Assessing the potential impact of invasive cane toads on a commercial freshwater fishery in tropical Australia

2011 ◽  
Vol 38 (5) ◽  
pp. 380 ◽  
Author(s):  
Ruchira Somaweera ◽  
Michael R. Crossland ◽  
Richard Shine
Keyword(s):  
Developmental Stages ◽  
Prey Type ◽  
Economic Damage ◽  
Wet Season ◽  
Cane Toad ◽  
North Eastern ◽  
Feeding Trials ◽  
Tropical Australia ◽  
Potential Impact ◽  
Eggs And Larvae

Context The toxins produced by cane toads (Rhinella marina) are fatal to many Australian predators that ingest these invasive anurans. To date, the potential economic impact of the cane toad invasion has attracted little attention. Toads have recently arrived at a large impoundment (Lake Argyle) in north-eastern Western Australia, that supports a commercial fishery for silver cobbler (shovel-nosed catfish, Arius midgleyi), raising concern that the toads may inflict significant economic damage by killing fish. Aims Our research aimed to clarify the vulnerability of silver cobblers to the eggs and larvae of cane toads by determining (a) whether catfish are adversely affected if they prey on toad eggs or tadpoles, and (b) whether surviving catfish learn to avoid cane toad eggs and tadpoles in subsequent encounters. Methods We conducted laboratory feeding trials to examine feeding responses of catfish to cane toad eggs and tadpoles in early and late developmental stages. Fish that survived exposure to toad eggs and/or tadpoles were re-tested with potential prey of the same sizes and developmental stages four days later. Key results Our laboratory trials confirmed that some catfish eat toad eggs and die; but most catfish avoided the eggs. Catfish readily consumed toad tadpoles at both early and late developmental stages, but without experiencing mortality; and soon learned not to consume this toxic new prey type. Conclusions and implications Despite potential frequent episodes of mortality of small numbers of catfish during the wet season, the overall impacts of cane toads on the Lake Argyle fishery likely will be minimal.

scholarly journals Comparative Transcriptomic Analysis of Riptortus pedestris (Hemiptera: Alydidae) to Characterize Wing Formation across All Developmental Stages

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 226
Author(s):  
Siying Fu ◽  
Yujie Duan ◽  
Siqi Wang ◽  
Yipeng Ren ◽  
Wenjun Bu
Keyword(s):  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Average Length ◽  
Transcriptome Assembly ◽  
Expression Profiles ◽  
Economic Losses ◽  
Future Research ◽  
Economic Damage ◽  
Wing Formation ◽  
Riptortus Pedestris

Riptortus pedestris (Hemiptera: Alydidae) is a major agricultural pest in East Asia that causes considerable economic losses to the soybean crop each year. However, the molecular mechanisms governing the growth and development of R. pedestris have not been fully elucidated. In this study, the Illumina HiSeq6000 platform was employed to perform de novo transcriptome assembly and determine the gene expression profiles of this species across all developmental stages, including eggs, first-, second-, third-, fourth-, and fifth-instar nymphs, and adults. In this study, a total of 60,058 unigenes were assembled from numerous raw reads, exhibiting an N50 length of 2126 bp and an average length of 1199 bp, and the unigenes were annotated and classified with various databases, such as the Kyoto Encyclopedia of Genes and Genomes (KEGG), Clusters of Orthologous Groups (COG), and Gene Ontology (GO). Furthermore, various numbers of differentially expressed genes (DEGs) were calculated through pairwise comparisons of all life stages, and some of these DEGs were associated with immunity, metabolism, and development by GO and KEGG enrichment. In addition, 35,158 simple sequence repeats (SSRs) and 715,604 potential single nucleotide polymorphisms (SNPs) were identified from the seven transcriptome libraries of R. pedestris. Finally, we identified and summarized ten wing formation-related signaling pathways, and the molecular properties and expression levels of five wing development-related genes were analyzed using quantitative real-time PCR for all developmental stages of R. pedestris. Taken together, the results of this study may establish a foundation for future research investigating developmental processes and wing formation in hemimetabolous insects and may provide valuable data for pest control efforts attempting to reduce the economic damage caused by this pest.

scholarly journals Species identification of Anguilla japonica by real-time PCR based on a sequence detection system: a practical application to eggs and larvae

2009 ◽  
Vol 66 (9) ◽  
pp. 1915-1918 ◽  
Author(s):  
Yuki Minegishi ◽  
Tatsuki Yoshinaga ◽  
Jun Aoyama ◽  
Katsumi Tsukamoto
Keyword(s):  
Real Time ◽  
Species Identification ◽  
Developmental Stages ◽  
Detection System ◽  
Anguilla Japonica ◽  
Sequence Detection ◽  
Target Region ◽  
System A ◽  
Sequence Variations ◽  
Eggs And Larvae

Abstract Minegishi, Y., Yoshinaga, T., Aoyama, J., and Tsukamoto, K. 2009. Species identification of Anguilla japonica by real-time PCR based on a sequence detection system: a practical application to eggs and larvae. – ICES Journal of Marine Science, 66: 1915–1918. To develop a practical method for identifying Japanese eel Anguilla japonica eggs and larvae to species by a sequence detection system using a real-time polymerase chain reaction (PCR), we examined (i) the sensitivity of the system using samples at various developmental stages, and (ii) influences of intra- and interspecific DNA sequence variations in the PCR target region. PCR amplifications with extracted DNA solution at 7.0 ng µl−1 or lower were efficient at distinguishing A. japonica from other anguillids. A single egg at the gastrula or later developmental stages could also be identified. Two sequence variations in the PCR target region were observed in 2 out of 35 A. japonica collected from three localities, and from four year classes at a single locality. These mutations, however, did not affect the result of species identification achieved by A. japonica-specific PCR primers and probe. The accuracy of this PCR-based method of species identification will help in field surveys of the species.

scholarly journals Neotectonics of the Pleistocene deposits in the northeast of Taman peninsula, the southern Asov sea region

2019 ◽  
pp. 12-35
Author(s):  
A. S. Tesakov ◽  
O. V. Guydalenok ◽  
S. A. Sokolov ◽  
P. D. Frolov ◽  
V. G. Trifonov ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Taman Peninsula ◽  
Matuyama Chron ◽  
Mud Volcanism ◽  
North Eastern ◽  
Quaternary Deformation ◽  
Reversed Polarity ◽  
Definition Of ◽  
Middle Member ◽  
North Eastern Part

Studies in paleomagnetism, structural geology, and paleontology (mammals, molluscs, palynology) in the coastal sections of the Taman Peninsula north-eastern part (2017–18) resulted in definition of three sedimentary members. The sandy and clayey lower member (I) formed at 2.1–1.7 Ma. It contains a normally magnetised zone within deposits of reversed polarity correlated to the Olduvai Subchron and the Matuyama Chron. The middle member (II) is composed of the basal pebbles overlain by sands. The reversely magnetised deposits hosting the Sinyaya Balka site, the type locality of the Tamanian faunal complex, is correlated to the basal bed of the middle member II. The overlying sands are normally magnetised (Jaramillo Subchron) in the lower part and show reverse polarity (late Matuyama Chron) in the upper part. The member II is dated in the range of 1.3–0.78 Ma. The silty upper member (III) represents Middle-Late Pleistocene. The dissimilar displacement degree of the members reflect developmental stages of the Quaternary deformation. The member I is characterised by dip angles up to 70° is fragmented by faults into blocks. The member II filled the relief of the eroded surface of the Member I and also displaced by faults. The faulting separated the bone-bearing body of the Taman faunal complex as a rock land-slide. The attitude of the member III outline an anticline with a gentle south-western and a steeper north-eastern limbs eroded by land-slides and marine abrasion. During its entire life the anticline was affected by mud volcanism. The anticline continues its development at the present stage.

scholarly journals THE PERIOD OF THE CATTLE BUNOSTOM DEVELOPMENT OF THE IN THE AMUR REGION

2019 ◽  
pp. 128-132
Author(s):  
T. I. Trukhina ◽  
I. A. Solovieva ◽  
G. A. Bonadrenko
Keyword(s):  
Infection Rate ◽  
Small Ruminants ◽  
Amur Region ◽  
Mature Stage ◽  
Economic Damage ◽  
Veterinary Science ◽  
Age Related ◽  
Eggs And Larvae ◽  
Sexually Mature ◽  
Cattle And Sheep

The authors focus on the fight against the most common helminthic diseases of agricultural animals as they see it as an important part of the veterinary science. Bunostomosis is one of such diseases; it is a helminthiasis of ruminants caused by vipostomum trigonocephalum nematodes (in sheep and goats) and vipostomum phlebotomum (mainly in the cattle), which are parasitic in the small intestines. The disease is characterized by diarrhea, exhaustion and death of ruminants. The disease is widespread and causes great economic damage. The authors explored the prevalence of tuberculosis and age-related infection with tuberculosis by ovoscopy and levoscopy in the Amur region. They examined 2655 animals, including 1415 small ruminants and 1240 cattle from five districts of the Amur region. The researchers examined 4 calves and 4 lambs aged 4 inorder to study the period of bunostom development in the organism of animals, which were infected with percutaneously and orally. Brown larvae received from faeces of spontaneously infested animals is considered to be the material for infection. The development and survival of larvae in the environment were investigated in 2016-2017. The authors found out that in the Amur region larvae develop at the temperatures above 40С. The period of development at the temperature from 40С tо 9 0С was 23 days. When the temperature was increasing, the development period was reduced to 5-7 days. In October larvae stop their development. The underdeveloped eggs and larvae left die in winter. At the farms of the Amur region, the infection rate of cattle and sheep is 31.9 and 49.6%. The bunostome infection of the cattle aged 1-11 months is 59,8%; 1-2 years - 26,0; 3 years and more - 19,9; sheep aged 4-11 months infection rate is 52,9; 1 year - 60,9, 3 years and more - 38,7%. The authors observed bunostomes development during 89-102 days in the ruminant organism before the sexually mature stage in the conditions of the Amur region.

Evaluation of Appropriate Reference Genes For Investigating Gene Expression in Chlorops oryzae (Diptera: Chloropidae)

2019 ◽  
Vol 112 (5) ◽  
pp. 2207-2214 ◽  
Author(s):  
Ping Tian ◽  
Lin Qiu ◽  
Ailin Zhou ◽  
Guo Chen ◽  
Hualiang He ◽  
...  
Keyword(s):  
Gene Expression ◽  
Ribosomal Protein ◽  
Reference Genes ◽  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Quantitative Polymerase Chain Reaction ◽  
Housekeeping Genes ◽  
Future Research ◽  
Economic Damage ◽  
Physiological Processes

Abstract Reverse transcription quantitative polymerase chain reaction (PCR) has become an invaluable technique for analyzing gene expression in many insects. However, this approach requires the use of stable reference genes to normalize the data. Chlorops oryzae causes significant economic damage to rice crops throughout Asia. The lack of suitable reference genes has hindered research on the molecular mechanisms underlying many physiological processes of this species. In this study, we used quantitative real-time PCR to evaluate the expression of eight C. oryzae housekeeping genes glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β-actin (βACT), beta-tubulin (βTUB), Delta Elongation factor-1 (EF1δ), ribosomal protein S11 (RPS11), RPS15, C-terminal-Binding Protein (CtBP), and ribosomal protein 49 (RP49) in different developmental stages and tissues in both larvae and adults. We analyzed the data with four different software packages: geNorm, NormFinder, BestKeeper, and RefFinder and compared the results obtained with each method. The results indicate that PRS15 and RP49 can be used as stable reference genes for quantifying gene expression in different developmental stages and larval tissues. GAPDH and βACT, which have been considered stable reference genes by previous studies, were the least stable of the candidate genes with respect to larval tissues. GAPDH was, however, the most stable reference gene for adult tissues. We verified the candidate reference genes identified and found that the expression levels of Cadherins (Cads) changed when different reference genes were used to normalize gene expression. This study provides a valuable foundation for future research on gene function, and investigating the molecular basis of physiological processes, in C. oryzae.

The uneasy coexistence between Carpet Pythons and Cane Toads

2020 ◽  
Author(s):  
Gregory P. Brown ◽  
Jeremy Hemphill ◽  
Richard Shine
Keyword(s):  
Negative Impact ◽  
Prey Type ◽  
Direct Costs ◽  
Cane Toad ◽  
Predator Species ◽  
Indirect Benefits ◽  
Negative Impacts ◽  
Monitor Lizards ◽  
A Site ◽  
Free Ranging

We describe a case of a free-ranging Carpet Python Morelia spilota consuming a toxic Cane Toad Rhinella marina, and dying as a result. Such an encounter would not be surprising at the toad invasion front, where predators first confront this novel prey type. However, the encounter we describe occurred at a site near Darwin where toads have been present for fifteen years. Other reports suggest that the behaviour we observed occurs across the snake’s range. Lethal ingestion of toads has been suggested to threaten the viability of populations of Carpet Pythons, but paradoxically, our surveys at this site reveal a twofold increase in abundance of Carpet Pythons since the arrival of toads. Toad invasion likely has favoured pythons by reducing the abundance of large monitor lizards, that are both predators and competitors of Carpet Pythons. That advantage has outweighed occasional cases where a snake is fatally poisoned by consuming a toad. Thus, the overall impact of Cane Toads on Carpet Pythons (and likely, other predator species) is a balance between direct costs and indirect benefits. Negative impacts on individuals may not necessarily translate to a negative impact on the species.

Interdemic variation in the African cyprinid Barbus neumayeri: correlations among hypoxia, morphology, and feeding performance

2003 ◽  
Vol 81 (3) ◽  
pp. 430-440 ◽  
Author(s):  
Sarah Schaack ◽  
Lauren J Chapman
Keyword(s):  
Gill Filament ◽  
Prey Type ◽  
Adaptive Change ◽  
Filament Length ◽  
Low Oxygen ◽  
Feeding Performance ◽  
Internal Morphology ◽  
Processing Ability ◽  
Feeding Trials ◽  
Respiratory Apparatus

Adaptive change in one character may affect associated, but functionally unrelated, characters in adaptive or nonadaptive ways. For example, adaptive change in gill size (i.e., larger gills in hypoxic habitats) may alter adjacent feeding structures and therefore have indirect effects on feeding behavior. This study examines whether differences in total gill filament length among populations of the African cyprinid Barbus neumayeri correlate with variation in trophic structures and feeding performance. Morphological measurements revealed larger total gill filament length in populations from low-oxygen habitats. Differences in external and internal morphology of the trophic apparatus correlated with those found in gills and suggest a reduction in food capture and processing ability in fish with larger respiratory apparatus. In paired feeding trials on a novel prey type, large-gilled fish spent more time feeding than small-gilled fish of the same body size without ingesting more food. This suggests less efficient food uptake in large-gilled fish from hypoxic habitats. We suggest that variation in gill size facilitates the broad habitat distribution of B. neumayeri but may limit the success of phenotypes crossing physicochemical gradients.

Predation on toxic cane toads (Bufo marinus) may imperil bluetongue lizards (Tiliqua scincoides intermedia, Scincidae) in tropical Australia

2010 ◽  
Vol 37 (2) ◽  
pp. 166 ◽  
Author(s):  
Samantha J. Price-Rees ◽  
Gregory P. Brown ◽  
Richard Shine
Keyword(s):  
Population Decline ◽  
Bufo Marinus ◽  
Ecological Impacts ◽  
Laboratory Research ◽  
Direct Result ◽  
Population Declines ◽  
Cane Toad ◽  
Lizard Species ◽  
Stochastic Variation ◽  
Tropical Australia

Context. Detecting ecological impacts of invasive species can be extremely difficult. Even major population declines may be undetectable without extensive long-term data if the affected taxon is rare and/or difficult to census, and exhibits stochastic variation in abundance as a result of other factors. Our data suggest such a situation in an iconic Australian reptile species, the bluetongue lizard. Originally restricted to Central and South America, cane toads (Bufo marinus) are rapidly spreading through tropical Australia. Most native predators have no evolutionary history of exposure to the toads’ distinctive chemical defences (bufadienolides), and many varanid lizards, elapid snakes, crocodiles and marsupials have been killed when they have attempted to consume toads. Aims. Scincid lizards have not been considered vulnerable to toad invasion; however, one lineage (the bluetongues, genus Tiliqua) consists of large omnivores that may be affected. Our field and laboratory research aimed to elucidate this concern. Methods. Nightly surveys for bluetongue lizards (Tiliqua scincoides intermedia) and cane toads were conducted along two adjacent roadways on the Adelaide River floodplain of the Northern Territory. Scent discrimination trials in the laboratory assessed lizard responses to chemical cues from three food types (native frogs, cane toads and ‘preferred foods’) by counting tongue-flicks and biting elicited by cotton swabs. A subset of lizards was presented with live toads. Key results. Numbers of bluetongues encountered during standardised field surveys in the Darwin region declined soon after toads arrived, and we have not recorded a single lizard for the last 20 months. In the laboratory, foraging responses of bluetongues were as intense to cane-toad scent as to the scent of native frogs, and many of the lizards we tested attempted to consume toads, and were poisoned as a result. Conclusions and implications. The population decline of bluetongues in this region appears to have been the direct result of fatal ingestion of toxic cane toads. Our studies thus add a scincid lizard species to the list of native Australian predators imperilled by cane-toad invasion, and point to the difficulty of detecting invader impact even for an iconic species in a system subject to detailed survey work.

Sign in / Sign up

Export Citation Format

Share Document