The present study examines the inherent flexibility in the feeding responses of S. infraimmaculata larvae to various breeding places. In addition, the study examines the hypothesis that in dry conditions, the water br...The present study examines the inherent flexibility in the feeding responses of S. infraimmaculata larvae to various breeding places. In addition, the study examines the hypothesis that in dry conditions, the water breeding places are the limiting factor for the survival and completion of the life cycle of populations of S. infraimmaculata. In the breeding sites, the food for larvae is not available, and cannibalism is the specific adaptation for larvae to grow and complete metamorphosis. S. infraimmaculata larvae feed on various invertebrates in different habitats, and cannibalism involves the adaptation to breeding places where food is not available. The growth only by cannibalism as the only way to adapt to these habitats because no food is found in breeding places at the southern border of its distribution is described here for the first time, not only in salamanders but in other animals as well.展开更多
Good brand name translation involves knowledge and expertise from many disciplines,such as linguistics,translation studies,marketing,aesthetics,psychology,law,etc.It is really an interdisciplinary practice that requir...Good brand name translation involves knowledge and expertise from many disciplines,such as linguistics,translation studies,marketing,aesthetics,psychology,law,etc.It is really an interdisciplinary practice that requires strenuous research and experience.In addition,the research methodology thereof is also quite problematic.This paper aims at bringing a latest translation theory—cannibalism into brand name translation and test its applicability in brand name translation practice.展开更多
Previous observations of cannibalism have been made in the aphid Acyrthosiphon pisum (L.): this article seeks to quantify factors contributing to such be- haviors. We observed and quantified the responses of a numb...Previous observations of cannibalism have been made in the aphid Acyrthosiphon pisum (L.): this article seeks to quantify factors contributing to such be- haviors. We observed and quantified the responses of a number of clones and life stages to varying levels of starvation, in the form of increasingly desiccated Vicafaba L. plants (receiving 50, 25, or 10 mL every second day) or a complete absence of host plant. We found that, while the longest incidences of cannibalism are carried out by juveniles (F = 3.45, P = 0.019, df = 3) and targeted at adults, the starvation treatments had the most significant effect on the prevalence of cannibalism in mature A. pisum (F ---- 2.24, P = 0.025, df = 9). Furthermore, there was no difference between the prevalence or dura- tion of cannibalistic activities within and between different clones (P 〉 0.05 in all cases), though juveniles were more likely to target unrelated aphids (V = 6 112, P = 0.011), and spent more time feeding on aphids from the same culture (V = 6 062, P = 0.018).展开更多
Colony cages for natural mating have been applied on many layer breeder farms.However,feather pecking and cloacal cannibalism are considered as prominent problems for these systems.This study aimed to investigate the ...Colony cages for natural mating have been applied on many layer breeder farms.However,feather pecking and cloacal cannibalism are considered as prominent problems for these systems.This study aimed to investigate the effects on feather pecking and vent pecking behaviors by providing layer breeders with nest boxes(0.90 m L×0.40 m W×0.60 m H)in colony cages for natural mating(4.80 m L×1.20 m W×0.71 m H).Video recording and artificial observation were adopted.The results showed that the usage of nest boxes gradually increased from the beginning of nest boxes providing at the age of 37 weeks to the end of the experiment at the age of 55 weeks.The utilization rates of nest boxes were 36.75%,44.75%and 50.38%at the ages of 41 weeks,47 weeks and 53 weeks,respectively.The hens in the cages without nest boxes showed significantly more frequent gentle feather pecks(both given and received)than hens in the cages with nest boxes at the ages of 41 weeks,47 weeks and 53 weeks.A decreasing trend of gentle feather pecking frequency(both given and received)was found with the increasing age for both the two groups.No significant difference was found in the number of given or received severe feather pecks at the age of 41 weeks.The hens in the cages without nest boxes showed a significantly higher frequency of given and received severe feather pecks than hens in the cages with nest boxes at the ages of 47 weeks and 53 weeks(p<0.05).Both cannibalistic injury occurrence and mortality rate in the cages with nest boxes were significantly lower than those in the cages without nest boxes.In conclusion,providing nest boxes in colony cages for natural mating could decrease abnormal pecking behaviors and improve animal welfare conditions of layer breeders.展开更多
While juvenile cannibalism plays an important role in the evolution of organisms in natural populations,it is a serious problem in aquaculture.A number of genetic and environmental factors result in different rates of...While juvenile cannibalism plays an important role in the evolution of organisms in natural populations,it is a serious problem in aquaculture.A number of genetic and environmental factors result in different rates of cannibalism.Whether there is kin recognition in juvenile cannibalism in fish is poorly understood.We studied cannibalism and kinship recognition in juveniles of Asian seabass using molecular parentage analysis with polymorphic microsatellites.In the three mass crosses,under an ordinary feeding scheme without size grading,the rate of juvenile loss due to cannibalism was 1.08% per day.In the group without feeding for 24 h,2.30%±0.43% of offspring per day were lost within 24 h due to cannibalism.We detected that juveniles avoided cannibalizing their siblings when they were not hungry,whereas cannibalism among siblings increased when they were hungry.These data suggest that there is kin discrimination in fish cannibalism.Raising genetically closely related offspring in the same tanks and appropriate levels of feeding may reduce the rate of cannibalism.We hypothesized that the chemical cues for kin discrimination might be secreted by fish skins.To test this hypothesis,we analyzed gene expression profiles in the skins of juveniles under slightly and very hungry conditions using RNA sequencing and bioinformatics analysis.Genes differently expressed under slightly and very hungry conditions were identified.Among them,genes from the trypsin family were significantly downregulated under starved conditions,suggesting that they may play a role in kin discrimination.展开更多
Cannibalism is common in spiders.Wolf spider(Lycosidae)females,which exhibit extensive maternal care,have been reported to cannibalize less when they are carrying egg sacs and juveniles.In a laboratory experiment,we d...Cannibalism is common in spiders.Wolf spider(Lycosidae)females,which exhibit extensive maternal care,have been reported to cannibalize less when they are carrying egg sacs and juveniles.In a laboratory experiment,we demonstrated that cannibalism of early-instar spiderlings(EIS)by a wolf spider(Pardosa pseudoannulata)mother was almost completely inhibited when she was carrying spiderlings.Compared with virgin and mated-females,mother spiders tolerated more and predated fewer spiderlings,including gregarious pulli and newly dispersed spiderlings(NDS).Cannibalism of EIS by females during their reproductive period exhibited a V-shaped pattern,with a gradual decrease from the egg sac-carrying to pulli-carrying(PC)stage,and a recovery from the PC stage to post-reproductive(PR)stage.Notably,there was 0 cannibalism at the PC stage.PC females exhibited no interest in pulli,while PR females were attracted to and predated pulli and NDS as they did their natural prey,Nilaparvata lugens.Interestingly,PC females captured and released NDS in a foraging assay,although attraction was observed from olfactometer measurements.PC mothers possessed a cuticular volatile profile that was closer to that of pulli and NDS than to that of PR females.Moreover,NDS cuticular extract provoked an electrophysiological response in legs of PC females.Therefore,cuticular compound-mediated chemical communication may be involved in inhibiting cannibalism of EIS by spider mothers,and especially in eliminating cannibalism by PC mothers.Future studies will aim to characterize the specific cuticular compounds and chemoreception mechanism in females,which will facilitate our understanding of intraspecific recognition and cannibalism in spiders.展开更多
Cannibalism, or intraspecific predation, can play a major role in changing individual fitness and population processes. In insects, cannibalism frequently occurs across life stages, with cannibals consuming a smaller ...Cannibalism, or intraspecific predation, can play a major role in changing individual fitness and population processes. In insects, cannibalism frequently occurs across life stages, with cannibals consuming a smaller or more vulnerable stage. Predation of adult insects on one another is considered to be uncommon. We investigated adult cannibalism in the Colorado potato beetle, Leptinotarsa decemlineata (Say), which is an oligophagous herbivore specializing on plants in family Solanaceae, and an important agricultural pest. Under laboratory conditions, starvation and crowding encouraged teneral adults to feed upon each other, which reduced their weight loss during the period of starvation. However, pupae were attacked and consumed before adults. Injured beetles had a higher probability of being cannibalized than intact beetles. Males were more frequently attacked than females, but that appeared to be a function of their smaller size rather than other gender-specific traits. Cannibalizing eggs at a larval stage did not affect beetle propensity to cannibalize adults at an adult stage. When given a choice between conspecific adults and mealworrns, the beetles preferred to eat conspecifics. Cannibalistic behavior, including adult cannibalism, could be important for population persistence in this species.展开更多
Zoophytophagous mirid species,that feed and develop either on prey or plant resources,are often found simultaneously on the same host.Hence,these species can engage in both intraguild predation and cannibalism,which c...Zoophytophagous mirid species,that feed and develop either on prey or plant resources,are often found simultaneously on the same host.Hence,these species can engage in both intraguild predation and cannibalism,which can pose a threat to mirid eggs.Ovipositing females may respond to such risks of predation on their eggs by reducing the number of eggs laid or selecting safer oviposition sites.We tested the oviposition behavior of Macrolophus pygmaeus(Rambur)(Hemiptera:Miridae)females under the risk of cannibalism by M.pygmaeus males and intraguild predation by Nesidiocoris tenuis(Reuter)males(Hemiptera:Miridae)under laboratory conditions.Intraguild predators and cannibals were introduced during or after the oviposition period.The number of eggs laid(using counts of newly hatched nymphs)and their proportion on each part of a tomato plant were both measured.The results reveal that only cannibalism by M.pygmaeus males after the period of oviposition significantly decreased the number of hatched eggs.Cannibalism thus represents a greater risk to mirid eggs than intraguild predation.The M.pygmaeus female responded to the presence of potential intraguild predators(or competitors)by decreasing the nu mber of eggs laid in the upper leaves.The results suggest that M.pygmaeus females avoid competition by N.tenuis,by laying fewer eggs on upper leaves.Cannibalism could regulate zoophytophagous predator populations under prey scarcity conditions and minimize the risk of crop damage associated with those biological control agents.展开更多
Sexual conflict is common in animals,and female sexual cannibalism represents an extreme form of sexual conflict.Males in many species have evolved a variety of strategies to circumvent or decrease the risk of female ...Sexual conflict is common in animals,and female sexual cannibalism represents an extreme form of sexual conflict.Males in many species have evolved a variety of strategies to circumvent or decrease the risk of female sexual cannibalism.Opportunistic mating,by which a male mates with a female when she is disturbed or when she is feeding or undertaking moulting,is one of such kinds of strategies,and widely occurs in many animals,especially in spiders.However,whether the occurrence of male opportunistic mating depends on the intensity of female sexual cannibalism remains largely unexplored.We predicted a positive correlation between them.In this study,we tested this prediction by performing a series of mating trials in the laboratory using 3 species of web-building spiders with different intensities of female sexual cannibalism:Nephila pilipes,Nephilengys malabarensis,and Parasteatoda tepidariorum.We found that the occurrence of male opportunistic mating was positively,though not statistically significantly,correlated with the intensity of female sexual cannibalism,thus supporting our hypothesis.All together,we provide evidence that male opportunistic mating may have evolved to respond to the selection pressure posed by female sexual cannibalism.展开更多
Although widely thought to be aggressive, solitary,and potentially cannibalistic, some spider species have evolved group-living behaviors. The distinct transition provides the framework to uncover groupliving evolutio...Although widely thought to be aggressive, solitary,and potentially cannibalistic, some spider species have evolved group-living behaviors. The distinct transition provides the framework to uncover groupliving evolution. Here, we conducted a comparative transcriptomic study and examined patterns of molecular evolution in two independently evolved group-living spiders and twelve solitary species. We report that positively selected genes among groupliving spider lineages are significantly enriched in nutrient metabolism and autophagy pathways. We also show that nutrient-related genes of group-living spiders convergently experience amino acid substitutions and accelerated relative evolutionary rates. These results indicate adaptive convergence of nutrient metabolism that may ensure energy supply in group-living spiders. The decelerated evolutionary rate of autophagy-related genes in group-living lineages is consistent with an increased constraint on energy homeostasis as would be required in a group-living environment. Together, the results show that energy metabolic pathways play an important role in the transition to group-living in spiders.展开更多
At the end of the eighteenth century in Britain,due to the development of capitalism,money has become more and more important.Jane Austen describes in the Sense and Sensibility that under the influence of money,people...At the end of the eighteenth century in Britain,due to the development of capitalism,money has become more and more important.Jane Austen describes in the Sense and Sensibility that under the influence of money,people's values have become dis⁃torted,such as some have become family cannibalism,and some have become betrayers of love.At the same time,Austen also ex⁃presses her attitude towards money which gives us a lot of enlightenment.展开更多
Kin recognition has been widely observed in various taxa.Cannibalism avoidance may be a strong driver for the evolution of kin recognition,as it may avoid a reduction in inclusive fitness.Kin recognition has recently ...Kin recognition has been widely observed in various taxa.Cannibalism avoidance may be a strong driver for the evolution of kin recognition,as it may avoid a reduction in inclusive fitness.Kin recognition has recently been observed in a generalist phytoseiid,Amblyseius herbicolus(Acari:Phytoseiidae).This study experimentally examined the degree of relatedness needed between prey larvae and cannibal adults of A.herbicolus for the occurrence of kin discrimination.The adults were individually placed in enclosed arenas with two prey,a daughter and a more distant related larva,to observe their cannibalizing choice.The adults of A.herbicolus did not discriminate between close relatives(daughter versus niece)but preferably cannibalized more distant kin(i.e.,first and second cousins once removed).Phenotype matching and familiarization seem prominent as recognition mechanisms used by A.herbicolus adults.The effect of learning on kin recognition through prior contact in A.herbicolus requires further investigation.Studies on other adaptive functions of kin recognition of A.herbicolus,such as cooperation and parental care,may provide meaningful insights.展开更多
Two congeneric aphidophagous ladybirds, Coccinella septempunctata and Coccinella transversalis, were reared on three aphid species, Lipaphis erysimi, Myzus persicae and Aphis nerii, to estimate the effect of prey qual...Two congeneric aphidophagous ladybirds, Coccinella septempunctata and Coccinella transversalis, were reared on three aphid species, Lipaphis erysimi, Myzus persicae and Aphis nerii, to estimate the effect of prey quality and intra- and interspecific interactions on their survival and development of life stages. Mortality of first instar ladybirds of both species was highest feeding on A. nerii. Preimaginal mortafity was lowest when feeding on L. erysimi (C. septempunctata, 1.6% and C. transversalis, 3.2%), and highest when feeding on A. nerii ( C. septempunctata, 6.2% and C. transversalis, 8.2%). Comparatively higher weight and larger size of C. septempunctata along with the lower levels of mortality recorded suggested that it is more likely to have acted as an intraguild predator than C. transversalis. High recorded mortality of C. transversalis is attributed to probable intraguild predation on account of its smaller size. The major sources of mortality were probably cannibalism, intraguild predation and other unknown factors. Lower prey quality increased the incidence of cannibalism and intraguild predation, especially in C. transversalis. The investigation suggests an intrinsic competitive advantage for C. septempunctata over C. transversalis in guilds of three aphid species.展开更多
Cannibalism is a life trait occurring in a wide variety of species.To describe the population dynamics of cannibalistic species,we develop a stage-structured population model in which axJults prey on juveniles with a ...Cannibalism is a life trait occurring in a wide variety of species.To describe the population dynamics of cannibalistic species,we develop a stage-structured population model in which axJults prey on juveniles with a Holling type I functional response.We make a rigorous analysis of the global dynamics in the model.The results of theoretical analysis show that the model has no boundary equilibrium other than the extinction one since juveniles and adults are cooperative(adults reproduce juveniles and juveniles grow into adults).Under certain conditions,the model has multiple interior equilibria and exhibits several types of bistable dynamics,in which different initial densities of juveniles and adults produce different long-term outcomes.展开更多
The Diary of A Madman (Kuangren r/j/), Lu Xun's first well-known short stoW and the alleged first modem short stow in vernacular Chinese, is famous for its first-person narrative by an intellectual that is sufferin...The Diary of A Madman (Kuangren r/j/), Lu Xun's first well-known short stoW and the alleged first modem short stow in vernacular Chinese, is famous for its first-person narrative by an intellectual that is suffering from a persecution complex. As acknowledged by Lu Xun himself and argued by most scholars, this short stoW was influenced by Gogol's homonymic short stow, but has developed more profound melancholy and indignation. However, as my paper demonstrates, this perspective neglects the role of Japan as an intermediary in the transculturation of madness. First, Lu Xun's initial encounter with Gogol's Diary of A Madman was through his reading of Futabatei Shimei's translation in the Japanese magazine Ky6mi. Second, the framed narrative and contrasting styles of Lu Xun's short stow, which are not features of Gogol's, might also be due to the inspiration from the Japanese genbun itchi movement in the Meiji period. Third, and most importantly, cannibalism, a major theme in Lu Xun's Diary of A Madman, was arguably shaped by the heated discussion in Japan on national character and cannibalism. My paper will trace the double origin of the depiction of madness and cannibalism in Lu Xun's work and illustrate the importance of the role of Japan in the transculturation of the stow of a madman.展开更多
With the rapid development of e-Commerce and takeaway platforms, retailers have gradually developed multi-channel operations. However, limited empirical studies explored the effects of an online channel offered by tak...With the rapid development of e-Commerce and takeaway platforms, retailers have gradually developed multi-channel operations. However, limited empirical studies explored the effects of an online channel offered by takeaway platforms on the store performance. Does an online channel addition have a synergy effect or a cannibalization effect on store performance? We empirically investigate these effects by analyzing a large dataset including diverse samples collected from multiple retailers across various regions. The dataset includes 2115 stores across 25 retailers for 10 months that includes two types of retail formats and covers 16 provinces and 21 cities of China. We study the impacts of the newly introduced online channel on the incumbent offline channel and the overall store performance.The empirical results reveal that the online channel addition mainly has a synergy effect. Specifically,for the overall store, it has a positive effect on the sales and product variety, whereas it has a negative effect on the basket size. Surprisingly, an online channel addition also has a positive effect on the offline sales. Our study adds novel values to multi-channel retailing literature by empirically researching the cannibalization and synergy effect of a new type of online channel, offered by takeaway platforms. It can provide insights for retail enterprises who are interested in introducing O2 O model.展开更多
In technology-intensive markets, it is a common strategy for companies to develop long-term multiple generation product lines instead of releasing consecutive single products. Even though this strategy is more profita...In technology-intensive markets, it is a common strategy for companies to develop long-term multiple generation product lines instead of releasing consecutive single products. Even though this strategy is more profitable than sequentially introducing single product generations, it can also result in inter-product line cannibalization. Cannibalization of multiple-generation product lines is a complex problem that needs to be taken into account at the early product line planning stage in order to sustain long-term profitability. In this paper, we propose an agent-based model that can simulate the potential cannibalization scenarios within a multiple-generation product line. We view a multiple-generation product line (MGPL) as complex adaptive system where each product generation in the MGPL adjusts its sales price over time based on the shifts in the market demand. The proposed model provides insights into how various pricing strategies impact the overall lifecycle profitability of MGPL and can be used to assist companies in developing appropriate dynamic pricing strategies at the early product line planning stages.展开更多
This study examines the optimal pricing and production strategy of a closed-loop supply chain consisting of a manufacturer, a recycler, and consumers. Considering the cannibalization and promotion effects of remanufac...This study examines the optimal pricing and production strategy of a closed-loop supply chain consisting of a manufacturer, a recycler, and consumers. Considering the cannibalization and promotion effects of remanufactured products on new and secondhand products, we constructed Stackelberg game models under different scenarios. We analyze the impact of the changes in the two effects on the optimal prices and production strategies of the manufacturer and recycler, as well as their countermeasures. We find that (i) how the cannibalization and promotional effects influence the manufacturer and the recycler's pricing and production strategies differ under different scenarios;(ii) when the two effects exceed a threshold, the manufacturer abandons new or remanufactured products, and the recycler prefers to stop production on its new products or continue to remanufacture products;and (iii) the two effects always reduce the profits of the manufacturer and increase the profits of the recycler.展开更多
文摘The present study examines the inherent flexibility in the feeding responses of S. infraimmaculata larvae to various breeding places. In addition, the study examines the hypothesis that in dry conditions, the water breeding places are the limiting factor for the survival and completion of the life cycle of populations of S. infraimmaculata. In the breeding sites, the food for larvae is not available, and cannibalism is the specific adaptation for larvae to grow and complete metamorphosis. S. infraimmaculata larvae feed on various invertebrates in different habitats, and cannibalism involves the adaptation to breeding places where food is not available. The growth only by cannibalism as the only way to adapt to these habitats because no food is found in breeding places at the southern border of its distribution is described here for the first time, not only in salamanders but in other animals as well.
文摘Good brand name translation involves knowledge and expertise from many disciplines,such as linguistics,translation studies,marketing,aesthetics,psychology,law,etc.It is really an interdisciplinary practice that requires strenuous research and experience.In addition,the research methodology thereof is also quite problematic.This paper aims at bringing a latest translation theory—cannibalism into brand name translation and test its applicability in brand name translation practice.
文摘Previous observations of cannibalism have been made in the aphid Acyrthosiphon pisum (L.): this article seeks to quantify factors contributing to such be- haviors. We observed and quantified the responses of a number of clones and life stages to varying levels of starvation, in the form of increasingly desiccated Vicafaba L. plants (receiving 50, 25, or 10 mL every second day) or a complete absence of host plant. We found that, while the longest incidences of cannibalism are carried out by juveniles (F = 3.45, P = 0.019, df = 3) and targeted at adults, the starvation treatments had the most significant effect on the prevalence of cannibalism in mature A. pisum (F ---- 2.24, P = 0.025, df = 9). Furthermore, there was no difference between the prevalence or dura- tion of cannibalistic activities within and between different clones (P 〉 0.05 in all cases), though juveniles were more likely to target unrelated aphids (V = 6 112, P = 0.011), and spent more time feeding on aphids from the same culture (V = 6 062, P = 0.018).
基金This research was funded by China Agricultural Research System(CARS-40)Beijing Science&Technology Committee Special Project(Z171100002217018).
文摘Colony cages for natural mating have been applied on many layer breeder farms.However,feather pecking and cloacal cannibalism are considered as prominent problems for these systems.This study aimed to investigate the effects on feather pecking and vent pecking behaviors by providing layer breeders with nest boxes(0.90 m L×0.40 m W×0.60 m H)in colony cages for natural mating(4.80 m L×1.20 m W×0.71 m H).Video recording and artificial observation were adopted.The results showed that the usage of nest boxes gradually increased from the beginning of nest boxes providing at the age of 37 weeks to the end of the experiment at the age of 55 weeks.The utilization rates of nest boxes were 36.75%,44.75%and 50.38%at the ages of 41 weeks,47 weeks and 53 weeks,respectively.The hens in the cages without nest boxes showed significantly more frequent gentle feather pecks(both given and received)than hens in the cages with nest boxes at the ages of 41 weeks,47 weeks and 53 weeks.A decreasing trend of gentle feather pecking frequency(both given and received)was found with the increasing age for both the two groups.No significant difference was found in the number of given or received severe feather pecks at the age of 41 weeks.The hens in the cages without nest boxes showed a significantly higher frequency of given and received severe feather pecks than hens in the cages with nest boxes at the ages of 47 weeks and 53 weeks(p<0.05).Both cannibalistic injury occurrence and mortality rate in the cages with nest boxes were significantly lower than those in the cages without nest boxes.In conclusion,providing nest boxes in colony cages for natural mating could decrease abnormal pecking behaviors and improve animal welfare conditions of layer breeders.
基金This research is supported by the National Research Foundation,Prime Minister's Office,Singapore under its competitive Research Program(CRP Award No.NRF-CRP002-001)and administered by NRF.
文摘While juvenile cannibalism plays an important role in the evolution of organisms in natural populations,it is a serious problem in aquaculture.A number of genetic and environmental factors result in different rates of cannibalism.Whether there is kin recognition in juvenile cannibalism in fish is poorly understood.We studied cannibalism and kinship recognition in juveniles of Asian seabass using molecular parentage analysis with polymorphic microsatellites.In the three mass crosses,under an ordinary feeding scheme without size grading,the rate of juvenile loss due to cannibalism was 1.08% per day.In the group without feeding for 24 h,2.30%±0.43% of offspring per day were lost within 24 h due to cannibalism.We detected that juveniles avoided cannibalizing their siblings when they were not hungry,whereas cannibalism among siblings increased when they were hungry.These data suggest that there is kin discrimination in fish cannibalism.Raising genetically closely related offspring in the same tanks and appropriate levels of feeding may reduce the rate of cannibalism.We hypothesized that the chemical cues for kin discrimination might be secreted by fish skins.To test this hypothesis,we analyzed gene expression profiles in the skins of juveniles under slightly and very hungry conditions using RNA sequencing and bioinformatics analysis.Genes differently expressed under slightly and very hungry conditions were identified.Among them,genes from the trypsin family were significantly downregulated under starved conditions,suggesting that they may play a role in kin discrimination.
基金supported by the National Natural Science Foundation(32172482)Fundamental Research Funds for the Central Universities(KJQN201809)the National Natural Science Foundation(31772185,31972296).
文摘Cannibalism is common in spiders.Wolf spider(Lycosidae)females,which exhibit extensive maternal care,have been reported to cannibalize less when they are carrying egg sacs and juveniles.In a laboratory experiment,we demonstrated that cannibalism of early-instar spiderlings(EIS)by a wolf spider(Pardosa pseudoannulata)mother was almost completely inhibited when she was carrying spiderlings.Compared with virgin and mated-females,mother spiders tolerated more and predated fewer spiderlings,including gregarious pulli and newly dispersed spiderlings(NDS).Cannibalism of EIS by females during their reproductive period exhibited a V-shaped pattern,with a gradual decrease from the egg sac-carrying to pulli-carrying(PC)stage,and a recovery from the PC stage to post-reproductive(PR)stage.Notably,there was 0 cannibalism at the PC stage.PC females exhibited no interest in pulli,while PR females were attracted to and predated pulli and NDS as they did their natural prey,Nilaparvata lugens.Interestingly,PC females captured and released NDS in a foraging assay,although attraction was observed from olfactometer measurements.PC mothers possessed a cuticular volatile profile that was closer to that of pulli and NDS than to that of PR females.Moreover,NDS cuticular extract provoked an electrophysiological response in legs of PC females.Therefore,cuticular compound-mediated chemical communication may be involved in inhibiting cannibalism of EIS by spider mothers,and especially in eliminating cannibalism by PC mothers.Future studies will aim to characterize the specific cuticular compounds and chemoreception mechanism in females,which will facilitate our understanding of intraspecific recognition and cannibalism in spiders.
文摘Cannibalism, or intraspecific predation, can play a major role in changing individual fitness and population processes. In insects, cannibalism frequently occurs across life stages, with cannibals consuming a smaller or more vulnerable stage. Predation of adult insects on one another is considered to be uncommon. We investigated adult cannibalism in the Colorado potato beetle, Leptinotarsa decemlineata (Say), which is an oligophagous herbivore specializing on plants in family Solanaceae, and an important agricultural pest. Under laboratory conditions, starvation and crowding encouraged teneral adults to feed upon each other, which reduced their weight loss during the period of starvation. However, pupae were attacked and consumed before adults. Injured beetles had a higher probability of being cannibalized than intact beetles. Males were more frequently attacked than females, but that appeared to be a function of their smaller size rather than other gender-specific traits. Cannibalizing eggs at a larval stage did not affect beetle propensity to cannibalize adults at an adult stage. When given a choice between conspecific adults and mealworrns, the beetles preferred to eat conspecifics. Cannibalistic behavior, including adult cannibalism, could be important for population persistence in this species.
基金the Spanish Ministry of Economy and Competitiveness(Project AGL2011-24349)the CERCA Programme of the Generalitat de Catalunya.
文摘Zoophytophagous mirid species,that feed and develop either on prey or plant resources,are often found simultaneously on the same host.Hence,these species can engage in both intraguild predation and cannibalism,which can pose a threat to mirid eggs.Ovipositing females may respond to such risks of predation on their eggs by reducing the number of eggs laid or selecting safer oviposition sites.We tested the oviposition behavior of Macrolophus pygmaeus(Rambur)(Hemiptera:Miridae)females under the risk of cannibalism by M.pygmaeus males and intraguild predation by Nesidiocoris tenuis(Reuter)males(Hemiptera:Miridae)under laboratory conditions.Intraguild predators and cannibals were introduced during or after the oviposition period.The number of eggs laid(using counts of newly hatched nymphs)and their proportion on each part of a tomato plant were both measured.The results reveal that only cannibalism by M.pygmaeus males after the period of oviposition significantly decreased the number of hatched eggs.Cannibalism thus represents a greater risk to mirid eggs than intraguild predation.The M.pygmaeus female responded to the presence of potential intraguild predators(or competitors)by decreasing the nu mber of eggs laid in the upper leaves.The results suggest that M.pygmaeus females avoid competition by N.tenuis,by laying fewer eggs on upper leaves.Cannibalism could regulate zoophytophagous predator populations under prey scarcity conditions and minimize the risk of crop damage associated with those biological control agents.
基金This work was supported by grants from the National Natural Science Foundation of China(NSFC-31801979 and 31872229)the Singapore Ministry of Education(MOE)AcRF Tier 1 grant(R-154-000-B18-114).
文摘Sexual conflict is common in animals,and female sexual cannibalism represents an extreme form of sexual conflict.Males in many species have evolved a variety of strategies to circumvent or decrease the risk of female sexual cannibalism.Opportunistic mating,by which a male mates with a female when she is disturbed or when she is feeding or undertaking moulting,is one of such kinds of strategies,and widely occurs in many animals,especially in spiders.However,whether the occurrence of male opportunistic mating depends on the intensity of female sexual cannibalism remains largely unexplored.We predicted a positive correlation between them.In this study,we tested this prediction by performing a series of mating trials in the laboratory using 3 species of web-building spiders with different intensities of female sexual cannibalism:Nephila pilipes,Nephilengys malabarensis,and Parasteatoda tepidariorum.We found that the occurrence of male opportunistic mating was positively,though not statistically significantly,correlated with the intensity of female sexual cannibalism,thus supporting our hypothesis.All together,we provide evidence that male opportunistic mating may have evolved to respond to the selection pressure posed by female sexual cannibalism.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB31000000) to S.Q.L。
文摘Although widely thought to be aggressive, solitary,and potentially cannibalistic, some spider species have evolved group-living behaviors. The distinct transition provides the framework to uncover groupliving evolution. Here, we conducted a comparative transcriptomic study and examined patterns of molecular evolution in two independently evolved group-living spiders and twelve solitary species. We report that positively selected genes among groupliving spider lineages are significantly enriched in nutrient metabolism and autophagy pathways. We also show that nutrient-related genes of group-living spiders convergently experience amino acid substitutions and accelerated relative evolutionary rates. These results indicate adaptive convergence of nutrient metabolism that may ensure energy supply in group-living spiders. The decelerated evolutionary rate of autophagy-related genes in group-living lineages is consistent with an increased constraint on energy homeostasis as would be required in a group-living environment. Together, the results show that energy metabolic pathways play an important role in the transition to group-living in spiders.
文摘At the end of the eighteenth century in Britain,due to the development of capitalism,money has become more and more important.Jane Austen describes in the Sense and Sensibility that under the influence of money,people's values have become dis⁃torted,such as some have become family cannibalism,and some have become betrayers of love.At the same time,Austen also ex⁃presses her attitude towards money which gives us a lot of enlightenment.
基金This study was supported in part by New Zealand Government core funding for Crown Research Institutes from the Ministry of Business,Innovation and Employment’s Science and Innovation Group.
文摘Kin recognition has been widely observed in various taxa.Cannibalism avoidance may be a strong driver for the evolution of kin recognition,as it may avoid a reduction in inclusive fitness.Kin recognition has recently been observed in a generalist phytoseiid,Amblyseius herbicolus(Acari:Phytoseiidae).This study experimentally examined the degree of relatedness needed between prey larvae and cannibal adults of A.herbicolus for the occurrence of kin discrimination.The adults were individually placed in enclosed arenas with two prey,a daughter and a more distant related larva,to observe their cannibalizing choice.The adults of A.herbicolus did not discriminate between close relatives(daughter versus niece)but preferably cannibalized more distant kin(i.e.,first and second cousins once removed).Phenotype matching and familiarization seem prominent as recognition mechanisms used by A.herbicolus adults.The effect of learning on kin recognition through prior contact in A.herbicolus requires further investigation.Studies on other adaptive functions of kin recognition of A.herbicolus,such as cooperation and parental care,may provide meaningful insights.
文摘Two congeneric aphidophagous ladybirds, Coccinella septempunctata and Coccinella transversalis, were reared on three aphid species, Lipaphis erysimi, Myzus persicae and Aphis nerii, to estimate the effect of prey quality and intra- and interspecific interactions on their survival and development of life stages. Mortality of first instar ladybirds of both species was highest feeding on A. nerii. Preimaginal mortafity was lowest when feeding on L. erysimi (C. septempunctata, 1.6% and C. transversalis, 3.2%), and highest when feeding on A. nerii ( C. septempunctata, 6.2% and C. transversalis, 8.2%). Comparatively higher weight and larger size of C. septempunctata along with the lower levels of mortality recorded suggested that it is more likely to have acted as an intraguild predator than C. transversalis. High recorded mortality of C. transversalis is attributed to probable intraguild predation on account of its smaller size. The major sources of mortality were probably cannibalism, intraguild predation and other unknown factors. Lower prey quality increased the incidence of cannibalism and intraguild predation, especially in C. transversalis. The investigation suggests an intrinsic competitive advantage for C. septempunctata over C. transversalis in guilds of three aphid species.
基金supported by the NSF of China(11971059)Q.Huang was supported by the NSF of China(11871060)+1 种基金the Venture and Innovation Support Program for Chongqing Overseas Returnees(7820100158),the Fundamental Research Funds for the Central Universities(XDJK2018B031)the faculty startup fund from Southwest University(20710948).
文摘Cannibalism is a life trait occurring in a wide variety of species.To describe the population dynamics of cannibalistic species,we develop a stage-structured population model in which axJults prey on juveniles with a Holling type I functional response.We make a rigorous analysis of the global dynamics in the model.The results of theoretical analysis show that the model has no boundary equilibrium other than the extinction one since juveniles and adults are cooperative(adults reproduce juveniles and juveniles grow into adults).Under certain conditions,the model has multiple interior equilibria and exhibits several types of bistable dynamics,in which different initial densities of juveniles and adults produce different long-term outcomes.
文摘The Diary of A Madman (Kuangren r/j/), Lu Xun's first well-known short stoW and the alleged first modem short stow in vernacular Chinese, is famous for its first-person narrative by an intellectual that is suffering from a persecution complex. As acknowledged by Lu Xun himself and argued by most scholars, this short stoW was influenced by Gogol's homonymic short stow, but has developed more profound melancholy and indignation. However, as my paper demonstrates, this perspective neglects the role of Japan as an intermediary in the transculturation of madness. First, Lu Xun's initial encounter with Gogol's Diary of A Madman was through his reading of Futabatei Shimei's translation in the Japanese magazine Ky6mi. Second, the framed narrative and contrasting styles of Lu Xun's short stow, which are not features of Gogol's, might also be due to the inspiration from the Japanese genbun itchi movement in the Meiji period. Third, and most importantly, cannibalism, a major theme in Lu Xun's Diary of A Madman, was arguably shaped by the heated discussion in Japan on national character and cannibalism. My paper will trace the double origin of the depiction of madness and cannibalism in Lu Xun's work and illustrate the importance of the role of Japan in the transculturation of the stow of a madman.
基金Supported by Beijing Natural Science Foundation(9212020)National Natural Science Foundation of China(72172145,71932002)the Fundamental Research Funds for the Central Universities。
文摘With the rapid development of e-Commerce and takeaway platforms, retailers have gradually developed multi-channel operations. However, limited empirical studies explored the effects of an online channel offered by takeaway platforms on the store performance. Does an online channel addition have a synergy effect or a cannibalization effect on store performance? We empirically investigate these effects by analyzing a large dataset including diverse samples collected from multiple retailers across various regions. The dataset includes 2115 stores across 25 retailers for 10 months that includes two types of retail formats and covers 16 provinces and 21 cities of China. We study the impacts of the newly introduced online channel on the incumbent offline channel and the overall store performance.The empirical results reveal that the online channel addition mainly has a synergy effect. Specifically,for the overall store, it has a positive effect on the sales and product variety, whereas it has a negative effect on the basket size. Surprisingly, an online channel addition also has a positive effect on the offline sales. Our study adds novel values to multi-channel retailing literature by empirically researching the cannibalization and synergy effect of a new type of online channel, offered by takeaway platforms. It can provide insights for retail enterprises who are interested in introducing O2 O model.
文摘In technology-intensive markets, it is a common strategy for companies to develop long-term multiple generation product lines instead of releasing consecutive single products. Even though this strategy is more profitable than sequentially introducing single product generations, it can also result in inter-product line cannibalization. Cannibalization of multiple-generation product lines is a complex problem that needs to be taken into account at the early product line planning stage in order to sustain long-term profitability. In this paper, we propose an agent-based model that can simulate the potential cannibalization scenarios within a multiple-generation product line. We view a multiple-generation product line (MGPL) as complex adaptive system where each product generation in the MGPL adjusts its sales price over time based on the shifts in the market demand. The proposed model provides insights into how various pricing strategies impact the overall lifecycle profitability of MGPL and can be used to assist companies in developing appropriate dynamic pricing strategies at the early product line planning stages.
文摘This study examines the optimal pricing and production strategy of a closed-loop supply chain consisting of a manufacturer, a recycler, and consumers. Considering the cannibalization and promotion effects of remanufactured products on new and secondhand products, we constructed Stackelberg game models under different scenarios. We analyze the impact of the changes in the two effects on the optimal prices and production strategies of the manufacturer and recycler, as well as their countermeasures. We find that (i) how the cannibalization and promotional effects influence the manufacturer and the recycler's pricing and production strategies differ under different scenarios;(ii) when the two effects exceed a threshold, the manufacturer abandons new or remanufactured products, and the recycler prefers to stop production on its new products or continue to remanufacture products;and (iii) the two effects always reduce the profits of the manufacturer and increase the profits of the recycler.