Caste-specific phenotypic plasticity of Asian weaver ants: Revealing the allometric and non-allometric component of female caste system of Oecophylla smaragdina (Hymenoptera: Formicidae) by using geometric morphometrics

In eusocial insects, particularly in ants, caste differentiation is extremely complicated when we rely on traditional taxonomy. In most species, the worker caste does not display any distinct morphological characters neither the caste’s central division according to their morphological size variations. We used a landmark-based geometric morphometric approach to quantify the morphological characteristics of female caste systems (queen, major and minor worker ant) of Oecophylla smaragdina. Our findings suggested that each caste has its unique shape and size. Especially in the worker caste, apart from the size variations, we can use the shape as a prominent tool for distinguishing between them. The O. smaragdina exhibits a triphasic allometry pattern. Studying the allometry and non-allometry components of each caste system revealed a highly complex size and shape relationship in the female caste systems. From the allometric and non-allometric analysis, we concluded that the major worker ants showed a closer relationship with the queen than the minor worker ant. This outcome demonstrated that Asian weaver ant exhibits complex shape variations related to size and is correlated to their functional modular characters. This research sheds new light on caste systems’ taxonomic uncertainties for eusocial hymenopteran groups, especially ants

Testicular and Epididymal Toxicity of Carbaryl in Sprague-Dawley Strain Rats

In the past decade, the use of carbamate has become exceedingly popular as that of the organophosphates. There is a growing concern that the exposure to these compounds is a chronic hazard to man and animals. The present study was conducted to investigate the testicular and epididymal toxicity of carbaryl on rats. Male rats of Sprague-Dawley strain were administered orally with carbaryl dissolved in olive oil at 50 - 150mg doses/Kg body weight/day for 30 days. At the end of the treatment, rats were weighed and killed. Body weights remained unchanged at the end of the treatment. The weights of testis and epididymis decreased significantly after the treatment along with significant reductions in epididymal sperm count, viability and sperm motility. Activities of 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase showed a significant decrease along with the reduction in the serum pituitary LH, FSH and testosterone. Carbaryl significantly decreased the activities of epididymal marker enzymes, phosphodiesterase and adenylate cyclase. These findings demonstrate the adverse effect of carbaryl on testicular steroidogenesis and epididymal functions contributing to the decline in the sperm counts of rats

NEW RECORD OF TWO PINNIDAE SPECIES (BIVALVIA: PINNIDAE): DNA BARCODING (COI) AND MORPHOLOGICAL ANALYSIS

The occurrence of two new species of bivalves from family Pinnidae is recorded for the first time from south west coast of India. These two species are under the family Pinnidae. The Pinnidae are marine bivalves. It includes large wedgeshaped bivalves that live in mud and sand or amongst rocks or corals. These bivalves are not popularly used in India as food or other industries. But it is a popular food source with a high commercial value in a number of other Asian Pacific areas. The present study is dealt with the taxonomy and distribution of pen shells based on their morphometry and molecular data. The samples were collected from the sandy shore amongst the rocky area of Vizhinjam, the south west coast of India. Two types of Pen shells, Pinna atropurpurea and Atrinavexillum were collected from the study area. Initially pen shells are classified into two based on their morphology. The two pen shells collected were showing differences in their external characteristics. Morphologically they are identified by nine characters of the valves. DNA barcoding is a powerful tool for species detection, identification and discovery. It is a useful tool for monitoring genetic variation and global distribution of aquatic bioresource. DNA barcoding of these two species were made and the data is also included and discussed in this paper