Coefficients for best fitting models predicting egg number per clutch. https://doi.org/10.1371/journal.pone.0077736.t003 1. Kyle CH, Plantz AL, Shelton T, Burks RL (2013) Count Your Eggs Before They ...Invade: Identifying and Quantifying Egg Clutches of Two Invasive Apple Snail Species (Pomacea).
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The widespread Pomacea canaliculata and Pomacea maculata in North America and Asia have caused significant adverse effects on the local ecological environment and residents' health. Timely knowledge ...of the distribution of eggs from the two Pomacea spp. in a certain region can effectively reduce the cost of treatment and improve prevention effectiveness. Most of the existing methods are only able to identify eggs from the two Pomacea spp. or detect them in specific but not natural environments while they cannot achieve good results in the face of a complex real-world scene. This letter proposes a model for detecting eggs from the two Pomacea spp. based on dynamic convolution and multiscale feature fusion. The model can identify and locate the eggs of the two Pomacea spp. effectively. At the same time, we combined the proposed model with scale invariant feature transform (SIFT) algorithm to design a system for counting eggs of the two Pomacea spp., which can automatically identify the eggs in the actual natural environment and alleviate duplicate counting caused by image acquisition. Besides, we also built a dataset of 20 000 images of Pomacea canaliculata eggs and Pomacea maculata eggs from unmanned aerial vehicle (UAV) aerial photography. Experimental results showed that the proposed deep learning model has a better performance than others, and the proposed computer vision system can be successfully applied to support Pomacea spp. disease management.
The most noxious apple snails (
Pomacea canaliculata
and
P. maculata
) native to South America, currently have two distinct invaded ranges in China and the United States. Whether the environmental ...niches of the two closely related species have changed or remained stable (niche conservatism hypothesis) during the invasion process has become an important issue in forecasting their potential geographic distributions. For each
Pomacea
snail, two ecological niche models (ENMs, employing BIOMOD2) were generated based on bioclimatic variables and occurrence records in: (1) the native range; (2) the different invaded range. Conservation of ecological niche between the native and invasive snail populations was then tested by principal component and niche dynamics analysis. According to all models, precipitation contributed most to distribution of
P. maculata
, whereas low temperature was another most influential factor for spread of
P. canaliculata
. Niche conservatism was indicated by niche similarity tests and high niche stability for both
Pomacea
snails during their invasions in two regions. Niche expansions of
P. canaliculata
were relatively larger than unfilling values, whereas niche expansions of
P. maculata
were lower than unfillings. High niche unfilling for
P. maculata
in the United States revealed a great potential for further expansion in this region. We discussed the possible roles of physiological tolerances, genetic variation, residence time and hybridization in shaping niche changes for
Pomacea
snails during their invasion processes. Findings of this work can improve the understanding of potential mechanisms for niche differentiation and provide a theoretical basis for forecasting the invasion potential of
Pomacea
snails.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The apple snails
,
and
(Gastropoda: Caenogastropoda: Ampullariidae) are invasive pests causing massive economic losses and ecological damage. We sequenced and characterized the complete mitochondrial ...genomes of these snails to conduct phylogenetic analyses based on comparisons with the mitochondrial protein coding sequences of 47 Caenogastropoda species. The gene arrangements, distribution and content were canonically identical and consistent with typical Mollusca except for the
absent in
. An identifiable control region (d-loop) was absent. Bayesian phylogenetic analysis indicated that all the Ampullariidae species clustered on the same branch. The genus
clustered together and then with the genus
. The orders Architaenioglossa and Sorbeoconcha clustered together and then with the order Hypsogastropoda. Furthermore, the intergenic and interspecific taxonomic positions were defined. Unexpectedly,
,
,
and
, traditionally classified in order Hypsogastropoda, were isolated from the order Hypsogastropoda in the most external branch of the Bayesian inference tree. The divergence times of the Caenogastropoda indicated that their evolutionary process covered four geological epochs that included the Quaternary, Neogene, Paleogene and Cretaceous periods. This study will facilitate further investigation of species identification to aid in the implementation of effective management and control strategies of these invasive species.
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Hydrological and trophic gradients influence primary consumer populations in aquatic ecosystems, but their impacts remain unresolved for some species. We quantified the effects of water depth ...variation on reproduction and the effects of metaphyton (food) total phosphorus (TP) on juvenile growth and survival of two species of apple snails. The two species (native
Pomacea paludosa
and non-native
P. maculata
) are the exclusive prey of the federally endangered Snail Kite (
Rostrhamus sociabilis
) in Florida, USA. Using observations of reproduction in an ecotone habitat across four wetlands over three years, we statistically modeled seasonal reproductive dynamics. We found that
P. paludosa
reproduction peaked at depths of 30 cm during periods of cool temperatures (20°C; Feb-Apr), and
P. maculata
reproduction peaked at deeper depths (52 cm) and longer photoperiods (Jun-Jul). From in situ cage experiments in the same wetlands, we found that juvenile growth of both species increased with TP (129–403 µg g
−1
), but non-native
P. maculata
responded more strongly than native
P. paludosa
. Survival of both species was high (> 97%) across all TP levels. In combination, the results were consistent with anecdotal distributional patterns across hydrologic and nutrient gradients and suggest a wider range of tolerance for the non-native
P. maculata
.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Climate change is expected to worsen GAS infestation and threaten food security.•Entomopathogenic fungi and nematodes are potential GAS biological controls.•Integrated and precision pest management ...improved pest monitoring system.
Golden apple snails (GAS) (Pomacea spp.) is one of the major pests that rampantly invaded many countries and brought a heavy bloom to agricultural cultivation. Their invasion had resulted in huge crop damage and ultimately caused massive economic loss. For the past few decades, many strategies had been developed to overcome the GAS infestation. Among all the strategies, chemical synthetic molluscicides had been the mainstay within the farmer community. Despite their effectiveness in controlling the GAS infestation, extensive use of chemical molluscicides has negative impacts on humans, non-targeted organisms, and the environment. Climate change is expected to hasten the reproduction of GAS, necessitating the development of more sustainable GAS mitigation strategies. This paper examines the current stage of GAS invasion and its implications for global rice production. This review also includes an in-depth discussion of the various potential biological based strategies involved in pest management, and the recent technological breakthroughs in entomopathogenic nematodes and entomopathogenic fungi as molluscicides, integrated pest management, and precision pest management. To summarize, this review provides a potential trend in the use of biocontrol as a substitute for chemically manufactured synthetic molluscicides for the sustainable management of GAS.
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Two new species of apple snails are described, Pomacea penai sp. nov. and Pomacea reevei sp. nov. that are used as food resources in Peruvian Amazonia. We used anatomical and conchological features ...to diagnose these two species. Pomacea penai sp. nov. is characterized by a highly variable shell morphology, spire that is prominent to immersed, apical penis sheath gland covering 1/3 penis sheath and elongated basal gland, prostate broad proximally, reduced stomach septum, green eggs, and commonly inhabits temporary flooded areas, creeks, and oxbow lakes. Pomacea reevei sp. nov. possesses a large shell, ranging from 81-137 mm, grey broad penis sheath, small apical penis sheath gland and the basal gland covering 1/3 penis sheath, tall stomach septum, white eggs, and found in deep lentic water bodies.
Growing evidence has suggested a strong link between gut microbiota and host fitness, yet our understanding of the assembly mechanisms governing gut microbiota remains limited. Here, we collected ...invasive and native freshwater snails coexisting at four independent sites in Guangdong, China. We used high-throughput sequencing to study the assembly processes of their gut microbiota. Our results revealed significant differences in the diversity and composition of gut microbiota between invasive and native snails. Specifically, the gut microbiota of invasive snails exhibited lower alpha diversity and fewer enriched bacteria, with a significant phylogenetic signal identified in the microbes that were enriched or depleted. Both the phylogenetic normalized stochasticity ratio (pNST) and the phylogenetic-bin-based null model analysis (iCAMP) showed that the assembly process of gut microbiota in invasive snails was more deterministic compared with that in native snails, primarily driven by homogeneous selection. The linear mixed-effects model revealed a significant negative correlation between deterministic processes (homogeneous selection) and alpha diversity of snail gut microbiota, especially where phylogenetic diversity explained the most variance. This indicates that homogeneous selection acts as a filter by the host for specific microbial lineages, constraining the diversity of gut microbiota in invasive freshwater snails. Overall, our study suggests that deterministic assembly-mediated lineage filtering is a potential mechanism for maintaining the diversity of gut microbiota in freshwater snails.
Invasive Alien Species (IAS) can become a tremendous burden to national economies; however, few studies have quantified the economic impacts of IAS, particularly for developing nations. The golden ...apple snail, Pomacea canaliculata (Lamarck), was introduced into Ecuador in 2005. By 2012, the snail had affected 94% of Ecuador's rice-growing areas. We used government surveys of rice production and snail distributions, as well as yearly production costs and rice prices, to estimate snail-associated losses to rice productivity and profitability between 2005 and 2015 – the first decade of P. canaliculata in Ecuador. Based on the intensity of the invasion and changing management practices, we estimate that the golden apple snail caused accumulated losses of 35.65 K tons of rice grain (worth US$23.10 M) with further productivity losses (lost inputs and labour) of US$9.61 M (total = US$32.71 M), until 2015. Based on survey information, we estimate that 90% of affected fields were treated with pesticides during the 5 years following initial establishment of the snail on individual rice farms. Pesticides potentially saved up to $10 M in damage during peak snail densities in 2012. By 2015, prophylactic molluscicide treatments were costing the nation US$15.24 M annually (including application costs: accumulated 10-year cost = $123.46 M, assuming 90% coverage). Increasing pesticide and labour costs, but relatively stable farm-gate rice prices, suggest that the continued chemical control of golden apple snail in Ecuador is economically unsustainable. We discuss possible alternatives to prophylactic molluscicide applications that can increase the economic and environmental sustainability of rice production in the face of high densities of apple snails during post-introduction outbreaks. We suggest that nations at high risk from invasive apple snails (e.g., Bangladesh, India, Colombia and Peru) could avoid substantial losses by pre-emptively researching and adopting mechanized crop establishment practices that not only reduce labour costs, but also prevent potential damage from apple snails to rice.
•Pomacea canaliculata, introduced in 2005, affected 94% of Ecuador's rice production by 2012.•We estimated snail-associated productivity losses and management costs between 2005 and 2015.•By 2015, snails reduced national yields by ≈ 36 K tons after management costs of > US$100 M.•Increasing application costs, but relatively stable rice prices suggest that chemical control is unsustainable.•We recommend mechanized transplanting or broadcasting of robust rice seedlings for countries at risk from apple snails.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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