Exploring spatiotemporal dynamics of flower visitor association pattern on two Avicennia mangroves: a network approach.

Plant-flower visitor interaction is one of the most important relationships regarding the co-existence of the floral and faunal communities. The implication of network approaches is an efficient way to understand the impact of community structure on ecosystem functionality. To understand the association pattern of flower visitors, we performed this study on Avicennia officinalis and Avicennia marina mangroves from the islands of Indian Sundarban over three consecutive years. We found that visiting time and sites (islands) influenced the abundance of visitors. The bipartite networks showed a significant generalized structure for both site-visitor and visiting time-visitor networks where the strength and specialization of visitor species showed a highly and moderately significant positive correlation between both networks respectively. All the site-wise visiting time-visitor networks and year-wise site-visitor networks were significantly modular in structure. For both the plants, most of the visitors showed a generalized association pattern among islands and also among visiting times. Additionally, the study of the foraging behavior of dominant visitors showed Apis dorsata and Apis mellifera as the potential visitors for these plants. Our results showed that flower visitor networks are spatiotemporally dynamic. The interactions of visitors with flowers at different times influence their contribution to the network for becoming a generalist or peripheral species in the context of their visiting time, which may subsequently change over islands. This approach will help to devise more precise plant species-specific conservation strategies by understanding the contribution of visitors through the spatiotemporal context.

Association of p38MAPK-p53-Fas aggregation in S-allyl cysteine mediated regulation of hepatocarcinoma.

Bioactive components of dietary phytochemicals have been reported to possess antitumor activities. Evidences suggested key role of stress responsive p38MAPK in the induction of nutraceuticals mediated apoptosis in hepatocellular carcinoma (HCC). Current study demonstrated detailed molecular bagatelle associated with p38 MAPK mediated effective suppression of cell growth both in HepG2 and chemically induced liver carcinoma after S-allyl cysteine (SAC) treatment. SAC promoted p38MAPK activity responsible for p53 phosphorylation, its stabilization followed by nuclear translocation leading to induction in expression and oligomerization of Fas protein. Distinctive p38MAPK-p53 axis dependent Fas-FasL-FADD mediated caspase activities along with perturbed cell cycling became normalized with continuation of SAC treatment for another month to diethylnitrosamine induced liver carcinoma. Co-treatment with SB203580, the p38MAPK inhibitor, prevented pro-apoptotic effect of SAC by altering p53 phosphorylation and death inducing signaling complex conformation in HepG2 and induced HCC. Collectively study suggested significant contribution of p38MAPK-p53-DISC-Caspase pathway in the regulation of anti-neoplastic activity of SAC against HCC.

Using pupae as appetitive reinforcement to study visual and tactile associative learning in the Ponerine ant Diacamma indicum.

Associative learning is of great importance to animals, as it enhances their ability to navigate, forage, evade predation and improve fitness. Even though associative learning abilities of Hymenopterans have been explored, many of these studies offered food as appetitive reinforcement. In the current study, we focus on tactile and visual cue learning in an ant Diacamma indicum using a Y-maze setup with pupa as a positive reinforcement. Using pupa as a reward resulted in a significantly higher proportion of ants completing the training in a shorter time as compared to using food as reinforcement. Ants spent significantly more time in the conditioned arm for both visual cues (white dots or black dots) and tactile cues (rough or smooth surfaces) presented on the floor when associated with pupa, thus showing that they were capable of associative learning. On encountering a conflict between visual and tactile cues during the test, ants chose to spend significantly more time on the arm with the tactile cues indicating that they had made a stronger association between pupa and the tactile cue as compared to the visual cue during training. Using pupa as an ecologically relevant reward, we show that these solitary foraging ants living in small colonies are capable of visual and tactile associative learning and are likely to learn tactile cues over visual cues in association with pupa.

Island Based Assemblage Pattern and Foraging Profile of Insect Flower Visitors on Aegialitis rotundifolia -a Near Threatened Mangrove Plant from Indian Sundarban.

Understanding the association pattern and foraging behaviour of flower visitors is crucial to determine their role in the interaction with plants. To analyse the insect flower visitor association as well as their foraging profile on Aegialitis rotundifolia Roxb.-a near threatened mangrove plant, present study has been conducted among four islands of Indian Sundarban for three consecutive years. Results using first three Hill numbers depicted that, the species richness and Shannon and Simpson diversity of flower visitors were higher among the islands situated far from the sea than the islands neighbouring to the sea. NMDS analysis showed moderately ordinate data structure for island-year-based flower visitor association. Furthermore, network analysis for island-based visitor assemblage showed a significantly generalised network with no specialisation among islands. Five abundant visitors were further analysed for foraging profile, where the highest foraging rate was shown by Apis dorsata Fabricius, 1793 and the highest handling time was shown by Micraspis discolor (Fabricius, 1798). Moreover, all the visitors except M. discolor showed a significant variation in their foraging rate among different time frames. Furthermore, only M. discolor showed significant variation in their foraging behaviour when compared individually with each visitor in all the time frames. Present findings conclude that, flower visitors showed a generalised assemblage pattern among islands. Both honey bees provided excellent foraging on this plant and butterflies were good foragers too. Therefore, to device conservation strategies for this plant, protection of flower visitors must be of paramount concern.