Length-Weight Relationship, Condition Factor and Feeding Habit of Fishes from Mangrove of Santubong Estuary, Sarawak, Malaysia

Length-weight relationship (LWR), condition factor (K) and feeding habits of Coilia dussumieri, Nemapteryx nenga and Nibea soldado from Santubong Estuary, Sarawak, Malaysia were reported in the present study. The sampling was conducted during the non-monsoon season and monsoon season from April to November 2017 at Buntal, Penambir and Demak rivers using three-layered gillnets. A total of 182 fish samples were caught and measured for the total length and body weight. Then, the data were analysed by the equations for LWR and K. The feeding behaviour analysis was carried out using Relative Gut Index (RGI) and Frequency of Food Occurrence method. The log-transformed regression showed that most of the fishes exhibited negative allometric. K showed a significant difference between seasons. The RGI values of the fishes showed that they were carnivorous. The highest frequency of food occurrence in both seasons was gastropods (94-95 %) and the food items were found to be more variable during monsoon season (gastropods insect, worms, fish, asteroidea, phytoplankton and bivalve). The b value is an exponent to measure the growth pattern of fish and in this study, the b values were in the expected range of 2.5-3.5 and not affected by seasonal variation. The K values suggesting that most of the species were surviving well in the river and was influenced by seasonal change. The RGI and frequency of food occurrence showed that all fish in this study species were carnivorous with more variability in food was observed during the monsoon season. The data of this study are important for a sustainable fisheries management in this area.

Diet reflects opportunistic feeding habit of the Asian water monitor (Varanus salvator)

The Asian water monitor (Varanus salvator) is a large generalist predator and scavenger lizard. This species has a widespread distribution throughout South and Southeast Asia and is frequently encountered around the edges of urban settlements. Here, we present information on diet diversity and habitat utilisation of a population of Asian water monitors inhabiting the University of Malaysia Terengganu campus located on the east coast of mainland Malaysia. The stomach contents of 30 Asian water monitors were examined by stomach flushing, and 47.6% of stomach contents was mangrove crab, 26.2% was human waste and 26.2% was other natural foods consisting of fruits, fishes, leeches, snails, birds and insects. We then recorded the locations and habitats utilised by patrolling the campus area and found Asian water monitors preferred to use water and mangrove forest habitats that fringed and crisscrossed the campus. The broad diversity of stomach contents reflected food available at this location and indicates the opportunistic feeding habit of this species. Given that this species widely distributed in Southeast Asia, its broad diet diversity and habitat variations may promote the adaptation of Asian water monitor to different environments.

Ultrastructural Variations of Antennae and Labia Are Associated with Feeding Habit Shifts in Stink Bugs (Heteroptera: Pentatomidae)

The family Pentatomidae (stink bugs) is one of the largest groups in Heteroptera, containing many important pests and natural enemies. They exhibit highly diversified feeding habits and related structural modifications, but the key morphological characteristics associated with feeding habit radiation remain unclear. In the current study, we address this question by analyzing morphological variations of feeding related organs. We compare the ultrastructures of antennae and mouthparts across the chosen 17 species in Pentatomidae, representing both plant feeders and predators from four subfamilies. A strong association between ultrastructural adaptation and feeding habit transition has been revealed. The long, sharp, and hook-like mandibular teeth and maxillary barbs are exclusively present in predatory Pentatomidae, suggesting their tight association with the shift of feeding habit from phytophagy to predation. Significant differences between phytophagous and predatory species are also found in antennal and labial sensilla types and arrangements, implying their important function in food selection. Our data identify a series of key morphological structures associated with feeding habit variations among stink bugs, which will facilitate future studies on adaptive evolution of feeding habits, utilization, and population control of economic species in Pentatomidae as well as in other heteropteran lineages.

Redescription of Paracles vulpina (Hübner, [1825]) (Lepidoptera: Erebidae), with comments of the aquatic habit of larval instars

The genus Paracles Walker, 1855 is one of the most diverse genera present in Arctiinae and some species have larvae with aquatic habits. Several larvae were found swimming in flooded areas in different grasslands and were bred to adults to identify the species: Paracles vulpina (Hübner, [1825]). The current knowledge of immature stages of this species is not useful to identify and discriminate from other species of Paracles. For this reason, we proposed to redescribe adults of P. vulpina, showing for the first time the male and female genitalia, and improve the information on the immature stages and their habits. The adults can be recognized by the whitish paler brown band in the costal area in the forewing and whitish paler brown antenna. The final larval stage of P. vulpina can be differentiated from other species because it shows a body with a black pubescence except for a ferruginous subventral pubescence, blue dorsal verrucae, red lateral verrucae, and dorsal plastron with longest white setae. Because of its polyphagous feeding habit on aquatic and non aquatic plants we consider the aquatic larval habit is not a necessary strategy and could depend on the ground topography or weather of the locality.

Report of Sastroides besucheti Medvedev (Coleoptera, Chrysomelidae) on Malabar nutmeg

Massive infestation of Sastroides besucheti Medvedev (Coleoptera: Chrysomelidae), is reported on Malabar nutmeg Myristica malabarica Lam.(Myristicaceae), endemic to south India. All the 25 trees in the study area were infested; however, the intensity was lesser on male plants. Eggs, larvae, prepupae and pupae were observed. Pattern of egg laying, feeding habit of grubs and site of pupation were recorded. Infested female trees shed more than 70 per cent of the leaves and the branches dried up from tip downwards. Survival and regeneration of heavily infested female trees are doubtful. This is the first report of S. besucheti on M. malabarica.