Sponge digestive system diversity and evolution: filter feeding to carnivory.

Sponges are an ancient basal life form, so understanding their evolution is key to understanding all metazoan evolution. Sponges have very unusual feeding mechanisms, with an intricate network of progressively optimized filtration units: from the simple choanocyte lining of a central cavity, or spongocoel, to more complex chambers and canals. Furthermore, in a single evolutionary event, a group of sponges transitioned to carnivory. This major evolutionary transition involved replacing the filter-feeding apparatus with mobile phagocytic cells that migrate collectively towards the trapped prey. Here, we focus on the diversity and evolution of sponge nutrition systems and the amazing adaptation to carnivory.

Larviculture of a carnivorous freshwater catfish, Lophiosilurus alexandri, screened by personality type.

Considering that each personality type in animals presents distinct physiological and behavioural responses, this study evaluated the efficiency of the Novel Environment test to classify larvae of Lophiosilurus alexandri into bold and shy individuals, which were then investigated for growth, cannibalism and mortality in larviculture of pure and mixed groups. Larvae with an average weight of 24.0±1.7mg and length of 14.1±0.4mm, were subjected to a Novel Environment test to classify their personality type (bold and shy larvae). After the larvae were classified according to personality type, they were subjected to larviculture for 15days. Three treatments were tested: only bold larvae, only shy larvae, and a mixed treatment (bold larvae+shy larvae) at a density for 16 larvae/L, which were fed 3 times a day with Artemia nauplii. After larviculture, there were no differences in the final lengths of larvae of the bold, shy, and mixed treatments (26.9±0.76mm, 26.7±1.00mm, and 26.8±1.24mm, respectively); however, shy larvae possessed weighed less (0.22±0.01g) than the bold and mixed treatments, which did not differ significantly (0.25±0.02g and 0.27±0.02g, respectively). The bold and mixed treatments had the highest cannibalism rate (11.2±5.1% and 23.1±12.3%, respectively). Overall survival was lowest in the mixed treatment (62.5±13.0%), while that of the bold and shy treatments were similar (82.5±9.2% and 86.2±9.2%, respectively). The separation of L. alexandri larvae by traits can ensure a decrease in cannibalism and hence, more productive larviculture.

The Carnism Inventory: Measuring the ideology of eating animals.

Beliefs surrounding the practice of eating animals are widely held, and have been argued to constitute an ideology named carnism (Joy, 2009). We developed and validated the novel Carnism Inventory to measure two positively related components of carnistic beliefs: carnistic defense and carnistic domination. We anticipated that carnistic defense would legitimate the practice of eating animals, while carnistic domination would support the killing of animals for their meat. The Carnism Inventory showed the hypothesized two-dimensional structure as well as good internal consistencies and stability (N = 302, Study 1). We also demonstrated the convergent and discriminant validity of the Carnism Inventory (N = 781, Study 2a). As expected, carnistic defense predicted meat consumption, while carnistic domination was a significant predictor of having slaughtered an animal (N = 478, Study 2b). Both scales were significantly related to sociopolitical beliefs, including right-wing authoritarianism and social dominance orientation, but only carnistic domination was related to symbolic racism and sexism (N = 373, Study 3). Taken together, our findings highlight the utility of the two-dimensional conceptualization and measurement of carnistic beliefs and offer new insights into one of the most common human behaviors: Eating animals is not only a gustatory behavior, as widely believed, but also an ideological one.

Meat eaters by dissociation: How we present, prepare and talk about meat increases willingness to eat meat by reducing empathy and disgust.

Many people enjoy eating meat but dislike causing pain to animals. Dissociating meat from its animal origins may be a powerful way to avoid cognitive dissonance resulting from this 'meat paradox'. Here, we provide the first comprehensive test of this hypothesis, highlighting underlying psychological mechanisms. Processed meat made participants less empathetic towards the slaughtered animal than unprocessed meat (Study 1). When beheaded, a whole roasted pork evoked less empathy (Study 2a) and disgust (Study 2b) than when the head was present. These affective responses, in turn, made participants more willing to eat the roast and less willing to consider an alternative vegetarian dish. Conversely, presenting a living animal in a meat advertisement increased empathy and reduced willingness to eat meat (Study 3). Next, describing industrial meat production as "harvesting" versus "killing" or "slaughtering" indirectly reduced empathy (Study 4). Last, replacing "beef/pork" with "cow/pig" in a restaurant menu increased empathy and disgust, which both equally reduced willingness to eat meat and increased willingness to choose an alternative vegetarian dish (Study 5). In all experiments, effects were strongly mediated by dissociation and interacted with participants' general dissociation tendencies in Study 3 and 5, so that effects were particularly pronounced among participants who generally spend efforts disassociating meat from animals in their daily lives. Together, this line of research demonstrates the large role various culturally-entrenched processes of dissociation play for meat consumption.

Not appropriate dinner table conversation? Talking to children about meat production.

Although Australians on average consume large quantities of meat, their attitudes to farm animal welfare are poorly understood. We know little about how farm animal production is discussed in Australian households or how children learn about the origins of meat. This study consisted of an online survey completed by 225 primary carers throughout Australia recruited through social media. Findings include that conversations about the origin of meat were generally stimulated by meal preparation within the home rather than visits to agricultural shows or similar activities. Parents preferred to initiate conversations with children about meat production before they were 5 years of age. Urban parents were more likely than rural parents to reveal that they were conflicted about eating meat and would be more empathetic to children who chose to stop eating meat. Rural parents were more likely than urban parents to feel that children should eat what they are given and that talking about meat is not a major issue. Both groups felt that it was important that children should know where their food comes from. The findings of this study suggest that parental attitudes to meat production and consumption influence conversations about meat origins with children.

Hunting, Food Preparation, and Consumption of Rodents in Lao PDR.

A cross-sectional study was conducted in 29 villages of Khamkeuth District in Bolikhamxay Province in the Lao PDR during March to May 2013. The study aimed to determine the characteristics associated with rodent consumption and related behaviors among different ethnic groups, ages, and genders. Five-hundred-eighty-four (584) males and females from 18-50 years of age participated in this study. Half of them were Hmong (292, 50%) while 152 respondents were Lao-Tai (26%) or other ethnic groups (140, 24%). Most of the respondents (79.5%) had farming as their main occupation. Prevalences of the studied outcomes were high: 39.9 for hunting or capturing rodents in the previous year, 77.7% for preparing rodents as food, and 86.3% for rodent consumption. Multivariable logistic regression analysis showed that likelihood of these types of rodent contact was more consistently associated with behavioral factors (gathering things from the forest and elsewhere, cultivation-related activities, and taking measures to prevent rodent-borne disease) than with socio-demographic, environmental, or cultural factors. The strongest associations were observed for gathering things; these associations were consistently positive and statistically significant. Although this study did not directly assess rodent-borne zoonosis risk, we believe that study findings raise concern that such risk may be substantial in the study area and other similar areas. Further epidemiological studies on the association between rodent-borne disease infection and rodent hunting, preparation for food, and consumption are recommended. Moreover, further studies are needed on the association between these potential exposure factors (i.e., rodent hunting, preparation for food, and consumption) and rodent-borne infections, especially among ethnic groups like the Hmong in Lao PDR and those in neighboring countries with similar socio-demographic, environmental, behavioral and cultural contexts.

Birds in Anthropogenic Landscapes: The Responses of Ecological Groups to Forest Loss in the Brazilian Atlantic Forest.

Habitat loss is the dominant threat to biodiversity and ecosystem functioning in terrestrial environments. In this study, we used an a priori classification of bird species based on their dependence on native forest habitats (forest-specialist and habitat generalists) and specific food resources (frugivores and insectivores) to evaluate their responses to forest cover reduction in landscapes in the Brazilian Atlantic Forest. From the patch-landscapes approach, we delimited 40 forest sites, and quantified the percentage of native forest within a 2 km radius around the center of each site (from 6 - 85%). At each site, we sampled birds using the point-count method. We used a null model, a generalized linear model and a four-parameter logistic model to evaluate the relationship between richness and abundance of the bird groups and the native forest amount. A piecewise model was then used to determine the threshold value for bird groups that showed nonlinear responses. The richness and abundance of the bird community as a whole were not affected by changes in forest cover in this region. However, a decrease in forest cover had a negative effect on diversity of forest-specialist, frugivorous and insectivorous birds, and a positive effect on generalist birds. The species richness and abundance of all ecological groups were nonlinearly related to forest reduction and showed similar threshold values, i.e., there were abrupt changes in individuals and species numbers when forest amount was less than approximately 50%. Forest sites within landscapes with forest cover that was less than 50% contained a different bird species composition than more extensively forested sites and had fewer forest-specialist species and higher beta-diversity. Our study demonstrated the pervasive effect of forest reduction on bird communities in one of the most important hotspots for bird conservation and shows that many vulnerable species require extensive forest cover to persist.

Bone accumulation by leopards in the Late Pleistocene in the Moncayo massif (Zaragoza, NE Spain).

Eating habits of Panthera pardus are well known. When there are caves in its territory, prey accumulates inside them. This helps to prevent its kill from being stolen by other predators like hyenas. Although the leopard is an accumulator of bones in caves, few studies have been conducted on existing lairs. There are, however, examples of fossil vertebrate sites whose main collecting agent is the leopard. During the Late Pleistocene, the leopard was a common carnivore in European faunal associations. Here we present a new locality of Quaternary mammals with a scarce human presence, the cave of Los Rincones (province of Zaragoza, Spain); we show the leopard to be the main accumulator of the bones in the cave, while there are no interactions between humans and leopards. For this purpose, a taphonomic analysis is performed on different bone-layers of the cave.

Don't mind meat? The denial of mind to animals used for human consumption.

Many people like eating meat, but most are reluctant to harm things that have minds. The current three studies show that this dissonance motivates people to deny minds to animals. Study 1 demonstrates that animals considered appropriate for human consumption are ascribed diminished mental capacities. Study 2 shows that meat eaters are motivated to deny minds to food animals when they are reminded of the link between meat and animal suffering. Finally, Study 3 provides direct support for our dissonance hypothesis, showing that expectations regarding the immediate consumption of meat increase mind denial. Moreover, this mind denial in turn reduces negative affect associated with dissonance. The findings highlight the role of dissonance reduction in facilitating the practice of meat eating and protecting cultural commitments.