Consumo de Savia por Melanerpes cactorum y su Rol en la Estructuración de Ensambles de Aves en Bosques Secos

The White-fronted Woodpecker (Melanerpes cactorum) drills holes in branches and trunks to feed on sap flows, providing an energy-rich food resource for other birds. Here we describe ecological and behavioral traits of the White-fronted Woodpecker related to its sap-feeding habits in the semiarid Chaco of Argentina and explore the structure of the avian assemblage in relation to the sap resource. Sap consumption by the White-fronted Woodpecker and other sap-feeding species was strongly seasonal and positively associated with periods of resource scarcity. The White-fronted Woodpecker actively defended the sap wells from smaller birds. Specialist and facultative nectarivores that assimilate sucrose at a high rate represented an important proportion of sap-feeding birds. In this system of woodpecker, sap, and other sap-feeding species, each species’ consumption depends on its physiological and behavioral characteristics as well as on the availability of other food in the surrounding environment.Melanerpes cactorum perfora ramas y troncos de árboles y arbustos para consumir la savia que fluye de las perforaciones, posibilitando a otras especies de aves el acceso a un recurso de alto contenido energé- tico. En este estudio describimos rasgos de la historia natural de M. cactorum relacionados con su alimentación en el Chaco semiárido de Argentina e investigamos la estructuración de ensambles de aves en torno al recurso savia. Para M. cactorum y las especies de aves que consumieron savia, el consumo de savia fue marcadamente estacional, posiblemente asociado a periodos de escasez de recursos. Melanerpes cactorum defendió activamente las perforaciones ante algunas especies de aves cuya masa corporal fue menor a la de los carpinteros. Las especies nectarívoras especialistas y facultativas con alta tasa de asimilación de sacarosa representaron una importante proporción de las aves que consumieron savia. En el sistema carpinteros–savia–aves consumidoras de savia, el consumo de este recurso depende de características fisiológicas y comportamentales de las especies, como así también de la disponibilidad de otros recursos alimenticios en los ambientes que habitan.Fil: Nuñez Montellano, Maria Gabriela. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: Blendinger, Pedro Gerardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: Macchi, Leandro. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; Argentin

Fossil Carder Bee's nest from the Hominin locality of Taung, South Africa

The Buxton-Norlim Limeworks southwest of Taung, South Africa, is renowned for the discovery of the first Australopithecus africanus fossil, the ‘Taung Child’. The hominin was recovered from a distinctive pink calcrete that contains an abundance of invertebrate ichnofauna belonging to the Coprinisphaera ichnofacies. Here we describe the first fossil bee’s nest, attributed to the ichnogenus Celliforma, from the Plio-Pleistocene of Africa. Petrographic examination of a cell lining revealed the preservation of an intricate organic matrix lined with the calcitic casts of numerous plant trichomes–a nesting behaviour unique to the modern-day carder bees (Anthidiini). The presence of Celliforma considered alongside several other recorded ichnofossils can be indicative of a dry, savannah environment, in agreement with recent work on the palaeoenvironment of Plio-Pleistocene southern Africa. Moreover, the occurrence of ground-nesting bees provides further evidence that the pink calcrete deposits are of pedogenic origin, rather than speleogenic origin as has previously been assumed. This study demonstrates the potential value of insect trace fossils as palaeoenvironmental indicators

Approximate Trapdoors for Lattices and Smaller Hash-and-Sign Signatures

We study a relaxed notion of lattice trapdoor called approximate trapdoor, which is defined to be able to invert Ajtai\u27s one-way function approximately instead of exactly. The primary motivation of our study is to improve the efficiency of the cryptosystems built from lattice trapdoors, including the hash-and-sign signatures. Our main contribution is to construct an approximate trapdoor by modifying the gadget trapdoor proposed by Micciancio and Peikert. In particular, we show how to use the approximate gadget trapdoor to sample short preimages from a distribution that is simulatable without knowing the trapdoor. The analysis of the distribution uses a theorem (implicitly used in past works) regarding linear transformations of discrete Gaussians on lattices. Our approximate gadget trapdoor can be used together with the existing optimization techniques to improve the concrete performance of the hash-and-sign signature in the random oracle model under (Ring-)LWE and (Ring-)SIS assumptions. Our implementation shows that the sizes of the public-key and signature can be reduced by half from those in schemes built from exact trapdoors

La presencia de Proctotretus pectinatus (Sauria: iguanidae) en el norte de Córdoba

Proctotretus pectinatus es definida por Gallardo (1966 y 1971) como una especie pampásica. Los datos de distribución tomados de estos trabajos confirman su presencia exclusivamente al sur de 34° de latitud sur, en el sudoeste de Buenos Aires y en el este de La Pampa. No existen citas bibliográficas fidedignas que indiquen su presencia fuera de esta área.Asociación Herpetológica Argentin

Case 3360. The ichnogenus Coprinisphaera Sauer, 1955 (Ichnotaxa, Insecta, Coleoptera, Coprinisphaeridae): proposed conservation

Volume: 63Start Page: 243End Page: 24

Fig. 1 in Nests and Brood Balls of Two South American Species ofSulcophanaeusOlsoufieff, 1924 (Coleoptera: Scarabaeidae: Scarabaeinae: Phanaeini)

Fig. 1. Nests of Sulcophanaeus menelas and Sulcophanaeus imperator. A–C) Three morphologies of S. menelas nests: L-shaped tunnel partially filled with dung (A), straight and almost vertical tunnel containing a female (white arrow) (B), forked tunnel composed of two inclined branches provisioned with meniscate dung (C) (scale bars = 5 cm), D–E) Nesting chambers of S. menelas: shallow chamber laterally connected to a horizontal, angled tunnel (scale bar = 5 cm) (D) and deeper, closed chamber containing a brood ball located with the plug slightly inclined from the vertical axis (scale bar = 1 cm) (E), F–G) Branched nests of S. imperator composed of horizontal and shallow tunnels: T-shaped tunnel showing dung (black arrow) provisioned in the long branch and a female (white arrow) in a third parallel burrow (spatula = 25 cm) (F) and four interconnected tunnels, one of them Y-shaped (calipers = 21 cm) (G).Published as part of <i>Sánchez, M. V., Sarzetti, L., Dinghi, P. A. & Genise, J. F., 2012, Nests and Brood Balls of Two South American Species ofSulcophanaeusOlsoufieff, 1924 (Coleoptera: Scarabaeidae: Scarabaeinae: Phanaeini), pp. 55-62 in The Coleopterists Bulletin 66 (1)</i> on page 57, DOI: 10.1649/072.066.0114, <a href="http://zenodo.org/record/10107987">http://zenodo.org/record/10107987</a&gt