The mating behavior of Leucothyreus marginaticollis Blanchard, 1843 (Coleoptera: Scarabaeidae: Rutelinae)

In Brazil, there are several species of the genus Leucothyreus Macleay, 1819 occurring throughout the country; however, there are only a few studies describing their biological aspects, times of occurrence, associations of adults and juveniles with native or cropped plants, as well as their mating behavior. Thus, this study aimed to assess the mating behavior of Leucothyreus marginaticollis Blanchard, 1843. The study took place in an experimental area of the State University of Mato Grosso do Sul, in Aquidauana, MS, Brazil. Firstly, we sampled adult insects using light traps, from October to November 2013. Simultaneously, we registered the flight period in the field. Afterward, in the laboratory, males and females were separated and then combined into couples for observations of the mating steps. A large number of the adults mated, which lasted on average 22.71 min and occurred from 7 to 11 pm. After mating, part of the males released the females and the other part remained attached to them, which must have happened as an attempt to inhibit other males from mating with them. Moreover, a few females refused to mate with the established male, reinforcing the fact that the pairing of couples occurs after chemical identification among adults. In the field, the largest amount of adults was collected from 8 to 10 pm. Regarding eating habits, adults feed mostly on acerola leaves and flowers (Malpighia emarginata DC, Malpighiaceae), mastic gum leaves (Myracrodruon urundeuva Allemão, Anacardiaceae), grapes (Vitis vinifera L., Vitaceae), apples (Malus domestica Borkh., Rosaceae), and bananas (Musa sp. L., Musaceae). To the end of the experiment, we could clarify the mating steps of L. marginaticollis in order to assist in further extraction and identification of sexual pheromone.

Sensorless Vibratory Manipulation of the Automatically Assembled Parts

Presented paper considers the experimental analysis of vibratory manipulation and interdependent alignment of the parts prior to automated assembly. Different values of vibration parameters and parameters of the dynamic system provide possibility to influence the duration of part alignment process. Mating part manipulation on the plane, excited along two perpendicular directions, was also analyzed and different search trajectories were considered.

Repair of Parts by Coating

The worn surface is usually coated with a layer, which thickness exceeds magnitude of wear. In order to provide required clearances (or tightness) in the assembling of parts, uniform clearances (this suggests the presence of the perfect mating should be provided. In the paper, the effects on the layer were discussed and forecasting the clearance sizes or (when the limit values are specified) determining the assembly life. In the process of repairing, the worn surface is usually coated with the layer, which thickness exceeds magnitude of wear. After the surface is coated it is machined by one of the available methods. During recent years, new so-called “cold” methods of coating have appeared, some of them (particularly galvanomechanical machining) enables to obtain required dimensions and quality metrics of surface layer without complete machining. The final goal of repair is to provide required clearances (or tightness) in the assembling of parts. It is required to provide uniform clearances (this suggests the presence of the perfect mating surfaces before assembly). Depending on accuracy grade, variations in the clearance dimensions may be within the limits from some microns to decile of millimeter. This depends on mating surface accuracies and is independent of the fact whether these surfaces were repaired or not. If the parts were machined separately, thickness of the layer shall be determined subject to the actual size of mating part areas, size and dimensional tolerances of clearance. When developing the process of parts repair, the following shall be considered: - wear degree of contact mating locations; - requirements for quality of surface layer in part assemblies; - permissible errors of mating surfaces; - allowance (or tightness) between mating parts and its variation limits in the assembly. The wear in mating locations is determined by supervision of part defects before repair. The limiting wear of products shall not exceed capability of galvanomechanical method. It is required for qualitative surface coating to limit the thickness to 0,5-0,6 mm. Depending on wear degree, two methods of repair can be used: -smoothing of macrosurface with a galvanomechanical coating, for example with chromium and thereafter application of qualitative surface layer. Such process shall be applied in the case when degree of surface unevenness does not exceed 50%. If wear degree is out of the stated limits, preliminary machining is required. This machining is necessary to reduce surface unevenness up to 50%. After this procedure, effective thickness of coating shall be applied. The acceptable surface unevennesses with different degrees of wear are shown on Fig.1 At the first stage of coating the stock shall be evened. After this, the surface roughness does not exceed the roughness coefficient specified for a new part, but other quality indexes of the surface (residual stress character, wear-resistance) are not in conformance with the requirements for the repaired parts. Therefore, after evening, another “slower” method of galvanomechanical repair with specified contact pressure and mechanical effect conditions is applied. As a result of this method, the following indexes are available. See Table 1.

Force-Based Reasoning in Assembly Planning

A new approach to assembly planning based on force-based reasoning of decomposable subassemblies is presented. By decomposable subassemblies, we mean those clusters of parts that are naturally broken apart from an assembly by decomposition forces. The key feature of the proposed approach is that decomposable subassemblies can be identified from the minimal cut-sets of force-flow networks constructed by assigning bidirectional flow capacity to individual part mating. The flow capacity between two mating parts is defined here as the maximum amount as force that one can exert against its mating part (hypothesized fixed in space) in a chosen direction. Finally, the assemblability of decomposable subassemblies is verified by testing, through force-flow networks, whether the decomposed subassemblies can be reassembled by the mating forces opposite to the decomposition forces. The proposed force-based approach is advantageous due to the polynomial time complexity of a max-flow/min-cut algorithm, as well real-world application.

Equilibrium behavior of population genetic models with non-random mating. Part II: Pedigrees, Homozygosity and Stochastic Models

Wright (1921) computed various correlations of relatives by a rather cumbersome procedure called the “method of path coefficients”. Wright's method is basically a disguised form of the use of Bayes' rule and the law of total probabilities. Malecot (1948) reorganized Wright's calculations by introducing the fundamental concept of identity by descent and exploiting its properties. The method of identity by descent has been perfected and developed by Malécot and his students, especially Gillois, Jauquard and Bouffette. Kempthorne (1957) has applied the concept of identity by descent to the study of quantitative inheritance. Kimura (1963) elegantly employed the ideas of identity by descent in determining rates of approach to homozygosity in certain mating situations with finite population size. Later in this chapter we will extend and refine the results of Kimura (1963) to give a more complete study of rates of approach to homozygosity. Ellison (1966) established several important limit theorems corresponding to polyploid, multi-locus random mating infinite populations by judicious enlargement of the concepts of identity by descent. Kesten (unpublished)) has recently refined the technique of Ellison.

Equilibrium behavior of population genetic models with non-random mating. Part II: Pedigrees, Homozygosity and Stochastic Models

Wright (1921) computed various correlations of relatives by a rather cumbersome procedure called the “method of path coefficients”. Wright's method is basically a disguised form of the use of Bayes' rule and the law of total probabilities. Malecot (1948) reorganized Wright's calculations by introducing the fundamental concept of identity by descent and exploiting its properties. The method of identity by descent has been perfected and developed by Malécot and his students, especially Gillois, Jauquard and Bouffette. Kempthorne (1957) has applied the concept of identity by descent to the study of quantitative inheritance. Kimura (1963) elegantly employed the ideas of identity by descent in determining rates of approach to homozygosity in certain mating situations with finite population size. Later in this chapter we will extend and refine the results of Kimura (1963) to give a more complete study of rates of approach to homozygosity. Ellison (1966) established several important limit theorems corresponding to polyploid, multi-locus random mating infinite populations by judicious enlargement of the concepts of identity by descent. Kesten (unpublished)) has recently refined the technique of Ellison.