Search Results (166)

In marketing science, product categorization using cannibalization relationship data is an emerging but still underdeveloped area, where clustering using price effect information is a novel direction that is worth further exploration. In this study, by assuming a realistic modeling of the cross-price effect, we developed and experimentally validated with simulations an agglomerative clustering algorithm that outputs clustering results closer to the ground truth compared with other agglomerative algorithms based on traditional cluster linkages. Full article

In this study, the seeking behaviour and food acceptance of larvae of Plodia interpunctella Hübner (Lepidoptera: Pyralidae) were analysed under laboratory conditions. Larval orientation and feeding preferences were assessed using a selection arena for neonate larvae and a four-way olfactometer for third-instar larvae. Stimulants included amaranth bars with additives (honey and chocolate) and natural amaranth (toasted grain only). The results showed that amaranth volatiles influence the orientation and feeding behaviour of this polyphagous insect. A marked preference for sugar-rich foods was observed, with amaranth with honey and amaranth with chocolate being the food sources most frequently chosen by the neonate larvae. These individuals exhibited a gregarious feeding behaviour and did not engage in cannibalism. The third-instar larvae also showed a preference for sweet food but were more attracted to the amaranth–additive combination. In the four-way olfactometer bioassays, chocolate was the most frequently chosen stimulus, while cellophane did not differ significantly from air. An analysis of volatile compounds by gas chromatography mass spectrometry (GC-MS) revealed that amaranth with chocolate releases more volatile compounds (16) compared with honey (12) and natural amaranth (6), suggesting that these volatiles could possibly influence the larvae’s choice of food source. Full article

Background: The relationship between genetic diversity and fitness is well understood, but few studies have investigated how behavior influences genetic diversity, or vice versa. We investigated the relationship between feeding behavior (on a pelleted diet) and genetic diversity in pikeperch, a piscivorous species. Methods: A total of 135 juvenile pikeperch from the same stock were grouped into three behavioral groups: pellet consuming, pellet refusing, and cannibalistic. Eighteen microsatellite markers were used to characterize the genetic diversity and structure of individuals. Results: The juveniles were classified into two genetic clusters: one dominated by pellet-consuming individuals and the other by pellet-refusing individuals containing equal proportions of cannibal individuals. Three of the microsatellite markers were under selection, but only one showed significant genetic segregation between the groups. For this marker, the pellet consumption was associated with low fragment length. Individual multilocus heterozygosity was significantly higher in the pellet-refusing group. Conclusions: These results suggest that pellet consumption acts as an uncontrolled selective force during domestication, influencing the genetic variability of domesticated populations. The ability to habituate to pellets has a significant genetic basis. Cannibalism does not affect genetic variability, and the emergence of the trait is independent of the propensity to consume pellets. Full article

Spiders and other arthropods can sometimes consume others of their kind, and this is most often associated with mating activity, whereby females cannibalize males during or after mating, or during mating attempts. Nonsexual cannibalism is less common but may be associated with food availability or territorial aggression. In the Southeastern United States, a non-native orb-weaving spider, Trichonephila clavata (the “jorō spider”), is expanding its range. Prior lab experiments indicated this species to be “shy” compared to other native spiders, based on behavioral reactions to stimuli. Here, we report descriptive observations and photo-documentation of nonsexual cannibalism by this species, including from anecdotal observations, plus findings from controlled pairings of spiders, both in the lab and in natural webs in the field. In the cases where cannibalism was witnessed, it involved one female biting and killing another, typically after a short fight. When two females of a similar size were placed together in a container (n = 25 trials), fights ensued 40% of the time. When females of different sizes were paired (n = 27 trials), fights happened 18% of the time, and the larger females were not always the aggressor. Across all the lab trials (n = 52), six bouts (9%) led to the direct killing of one female. In field trials where two females were placed on an empty web (n = 14 trials), we observed one fight (7%) where the aggressor ended up killing and wrapping the other spider in silk. Given that some of these instances happened away from any web, these observations imply that the aggression is not necessarily an act of territoriality. The intraspecific aggression could arise when females are provoked or stressed, which deserves more study. Full article

Nucleopolyhedroviruses of lepidopteran larvae (Alphabaculovirus, Baculoviridae) form the basis for effective and highly selective biological insecticides for the control of caterpillar pests of greenhouse and field crops and forests. Horizontal transmission is usually achieved following the release of large quantities of viral occlusion bodies (OBs) from virus-killed insects. In the present review, I examine the evidence for productive midgut infection in different host species and the resulting transmission through the release of OBs in the feces (frass) of the host. This has been a neglected aspect of virus transmission since it was initially studied over six decades ago. The different host–virus pathosystems vary markedly in the quantity of OBs released in feces and in their ability to contaminate the host’s food plant. The release of fecal OBs tends to increase over time as the infection progresses. Although based on a small number of studies, the prevalence of transmission of fecal inoculum is comparable with that of recognized alternative routes for transmission and dissemination, such as cannibalism and interactions with predators and parasitoids. Finally, I outline a series of predictions that would affect the importance of OBs in feces as a source of inoculum in the environment and which could form the basis for future lines of research. Full article

Filial cannibalism is the consumption of one’s own viable progeny. It occurs in a range of taxa but is particularly well-documented in fish species. Since parental care in fishes is typically male-biased, it is usually assumed that filial cannibalism is predominantly performed by the parental male while he is providing care to offspring. Filial cannibalism by females is less studied in fish. Video-recorded observations of ten pairs of adults housed in captivity revealed the first documentation of female filial cannibalism in the redhead goby (Elacatinus puncticulatus). Females were observed consuming both their own eggs and larvae. We discuss non-adaptive and adaptive explanations for female filial cannibalism in the redhead goby, including confinement due to captivity, nutritional or energetic need, and a possible lack of kin recognition. Understanding the evolutionary significance of filial cannibalism exhibited by females is an important biological inquiry. Since the redhead goby is a species used in the aquarium trade, understanding the conditions that influence female filial cannibalism in captivity may yield practical implications. Full article

This paper examines how the slope of the merit-order curve and the share of non-zero-dollar dispatched energy affect photovoltaic (PV) price cannibalization and the declining market value of all generation types. Using historical merit-order data from Alberta, Canada—during its coal-to-gas transition—we simulated the introduction of zero-marginal-cost PV offers. The increased PV penetration rapidly suppresses midday electricity prices, forming a “duck curve” that challenges solar project economics. Emission reductions improve with rising carbon prices, indicating environmental benefits despite declining market revenues. Years with steeper merit-order slopes and lower non-zero-dollar dispatch shares show intensified price cannibalization and a reduced PV market value. The integration of battery storage alongside PV significantly flattened daily price profiles—raising the trough prices during charging and lowering the highest prices during discharging. While this reduces price volatility, it also diminishes the market value of all generation types, as batteries discharge at zero marginal cost during high-price hours. Battery arbitrage remains limited in low- and moderate-price regimes but becomes more profitable under high-price regimes. Overall, these dynamics underscore the challenges of integrating large-scale PV in energy-only markets, where price cannibalization erodes long-term investment signals for clean energy technologies. These insights inform sustainable energy policy design aimed at supporting decarbonization, and investment viability in liberalized electricity markets. Full article

We report a sequence of unusual male behaviors observed in Nephila pilipes (Fabricius, 1793) (Araneae: Nephilidae Simon, 1894), a sexually size dimorphic tropical spider species in Singapore. We documented a male suitor using his mouth parts (chelicerae) rather than his copulatory organs (pedipalps) to repeatedly probe female genitals. The behaviors may have served as a strategy to assess the female’s mating status, functioned as a courtship strategy, or, most plausibly, represented an attempt to remove a genital plug. The documented chrono-sequence culminated in the male’s attempted commensalism, followed by an aggressive attack by the female, resulting in near-fatal injury to the male. Notably, the attack did not escalate into cannibalism, suggesting that the extreme size difference in Nephila may render small males unappealing as prey. Full article

The diet of the invasive ctenophore Mnemiopsis leidyi in the Gulf of Trieste was examined during its peak occurrence in the summer and early-autumn months (July to October) from 2017 to 2019, through the analysis of stomach contents. Altogether 506 specimens were individually caught for the analysis. A total of 3215 prey items were isolated and identified. Copepods emerged as the primary prey (relative abundance 66.7%), followed by cladocerans (7.7%), and bivalve larvae (6%). Notably, specimens of M. leidyi constituted a significant portion of the diet (5.4.%), providing further evidence of cannibalism within this species. Copepods were also the most commonly occurring prey items in the diet of M. leidyi. Most of them were represented by calanoid and cyclopoid nauplii (48.2%), followed by a harpacticoid M. norvegica (28.3%), and calanoids (26.8%). Other frequently occurring taxa were bivalve larvae (19.3%), M. leidyi (18.7%), and cladoceran Penilia avirostris (16.1%). The rate of cannibalism peaked in July, coinciding with a period of limited food availability. Additionally, the study revealed that fish eggs and larvae were infrequently found in the stomachs of M. leidyi. However, the presence of massive aggregations of M. leidyi may impact microzooplankton populations in late summer or autumn, potentially leading to competition with small pelagic fish. Full article

Trematomus bernacchii is a widely distributed, commercially valuable species that plays a significant role in the Benthic ecosystem of the Southern Ocean. Current research mainly explores its molecular responses to cold adaptation and environmental stress, while questions regarding its biological characteristics, such as length-related and sex-related differences in diet, remain to be addressed. This study assessed the age and feeding habits of T. bernacchii in the Ross Sea through stomach content morphological analysis and DNA metabarcoding analysis, examining dietary shifts by growth and sex. The research revealed that T. bernacchii primarily feeds on fish eggs, polychaetes, echinoderms, and mollusks. Other dietary components include algae, cnidarians, and crustaceans. Minor dietary differences were found between sexes. Polychaetes dominated all size classes, with Crustacea and Cnidaria declining as body length increased, while Echinoderms and Mollusca were more abundant in larger specimens. Evidence of egg cannibalism was also noted. These findings enhance our understanding of the trophic ecology of T. bernacchii and contribute to the construction of the Benthic food web of the Ross Sea. Full article

The green ecological property is increasingly recognized as a sustainable option in remanufacturing. In practice, despite the environmental concerns expressed by consumers, the growth of the remanufacturing industry falls short of expectations, largely due to the fact that, although remanufacturing conserves costs and is beneficial to our environment, it may not be a profitable option for OEMs, a major barrier in its appearance to green consumers. Many researchers have proposed that environmental groups and similar entities should provide necessary subsidies to encourage green consumerism and improve the profitability of the remanufacturing industry. In this paper, we intend to address how the subsidy policy on green consumerism impacts an OEM’s incentives in remanufacturing; more specifically, we develop two theoretical models: Model N, in which the OEM does not undertake remanufacturing, and Model R, in which the OEM does undertake remanufacturing under the subsidy policy for encouraging green consumerism. In addition to confirming the traditional wisdom that the subsidy policy encourages the remanufacturing industry, our analysis surprisingly reveals that, if a few consumers characterize green consumerism, the aggressive subsidy policy may potentially result in a cannibalization problem, in which remanufacturing hurts the OEM’s overall profits. Therefore, the government and environmental protection agencies need to fully consider the characteristics of the industry to avoid a “good intention, bad result” situation. Full article

Natural populations of crayfish in Europe have experienced significant declines due to the spread of crayfish plague, overfishing, competition with invasive crayfish species, and habitat degradation. Consequently, crayfish farming has gained importance in meeting the increasing demand for crayfish products. Although Russia boasts abundant water resources, the development of crayfish aquaculture remains nascent. In this review, we consolidate recent studies by Russian researchers that focus on various aspects of crayfish cultivation. Extensive cultivation in open ponds is the most suitable method, owing to its accessibility and lower costs; however, it necessitates suitable environmental conditions within the water bodies. The production cycle encompasses pond preparation, stocking, exploration, restoration, and monitoring. Controlled cultivation of egg-bearing females is essential for producing high-quality seedstock for subsequent rearing. Experimental evidence suggests that crayfish exhibit high adaptability to artificial conditions, with formulated diets comprising artificial feeds for sturgeon and powdered dried beef by-products demonstrating promising results in terms of growth performance. Plastic tangled threads and mink shelters are recommended to reduce cannibalism. Short-term grow-out of juvenile crayfish can yield a profit margin of 17%, while a complete two-year production cycle is projected to achieve financial break-even over three years. The primary challenges confronting the industry include disease management, cannibalism, the need for skilled technical personnel, and insufficient financial and policy support. Full article

This article reads Karl Marx’s Capital (volume 1, 1867) as the Bildungsroman of a congenital criminal: its eponymous character, Capital. Following Friedrich Engels’s The Condition of the Working Class in England (1845), Marx detects and dissects capitalism’s crimes. Capital has been called Marx’s ‘Victorian novel’ and compared to English realism’s triple-deckers. Yet his indispensable informants include factory inspectors whose reports, according to Fredric Jameson, provide testimony beyond anything realism can represent. How, then, does Marx’s apparently realist aesthetic convey Capital’s criminal deeds and criminogenic drive? To address this matter, the article examines the Gothicism of Marx’s realism. It highlights his development of Engels’s Gothic realism, demonstrates how Capital begins in media res—its first sentence presenting an immense, monstrous collection of evidence of Capital’s cannibalism—and links this opening crime scene to Marx’s portrayal of the 1863 case of Mary Anne Walkley. Murdered in her workplace, Walkley inhabits an underworld overpopulated by fellow workers killed by wage-labour. The article argues that, because actuality under the rule of Capital is structurally and monstrously criminal, Marx’s Gothic constitutes a realistic medium to represent criminal monsters and structures. Full article

Interspecific competition between mosquito larvae may affects adult vectorial capacity, potentially reducing disease transmission. It also influences population dynamics, and cannibalistic and predatory behaviors. However, knowledge of interspecific competition between Ae. aegypti and Anopheles species is limited. The study examined interspecific competition between Ae. aegypti larvae and either An.arabiensis, An. gambiae, or An. funestus on individual fitness in semi-field settings. The experiments involved density combinations of 100:100, 200:0, and 0:200 (Ae. aegypti: Anopheles), reared with and without food, in small habitats (8.5 cm height × 15 cm diameter) with 0.5 liters of water and large habitats (15 cm height × 35 cm diameter) with 1 liter of water. The first group received Tetramin^® fish food (0.02 g), while the second group was unfed to assess cannibalism and predation. While interspecific competition affected both genera, Anopheles species experienced greater effects, with reduced survival and delayed development, compared to Ae. aegypti. The mean wing lengths of all species were significantly small in small habitats with a mixed population (p < 0.001). The presence of food reduced cannibalism and predation compared to its absence. These interactions have implications for diseases transmission dynamics and can serve as biological indicators to signal the impacts of vector control interventions. Full article

The sub-Saharan region shows fast growth in aquaculture, but current production is dominated by two species, the African catfish and tilapia. In order to support the expansion of the industry and ensure food resilience of the sector, diversification is desirable. Indeed, several candidates have been identified, among them the African snakehead Parachanna obscura. In contrast to the fast expansion of Asian snakehead farming, African aquaculture does not anticipate this trend. Still, looking at Asia, recent scientific literature provides impulses and solutions for the most pressing problems such as dry feed, cannibalism of juvenile stages and reproduction. In this review, we illustrate future research needs, integrating the recent progress in snakehead farming. Based on the recent progress in commercial diets in Clarias and protocols established for the reproduction of Channa species, an expansion of African snakehead farming seems feasible in the near future. Full article