A theory of reference-dependent behavior

Extensive field and experimental evidence in a variety of environments show that behavior depends on a reference point. This paper provides an axiomatic characterization of this dependence. We proceed by imposing gradually more structure on both choice correspondences and preference relations, requiring increasingly higher levels of rationality, and freeing the decision-maker from certain types of inconsistencies. The appropriate degree of behavioral structure will depend on the phenomenon that is to be modeled. Lastly, we provide two applications of our work: one to model the status-quo bias, and another to model addictive behavior.

Effects of sex, host-plant deprivation and presence of conspecific immatures on the cannibalistic behavior of wild Ascia monuste orseis (Godart) (Lepidoptera, Pieridae)

Effects of sex, host-plant deprivation and presence of conspecific immatures on the cannibalistic behavior of wild Ascia monuste orseis (Godart) (Lepidoptera, Pieridae). The specialist cabbage caterpillar Ascia monuste orseis (Lepidoptera, Pieridae) feeds on plants of the Brassicaceae family, but may eventually ingest conspecific eggs and larvae during the larval stage. The present study examines feeding behavior of 4th and 5th instar cabbage caterpillars in relation to sex, host-plant deprivation and presence of conspecifics. We recorded number of egg ingested per larvae, developmental indices and duration of feeding, exploratory and resting behavior. Kale deprived caterpillars presented high rates of cannibalism, development delay and decreased fecundity. Cannibalism rates were not influenced by the sex of the larvae. In general, the presence of conspecific eggs did not interfere with the frequency and duration of the categorical behavioral events. We conclude that food availability is a strong factor influencing the extent to which A. monuste orseis caterpillars cannibalize.

On the short-time behavior of the implied volatility for jump-diffusion models with stochastic volatility

In this paper we use Malliavin calculus techniques to obtain an expression for the short-time behavior of the at-the-money implied volatility skew for a generalization of the Bates model, where the volatility does not need to be neither a difussion, nor a Markov process as the examples in section 7 show. This expression depends on the derivative of the volatility in the sense of Malliavin calculus.

Bridging the Accountability Gap: Rights for New Entities in the Information Society?

Technological developments in the information society bring new challenges, both to the applicability and to the enforceability of the law. One major challenge is posed by new entities such as pseudonyms, avatars, and software agents that operate at an increasing distance from the physical persons "behind" them (the "principal"). In case of accidents or misbehavior, current laws require that the physical or legal principal behind the entity be found so that she can be held to account. This may be problematic if the linkability of the principal and the operating entity is questionable. In light of the ongoing developments in electronic agents, there is sufficient reason to conduct a review of the literature in order to more closely examine arguments for and against legal personhood for some nonhuman acting entities. This article also includes a discussion of alternative approaches to solving the "accountability gap."

First record of the behavior of latex drainage by Trigona spinipes (Fabricius) (Hymenoptera, Apidae) in laticiferous flowers

This paper describes the behavior of the bee Trigona spinipes, to avoid the latex, when piercing the base of the tubular corolla of the flowers of Mandevilla guanabarica in order to steal the nectar.

Self-paced Movement Intention Detection from Human Brain Signals: Invasive and Non-invasive EEG

Neural signatures of humans' movement intention can be exploited by future neuroprosthesis. We propose a method for detecting self-paced upper limb movement intention from brain signals acquired with both invasive and noninvasive methods. In the first study with scalp electroencephalograph (EEG) signals from healthy controls, we report single trial detection of movement intention using movement related potentials (MRPs) in a frequency range between 0.1 to 1 Hz. Movement intention can be detected above chance level (p<0.05) on average 460 ms before the movement onset with low detection rate during the on-movement intention period. Using intracranial EEG (iEEG) from one epileptic subject, we detect movement intention as early as 1500 ms before movement onset with accuracy above 90% using electrodes implanted in the bilateral supplementary motor area (SMA). The coherent results obtained with non-invasive and invasive method and its generalization capabilities across different days of recording, strengthened the theory that self-paced movement intention can be detected before movement initiation for the advancement in robot-assisted neurorehabilitation.

Parasitizing behavior of Cervellus piranga Penteado-Dias (Hymenoptera, Braconidae, Braconinae) on papaya borer weevil Pseudopiazurus obesus Marshall (Coleoptera, Curculionidae)

Parasitizing behavior of Cervellus piranga Penteado-Dias (Hymenoptera, Braconidae, Braconinae) on papaya borer weevil Pseudopiazurus obesus Marshall (Coleoptera, Curculionidae). The papaya borer weevil Pseudopiazurus obesus is a pest associated with papaya crops in Brazil and Cervellus piranga is a naturally-occurring parasitoid which may contribute to regulate populations of this pest. We aimed at describing the parasitizing behavior of the parasitoid C. piranga on papaya borer weevil P. obesus larvae under field conditions. The sequence of events related to the parasitizing behavior of C. piranga is similar to other braconid species and includes the location and recognition of the attacked host plant followed by walks on the host plant and touching it with the tip of the antennae and the ovipositor. In the following event, the parasitoid assesses the suitability of the host by speeding up antennae and ovipositor movements. After locating and accepting the host, the parasitoid remains inactive on oviposition aperture sites and starts moving the antennae. Afterwards, the parasitoid inserts its ovipositor and starts cleaning it repeatedly. The female of C. piranga inserts the ovipositor through the hole and lay one egg into the papaya weevil borer. After oviposition, the female cleans continuously both ovipositor and antennae before leaving to forage for a new host.

Ethical differentiation and market behavior: An experimental approach

Does ethical differentiation of products affect market behavior? We examined this issue in triopolistic experimental markets where producers set prices. One producer s costs were higher than the others. In two treatments, the additional costs were attributed tocompliance with ethical guidelines. In the third, no justification was provided. Manyparticipants playing the role of consumers reduced their experimental gains by purchasing the ethically differentiated product at a higher price whether or not they knew the amount of extra cost. Individual differences were important (students of business/economics paid smaller premia than others). Finally, we speculate about the observed demand function for ethics and emphasize the use of experimental methodology to complement empirical studies designed to assess the potential market for ethically differentiated products.

Globalization and culture shaping the gender gap: A comparative analysis of urban Latin America and East Asia (1970 - 2000)

In this paper we present: 1. The available data on comparative gender inequality at themacroeconomic level and 2. Gender inequality measures at the microeconomic and case studylevel. We see that market openness has a significant effect on the narrowing of the human capitalgender gap. Globalization and market openness stand as factors that improve both the humancapital endowments of women and their economic position. But we also see that the effects ofculture and religious beliefs are very different. While Catholicism has a statistically significantinfluence on the improvement of the human capital gender gap, Muslim and Buddhist religiousbeliefs have the opposite effect and increase human capital gender differences.In the second global era, some Catholic Latin American countries benefited from market opennessin terms of the human capital and income gender gap, whereas we find the opposite impact inBuddhist and Muslim countries like China and South Korea where women s economic positionhas worsened in terms of human capital and wage inequality.

Effect of Citrus floral extracts on the foraging behavior of the stingless bee Scaptotrigona pectoralis (Dalla Torre)

Effect of Citrus floral extracts on the foraging behavior of the stingless bee Scaptotrigona pectoralis (Dalla Torre). Stingless bees have an important role as pollinators of many wild and cultivated plant species in tropical regions. Little is known, however, about the interaction between floral fragrances and the foraging behavior of meliponine species. Thus we investigated the chemical composition of the extracts of citric (lemon and orange) flowers and their effects on the foraging behavior of the stingless bee Scaptotrigona pectoralis. We found that each type of flower has its own specific blend of major compounds: limonene (62.9%) for lemon flowers, and farnesol (26.5%), (E)-nerolidol (20.8%), and linalool (12.7%) for orange flowers. In the foraging experiments the S. pectoralis workers were able to use the flower extracts to orient to the food source, overlooking plates baited with hexane only. However, orange flower extracts were seemingly more attractive to these worker bees, maybe because of the particular blend present in it. Our results reveal that these fragrances are very attractive to S. pectoralis, so we can infer that within citric orchards they could be important visitors in the study area; however habitat destruction, overuse of pesticides and the competitive override by managed honeybees might have put at risk their populations and thus the ecological services they provide to us.

Does the aggressiveness of the prey modify the attack behavior of the predator Supputius cincticeps (Stål) (Hemiptera, Pentatomidae)?

Does the aggressiveness of the prey modify the attack behavior of the predator Supputius cincticeps (Stål) (Hemiptera, Pentatomidae)? The stink bug Supputius cincticeps (Stål) (Hemiptera, Pentatomidae) is a predator found in several Brazilian regions, which possesses desirable attributes as a natural control agent and in biological control programs. The aim of this study was to test if the attack behavior and predation success of S. cincticeps were affected by prey species. Larvae of Tenebrio molitor (L.) (Coleoptera, Tenebrionidae), Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae), and Thyrinteina arnobia (Stoll) (Lepidoptera, Geometridae) were offered to S. cincticeps in laboratory bioassays where predatory attack and prey defensive behaviors were observed for 2-hour periods. The attack behavior of S. cincticeps changed with the prey species offered. More than 25% of T. molitor and S. frugiperda larvae were immediately attacked, but T. arnobia was not immediately attacked by S. cincticeps. Successful attack (i.e., successful insertion of the predator stylets into the prey) depends on the region of the body attacked, with a greater proportion of successful attacks in the anterior than in the median or posterior regions. Larvae of T. arnobia and S. frugiperda displayed a sequence of abrupt head and body movements in response to S. cincticeps attack. Attempts of predation were more successful on T. molitor and S. frugiperda than on T. arnobia. Information about the differential attack behavior of S. cincticeps on different prey species is important for designing successful biological control programs using this hemipteran predator.

Entering behavior of Gasteruption brachychaetum Schrottky (Hymenoptera, Gasteruptiidae) into a nest of Hylaeus Fabricius (Hymenoptera, Colletidae)

Nests of Hylaeus aff. guaraniticus (Schrottky, 1906) were parasited by females of Gasteruption brachychaetum Schrottky, 1906 in trap nests in São Paulo (Brazil). This is thefirst host record of a Gasteruptiidae in the Neotropical Region. The behavior of a G.brachychaetum female entering a host's nest is described as follows: an inquiline female hovered near the host's nest, landed and detected that a female of H. aff. guaraniticus was inside the nest, waited for the host female to fly out, entered backwards into the nest, remained there for almost six minutes, and then went out the nest. The development time of immature stages of G.brachychaetum varied between 16 and 299 days.

Human nature and institutional analysis

This essay reviews some findings in cognition sciences and examines their consequences for the analysis of institutions. It starts by exploring how humans specialization in producing knowledge ensures our success in dominating the environment but also changes fast our environment. So fast that it did not give time to natural selection to adapt our biology, causing it to be potentially maladapted in important dimensions. A main function of institutions is therefore to fill the gap between the demands of our relatively new environment and our biology, still adapted to our ancestral environment as hunter-gatherers. Moreover, institutions are built with the available elements, which include our instincts. A deeper understanding of both aspects, their adaptive function and this recruitment of ancestral instincts, will add greatly to our ability to manage institutions.

On the complexity of rationalizing behavior

We study the complexity of rationalizing choice behavior. We do so by analyzing two polar cases, and a number of intermediate ones. In our most structured case, that is where choice behavior is defined in universal choice domains and satisfies the "weak axiom of revealed preference," finding the complete preorder rationalizing choice behavior is a simple matter. In the polar case, where no restriction whatsoever is imposed, either on choice behavior or on choice domain, finding the complete preordersthat rationalize behavior turns out to be intractable. We show that the task of finding the rationalizing complete preorders is equivalent to a graph problem. This allows the search for existing algorithms in the graph theory literature, for the rationalization of choice.

Energetic cost of digging behavior in workers of the leaf-cutting ant Atta sexdens (Fabricius)

Energetic cost of digging behavior in workers of the leaf-cutting ant Atta sexdens (Fabricius). During nest excavation, leaf-cutting ant workers undergo reduction in their body reserve, particularly carbohydrates. In order to estimate the energetic cost of digging, groups of 30 workers of the leaf-cutting ant Atta sexdens were sealed in a hermetic chamber for 24, 48 and 72 hours, with and without soil for digging, and had the CO2 concentration measured using respirometric chambers as well as volume of soil excavated (g). As expected, the worker groups that carried out soil excavation expelled more carbon dioxide than the groups that did not excavate. Therefore, a worker with body mass of 9.65 ± 1.50 mg dug in average 0.85 ± 0.27 g of soil for 24 hours, consuming ca. 0.58 ± 0.23 J. In this study, we calculate that the energetic cost of excavation per worker per day in the experimental set-up was ca. 0.58 J.