipality, Morelos, Mexico, we collected damaged tuberose bulbs, from  which we obtained S. acupunctatus larvae of different stages, which we  separated in the laboratory and placed individually in 100-mL plastic  containers each with a tuberose-bulb and moistened paper filter. Next the containers were placed in a Precision[R] model 818 incubator at 27  [+ or -] 1 [degrees]C, 60-70% RH, and 12:12 h L:D until the emergence of  the adults. We placed sets of 40 pairs of the emerged adults in 5.8 x 2.7 cm plastic containers each with perforations in the container top to  promote air circulation and to help avoid the growth of fungi; 20 g of  the tuberose bulb was placed within each container for feeding and  oviposition. This tuberose was replaced every 3 d, and with the aid of a Nikon stereoscopic microscope, part of the epidermis was removed to  expose the eggs. The eggs were removed with a no. 1 marten hair brush and deposited in 15 x60 mm petri dishes with wet filter paper and stored  in the incubator until eclosion. We evaluated 4 diets; all diets included the following: 6.25 g agar Bioxon; vitamins Centrum, 1.45 g Wyeth, S. A. de C. V.; 15.62 g  sucrose, 6.25 g brewer's yeast, 19.86 g wheat bran, 0.50 g  cholesterol, 1.0 g Wesson salt mixture,all diets were prepared with 56  mL of distilled water to blend the ingredients plus 180 mL to dissolve  the agar. In 3 of the diets, we also used, as phagostimulant and as a growth promoter, part of the tuberose host-plant bulb of Polianthes tuberosa  and jicama Pachyrhizus erosus R. T. Clausen Urb.; Fabales: Fabaceae,  also known as yam bean or Mexican turnip. The jicama-based diets J 27.97 g and tuberose-based diets 27.97 g diet A included the same amounts of the following ingredients:0.30 g  sorbic acid, 0.97g ascorbic acid, 0.55 g methyl P-hydroxybenzoate. In diet B 30 g tuberose bulb and diet C, 35 g tuberose bulb, the  concentra tions of the antimicrobials was increased, i.e.,0.35 g sorbic  acid, 1.02 g ascorbic acid, 0.60 g methyl Phydroxybenzoate, in order to  compensate for the greater proportion of tuberose, which could support  greater microbial growth yeasts, bacteria, and fungi  Find out more on  casino guide