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

2021 ◽  
pp. 1-11
Author(s):  
Xin Yu ◽  
Akalili B.T. Mohd Zanudin ◽  
Mohd Uzair Rusli ◽  
David T. Booth ◽  
Juan Lei
Keyword(s):  
Southeast Asia ◽  
Stomach Contents ◽  
Feeding Habit ◽  
Generalist Predator ◽  
Diet Diversity ◽  
Mangrove Crab ◽  
Urban Settlements ◽  
Varanus Salvator ◽  
Asian Water ◽  
Opportunistic Feeding

Abstract 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.

Anticancer Properties of Asian Water Monitor Lizard (Varanus salvator), Python (Malayopython reticulatus) and Tortoise (Cuora kamaroma amboinensis)

2020 ◽  
Vol 20 (13) ◽  
pp. 1558-1570
Author(s):  
Shareni Jeyamogan ◽  
Naveed A. Khan ◽  
Kuppusamy Sagathevan ◽  
Ruqaiyyah Siddiqui
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Amino Acid ◽  
Anticancer Agents ◽  
Liquid Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Adenocarcinoma Cells ◽  
Monitor Lizard ◽  
Varanus Salvator ◽  
Asian Water

Background: Cancer contributes to significant morbidity and mortality despite advances in treatment and supportive care. There is a need for the identification of effective anticancer agents. Reptiles such as tortoise, python, and water monitor lizards are exposed to heavy metals, tolerate high levels of radiation, feed on rotten/germ-infested feed, thrive in unsanitary habitat and yet have prolonged lifespans. Such species are rarely reported to develop cancer, suggesting the presence of anticancer molecules/mechanisms. Methods: Here, we tested effects from sera of Asian water monitor lizard (Varanus salvator), python (Malayopython reticulatus) and tortoise (Cuora kamaroma amboinensis) against cancer cells. Sera were collected and cytotoxicity assays were performed using prostate cancer cells (PC3), Henrietta Lacks cervical adenocarcinoma cells (HeLa) and human breast adenocarcinoma cells (MCF7), as well as human keratinized skin cells (Hacat), by measuring lactate dehydrogenase release as an indicator for cell death. Growth inhibition assays were performed to determine the effects on cancer cell proliferation. Liquid chromatography mass spectrometry was performed for molecular identification. Results: The findings revealed that reptilian sera, but not bovine serum, abolished viability of Hela, PC3 and MCF7 cells. Samples were subjected to liquid chromatography mass spectrometry, which detected 57 molecules from V. salvator, 81 molecules from Malayopython reticulatus and 33 molecules from C. kamaroma amboinensis and putatively identified 9 molecules from V. salvator, 20 molecules from Malayopython reticulatus and 9 molecules from C. kamaroma amboinensis when matched against METLIN database. Based on peptide amino acid composition, binary profile, dipeptide composition and pseudo-amino acid composition, 123 potential Anticancer Peptides (ACPs) were identified from 883 peptides from V. salvator, 306 potential ACPs from 1074 peptides from Malayopython reticulatus and 235 potential ACPs from 885 peptides from C. kamaroma amboinensis. Conclusion: To our knowledge, for the first time, we reported comprehensive analyses of selected reptiles’ sera using liquid chromatography mass spectrometry, leading to the identification of potentially novel anticancer agents. We hope that the discovery of molecules from these animals will pave the way for the rational development of new anticancer agents.

Water in Cities

2005 ◽  
Author(s):  
Goh Kim Chuan ◽  
Avijit Gupta
Keyword(s):  
Water Supply ◽  
Southeast Asia ◽  
Distribution System ◽  
Significant Proportion ◽  
Water Shortage ◽  
Current Status ◽  
Annual Rainfall ◽  
Large Cities ◽  
Success Stories ◽  
Urban Settlements

Southeast Asia, with most of its area receiving an annual rainfall of more than 2000 mm, is a region of positive water balance. It is also an area where unfulfilled demand for water is not unknown. Such a contradiction happens at times in its towns and cities. Several Malaysian urban settlements, for example, suffer occasionally from water shortage in a country with an average annual rainfall of about 3000 mm. Kuala Lumpur went through a prolonged period of water shortage in 1998 (Hamirdin 1998) in spite of large allocations made earlier in various five-year plans towards developing water supply infrastructure. Such shortages are common during long dry periods associated with El Niño. Regional water shortages may become more common in future, especially with the rising population and economic expansion. The shortages are the result of an inability to meet the rising demand of water in cities driven by both increasing population and progressive prosperity. Serious shortage occurs in large cities such as Jakarta, Bangkok, and Manila where a significant proportion of their population has no immediate access to municipal potable water. Even where piped connection exists, supplies are not available round the clock and often do not meet the required water quality standards. In many cities the local sources are inadequate and water has to be brought in from rural areas. The demand for water in a city has to be met on both quantitative and qualitative terms. For example, drinking water supplied to households by a municipal administration has to meet a given standard (WHO 1993). Ideally a city should have enough water to drink, to meet industrial demand, and to be able to store an adequate volume under pressure for firefighting and street cleansing. Supplying a city with water requires water sources, a treatment system, a distribution system, and arrangements for treating waste water and its disposal. In this chapter we review the current status of water supply in urban Southeast Asia and the sources that are available, concentrating on the major cities. We indicate the success stories as well as the shortcomings.

scholarly journals Variability in the diet diversity of catfish highlighted through DNA barcoding

2020 ◽  
Author(s):  
Chinnamani Prasannakumar ◽  
Gunasekaran Iyyapparajanarasimapallavan ◽  
M. Ashiq Ur Rahman ◽  
P. Mohanchander ◽  
T. Sudhakar ◽  
...  
Keyword(s):  
Dna Barcoding ◽  
Monsoon Season ◽  
Stomach Contents ◽  
Hermit Crabs ◽  
Gut Contents ◽  
Reference Database ◽  
Perna Viridis ◽  
Fish Diet ◽  
Diet Diversity ◽  
Post Monsoon

AbstractIdentification and quantification of fish diet diversity was the first step in understanding the food web dynamics and ecosystem energetics, where the contribution of DNA barcoding technique has been important. We used DNA barcoding to identify the stomach contents of a euryhaline, benthophagous catfish Ariius maculatus. From 40 catfish stomach items sampled in two different seasons, we barcoded 67 piscine and macro-invertebrates prey items, identified as belonging to 13 species in 4 major phyla (viz., Chordate, Arthropod, Annelida and Mollusca). It is important to note that the mollusc taxa (Meritrix meritrix and Perna viridis) and a species of fish (Stolephorus indicus) could not be found among the gut contents of A. maculatus sampled during the pre- and post-monsoon season, respectively. Among the piscine diets of A. maculatus, Eubleekeria splendens (23.5%) and Stolephorus indicus (23.5%) were the major prey taxa during pre-monsoon season. The hermit crabs forms the major constituents of both pre- and post-monsoon seasons, among invertebrate taxa. Polychaete, Capitella capitata (25.92%) was abundantly consumed invertebrates next to hermit crabs. We noticed that in pre-monsoon A. maculatus was more piscivorous than post-monsoon. As revealed through Kimura-2 parametric pair­wise distance analysis, the diet diversity was relatively higher in post-monsoon. The accumulation curve estimated 57 haplotypes within 14 barcoded species (including the host A. maculatus). Majority of haplotypes were found among fishes (47.36%) followed by Arthropods (28.07%), Annelids (14.03%) and Mollusca (10.52%), respectively. This study also highlights that there is a growing concern about A. maculatus’s aggressive predation on commercially important stocks of fish and invertebrates. We will continue to expand the coverage of species barcoded in the reference database, which will become more significant as meta- and environmental DNA barcoding techniques become cheaper and prevalent.

scholarly journals Anatomy of the Male Reproductive Organ of Water Monitor Lizard, Varanus salvator bivittatus (Reptil: Varanidae)

2019 ◽  
Author(s):  
mahfud
Keyword(s):  
Reproductive Organs ◽  
Reproductive Organ ◽  
Male Reproductive Organ ◽  
Monitor Lizard ◽  
Varanus Salvator ◽  
Biological Aspects ◽  
Male Reproductive Organs ◽  
Monitor Lizards ◽  
Almost All ◽  
Asian Water

One of the majority species of Varanidae is Varanus salvator or which commonly known as water monitor lizards (water monitor) or Asian water monitor lizard. This species is the most widely spread out of the all varanids. In Indonesia, V. salvator are distributed in almost all islands, from Sumatra, Java, Sulawesi, Maluku and Flores. Subspecies V. s. bivittatus was found only in Java, Bali and South East Islands [1]. The information on reproductive biological aspects of the V. s. bivittatus, especially the male reproductive organs is limited. Therefore, the study was aim to explore the male reproductive organs system of V. s. bivittatus that focused on macroscopic evaluation. Two adult male lizards with 45.60 cm SVL from Bogor area were used in this study. The lizard were anesthetized and exanguinated to sacrifice and fixed in 4 % paraformaldehyde through perfusion then followed by visceral observation and morphometric carefully measurement. All the observation finding and collected data were analyzed descriptively and presented in the form of tables and figures. Morphometric data were tabulated in the form of the average (mean) ± standard deviation (SD). Male reproductive organs of the V. s. bivittatus were generally similar to other reptiles such as snakes and lizards, with characteristics a pair of hemipenes. Epididymis was not formed of head, body and radix segment. The deferent duct is a small, straight and short duct which connected the epididymis to cloaca.

scholarly journals Dorsal Colour Patterns of Asian Water Monitor, Varanus salvator Collected for Trade in Cirebon, Indonesia

2020 ◽  
Vol 3 (2) ◽  
pp. 133-138
Author(s):  
Elika Boscha ◽  
Evy Arida ◽  
Donan Satria Yudha
Keyword(s):  
Meat Consumption ◽  
Color Pattern ◽  
Dorsal Side ◽  
The Other ◽  
Unique Pattern ◽  
Round Shape ◽  
Varanus Salvator ◽  
Craft Industry ◽  
Colour Patterns ◽  
Asian Water

The Asian water monitor, Varanus salvator, has been exploited for its skin and meat in Indonesia. We found evidence of trade on this species in the greater Cirebon area in the province of Jawa Barat and linked the trade to raw skin supplies for local craft markets. Skins of water monitor distributed on Java were unique in their pattern, where a series of yellowish and dark grey scales that form a round shape called ocelli are arranged into two compact transverse bands on the back near the front limbs. This unique pattern found in our sample may be useful to identify the origin of skins collected for trade and the subsequent craft products. However, this pattern was absent in the craft products available for display in one of the warehouses visited for this study. On the other hand, we observed stockpiles of water monitor raw skins at the warehouses and found a slight difference in the dorsal color pattern. These raw skins in stock were lacking in “double banded” pattern on the dorsal side and were likely to be originated from other areas in Indonesia, possibly Sumatra or Kalimantan. Live animals for sale at the warehouses maybe used for other purposes than to supply materials for local craft industry, for example meat consumption or feed for catfish.

Asian water monitors (Varanus salvator) remain common in Peninsular Malaysia, despite intense harvesting

2019 ◽  
Vol 46 (3) ◽  
pp. 265 ◽  
Author(s):  
Syarifah Khadiejah ◽  
Norazlinda Razak ◽  
Georgia Ward-Fear ◽  
Richard Shine ◽  
Daniel J. D. Natusch
Keyword(s):  
International Trade ◽  
Sustainable Use ◽  
Significant Proportion ◽  
Cost Effective ◽  
Peninsular Malaysia ◽  
Natural Habitats ◽  
Wild Fauna ◽  
Varanus Salvator ◽  
In The Wild ◽  
Asian Water

Context Each year, between 50000 and 120000 Asian water monitors (Varanus salvator, to >2 m total length) are harvested from the wild in Peninsular Malaysia for their skins. Under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), international trade is allowable only if it is sustainable. Aims To assess the sustainability of Malaysia’s harvest of water monitors by quantifying the abundance and demography of V. salvator in the wild, and to develop cost-effective methods for estimating the parameters needed to evaluate sustainability. Methods We conducted trapping surveys to determine the abundance, population demography and density of V. salvator in four habitat types in five states in Peninsular Malaysia in 2010, 2011, 2012 and 2018. Key results Of 1025 lizards captured, only 63% (mostly females) were within the preferred body-size range exploited for commercial trade. Densities were high (37–372 lizards km–2 based on estimated population sizes; 1–35 lizards km–2 based on number of animals captured). Anthropogenic habitats (e.g. oil palm plantations) contained denser populations of monitors than did natural habitats where no hunting occurs, but mean body sizes were smaller. Conclusions Despite intensive harvesting for many decades, V. salvator remains abundant and widespread. Harvesting alters the demographic structure of lizard populations, but harvests of V. salvator in Malaysia are likely to be sustainable because a significant proportion of the population is not exploited. Implications Ongoing monitoring is required to continually reassess harvest sustainability. For this purpose, relatively simple population approaches, such as line-trapping transects to elucidate relative abundances, can provide important data on the makeup of hunted populations of water monitors more cost-effectively than can mark–recapture studies for assessments of sustainable use of these economically important lizards.

Feeding habits and trophic status of Merluccius hubbsi along the northernmost limit of its distribution in the South-western Atlantic

2019 ◽  
Vol 99 (06) ◽  
pp. 1399-1408
Author(s):  
Paulo A. S. Costa ◽  
Adriana C. Braga ◽  
Giovanna S. Malavolti ◽  
Marcos A. L. Franco ◽  
Pedro V. Gatts ◽  
...  
Keyword(s):  
Total Mercury ◽  
Trophic Status ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Generalist Predator ◽  
Isotopic Niche ◽  
Benthic Fish ◽  
Ontogenetic Changes ◽  
Western Atlantic ◽  
Feeding Plasticity

AbstractStomach contents analysis and stable isotope results indicate M. hubbsi is a generalist predator that feeds mainly on demersal fishes, followed by crustaceans and cephalopods. Ontogenetic changes in diet were identified, with fish importance increasing in the diet with hake size. Smaller hake (<250 mm) fed mostly on the sepiolid Semirossia tenera (89.45%IRI) and engraulid fish (89.96%IRI). Mid-sized hake (250–300 mm) fed mainly on benthic fish such as Bellator brachychir (95.63%IRI) and euphausiids (56.46%IRI), while larger hake (>300 mm) fed heavily on Dactylopterus volitans (94.80%IRI) and occasionally on a variety of teleosts. Significant correlations between δ13C (P < 0.05), THg (P < 0.001) and hake size occurred, whereas no relationship was observed between δ15N and hake size or δ15N and total mercury. Signatures were lowest in smaller hake with a tendency of increasing with size. Smaller and larger hake were significantly different in δ13C. Differences regarding isotopic niche width were quantified for each size group; trophic diversity and trophic redundancy among them were negligible, but hake >300 mm possibly have a larger feeding plasticity due to the combination of prey from a wide trophic level range.

Feeding in a Nocturnally active fish, Galaxias brevipinnis, in a New Zealand stream

1989 ◽  
Vol 40 (3) ◽  
pp. 231 ◽  
Author(s):  
GJ Glova ◽  
PM Sagar
Keyword(s):  
New Zealand ◽  
Benthic Invertebrates ◽  
Stomach Contents ◽  
Feeding Habit ◽  
Native Fish ◽  
Selective Feeding ◽  
Chironomid Larvae ◽  
Feeding Periodicity ◽  
Active Fish ◽  
Fish Stomach

To determine the diel feeding periodicity and diet of a lake-inlet population of Galaxias brevipinnis in New Zealand, samples of benthos, drift and fish were collected over a 24-h period in summer. Both numerically and gravimetrically, fish stomach contents revealed that feeding started some time after sunset, peaked towards midnight, and virtually ceased after sunrise. Benthic invertebrates were consumed almost exclusively, with ephemeropterans, trichopterans, and dipterans constituting 95% of the total foods eaten, a major proportion being chironomid larvae. Size of prey eaten compared with size of invertebrates in the benthos differed significantly during the night; this indicated that some size-selective feeding occurred. The benthic feeding habit of Galaxias brevipinnis appears to allow it to forage on relatively small prey during the night, a phenomenon that has been reported for other bottom-dwelling native fish species in New Zealand.

scholarly journals Behavior And Feeding Habit of Dog Conch (Strombus turturella) in South Bangka Regency, Bangka Belitung Islands Province

el–Hayah ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 15
Author(s):  
Okto Supratman ◽  
Tati Suryati Syamsudin
Keyword(s):  
Feeding Behavior ◽  
Initial Treatment ◽  
Stomach Contents ◽  
Feeding Habit ◽  
Sediment Layer ◽  
Economic Values

Dog conch (Strombus turturella) is one of important sources of fishery commodities with  high economic values in Bangka Belitung. The needs of Dog conch as consumption still depends on fishermen harvest since its aquaculture has not been cultured until now. This study aims at determining behavior and feeding habit of dog conch. The study was conducted in July 2014 to January 2015. The experiments passed some stages 1) samples was taken in the field by hand collecting, 2) the experiment of seagrass consumed preference, 3) feeding behavior, and 4) Analysis of the stomach contents. The results indicate dog conch does not consume seagrass immediately, but detritus and microalgae species of Thalassiosira sp., Synedra sp., Nitzschia sp., Navicula sp. Dog conch eats by put the probiosis of the shell, then it grinds sediment layer, seagrass leaves and shells of other individuals as source if food. Dog conch behavior from beginning to  ending of the observation includes several stages: 1) Initial treatment actively foraging, 2) Individuals dog conch assembled or in pairs, 3) on the second day, the dog conch hoards himself on the base of the substrate and only elastic probiosis which occasionally appear occasionally at the substrate bottom.

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