Attraction to conspecifcs in Rhinella icterica and R. ornata tadpoles (Anura: Bufonidae) / Atração por coespecíficos em girinos de Rhinella icterica e R. ornata (Anura: Bufonidae)

Abstract: Tadpoles are able to perceive and discriminate signals from environment and they may use this ability in behaviors and ecological processes. Recognition mechanisms may be involved in schooling by means of attraction among individuals, characterizing a social process. By means of laboratory experiments the present study investigated the presence or absence of attraction to conspecifics in tadpoles of Rhinella icterica and R. ornata, two sympatric species from the Atlantic Forest of southeastern Brazil. We collected eggs of these two species in the field and reared them in laboratory according to two different methods (isolated or in groups of siblings). Tadpoles were submitted to experiments of choice between conspecifics, heterospecifics, and an empty compartment. Rhinella icterica tadpoles preferred to associate with conspecifics rather than R. ornata tadpoles, and we verified this is an innate behavior. Rhinella ornata tadpoles failed to discriminate between conspecifics and R. icterica tadpoles. When submitted to choice between a group of tadpoles of the other species and an empty compartment, R. icterica tadpoles presented random distribution, while R. ornata tadpoles preferred to associate with heterospecifics. Our results indicate R. icterica tadpoles have preference to associate with conspecifics, while R. ornata tadpoles may school indiscriminately. This study contributes for a better understanding of larval anuran social behavior.

Resumo: Os girinos são capazes de perceber e discriminar sinais do ambiente e podem usar essa capacidade em comportamentos e processos ecológicos. Mecanismos de reconhecimento podem estar envolvidos na agregação por meio da atração entre indivíduos, caracterizando um processo social. O presente estudo investigou, por meio de experimentos de laboratório, a presença ou ausência de atração por coespecíficos em girinos de Rhinella icterica e R. ornata, duas espécies simpátricas, da Mata Atlântica do sudeste do Brasil. Coletamos ovos dessas duas espécies no campo e os cultivamos em laboratório de acordo com dois métodos diferentes (isolados ou em grupo de irmãos). Os girinos foram submetidos a experimentos de escolha entre coespecíficos, heteroespecíficos e compartimento vazio. Girinos de Rhinella icterica preferiram associar-se a coespecíficos do que com girinos de R. ornata, e verificamos que este é um comportamento inato. Os girinos de Rhinella ornata não conseguiram discriminar entre coespecíficos e girinos de R. icterica. Quando submetidos à escolha entre um grupo de girinos da outra espécie e um compartimento vazio, os girinos de R. icterica apresentaram distribuição aleatória, enquanto os girinos de R. ornata preferiram associar-se a girinos heteroespecíficos. Nossos resultados indicam que girinos de R. icterica preferem associar-se a coespecíficos, enquanto girinos de R. ornata podem agregar-se indiscriminadamente. Este estudo contribui para uma melhor compreensão do comportamento social de larvas de anuros.

Effects of hydrological cycles and water body connectivity on abundance and co-occurrence of two Neotropical Curculionidae species / Efeito do ciclo hidrológico e da conectividade das baías do Pantanal na abundância e co-ocorrência de duas espécies de Curculionidae Neotropical

Abstract: The effect of the hydrological cycle on the abundance of adults and larvae of the weevils Cyrtobagous salviniae and Cyrtobagous singularis in the Pantanal was tested and related to the host-plant abundance, limnological variables, and hydrological connectivity of 10 "bays" (lakes and ponds) along the Cuiabá River. Adults and larvae of C. salviniae were more abundant than C. singularis, and larvae and adult abundance differed significantly both within and between the two species. Adults and larvae of both species were more abundant in connected bays, but only C. salviniae responded to both connectivity and hydrological cycle, with the highest abundances during the high-water and rising-water periods for adults and larvae, respectively. Abundance of C. singularis was negatively related to the predominance of C. salviniae, and populations of adults and larvae of both species were slightly and negatively related to the limnological variables and host-plant abundance. The results showed that the temporal variation in larval and adult abundance and dominance of C. salviniae is influenced by hydrological cycle and connectivity, but not by limnological variables and host-plant abundance.

Resumo: O efeito do ciclo hidrológico sobre a abundância de adultos e larvas dos curculionídeos Cyrtobagous salviniae e Cyrtobagous singularis do Pantanal foi testado e relacionado com a abundância das plantas hospedeiras, variáveis limnológicas e conectividade hidrológica de 10 baías do rio Cuiabá. Os adultos e larvas de C. salviniae foram mais abundantes do que C. singularis, e a abundância de larvas e adultos diferiu significativamente intra e interespecificamente. Adultos e larvas de ambas espécies foram mais abundantes em baías conectadas, mas apenas C. salviniae respondeu ao ciclo hidrológico, com a maior abundância de adultos durante o período de cheia, e maior abundância de larvas na enchente. A abundância de C. singularis foi relacionada negativamente com a predominância de C. salviniae, e a abundância de adultos e larvas de ambas espécies foi fraca e negativamente relacionada com as variáveis limnológicas e abundância das plantas hospedeiras. Os resultados demonstraram que a variação temporal na abundância de larvas e adultos e a dominância de C. salviniae foram influenciadas pela conectividade e ciclo hidrológico, mas não pelas variáveis limnológicas e abundância das macrófitas aquáticas.

Feeding ecomorphologies in the fish genus Herichthys (Perciformes: Cichlidae) based on stomach content and lower pharyngeal jaw shape

Speciation is a multifactorial process with factors acting at different scales of space and time. Trophic niche segregation has promoted the diversification of cichlids fishes in lentic (lacustrine) environments, whether this is also the case in lotic (riverine) systems remains unknown. Herichthys is the genus of cichlids with the most boreal distribution in the Americas comprising 12 currently recognized species, most micro-endemic and only two with a wide distribution. In the present work, we analyzed the stomach content and lower pharyngeal jaw morphologies of the species of the genus to evaluate the possible role of feeding ecology in the diversification of the group. Trophic strategies varied widely, including omnivores, piscivores, invertivores, molluskivores, detritivores, herbivores and algivores. Low values of Pianka's index of niche overlap were found in the sympatric micro-endemic species, while in the widely distributed species the indices ranged from low to very high. The analysis of lower pharyngeal jaw morphologies allowed discriminating a shape associated with piscivorous species from other foraging groups. The results of this study suggest that trophic niche segregation is a factor that could promotes diversification within the genus Herichthys although additional studies need to be performed to fully understand the speciation process in this group of Neotropical cichlid fishes.

La especiación es un proceso con múltiples factores que actúan a diferentes escalas de espacio y tiempo. La segregación de nichos tróficos es un proceso que ha promovido la diversificación en cíclidos en entornos lacustres, pero en el caso de los ríos no está claro. Herichthys es un género de cíclidos cuya distribución es la más boreal en América, el cual comprende 12 especies actualmente reconocidas, la mayoría microendémicas y solo dos con una amplia distribución. En el presente trabajo, se analizó el contenido estomacal y las morfologías de la mandíbula faríngea inferior de las especies del género para compararlas y evaluar su posible papel en la diversificación del grupo. La dieta en dichas especies es muy variada e incluyó tanto especies que pueden ser consideradas omnívoras como especialistas. Se encontraron valores bajos del índice de solapamiento alimentario (índice de Pianka) en las especies simpátricas microendémicas, mientras que en las especies ampliamente distribuidas el índice fue muy variable. El análisis de morfometría geométrica de la mandíbula faríngea inferior permite discriminar dos formas principales, una que incluye la especie piscívora y otra que incluye a los otros grupos alimentarios. Los resultados encontrados en este estudio sugieren que la segregación de nicho trófico es un factor que promueve claramente la diversificación dentro del género Herichthys, aunque se deben realizar estudios adicionales para comprender completamente el proceso de especiación en este grupo de peces neotropicales.

Curculionídeos associados à Pistia stratiotes L. (Araceae) na Amazônia Central, com novos registros para Argentinorhynchus Brèthes (Coleoptera, Curculionidae) / Weevils associated with Pistia stratiotes L. (Araceae) in the Central Amazon Region, with new records for Argentinorhynchus Brèthes (Coleoptera, Curculionidae)

São apresentados, pela primeira vez para o Brasil, dados sobre a ocorrência de dez espécies de curculionídeos associadas à Pistia stratiotes L. (Araceae), provenientes da Ilha de Marchantaria, Manaus (Amazonas, Brasil). Durante o período de março a agosto de 2005 foram amostrados 809 espécimens de curculionídeos sobre P. stratiotes, distribuídos em nove espécies alocadas em cinco gêneros de Stenopelmini, e uma espécie não identificada pertencente à Cryptorhynchinae. Dentre os Stenopelmini, Argentinorhynchus breyeri Brèthes, 1910 (N = 665) foi a espécie dominante, com a maior abundância em julho (N = 189), e a menor em agosto (N = 11); Ochetina uniformis Pascoe, 1881 (N = 63), Neochetina bruchi Hustache, 1926 (N = 45), Neohydronomus pulchellus Hustache, 1926 (N = 15), Neohydronomus affinis Hustache, 1926 (N = 10), A. squamosus (Hustache, 1926) (N = 5), Neochetina eichhorniae Warner, 1970 (N = 4), A. minimus O'Brien & Wibmer, 1989b (N = 1) e Tanysphiroideus sp. (N = 1) apresentaram abundância inferior. Além disto, registra-se para o Brasil a co-ocorrência de A. breyeri, A. minimus e A. squamosus sobre P. stratiotes, e para o estado do Amazonas, o primeiro registro de A. minimus e A. squamosus.

Data on the occurrence of ten weevils species associated with Pistia stratiotes L. (Araceae), from Ilha de Marchantaria, Manaus (Amazonas, Brazil) are presented for the first time. During the period from March to August 2005, 809 weevils specimens were sampled on P. stratiotes, distributed across nine species allocated in five genera of Stenopelmini, in addition to one unidentified species in the Cryptorhynchinae. Among the Stenopelmini, Argentinorhynchus breyeri Brèthes, 1910 (N = 665) was the dominant species, with the highest abundance in July (N = 189) and the lowest in August (N = 11), while Ochetina uniformis Pascoe, 1881 (N = 63), Neochetina bruchi Hustache, 1926 (N = 45), Neohydronomus pulchellus Hustache, 1926 (N = 15), Neohydronomus affinis Hustache, 1926 (N = 10), A. squamosus (Hustache, 1926) (N = 5), Neochetina eichhorniae Warner, 1970 (N = 4), A. minimus O'Brien & Wibmer, 1989b (N = 1), and Tanysphiroideus sp. (N = 1) had lower abundances. In addition, the co-occurrences of A. breyeri, A. minimus, and A. squamosus on P. stratiotes were recorded for Brazil and the first records of A. minimus and A. squamosus were observed for the State of Amazonas.

Diferenciación morfológica y molecular de Oleria makrena (Hewitson) y Oleria fumata (Haensch) (Lepidoptera: Ithomiinae) / Molecular and morphological differentiation of Oleria makrena (Hewitson) and Oleria fumata (Haensch) (Lepidoptera: Ithomiinae)

Oleria spp. (tribu Olerinii) es un género de gran interés a nivel ecológico y evolutivo entre los Ithomiinae. La identificación de sus especies con base en caracteres morfológicos puede ser compleja debido a que la mayoría de ellas están involucradas en anillos miméticos y poseen grandes similitudes. En muestreos de mariposas ithomiinae realizados en el Suroeste Antioqueño, Colombia, se encontraron especímenes con patrones alares que dificultaron el registro de una o dos especies en la zona de estudio. Los especímenes se examinaron en detalle incluyendo observaciones de los genitales de machos y hembras y obtención de secuencias nucleotídicas además de los caracteres tradicionales de venación y coloración alar. Se verificó la presencia de Oleria makrena (Hewitson) y Oleria fumata (Haensch) y se precisó la utilidad de cada uno de los caracteres en la diferenciación de las dos especies. En los machos, la separación de ambas especies pudo realizarse con base en la morfología alar y coincidió con la realizada mediante los genitales y las secuencias de ADN. Sin embargo, en el caso de las hembras los patrones de venación alar fueron confusos y se requirió el uso de los genitales. Las secuencias de la región corta de ADN (gen ND4) usada, permitieron realizar una diferenciación rápida y acertada de las especies que coincidió con la obtenida por los genitales tanto femeninos como masculinos. El análisis del fragmento de 579 pb señaló la existencia de 46 diferencias nucleotídicas entre las dos especies.

Oleria (Olerinii tribe) is a genus of great ecological and evolutionary importance among the Ithomiinae (Nymphalidae). Species identification is very complex since most of them are involved in mimicry rings and share large morphological similarities. Ithomiinae specimens collected in the Antioquia Southwest - Colombia, showed confuse wing color pattern generating diffi culties to define the presence of one or two species at the sampled region. Collected specimens were studied in detail using male and female genitalia and nucleotide sequences besides traditional character of wing color and venation. Oleria makrena (Hewitson) and Oleria fumata (Haensch) were registered and the relative utility of each character for species identification was defi ned. For males, wing color pattern was enough to differentiate both species, and the separation of specimens by this character was congruent with the separation obtained by using genitalia and DNA sequences. However, for females, wing patterns were not enough for the adequate separation or species and genitalia-based characters were necessary. DNA sequences of a short fragment of the mitochondrial gene ND4 allowed for the rapid and precise differentiation of both species, coinciding with the separation using genitalia for both males and females. The analysis of 579 base pairs (bp) indicated 46 nucleotide differences between both species.

Genetic divergence between two sympatric species of the Lutzomyia longipalpis complex in the paralytic gene, a locus associated with insecticide resistance and lovesong production

The sandfly Lutzomyia longipalpis s.l. is the main vector of American Visceral Leishmaniasis. L. longipalpis s.l. is a species complex but until recently the existence of cryptic sibling species among Brazilian populations was a controversial issue. A fragment of paralytic (para), a voltage dependent sodium channel gene associated with insecticide resistance and courtship song production in Drosophila, was isolated and used as a molecular marker to study the divergence between two sympatric siblings of the L. longipalpis complex from Sobral, Brazil. The results revealed para as the first single locus DNA marker presenting fixed differences between the two species in this locality. In addition, two low frequency amino-acid changes in an otherwise very conserved region of the channel were observed, raising the possibility that it might be associated with incipient resistance in this vector. To the best of our knowledge, the present study represents the first population genetics analysis of insecticide resistance genes in this important leishmaniasis vector.

Advertisement calls of two anuran amphibians, Rana tigrina and Tomopterna breviceps.

Rana tigrina and Tomopterna breviceps occur as sympatric species at Dharwad, India. Sexually mature males produce advertisement calls. The advertisement call of both the species consist of a number of calls produced in series forming a call group· Each call group of Rana tigrina comprises 10-40 calls, whereas that of Tomopterna breviceps consists 13-141 calls. Each call consists of a pulse group with variable number of pulses which lack pulse interval. Calls of both the species exhibit similarities in (i) call consisting of series of calls with a pulse group in each call, (ii) absence of pulse interval within the pulse group, (iii) the amplitude of the first pulse being always small, and (iv) the frequency spectrum beginning from 200 Hz. Based on the similarities in the spectral features of the calls, it is suggested that the two species may be closely related to each other.