Fil: Lencinas, Maria Vanessa. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Austral de Investigaciones Cientificas; Argentina

The value of timber quality forests for insect conservation on Tierra del Fuego Island compared to associated non-timber quality stands

Clonality is a common characteristic of successful invasive species, but general principles underpinning the success of clonal invaders are not established. A number of mechanisms could contribute to invasion success including clones with broad tolerances and preferences, specialist clones and adaptation in situ. The majority of studies to date have been of plants and some invertebrate parthenogens, particularly aphids, and have not necessarily caught invasion at very early stages. Here we describe the early stages of an invasion by a Northern Hemisphere Hymenopteran model in three different land masses in the Southern Hemisphere. Nematus oligospilus Forster (Hymenoptera: Tenthredinidae), a sawfly feeding on willows (Salix spp.), was recently introduced to the Southern Hemisphere where it has become invasive and is strictly parthenogenetic. In this study, the number of N. oligospilus clones, their distribution in the landscape and on different willow hosts in South Africa, New Zealand and Australia were assessed using 25 microsatellite markers. Evidence is presented for the presence of two very common and widespread multilocus genotypes (MLGs) or ‘superclones’ dominating in the three countries. Rarer MLGs were closely related to the most widespread superclone; it is plausible that all N. oligospilus individuals were derived from a single clone. A few initial introductions to Australia and New Zealand seemed to have occurred. Our results point towards a separate introduction in Western Australia, potentially from South Africa. Rarer clones that were dominant locally putatively arose in situ, and might be locally favoured, or simply have not yet had time to spread. Data presented represent rare baseline data early in the invasion process for insights into the mechanisms that underlie the success of a global invader, and develop Nematus oligospilus as a valuable model to understand invasion genetics of clonal pests.

/pdf/unravelling-the-paradox-of-loss-of-genetic-variation-during-3q49l4d4c2.pdf

Unravelling the paradox of loss of genetic variation during invasion: superclones may explain the success of a clonal invader.

A synopsis of the sawflies (Hymenoptera: Symphyta) of America South of the United States: Tenthredinidae (Nematinae, Heterarthrinae, Tenthredininae).

Fil: Braccini, Celina L.. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion de Recursos Naturales. Instituto de Recursos Biologicos; Argentina

Both Volatiles and Cuticular Plant Compounds Determine Oviposition of the Willow Sawfly Nematus oligospilus on Leaves of Salix spp. (Salicaceae)

Interactions between landscape-scale processes and fine-grained habitat heterogeneity are usually invoked to explain species occupancy in fragmented landscapes. In variegated landscapes, however, organisms face continuous variation in micro-habitat features, which makes necessary to consider ecologically meaningful estimates of habitat quality at different spatial scales. We evaluated the spatial scales at which forest cover and tree quality make the greatest contribution to the occupancy of the long-horned beetle Microplophorus magellanicus (Coleoptera: Cerambycidae) in a variegated forest landscape. We used averaged data of tree quality (as derived from remote sensing estimates of the decay stage of single trees) and spatially independent pheromone-baited traps to model the occurrence probability as a function of multiple cross-scale combinations between forest cover and tree quality (with scales ranging between 50 and 400 m). Model support and performance increased monotonically with the increasing scale at which tree quality was measured. Forest cover was not significant, and did not exhibit scale-specific effects on the occurrence probability of M. magellanicus. The interactive effect between tree quality and forest cover was stronger than the independent (additive) effects of tree quality and particularly forest cover. Significant interactions included tree quality measured at spatial scales ≥200 m, but cross-scale interactions occurred only in four of the seven best-supported models. M. magellanicus respond to the high-quality trees available in the landscape rather than to the amount of forest per se. Conservation of viable metapopulations of M. magellanicus should consider the quality of trees at spatial scales >200 m.

Occupancy pattern of a long-horned beetle in a variegated forest landscape: linkages between tree quality and forest cover across spatial scales

SUMMARY In Moquehue, Pilhue and Filcun (Dept. of Alumine - Neuquen - Argentina) which are part of the north Subantarctic Forests the main tree-species are Araucaria araucana (Mol.) Koch (Araucariaceae) and Nothofagus dombeyi (Mirb.) Oerst., N. pumilio (Poepp. et Endl.) Krasser and N. antarctica (Forster) Oerst. (Fagaceae). Information concerning the entomological fauna and flora of these native forests exploited since the 1950's for their timber, is scarce. The capture insects were associated with their hosts by observation and bibliography. The Lepidoptera collected belong to 55 species of 11 families, which are associated with Nothofagus spp.: 11, with forest grove vegetation: 17, with native forest species: 3, with exotic forest species: 7. There are 7 poliphagous species (some cosmopolitan) and 22 which do not have identified hosts. Some species, have more than one relationship. Species related with A. araucana were not found.

Lepidópteros de los bosques nativos del Departamento Aluminé (Neuquén-Argentina)*

N. desantisi was found, for the first time, as a new species in the lower valley of Rio Chubut, Argentina, in 1980/ 81. It showed an extensive and fast spread in this country (3.000 km in 9-10 years). It was detected in Santiago de Chile in 1983/84. It causes intensive defoliations and loss of trees in Salix sp., and it also damages Populus sp., very important trees in Patagonia. Consequently it was decided to study its bioecology in Rio Negro and Neuquen. The results indicate that, at present, it is found in the whole basin of the rio Negro. The following aspects are described: date of beginning the oviposition, date of starting in diapause, oviposition and morphology of egg, larvae, pupae and imago. It has 4-5 generations/year, and these are overlapped. Three new parasitoids were found which were classified by De Santis: Pteromalidae sp., Isdromas gigantii sp. nov. (Ichneumonidae) and Cirrospilus gracielae sp. nov. (Eulophidae). The following species are mentioned as new hosts: Salix alba, S. elegantissima, S. matsudana and Populus alba.

Bioecología de Nematus desantisi Smith (Hymenoptera: Tenthredinidae: Nematinae) en las provincias de Río Negro y Neuquén (Argentina)

Resumen en: The Pehuen District is in the sub-Antarctic forests of Argentina, between 37o 48' S and 40o S, and varies greatly in distance from its border with Chile ...

Lepidópteros de los bosques nativos del Departamento Aluminé (Neuquén-Argentina): II Contribución

Lepidoptera of the native forests in the Department of Aluminé, Neuquén, Argentina.

Periclista dapotoae, Smith, n. sp., is described from Argentina and Chile and separated from the described species ofPericJista from South America. It was reared from Nothofagus antarctica (Fagaceae). Periclista leucoma is a new combination.

Humberto Giganti

Papers

Lepidópteros de los bosques nativos del Departamento Aluminé (Neuquén-Argentina)*

Bioecología de Nematus desantisi Smith (Hymenoptera: Tenthredinidae: Nematinae) en las provincias de Río Negro y Neuquén (Argentina)

Lepidópteros de los bosques nativos del Departamento Aluminé (Neuquén-Argentina): II Contribución

Lepidoptera of the native forests in the Department of Aluminé, Neuquén, Argentina.

A new species of Periclista (Hymenoptera: Tenthredinidae) associated with Nothofagus (Fagaceae) in Argentina and Chile.