Seasonal dynamics of a drosophilid (Diptera) assemblage and its potencial as bioindicator in open environments

Drosophila Fallen, 1823 (Diptera, Drosophilidae) is for long a well-established model organism for genetics and evolutionary research. The ecology of these flies, however, has only recently been better studied. Recent papers show that Drosophila assemblies can be used as bioindicators of forested environment degradation. In this work the bioindicator potential of drosophilids was evaluated in a naturally opened environment, a coastal strand-forest (restinga). Data from nine consecutive seasonal collections revealed strong temporal fluctuation pattern of the majority of Drosophila species groups. Drosophila willistoni group was more abundant at autumns, whereas D. cardini and D. tripunctata groups were, respectively, expressive at winters and springs, and D. repleta group at both seasons. The exotic species D. simulans Sturtevant, 1919 (from D. melanogaster group) and Zaprionus indianus Gupta, 1970 were most abundant at summers. Overall, the assemblage structure did not show the same characteristics of forested or urban environments, but was similar to the forests at winters and to cities at summers. This raises the question that this locality may already been under urbanization impact. Also, this can be interpreted as an easily invaded site for exotic species, what might lead to biotic homogenization and therefore can put in check the usage of drosophilid assemblages as bioindicators at open environments.

Trophic ecology of Lontra longicaudis (Carnivora, Mustelidae) in lotic and semilotic environments in southeastern Brazil

Lontra longicaudis (Olfers, 1818) (Carnivora, Mustelidae) is a semi-aquatic animal spread through the Central and South America, except in Chile. The implantation of a hydroelectric power plant along a river alters the dynamics of the watercourse, transforming a lotic environment into a lentic or semilotic one, what can damage the otter's feeding. From April 2008 to March 2009 we analysed the otter's food habits in lotic (streamlet) and semilotic (hydroelectric reservoir) environments of Paranapanema Valley, in southeastern Brazil. Aiming to compare the otter's diet of these two environments, we analyzed statistically the frequency of occurrence of main items in the scats. Fishes represent the base of the diet both in the reservoir and in the streamlet and, despite of the total otter's diet showing up similarities in the two environments, the results evidenced modifications on the fish species consumed between them. In the reservoir the otters ate more exotic fish Oreochromis niloticus (Linnaeus, 1758) probably because it is an easy capture prey in this place. The fact that the otters get established and feed in the reservoir doesn't mean that this structure is benefic to the species because the food supplied for it consists mainly of exotic fish species.

Diet of Procyon cancrivorus (Carnivora, Procyonidae) in restinga and estuarine environments of southern Brazil

Despite its wide range and abundance on certain habitats, the crab-eating raccoon Procyon cancrivorus (G. Cuvier, 1798) is considered one of the less known Neotropical carnivore species. In the present study we analyzed the diet of P. cancrivorus in a peat forest and in an estuarine island in southernmost Brazil. Fruits of the gerivá palm tree Syagrus romanzoffiana were the most consumed item in the peat forest, followed by insects and mollusks. Small mammals, followed by Bromelia antiacantha (Bromeliaceae) fruits and brachyuran crustaceans were the most frequent items in the estuarine island. Other items found in lower frequencies were Solanum sp., Psidium sp., Smilax sp. and Dyospiros sp. fruits, diplopods, scorpions, fishes, anuran amphibians, reptiles (black tegu lizard and snakes), birds and medium-sized mammals (white-eared opossum, armadillo and coypu). Levin’s index values (peat forest: 0.38; estuarine island: 0.45) indicate an approximation to a median position between a specialist and a well distributed diet. Pianka’s index (0.80) showed a considerable diet similarity between the two systems. Procyon cancrivorus presented a varied diet in the studied areas and may play an important role as seed disperser on coastal environments in southernmost Brazil.

Diversity and population characteristics of terrestrial isopods (Crustacea, Oniscidea) across three forest environments in southern Brazil

Terrestrial isopods are important and dominant component of meso and macrodecomposer soil communities. The present study investigates the diversity and species composition of terrestrial isopods on three forests on the Serra Geral of the state of Rio Grande do Sul, Brazil. The area has two natural formations (Primary Woodland and Secondary Woodland) and one plantation of introduced Pinus. The pitfall traps operated from March 2001 to May 2002, with two summer periods and one winter. There were 14 sampling dates overall. Of the five species found: Alboscia silveirensis Araujo, 1999, Atlantoscia floridana (van Name, 1940), Benthana araucariana Araujo & Lopes, 2003 (Philoscidae), Balloniscus glaber Araujo & Zardo, 1995 (Balloniscidae) and Styloniscus otakensis (Chilton, 1901) (Styloniscidae); only A. floridana is abundant on all environments and B. glaber is nearly exclusive for the native forests. The obtained data made it possible to infer about population characteristics of this species. The Similarity Analysis showed a quantitative difference among the Secondary forest and Pinus plantation, but not a qualitative one. The operational sex ratio (OSR) analysis for A. floridana does not reveal significant differences in male and female proportions among environments. The reproductive period identified in the present study for A. floridana was from spring to autumn in the primary forest and Pinus plantation and during all year for the secondary forest. The OSR analysis for B. glaber reveals no significant differences in abundance between males and females for secondary forest, but the primary forest was a significant difference. The reproductive period for B. glaber extended from summer to autumn (for primary and secondary forest). This is the first record for Brazil of an established terrestrial isopod population in a Pinus sp. plantation area, evidenced by the presence of young, adults and ovigerous females, balanced sex ratio, expected fecundity and reproduction pattern, as compared to populations from native vegetation areas.

Intraspecific ecomorphological variations in Poecilia reticulata (Actinopterygii, Cyprinodontiformes): comparing populations of distinct environments

ABSTRACT Morphological variations, according to the principles of ecomorphology, can be related to different aspects of the organism way of life, such as occupation of habitats and feeding behavior. The present study sought to examine the intraspecific variation in two populations of Poecilia reticulata Peters, 1859, that occur in two types of environments, a lotic (Maringá Stream) and a lentic (Jaboti Lake). Due to a marked sexual dimorphism, males and females were analyzed separately. Thus, the proposed hypotheses were that the populations that occur in distinct environments present morphological differences. The morphological variables were obtained using morphometric measurements and the ecomorphological indexes. The data were summarized in a Principal Component Analysis (PCA). A Multivariate Analysis of Variance (Manova) was made to verify significant differences in morphology between the populations. Males and females showed similar ecomorphological patterns according to the environment they occur. In general the population from Maringá Stream had fins with major areas, and the Jaboti Lake population eyes located more dorsally. Additionally, others morphological differences such as wider mouth of the males from Maringá Stream, wider heads on Jaboti Lake females and more protractible mouths on males from Jaboti Lake suggest a set of environmental variables that can possibly influence the ecomorphological patterns of the populations, as the water current, availability of food resources and predation. In summary, the initial hypotheses could be confirmed, evidencing the occurrence of distinct ecomorphotypes in the same species according to the environment type.

Assessing the structural change of strategic mobility: determinants under hypercompetitive environments

The primary purpose of this exploratory empirical study is to examine the structural stability of a limited number of alternative explanatory factors of strategic change. On the basis of theoretical arguments and prior empirical evidence from two traditional perspectives, we propose an original empirical framework to analyse whether these potential explanatory factors have remained stable over time in a highly turbulent environment. This original question is explored in a particular setting: the population of Spanish private banks. The firms of this industry have experienced a high level of strategic mobility as a consequence of fundamental changes undergone in their environmental conditions over the last two decades (mainly changes related to the new banking and financial regulation process). Our results consistently support that the effect of most explanatory factors of strategic mobility considered did not remain stable over the whole period of analysis. From this point of view, the study sheds new light on major debates and dilemmas in the field of strategy regarding why firms change their competitive patterns over time and, hence, to what extent the "contextdependency" of alternative views of strategic change as their relative validation can vary over time for a given population. Methodologically, this research makes two major contributions to the study of potential determinants of strategic change. First, the definition and measurement of strategic change employing a new grouping method, the Model-based Cluster Method or MCLUST. Second, in order to asses the possible effect of determinants of strategic mobility we have controlled the non-observable heterogeneity using logistic regression models for panel data.

An ordinal shapley value for economic environments (Revised version)

We propose a new solution concept to address the problem of sharing a surplus among the agents generating it. The problem is formulated in the preferences-endowments space. The solution is defined recursively, incorporating notions of consistency and fairness and relying on properties satisfied by the Shapley value for Transferable Utility (TU) games. We show a solution exists, and call it the Ordinal Shapley value (OSV). We characterize the OSV using the notion of coalitional dividends, and furthermore show it is monotone and anonymous. Finally, similarly to the weighted Shapely value for TU games, we construct a weighted OSV as well.

Sharing the surplus: a just and efficient proposal for environments with externalities

Economic activities, both on the macro and micro level, often entail wide-spread externalities. This in turn leads to disputes regarding the compensation levels to the various parties affected. We propose a general, yet simple, method of deciding upon the distribution of the gains (costs) of cooperation in the presence of externalities. This method is shown to be the unique one satisfying several desirable properties. Furthermore, we illustrate the use of this method to resolve the sharing of benefits generated by international climate control agreements.

An ordinal shapley value for economic environments

We propose a new solution concept to address the problem of sharing a surplus among the agents generating it. The sharing problem is formulated in the preferences-endowments space. The solution is defined in a recursive manner incorporating notions of consistency and fairness and relying on properties satisfied by the Shapley value for Transferable Utility (TU) games. We show a solution exists, and refer to it as an Ordinal Shapley value (OSV). The OSV associates with each problem an allocation as well as a matrix of concessions ``measuring'' the gains each agent foregoes in favor of the other agents. We analyze the structure of the concessions, and show they are unique and symmetric. Next we characterize the OSV using the notion of coalitional dividends, and furthermore show it is monotone in an agent's initial endowments and satisfies anonymity. Finally, similarly to the weighted Shapley value for TU games, we construct a weighted OSV as well.

Bidding for the surplus: realizing efficient outcomes in general economic environments

In this paper, we consider two classes of economic environments. In the first type, agents are faced with the task of providing local public goods that will benefit some or all of them. In the second type, economic activity takes place via formation of links. Agents need both to both form a network and decide how to share the output generated. For both scenarios, we suggest a bidding mechanism whereby agents bid for the right to decide upon the organization of the economic activity. The subgame perfect equilibria of this game generate efficient outcomes.

New business formation and employment growth: some evidence for the Spanish manufacturing industry

This paper explores the effects of new business formation on employment growth in Spanish manufacturing industries. New firms are believed to make an important contribution to economic growth but the extent of this contribution is unclear. We consider time lags of new firm formation as explanatory variables of employment change and identify how long the effect of new firm entries on employment lasts. Our main results show that the effects of new business formation are positive in the short term, negative in the medium term and positive in the long term, thus confirming the existence of indirect supply-side effects found in similar studies for other countries. Key words: regional growth, firm entry, time lags and Spanish economy. JEL classifications: L00, L60, R11, R12

Public enterprise reforms and efficiency in regulated environments: the case of the postal sector

Purpose - This paper focuses on analyzing the effect that public reforms have on the efficiency of state-owned enterprises in regulated environments. Design/methodology/approach - The research is focused in the postal sector where public and private companies must obey a legal framework related to provide a universal service. The analysis is carried out using a panel of 7 European postal operators for the period 1997-2003. The activity analyzed was the letter mail division; we take as key variable the unit cost of a letter and use a translog cost function where as independent variables we include traffic levels, labor cost per employee, quality and availability of the service as well as the type of ownership (public or private). Additionally, in a second stage the geographical differences among countries are considered. Findings - Results indicate that postal operators that experienced organizational changes without being privatized, such as the Spanish and Greek operators, do not have higher unit costs than privatized postal operators like the one of Germany and the Netherlands. Moreover, we find that in all cases the operator of Ireland appear to be the most efficient. In this case restructuring process has been carried out giving an important leadership role to workers. This suggests us that labor culture could be a key variable to study when analyzing reform processes in public enterprises. Originality/value - Our findings show that in a regulated environment like in the postal sector, public and private companies can obtain similar efficiency levels in term of unit costs.

What works best for getting the unemployed back to work: employment services or small-business assistance programs? evidence from Romania

Recent empirical evidence has found that employment services and small-business assistance programmes are often successful at getting the unemployed back to work. Â One important concern of policy makers is to decide which of these two programmes is more effective and for whom. Â Using unusually rich (for transition economies) survey data and matching methods, I evaluate the relative effectiveness of these two programmes in Romania. Â While I find that employment services (ES) are, on average, more successful than a small-business assistance programme (SBA), estimation of heterogeneity effects reveals that, compared to non-participation, ES are effective for workers with little access to informal search channels, and SBA works for less-qualified workers and those living in rural areas. Â When comparing ES to SBA, I find that ES tend to be more efficient than SBA for workers without a high-school degree, and that the opposite holds for the more educated workers.