Mark Anthony J. Torres

Geometric morphometric tools in the analysis of shell shape of twelve local populations of the invasive snail Achatina fulica Bowdich from the Philippines

The shape of the giant African snail Achatina fulica Bowdich by visual examination seems to vary geographically. To test this observation, geometric morphometric analysis on a total of 976 A. fulica shells from several geographical locations in the Philippines was done. These were collected from the island of Bohol (Agapi, Ondol and Quinoguitan) and in the island of Mindanao - Davao City and Davao del Norte (Davao Riverside, Emily Homes, Las Arenas, New Corella, Nova Tierra and Panabo), Mindanao State University Main Campus, Mimbalut in Iligan City and Balangao, Zamboanga Sibugay. Images of the shells were captured, digitized and subjected to relative warp (RW), canonical variance (CVA) and linear regression analyses to determine whether populations in geographic isolation are phenotypically differentiated to serve as basis for the observation of geographical differentiation in A. fulica. Based on CVA, results showed differentiation of populations; however within population variability was also found to be high. This is in contrast with linear regression involving centroid shapes which revealed slight differentiation between populations. Based on RW analysis, results revealed shells of A. fulica have the following shapes - shells with elongated spire with narrow whorl and narrow aperture, elongated spire with narrow whorl and rounded aperture, short spire with wide whorl and rounded aperture, and short spire with wide whorl and narrow aperture. The findings in this study suggest that although there are notable morphological variations, it may not be substantial to conclude that speciation has taken place in this species.

Morphology of the Male Reproductive System and Spermiogenesis of Dendroctonus armandi Tsai and Li (Coleoptera: Curculionidae: Scolytinae)

Studying the reproductive attributes of pests is central to understanding their life cycle history and in crafting management strategies to regulate, if not bring down, their population below threshold levels. In this article, the morphology of the male reproductive tract, topology of the spermatozoa, and salient features of spermiogenesis in the Chinese white pine beetle, Dendroctonus armandi Tsai and Li was studied to provide baseline information for further pest management studies. Results showed that male reproductive tract of this species differs from those documented in other Coleopterans by having 20 testicular tubules in each testis and the presence of two types of accessory glands. The spermatozoon is seen having peculiar characteristics such as an “h”-shaped acrosomal vesicle with a “puff”-like expansion, one centriole, one large spongy body, and two accessory bodies. Despite with some morphological differences of the male reproductive organ, spermatogenesis in this organism is similar to other Coleopterans. Overall, detailed studies regarding the components of the primary male reproductive organ of this beetle species would expand the knowledge on the less-understood biology of Coleopteran pests and would help in designing regulatory measures to conserve endemic and indigenous pine trees in China.

Describing Variability in Wing Shapes among Three Populations of Plesispareichei Using Landmark-Based Geometric Morphometric Analysis

This study was conducted to describe variability in 3 populations of a coconut pest, Plesispareichei landmark-based geometric morphometric analysis of inner wing shapes. A total of 21 landmarks were used to represent dimensions in the left and right wings. Analysis of Variance, coordinate mapping, relative warp, Euclidean Distance Matrix and Cluster Analyses were used to analyze these landmarks. Results showed that significant variations were observed among populations. Variation in the left wing is mainly seen along the proximal landmark points but is variable in the right wing which may be an indication of asymmetry. Cluster analysis showed wing shape variations between populations indicating population differentiation in the pest. Distance was not a factor which may indicate differences in genetic structure between populations.

Assessment of Solid Waste Management in the Islamic City of Marawi, Philippines

This study was conducted to determine some issues and concerns of solid waste management in the city of Marawi, Philippines. Interviews were conducted on key informants .The respondents of this study were five (5) City Government Officials (Secretary, Office of the City mayor, City Planning and Development Officers, City General Services Officers, SP Representative-Committee on Environment, SP Secretary), and two (2) key officials/representatives from DOH and DENR. They were selected because of their direct involvement and participation in the implementation of the Solid Waste Management Program. This study used the descriptive-qualitative research method. Results show that theoretically the city government has the necessary mechanisms of how solid wastes be managed in the city but the implementation of the ecological waste management program as mandated by law is unsuccessfull. Several reasons are attributed to this - lack of personnel, funds, and also to the undisciplined behavior of the Maranaos in their waste disposal.

Landmark-based geometric morphometric analysis of the shape of the abdominal dorsum of Uroplata girardi Pic (Coleoptera: Chrysomelidae)

This study was conducted to describe and explain morphological variation within and among populations of Uroplata girardi Pic, an herbivore of an invasive weed Lantana camara using the geometric morphometric approach. The foundation of this research is to describe patterns of morphological variation in natural populations especially those found in different geographical locations and varieties of Lantana. These descriptions are then used to frame hypotheses on the roles natural selection and geographical isolation play in evolution. Two-thousand nine hundred fifty (2950) individuals were examined in this study collected from four varieties in fifteen (15) locations in Mindanao, Cebu and Bohol, Philippines. Results of landmark-based geometric morphometric analysis showed variability within and among populations of the beetle although there was minimal differentiation observed in this insect. This could explain why control measures using this “biocontrol agent” have been spotty and unpredictable. Results also showed that variability within, and among populations of the insect cannot be explained by geography alone as there were variations observed between those collected from different varieties. The results of this study are discussed in the light of how variation within populations is translated into differences between populations, species, and higher taxa.

Landmark-based geometric morphometrics in visualizing body shape dimorphism in the endemic cyprinid, Puntius tumba (Herre,1924), from Lake Lanao, Philippines

The major objective of this study is to determine shape dimorphism between sexes of the endemic cyprinid P. tumba from Lake Lanao, Philippines using landmark-based geometric morphometrics. A total of 84 pecimens (41 femal,43 males)were analysed. Nineteen landmark points were digitized on the specimens from whom relative warp scores were derived. Discriminant function analysis and thin-plate spline showed significant difference between body shapes of the sexes with males exhibiting bigger head, shallower body and longer anal and dorsal fin base. Sexual selection co-acting with ecological selection could account for expression of such dimorphism.