Rheotaxis of Biomphalaria glabrata on vertical substrates and its role in the recolonization of habitats treated with molluscicides

The authors observed specimens of Biomphalaria glabrata climbing up the vertical wall of a ditch against the current. The snails that showed this behavior during application of a molluscicide in the breeding site survived and probably played a role in repopulation, which was observed three months later. These observations motivated field and laboratory investigations which led the authors to conclude that: a) this species is able to climb vertical surfaces both in field and laboratory situations; b) the current of water, as a physical stimulus, is sufficient to trigger this behavior (rheotaxis); c) rheotaxis on vertical surfaces depends on the presence of a necessarily moderate current; d) there are indications that B. glabrata may undergo habituation with respect to rheotaxis on vertical walls, e) the relationship between rheotaxis and habituation should be considered as a factor causing snail grouping in water bodies which may contribute to their localization in the field; f) rheotaxis on vertical surfaces may facilitate population dispersal, and its occurrence should be considered when campaigns for the control of schistosomiasis transmission are planned. The authors present some proposals to avoid the manifestation of this behavior in some filed situations.

Adult abundance, biting behavior and parity of Anopheles aquasalis, Curry 1932 in two malarious areas of Sucre State, Venezuela

The principal vector of malaria in eastern Venezuela, Anopheles aquasalis, is exophagic and exophilic. Control using indoor insecticide house sprays has failed to lower the number of malaria cases. Therefore, studies were initiated in two villages of the eastern coastal state of Sucre to better understand this vector's biology and develop a more integrated control program. An. aquasalis was found to have a crepuscular biting behavior with a major peak at dusk and a minor peak at dawn. Mosquitos were collected more outdoors than indoors. Forty-seven percent of the biting took place before people went to bed (22:30 hr) and 69% of the mosquitos biting during this time period bite outdoors. Outdoor biting could be the reason why indoor spraying alone did not lower malaria cases. Seasonal abundance was greater in the rainy season compared to the dry season. Seasonal parous rates were high (78.3%-100%) and similar indoors and outdoors and between dry and wet season in Santa F e. In Guayana, the seasonal parity was lower (34.6%-42.2%) than Santa F e with indoor parity slightly higher than outdoors. Malaria cases were higher in Santa F e, but adult mosquito density was much lower than in Guayana. This difference could have been due to higher parity in Santa F e compared to Guayana. The greater distance to the nearest breeding site and presence of alternative hosts in Guayana can not be discounted as factors which contributed to the difference in malaria transmission between locations. We concluded that knowledge on seasonal occurrence, biting activity, resting behavior and breeding site location can be used to design a new control strategy for this vector.

Diversity of sandflies (Psychodidae: Phlebotominae) captured in sandstone caves from Central Amazonia, Brazil

In the present paper we describe the diversity of phlebotomine sandflies collected in three sandstone caves in the municipality of Presidente Figueiredo, state of Amazonas, Brazil. The phlebotomines were captured during 2006 with CDC light traps. Guano samples from inside the Gruta Refúgio do Maruaga were collected to investigate the presence of immature specimens. A total of 2,160 adult phlebotomines representing 15 species were captured. Pintomyia pacae was the dominant species in Gruta dos Animais (1,723 specimens) and Gruta dos Lages (50 specimens) and Deanemyia maruaga new comb (280 specimens) was the dominant species in Gruta Refúgio do Maruaga. A total of 18 guano samples were collected and seven of these samples included immature specimens. A total of 507 immature specimens were captured; 495 of these specimens were larvae and 12 were pupae. The presence of paca (Agouti paca) footprints near Gruta dos Animais and Gruta dos Lages suggests the association of Pi. pacae with this rodent. This finding may explain the abundance of Pi. pacae in these locations, while the species is relatively rare in the forest. Deanemyia maruaga is a cave species that uses guano to breed during its immature stages. Adult specimens of this species are apparently parthenogenetic and autogenous and represent the second record of parthenogenesis for the subfamily Phlebotominae.

Melanin-based colouration predicts natal dispersal in the barn owl, Tyto alba

Searching for a suitable breeding site is an important decision in the life of most animals. The decisions where to settle and how far to travel before doing so depend on many factors. Individual differences in dispersal distance could result from different strategies (e.g. specialists versus generalists), which might result in similar reproductive success in different habitats, or different competitive abilities to acquire a territory close to the natal site. The barn owl is polymorphic in melanic coloration, which is associated with many physiological and behavioural traits such as habitat choice, stress response and docility, raising the possibility that the coloration is also related to dispersal. We studied natal dispersal (from rearing site to site of first breeding attempt) and breeding dispersal (from one breeding site to the next) in barn owls using a long-term data set. Darker reddish individuals moved further than paler individuals during natal dispersal, but not during breeding dispersal. A cross-fostering experiment showed that the colour of the biological and foster parents had no influence on dispersal distance. The distance dispersed by parents and same-sex offspring was correlated, whereas natal and breeding dispersal were not repeatable within individuals, indicating that they are two different processes. Given that the distance travelled in natal dispersal appears to be heritable, the underlying genes might be coupled to those related to coloration. We discuss hypotheses to explain the potential adaptive function of the link between coloration and natal dispersal.

Effect of Bacillus sphaericus Neide on Anopheles (Diptera: Culicidae) and associated insect fauna in fish ponds in the Amazon

ABSTRACTWe analyzed the effects of Bacillus sphaericus on Anopheles larvae and on the associated insect fauna in fish farming ponds. Five breeding sites in the peri-urban area of the city of Manaus, AM, Brazil, were studied. Seven samples were collected from each breeding site and B. sphaericus was applied and reapplied after 15 days. The samples were made at 24 h before application, 24 h post-application and 5 and 15 days post-application. We determined abundance, larval reduction and larval density for Anopheles, and abundance, richness, Shannon diversity index and classified according to the functional trophic groups for associated insect fauna. A total of 904 Anopheles larvae were collected and distributed into five species. Density data and larval reduction demonstrated the rapid effect of the biolarvicide 24 h after application. A total of 4874 associated aquatic insects belonging to six orders and 23 families were collected. Regression analysis of diversity and richness indicated that the application of the biolarvicide had no influence on these indices and thus no effect on the associated insect fauna for a period of 30 days. B. sphaericus was found to be highly effective against the larvae of Anopheles, eliminating the larvae in the first days after application, with no effect on the associated insect fauna present in the fish ponds analyzed.

Geographic assignment of seabirds to their origin: combining morphology, genetics and biogeochemical analyses

Longline fisheries, oil spills, and offshore wind farms are some of the major threats increasing seabird mortality at sea, but the impact of these threats on specific populations has been difficult to determine so far. We tested the use of molecular markers, morphometric measures, and stable isotope (δ15N and δ13C) and trace element concentrations in the first primary feather (grown at the end of the breeding period) to assign the geographic origin of Calonectris shearwaters. Overall, we sampled birds from three taxa: 13 Mediterranean Cory's Shearwater (Calonectris diomedea diomedea) breeding sites, 10 Atlantic Cory's Shearwater (Calonectris diomedea borealis) breeding sites, and one Cape Verde Shearwater (C. edwardsii) breeding site. Assignment rates were investigated at three spatial scales: breeding colony, breeding archipelago, and taxa levels. Genetic analyses based on the mitochondrial control region (198 birds from 21 breeding colonies) correctly assigned 100% of birds to the three main taxa but failed in detecting geographic structuring at lower scales. Discriminant analyses based on trace elements composition achieved the best rate of correct assignment to colony (77.5%). Body measurements or stable isotopes mainly succeeded in assigning individuals among taxa (87.9% and 89.9%, respectively) but failed at the colony level (27.1% and 38.0%, respectively). Combining all three approaches (morphometrics, isotopes, and trace elements on 186 birds from 15 breeding colonies) substantially improved correct classifications (86.0%, 90.7%, and 100% among colonies, archipelagos, and taxa, respectively). Validations using two independent data sets and jackknife cross-validation confirmed the robustness of the combined approach in the colony assignment (62.5%, 58.8%, and 69.8% for each validation test, respectively). A preliminary application of the discriminant model based on stable isotope δ15N and δ13C values and trace elements (219 birds from 17 breeding sites) showed that 41 Cory's Shearwaters caught by western Mediterranean long-liners came mainly from breeding colonies in Menorca (48.8%), Ibiza (14.6%), and Crete (31.7%). Our findings show that combining analyses of trace elements and stable isotopes on feathers can achieve high rates of correct geographic assignment of birds in the marine environment, opening new prospects for the study of seabird mortality at sea.

Dynamics and foraging behaviour of adult hornet robberflies, Asilus crabroniformis: implications for conservation strategy

Mark resighting studies of the hornet robberfly, Asilus crabroniformis, were carried out during the flight seasons of 1999 and 2000 on agricultural land on the Chilterns in Oxfordshire, UK. Six patches of land were identified which contained characteristics thought to be attractive to hornet robberflies. One hundred and twenty eight adults were marked in 1999 and 257 in 2000. Marking was carried out on one of the patches, but resighting observations were collected from all six sites. The daily population sizes were estimated using the Jolly-Seber method. The daily population size peaked between 50 and 72 from 23 August until 13 September in 2000. This was very similar to the peak population size of between 50 and 74 estimated for 1999. Adults were found to be capable of living for nearly 5 weeks. The maximum linear distance from the point of marking that any individual moved across the study site was 625 m, but some individuals moved over 400 m in a single day. Unsuitable habitat (suburban gardens and a main road) did not present a barrier to dispersal. Males were more likely than females to loiter in sites peripheral to the breeding site, whilst females seemed to be more tied to the breeding site. Most adults were caught from dung piles, but insects avoided fresh dung and preferred instead dung that was well into the process of drying out. A variety of insect species were taken as prey, including many beetles and flies. The findings of the study are discussed in relation to the management of the landscape to enhance the long-term prospects of the hornet robberfly in the UK, and to achieve the UK Biodiversity Action Plan target for this species.

Multiple origins of vagrant Subantarctic fur seals: A long journey to the Brazilian coast detected by molecular markers

In this study, we present the first data about putative source populations of the vagrant Subantarctic fur seal, Arctocephalus tropicalis, found on the Brazilian coast, through the comparison of their mitochondrial DNA control sequences to exclusive haplotypes from the main breeding colonies of the species. The results indicated that, despite the majority of the vagrant individuals are from Gough Island (the closest breeding site to the Brazilian coast), they also come from other reproductive colonies, such as Crozet Island, a distance around 16,500 km from the Brazilian coast. Furthermore, the molecular data identified three possible management units: (1) Gough, (2) Amsterdam, and (3) Marion, Macquarie and Crozet. This significant genetic subdivision must be taken into account in any future management plan for the species conservation, including rehabilitation and even reintroduction of vagrant fur seals.

Bark and ambrosia beetle (Coleoptera : Scolytidae) responses to volatiles from aging loblolly pine billets

Many species of bark and ambrosia beetles use host volatiles as cues for breeding site location. In a study where the objectives were to identify the different volatiles released by Pinus taeda L. billets as they age, to determine the arrival sequence of scolytids (Colcoptera: Scolytidae), and to correlate volatile emission by the billets with beetle catches, 25 species of scolytids were trapped. Bark beetles were more attracted to the billets in the beginning of the period. whereas ambrosia beetles arrived later. Among the bark beetles, Dendroctonus terebrans (Olivier) was significantly more attracted during the Ist 3 wk after tree felling, Hylastes tenuis Eichhoff in the Ist 2 wk. Pityophtorus pulicarius (Zimmermann) in weeks 2 and 3, and Ips grandicollis (Eichhoff) was more attracted on weeks 3 and 4. Among the ambrosia beetles, Xyleborinus saxeseni (Ratzeburg) was more attracted to billets during weeks 4-6, whereas Xyleborus pubescens Zimmermann and Xyleborus californicus Wood were more attracted during week 6. The billets showed marked decline in attractiveness to all scolytids after 8 wk. Volatiles collected during the beetle trapping periods included 15 hydrocarbon monoterpenes, 18 oxygenated monoterpenes, 4-allylanisole, and ethanol. The hydrocarbon monoterpenes and 4-allylanisole decreased sharply over time, but oxygenated monoterpenes and ethanol increased up to weeks 4-6, after which they also decreased. Good correlations between certain billet volatiles and catches for some beetle species were obtained, but their biological significance could not be determined.

Culicídeos vetores em uma unidade de conservação da caatinga na região do seridó no Rio Grande do Norte aspectos da transmissão de doenças

The scarcity of occurrence records of culicid species, transmitting insects of etiologic agents for arboviruses, protozoan diseases and philarioses, and lack of information about their interactions with the forest environment make the Caatinga one of the most unknown biomes in Brazil. The aim of this study was to identify culicid species in a conservation unit located in a preserved area of the Caatinga and the possible associations with local abiotic factors, as well as characterize the natural and artificial ecotopes present in the Caatinga of Rio Grande do Norte state. The Ecological Station of Serido (ESEC-Seridó) is a Caatinga Conservation Unit located in a rural area of Rio Grande do Norte. The hot and dry climate of the Caatinga, along with a short rainy season, favor the adaptation and resistance of plants, resulting in completely distinct landscapes over the course of the year. The study took place over the course of one year, with monthly collections between 10h-12h, 14h-16h and 18h-20h. Adult mosquitoes were collected in a forest area using a manual suction trap with human bait as attractant at the three times and a Shannon trap for night collections. During the rainy season ovitraps were randomly distributed at different sites. The different capture sites were observed and photographed. Immature and adult insects captured were taken to the laboratory for identification. Of the 5081 insects collected in human-bait and Shannon traps, 75% were Mansonia wilsoni. In addition, Aedeomyia, Aedes, Anopheles, Coquillettidia, Culex, Haemagogus, Mansonia and Psorophora were identified. Of the 92 Haemagogus eggs found, 71 were collected on the banks of a reservoir. Mosquito larvae were found and photographed in an artificial breeding site of a neighboring rural area. Humidity had the greatest influence on culicid density in the Caatinga. Rain was important in the appearance of Haemagogus, Anopheles, Aedes and Psorophora. Temperature had a negative influence on Anopheles triannulatus. The occurence of important vector species of diseases in a little known preserved area of the Caatinga as well as environmental and sociocultural questions are factors that favor the emergence of transmitting insects, making these areas potential subject to the resurgence of diseases

Alternative reproductive modes of Atlantic forest frogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reproductive biology of an endemic Physalaemus of the Brazilian Atlantic forest, and the trade-off between clutch and egg size in terrestrial breeders of the P. signifer group

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Distribuição temporal e espacial de anuros em área de Pampa, Santa Maria, RS

Este estudo teve como objetivo determinar a riqueza, a constância de ocorrência, os modos reprodutivos, o padrão de distribuição da abundância, a temporada de vocalização e testar a correlação das variáveis climáticas sobre a atividade de vocalização dos anuros em uma região do Bioma Pampa, Santa Maria, Rio Grande do Sul. Durante o período de novembro de 2001 a outubro de 2002 foram realizadas coletas mensais empregando o método de busca em sítio de reprodução e exame de exemplares depositados na Coleção Herpetológica do Setor de Zoologia da Universidade Federal de Santa Maria (UFSM) (ZUFSM). Foi registrada a ocorrência de 25 espécies de anuros. A anurofauna registrada corresponde a 30% das espécies encontradas no Rio Grande do Sul e normalmente está associada a áreas abertas encontradas no estado e em países vizinhos. Foram registrados quatro modos reprodutivos: modo 1 (14 espécies; 58,3%); modos 11 e 30 (nove espécies; 37,5%) e modo 24 (uma espécie; 4,2%). A baixa diversificação de modos reprodutivos provavelmente está relacionada à homogeneidade do hábitat primariamente campestre. A maior parte das espécies mostrou-se constante ou acessória na área estudada e o padrão de distribuição da abundância das espécies apresentou ajuste aos modelos Broken Stick e Log-normal, caracterizados pela homogeneidade na distribuição da abundância das espécies. A maioria das espécies apresentou grande plasticidade na ocupação de hábitats, mas poucas foram plásticas no uso dos sítios de vocalização. Houve correlação positiva, ainda que fraca, da riqueza de espécies com a precipitação mensal acumulada e da abundância com a temperatura média máxima. As correlações obtidas indicaram que na área estudada a temperatura parece atuar mais sobre a abundância de machos em atividade de vocalização e a precipitação sobre a riqueza, apesar da riqueza de espécies ser significativamente maior durante o período mais quente do ano. Estes resultados revelaram que as variáveis climatológicas testadas explicaram muito pouco da ocorrência sazonal das espécies, assim a influência de outras variáveis ambientais merece ser testada em estudos futuros.

Reproductive biology of an endemic Physalaemus of the Brazilian Atlantic forest, and the trade-of between clutch and egg size in terrestrial breeders of the P. signifer group

Physalaemus crombiei is a small foam-nesting frog endemic to the Atlantic forest. It is a member of the P. signifer group known only from its type locality in Santa Teresa, State of Espírito Santo, and from another locality in the State of Bahia, Brazil. Most Physalaemus species are aquatic breeders, and species in the P. signifer group are the only ones exhibiting a tendency toward terrestrial reproduction in the genus. Here we describe the reproductive period, breeding site and reproductive modes of P. crombiei from a third population in the Atlantic forest, southeastern Brazil. We also investigated reproductive effort and size-fecundity relationships in females. Reproductive traits were compared to other species in the genus Physalaemus, especially those included in the P. signifer group. Physalaemus crombiei is a prolonged breeder, reproducing throughout the year with a peak of activity during the most rainy months (October-March). Males called from the humid forest foor and eggs embedded in foam nests were deposited in the water as well as on the humid foor amidst the leaf litter, or inside fallen leaves or tree holes containing rainwater on the forest foor. As expected, P. crombiei exhibited three alternative reproductive modes, as described for other species of the P. signifer group. The number of eggs produced per female varied from 91 to 250. Female body size is positively correlated both with ovary mass and clutch size (number of eggs per clutch). Variation in the number and size of eggs observed in Physalaemus species may be explained not only by female size, but also by the terrestrial reproductive mode exhibited by the species in the P. signifer group.

Contribuição ao conhecimento da fauna anofélica antropofílica da Praia da Saudade na Ilha de Cotijuba - Belém - Pará: uma área endêmica da malária

Apesar da sua localização perto de Belém, Pará, a Ilha de Cotijuba tem sido assolada por surtos de malária durante os últimos anos, principalmente nos meses de abril a maio. A ilha faz parte de um arquipélago situado às margens da baía do Marajó, a 29 km de Belém, constituindo uma parte insular dessa cidade, e possui uma área de cerca de 60 km² e uma costa com 20 km de praias, que corresponde a 66% da área total da ilha. Por causa da epidemia, tomou-se necessário conhecer as espécies de anofelinos vetores de malária na ilha. Nos anos de 2002 a 2004 foram realizadas coletas periódicas de larvas e adultos de mosquitos e os seus criatórios foram localizados e caracterizados. Os imaturos foram coletados com auxílio de conchas e em bandejas plásticas. Para os adultos utilizou-se o método de captura manual com isca humana. Duas coletas de adultos na floresta foram realizadas, uma no período seco e outra no período chuvoso, com duração de 24 horas ininterruptas. Seis coletas bimensais no peridomicílio foram feitas, com duração de 6 horas. Tanto na floresta como no peridomicilio foram registradas apenas duas espécies em atividade atacando o homem, Anopheles (Nyssorhynchus) aquasalis e Anopheles (Anopheles) intermedius. A. aquasalis foi mais freqüente no peridomicílio, enquanto A. intermedius teve maior freqüência na floresta. Verificou-se que o maior número de casos de malária na ilha ocorre dois meses depois do início das chuvas, no mês de maio. Na i, como um todo, existem quatro lagos que são os possíveis criatórios de anofelinos da ilha e o lago da Gabriela é o principal criatório da ilha de Cotijuba, sendo responslha de Cotijubaável por 42% dos casos de malária na ilha no ano de 2003. As condições climáticas, o comportamento dos residentes e a falta de recursos para o efetivo controle dos vetores da doença, entre outros fatores, favorecem a persistência de malária na Ilha de Cotijuba.