Zoologia (Curitiba), Volume: 30, Issue: 2, Published: 2013
  • The effect of increased light intensity on the aggressive behavior of the Nile tilapia, Oreochromis niloticus (Teleostei: Cichlidae) Behavior

    Carvalho, Thaís B.; Mendonça, Francine Z.; Costa-Ferreira, Roselene S.; Gonçalves-de-Freitas, Eliane

    Abstract in English:

    Animals show behavioral and physiological changes that emerge in response to environmental perturbations (i.e., emergency life-history stages). In this study, we investigate the effects of light intensity on aggressive encounters and social stability in groups of adult male Nile tilapia, Oreochromis niloticus (Linnaeus, 1758). The study compared the behavior observed under low (280.75 ± 50.60 lx) and high (1394.14 ± 520.32 lx) light intensities, with 12 replicates for each treatment. Adult fish were isolated in 36-L aquaria for 96 hours, and three males were grouped for 11 days in 140-L aquaria. Agonistic behavior was video-recorded (10 min/day) on the 3rd, 5th, 7th, and 9th day to quantify aggressive interactions and social stability. There was an effect of light intensity and day of observation on the total number of agonistic behaviors performed by the fish group. Besides, increased frequency of aggressive interactions (the sum of the four sessions) by the alpha, beta and gamma fish occurred at the higher light intensity. The dominance ranks of the fish remained unchanged across the observation sessions under both the low and high light intensities. We concluded that enhanced light intensity has a cumulative effect that increases the aggressiveness of the Nile tilapia but that this effect is not sufficiently strong to destabilize the social hierarchy.
  • Reproductive biology of the coypu, Myocastor coypus (Rodentia: Myocastoridae) in western Japan Biology

    Runami, Iori; Gunji, Yousuke; Hishinuma, Mitsugu; Nagano, Masashi; Takada, Tatsuyuki; Higaki, Shogo

    Abstract in English:

    We describe the reproductive biology of the coypu, Myocastor coypus (Molina, 1782), in western Japan, as an attempt to contribute to an efficient population control program of the coypu population. A total of 212 specimens (113 males and 99 females) were collected in the Tottori prefecture from February 2010 to January 2012. From the age estimation based on body weight and molar eruption pattern, we determined that both males and females reach sexual maturity at 4-6 months of age. Of the 72 mature females examined, 60 (83.3%) were pregnant, with a mean litter size of 6.5 ± 2.4 (mean ± SE). The onset of sexual maturity in the western Japanese population was relatively earlier when compared with indigenous and other introduced populations. Furthermore, the population in Japan had relatively higher pregnancy rates and larger litter sizes, without obvious seasonal fluctuation. These observations may imply that the hunting pressure in Japan in the past 50 years has been strong enough to select individuals that mature earlier; however, nothing in the present habitat of the coypu population seems to be limiting reproduction. The relatively high reproductive potential of the present population in the mild climate of western Japan must be considered when determining appropriate management measures for this species.
  • History, distribution, and seasonal abundance of the Least Tern Sternula antillarum (Aves: Charadriiformes: Sternidae) in Brazil Biology

    Carlos, Caio J.; Fedrizzi, Carmem E.

    Abstract in English:

    We review existing data on the distribution of the Least Tern, Sternula antillarum along the Brazilian coast, based on the literature and museum specimens, and present results of a year-long study (October 2008 to September 2009) on the seasonal abundance of this species on a large tidal flat area, Cajuais Bank, in the State of Ceará, north-eastern Brazil. We evaluate whether the observed variation in the abundance of terns is due to the occurrence of an undocumented breeding colony, or alternatively, whether it results from an influx of migrants from the Northern Hemisphere. The recovery of historical data revealed that all literature references on the distribution of birds in the Americas, published up to the late 1990s include Brazil in the non-breeding range of the Least Tern. This inclusion is based on a few, old (late 19th and early 20th centuries) museum specimens, all of which have been collected on the northern and north-eastern coasts of this country'. From the late 1980s, birds continued to be occasionally recorded along the coastline, running from the State of Amapá (01°N) up to the State of Bahia (10°S), with records of single individuals in south-eastern and southern Brazil. An alleged record from Rocas Atoll, 260 km off the Brazilian mainland, might tentatively refer to the Old World Little Tern S. albifrons. At Cajuais Bank, Least Terns occurred from October 2008 to April 2009, and in September 2009. The highest numbers (> 800 individuals) were recorded in January-February (Southern Hemisphere's summer). The species was observed in rather small numbers (< 30) in March-April (early-mid Southern Hemisphere fall) and in September (early Southern Hemisphere spring), being absent from the area in May-August (Southern Hemisphere's fall and winter). In October-December 2008 (Southern Hemisphere's spring), and September 2009 (early Southern Hemisphere's summer), no birds were in breeding plumage. In January, about 32% of the birds were in breeding plumage, while from February-April (Southern Hemisphere's summer to mid fall) all were in breeding plumage. This pattern is consistent with what would be expected for migratory birds. The Cajuais Bank itself (and adjacent beaches and inland environments) holds the largest numbers of Least Terns recorded in Brazil, thus being one of the most significant sites along the migratory route of the species.
  • Biology and life table of Dirphia araucariae (Lepidoptera: Saturniidae): A herbivore of potentially high impact on Araucaria angustifolia Biology

    Zenker, Mauricio M.; Specht, Alexandre; Fronza, Edegar; Poletto, Graziela; Marcon, Fernanda; Formentini, Aline C.; Gedoz, Mateus

    Abstract in English:

    The life-history and biology of Dirphia araucariae Jones, 1908, including its life fertility table, are here described. Moths were reared in the laboratory under controlled conditions on their host plant, Araucaria angustifolia (Bertoloni) O. Kuntze - Araucariaceae. We describe several life-history traits of the species, namely: developmental period, survival rate, growth rate, fertility, fecundity, sex ratio, cephalic capsule width, and pupal weight. Mean duration of life stages were: egg = 26.78 days; larva = 61.78 days; prepupa = 6.85 days; pupa = 62.46 days; adult = 8.37 days. We found statistically significant differences between sexes for adult, larval and pupal stage duration; larval stage was longer in females while pupal stage was longer in males. The survival rate of each life stage was: egg = 96.18%; larva = 95.38%; prepupa = 83.87%; pupa = 100%. The larvae developed through six instars and the mean growth rate was 1.418. The width of male and female cephalic capsules were different in last three instars, even though the total mean width between sexes was not different. Pupal mean weight ranged from 2.40 g to 4.79 g, with females being heavier than males. Fertility ranged from 66.78% to 100%, and the total fecundity was 358.45 eggs/female, including both laid eggs and eggs held in the abdomen. The sex ratio was 0.50 ± 0.05. The estimated biotic potential was 48731.08 specimens/female/year. We found the following values for the fertility life table: (Ro) = 117.21 females; (T) = 162.75 days; (r m) = 0.21; (l) = 1.23. Considering the biological parameters evaluated in this study, we conclude that D. araucariae is not able to cause primary damage in A. angustifolia forests, although further studies are needed to understand the reasons for occasional population outbreaks.
  • Threats to and viability of the giant anteater, Myrmecophaga tridactyla (Pilosa: Myrmecophagidae), in a protected Cerrado remnant encroached by urban expansion in central Brazil Conservation

    Diniz, Milena F.; Brito, Daniel

    Abstract in English:

    Urbanization poses a serious threat to wildlife populations inhabiting native vegetation remnants surrounded by the expanding urban and suburban sprawl. The close contact with human activities causes not only direct impacts, such as habitat loss, but also indirect negative effects, such as population isolation, roadkills and anthropogenic fires. The Parque Nacional de Brasília is a large Cerrado remnant almost completely surrounded by the city of Brasília, in central Brazil. Here, we use population viability analysis to model the impacts of urbanization on a population of Myrmecophaga tridactyla (Linnaeus, 1758) inhabiting that park. Our results show that roadkill mortality is by far the most serious threat to the long-term persistence of the giant anteater in the study site. The implementation of measures to better control vehicle speed in the vicinity of the park is urgently needed if we expect the giant anteater population to be effectively protected in the Parque Nacional de Brasília.
  • Changes in wild bee fauna of a grassland in Brazil reveal negative effects associated with growing urbanization during the last 40 years Conservation

    Martins, Aline C.; Gonçalves, Rodrigo B.; Melo, Gabriel A. R.

    Abstract in English:

    Bee fauna and associated flora from a grassland site in Brazil, surveyed 40 and 20 years ago, were newly surveyed with comparable methodology to evaluate changes in the bee fauna of this site, considering that human population and urbanization has exponentially increased in the last 40 years. In general, bee species richness has declined in 22%, as well as their abundance. Some of the previously abundant species are now absent, including Bombus bellicosus Smith, 1879, Gaesischia fulgurans (Holmberg, 1903) and Thectochlora basiatra (Strand, 1910). No particular trend of differential decrease among either taxonomic or functional groups was observed, except for a minor increase in the proportion of oligolectic species and a 50% reduction in the number of large species. The first two surveys were more similar to each other in species richness per bee genus, while the two most recent grouped together based on measures of anthropogenic impact. Furthermore, the number of plant species visited by bees increased, with a pronounced increase in ruderal and exotic species. Crop cultivation, competition with honeybees and climate changes may all be related to bee decline. Nevertheless, the effects of urbanization, in particular intense land occupation and few preserved natural areas can be pointed as the main causes of species decline. Due to continuing increase in human population, increased erosion in diversity is expected. Habitat protection is an additional challenge to bee conservation in the region, with no local conservation units set aside for grasslands. State and municipal agencies should urgently consider the establishment of reserves for the few remaining patches of natural grasslands.
  • Temporal and spatial investments in the protected area network of a megadiverse country Conservation

    Cabral, Rodolfo; Brito, Daniel

    Abstract in English:

    Protected area networks are the cornerstone strategy for biodiversity conservation worldwide. They are efficient even in the face of human pressures. Brazil is a megadiverse country and for this reason it should not be left out of discussions on biodiversity conservation. Here we present a temporal and spatial analysis of the historical national investments in the country's protected area network. We compare this investment in the light of international biodiversity agreements (e.g., CBD), and evaluate trends and biases in the establishment of protected areas. We obtained the following data from a database maintained by the Brazilian government: the number of protected areas, the dates when they were established, their size and category (strict protection or sustainable use). Our results show that Brazil does not meet the recommended international levels of protection, that its network coverage favors a few of its biomes only, and that the temporal flow of investments has varied greatly. Even though there is a tendency for an increase in the establishment of protected areas, there has been a noteworthy change in the categories more recent protected areas are inserted. Until the 1980's the network was comprised mostly of strict protection sites, whereas the newly created sites are mostly intended for sustainable use. This reflects a serious philosophical and practical change in the role of the national protected area network, and may affect its objectives in preserving the biodiversity of a country that plays a key role in the global biodiversity conservation scenario.
  • A comparison of abundance estimators for small mammal populations Ecology

    Pacheco, Marcelle; Kajin, Maja; Gentile, Rosana; Zangrandi, Priscilla L.; Vieira, Marcus V.; Cerqueira, Rui

    Abstract in English:

    A major difficulty in the application of probabilistic models to estimations of mammal abundance is obtaining a data set that meets all of the assumptions of the model. In this paper, we evaluated the concordance correlation among three population size estimators, the minimum number alive (MNA), jackknife and the model suggested by the selection algorithm in CAPTURE (the best-fit model), using long-term data on three Brazilian small mammal species obtained from three different studies. The concordance correlation coefficients between the abundance estimates indicated that the probabilistic and enumeration estimators were highly correlated, giving concordant population estimates, except for one species in one of the studies. The results indicate the adequacy of using enumeration estimates as indexes for population size when scarce data do not allow for the use of probabilistic methods. Differences observed in the behavior of enumeration and probabilistic methods among species and studies can be related to the exclusive sampling design of each area, species-specific movement characteristics and whether a significant portion of the population could be sampled.
  • Diversity and structure of the stomatopod (Crustacea) community on the Amazon continental shelf Ecology

    Silva, Kátia C. Araújo; Cintra, Israel H. A.; Martins, Déborah E. G.; Abrunhosa, Fernando A.

    Abstract in English:

    The present study aimed to characterize the biodiversity of the Stomatopoda species found off the coast of the northern Brazilian states of Amapá and Pará, within the region's Exclusive Economic Zone. Two distinct sectors were surveyed, to the north and to the south of Cape Norte. The specimens were collected during fishery surveys carried out between 1996 and 1998 by the Revizee Program, using bottom shrimp trawl nets. The specimens were identified at the Crustaceans Laboratory of the Center for Research and Management of Fishery Resources of the Northern Coast and the Carcinology Laboratory of the Federal Rural University of Pernambuco. The 189 identified specimens represented Lysiosquilla scabricauda (Lamarck, 1818) (n = 2), Parasquilla meridionalis Manning, 1916 (n = 1), Squilla empusa Say, 1818 (n = 6), and Squilla lijdingi Holthuis, 1959 (n = 180). Only three species were collected in each of the survey sectors, with L. scabricauda and S. lijdingi being captured in both sectors. Squilla lijdingi was dominant in both sectors, whereas the other species were considered to be rare. Squilla lijdingi was very frequent in the northern sector, although the other stomatopods were infrequent. In the southern sector, L. scabricauda was sporadic, S. empusa was frequent, and S. lijdingi was very frequent. A significant difference was observed in the number of specimens captured in both sectors. The Shannon index was 0.6144 bits.ind-1 for the northern sector and 0.2708 bits.ind-1 for the southern one, whereas equitability was 0.3876 in the North and 0.1708 in the South. The stomatopods were collected at depths between 32 and 109 m, and were captured primarily on gravelly bottoms in the northern sector, and on muddy substrates in the southern sector. Stomatopods were more abundant in the northern sector during the dry season from June to November, whereas they were more common in the South during rainy season, from December to May.
  • Species composition and temporal activity of Arctiinae (Lepidoptera: Erebidae) in two cerrado vegetation types Ecology

    Scherrer, Scheila; Ferro, Viviane G.; Ramos, Marina N.; Diniz, Ivone R.

    Abstract in English:

    Arctiinae moths include nearly 11,000 species worldwide, of which approximately 700 species occur in the Brazilian Cerrado. The aim of this study was to describe the species composition of Arctiinae, as well as the variation in annual and nightly moth activity, in two Cerrado vegetation types. We sampled moths one night per month from September 2008 to June 2009, in the gallery forest and in the cerrado sensu stricto in the Jardim Botânico de Brasília. We collected 395 tiger moths belonging to 65 morphospecies; 74% of the species belonged to the tribe Arctiini and 26% to Lithosiini. Thirty-one species (47.7%) occurred only in the gallery forest, 13 (20%) occurred only in the cerrado sensu stricto, and 21 (32.3%) occurred in both vegetation types. Additionally, we found the greatest species richness between 7:00 p.m. and 8:00 p.m., and these hours were associated with 21 and 22 species, respectively. Most species (51.8%) were active for up to three hours during the night. In general, the species composition differed between the dry and rainy seasons, and the similarity of the fauna also varied hourly. Based on our results, we suggest that rapid inventories of Arctiinae be performed in both rainy and dry seasons, and sampling should be carried out the entire night.
  • Determination of larval instars in Chironomus sancticaroli (Diptera: Chironomidae) using novel head capsule structures Morphology And Physiology

    Richardi, Vinicius S.; Rebechi, Débora; Aranha, José M. R.; Navarro-Silva, Mário A.

    Abstract in English:

    Determining the age composition of a population is important when conducting ecological, taxonomic and environmental assessments. Morphometric measurements of the head capsule, especially the length and width, are widely used in the identification of insect instars, but alternative ways for determining the age of insects can expand the options for the analysis of field and laboratory populations. This study evaluated the morphometry of the antennae, mandibles, mentum and ventromental plates to discriminate among the four larval instars of Chironomus sancticaroli Strixino & Strixino, 1981. The larvae were reared in the laboratory under constant temperature (25°C) and photoperiod of 12/12 hours for 19 days, with a supply of food. Fifteen larvae were removed randomly every day, cleared in KOH, and slide-mounted, and had the antennae, mandibles, mentum and ventromental plates measured. The dimensions of the four structures studied allowed us to statistically distinguish each of the four larval instars. The data fit an exponential equation according to the Brooks-Dyar rule, which allows an estimate of the larval instar of specimens collected in the field, even when development takes place under different conditions. The duration of each instar was also obtained from our data, and showed an overlap of instars during development.
  • A new species of Mucrosomia (Collembola: Isotomidae) from Brazil Taxonomy And Nomenclature

    Mendonça, Maria Cleide de; Queiroz, Gabriel Costa

    Abstract in English:

    A new species of Collembola, Mucrosomia alticola sp. nov., is described and illustrated based on material from "Parque Nacional da Serra dos Órgãos" (State of Rio de Janeiro) and from "Parque Nacional da Serra do Caparaó" (State of Minas Gerais). This is the first record of a species of Mucrosomia for Brazil. The genus has, up to date, only three species and can be diagnosed by the absence of eyes and pigmentation, PAO present, tenent hair pointed, Abd V and VI fused, manubrium with 1+1 chaetae on anterior side, long dens and a remarkable mucro with five teeth. The presence of chaetae on ventral thorax, between segments II-III, supports the new species.
  • New synonymies and a revalidation in the spider genera Eustala and Micrathena (Araneae: Araneidae) Taxonomy And Nomenclature

    Levi, Herbert W.; Santos, Adalberto J.

    Abstract in English:

    In this study, 10 nominal species of Eustala Simon, 1895 are synonymized with other species of the genus, mostly based on matching males and females erroneously described as different species. Parawixia rimosa (Keyserling, 1892) is considered a senior synonym of Eustala decemtuberculata Caporiacco, 1955. Eustala isosceles Mello-Leitão, 1939 is transferred to Kapogea Levi, 1997 and considered a senior synonym of Kapogea alayoi (Archer, 1958) based on abdomen shape and coloration. Micrathena beta Caporiacco, 1947 is redescribed, illustrated and transferred from Linyphiidae back to Araneidae. This species can be easily distinguished from other members of the genus by the male palpus with an enlarged and modified paracymbium and a narrower hook as a conductor. Micrathena sanctispiritus Brignoli, 1983 is removed from the synonymy with M. lindenbergi Mello-Leitão, 1940 and considered a senior synonym of M. guanabara Levi, 1985.
  • Revision of the South American Fonckia (Opiliones: Gonyleptidae: Pachylinae) with the description of two new species Taxonomy And Nomenclature

    Silva, Marília Pessoa; Hara, Marcos Ryotaro; Pinto-da-Rocha, Ricardo

    Abstract in English:

    Fonckia Roewer, 1913 is revised and two new species are described in it: Fonckia contulmo sp. nov., from Monumento Nacional Contulmo, Araucanía, Chile, diagnosed mainly by the enlarged tubercles on the lateral margins of the dorsal scutum, between the median region of scutal area II and the posterior margin of the scutal area III; and Fonckia sosia sp. nov., from Parque Nacional Conguillio, Malleco, Chile, distinguished mainly by the absence of a dorso-basal apophysis on femur IV of the male and a spiniform, enlarged retroapical tubercle on tibia IV of the male. We propose the generic synonymy of Diconospelta Canals, 1934 under Fonckia Roewer, 1913, and the specific synonymy of D. vazferreirae Mello-Leitão, 1946 under F. processigera (Sørensen, 1902). We also propose the new combination F. gallardoi (Canals, 1934) comb. nov. As a consequence, the genus is henceforth composed of four species. We present an identification key for the species of Fonckia, as well as diagnoses and a discussion of the Chilean Pachylinae.
  • Omorgus suberosus and Polynoncus bifurcatus (Coleoptera: Scarabaeoidea: Trogidae) in exotic and native environments of Brazil Short Communication

    Correa, César M. A.; Puker, Anderson; Korasaki, Vanesca; Ferreira, Kleyton R.

    Abstract in English:

    Trogidae beetles are important for the decomposition of organic material in ecosystems. In the Neotropical region, little is known about this family, except for their taxonomy. In this study, we report the presence of Omorgus suberosus (Fabricius, 1775) and Polynoncus bifurcatus (Vaurie, 1962) in exotic and native environments of Brazil, sampled with different baits. The beetles were captured in pastures with introduced grass (Brachiaria spp.) and in patches of native forest (Brazilian savanna). We used pitfall traps baited with carrion and human feces every two weeks, from January to December 2011, and with carrion, cow dung, human feces and pig manure at the beginning of the rainy season (October 2011). Over the course of one year, 24 individuals of O. suberosus were captured, 16 in the exotic and eight in the native environment, respectively. In the sampling performed at the beginning of the rainy season, 32 individuals of O. suberosus and seven of P. bifurcatus were obtained. Omorgus suberosus specimens were sampled in both environments, suggesting a possible tolerance to anthropogenic environments, as in the case of introduced grasses. Polynoncus bifurcatus individuals were captured only in native environments, which may indicate a strong relationship with more heterogeneous and/or relatively preserved habitats. We discuss such relationships in light of published data and new information provided here.
  • Scapteromys aquaticus (Rodentia: Sigmodontinae) in Brazil with comments on karyotype and phylogenetics relationships Short Communication

    Bonvicino, Cibele R.; Fernandes, Fabiano A.; Viana, Maria C.; Bernardo, R. Teixeira; D'Andrea, Paulo S.

    Abstract in English:

    The swamp rats are distributed in Argentina, southern Paraguay, Uruguay and southern Brazil, with two species currently accepted: Scapteromys aquaticus Thomas, 1920 and Scapteromys tumidus Waterhouse, 1837. While S. aquaticus occurs in Argentina, Paraguay and western Uruguay, S. tumidus occurs in Brazil and Uruguay. Here we report for the first time the occurrence of S. aquaticus in gallery forest remnants in Southern Brazil. Karyologic analysis showed 2n = 32 and FNa = 40. Phylogenetic analyses, based on DNA sequences from the mitochondrial cytochrome-b gene indicate that the Brazilian and the Argentinian specimens of S. aquaticus shared one haplotype, while median joining analysis showed lack of population structure. This register, plus the karyotype data available for Brazilian population, recovered four karyomorphotypes in Brazil, corresponding to the two known species of Scapteromys and two unnamed species. This scenario indicates that more multidisciplinary studies are necessary to understand the actual diversity of Scapteromys.
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