El registro más septentrional de la libélula gigante neotropical Megaloprepus caerulatus (Drury, 1782) (Odonata: Coenagrionidae) en el continente Americano

Megaloprepus caerulatus (Drury, 1782) is one of the largest damselfl ies in the world and it is recorded here for the fi rst time in Acomul, state of Hidalgo, Mexico, being this the northernmost record known in the American Continent, which allows us to discuss its current geographic distribution and its taxonomic status.Megaloprepus caerulatus (Drury, 1782) es una de las libélulas más grandes en el mundo y se registra aquí por primera vez en Acomul, Hidalgo, México, siendo éste el registro más septentrional conocido en el Continente Americano, lo que permite discutir su distribución geográfi ca actual y su estatus taxonómico

Synaptic vesicle binding of α-synuclein is modulated by β- and γ-synucleins

α-synuclein, β-synuclein, and γ-synuclein are abundantly expressed proteins in the vertebrate nervous system. α-synuclein functions in neurotransmitter release by binding to and clustering synaptic vesicles and chaperoning SNARE-complex assembly. Pathologically, aggregates originating from soluble pools of α-synuclein are deposited into Lewy bodies in Parkinson’s disease and related synucleinopathies. The functions of β-synuclein and γ-synuclein in presynaptic terminals remain poorly studied. Using in vitro liposome binding studies, circular dichroism spectroscopy, immunoprecipitation, and fluorescence resonance energy transfer (FRET) experiments on isolated synaptic vesicles in combination with subcellular fractionation of brains from synuclein mouse models, we show that β-synuclein and γ-synuclein have a reduced affinity toward synaptic vesicles compared with α-synuclein, and that heteromerization of β-synuclein or γ-synuclein with α-synuclein results in reduced synaptic vesicle binding of α-synuclein in a concentration-dependent manner. Our data suggest that β-synuclein and γ-synuclein are modulators of synaptic vesicle binding of α-synuclein and thereby reduce α-synuclein’s physiological activity at the neuronal synapse

Long-term studies of the red imported fire ant, Solenopsis invicta, infected with the microsporidia Vairimorpha invictae and Thelohania solenopsae in Argentina. Environmental Entomology 34

ABSTRACT A study was conducted on populations of the red imported Þre ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), infected with the microsporidia Vairimorpha invictae Jouvenaz and Ellis (Microsporidia: Burenellidae) and Thelohania solenopsae Knell, Allen, and Hazard (Microsporidia: Thelohaniidae). Fire ant populations and microsporidia prevalence were monitored three to Þve times per year for 3Ð 4 yr in eight Þeld plots in northern Argentina. The mean population index per plot showed an overall reduction of 69%. The percentage of infection with V. invictae and T. solenopsae showed ßuctuations that ranged from 29.2 to 1.4% and 13.6 to 2.6%, respectively. The highest infection rates were observed at the beginning of the study. A total of 394 colonies were sampled during the study: 325 (82.5%) were healthy and 69 (17.5%) were infected with microsporidia. The proportion of infected colonies with brood was 81% (56/69), similar to the proportion of healthy colonies with brood (78%; 255/325). The proportion of infected and healthy colonies in the population index categories was signiÞcantly different. Of the infected colonies with brood, 49.3% were medium and 1.4% were large in size. In contrast, healthy colonies were generally larger, with 29.7 and 10.4% being medium and large, respectively. The general environmental conditions in the area of the plots were appropriate for Þre ant population growth; consequently, they do not explain the overall reduction in the populations. These results, combined with additional evidence reported previously, suggest that infection with V. invictae and T. solenopsae has a deleterious effect on native populations of S. invicta

Fire Ants (Solenopsis spp.) and Their Natural Enemies in Southern South America

We review the fire ant research conducted by the ARS-South American Biological Control Laboratory (SABCL) since 1987 to find a complex of natural enemies in southern South America and evaluate their specificity and suitability for field release as self-sustaining biological control agents. We also include those studies conducted by the ARS-Center for Medical, Agriculture, and Veterinary Entomology in the United States with the SABCL collaboration. Ecological and biological information is reported on local fire ants and their microsporidia, nematodes, viruses, phorid flies, eucharitid wasps, strepsiptera, and parasitic ants. Their biology, abundance, distribution, detrimental effect, field persistence, specificity, and phenology are discussed. We conclude that the objectives of the ARS program in South America are being achieved and that the pioneering studies have served to encourage further investigations in the United States and other countries and advanced the implementation of biological control programs to decrease imported fire ant densities and damage. Still, several promising organisms should be further investigated for eventual field release in the near future

Local co-occurrence of several highly invasive ants in their native range: are they all ecologically dominant species?

An important goal of invasion ecology is to understand the colonization, establishment, and spread of exotic species. To accomplish this, it is essential to examine the ecology of introduced species in native populations. We examined organization patterns, spatial structure, and competitive abilities of ground-dwelling ants in different habitats of a protected area in east-central Argentina, where several highly invasive ant species naturally coexist, to determine whether all they are ecologically dominant in their native range as in their introduced range. We sampled ant communities at Otamendi Nature Reserve and found 49 ant species co-occurred with moderate separation among habitats, including five species that are global invaders; but only Solenopsis richteri (the most numerically dominant) and Linepithema humile (the best mass recruiter) were ecologically co-dominant along with another three non-invasive species in locally rich assemblages. Their co-occurrence was apparently facilitated by both niche and competitive differences. However, we found no evidence for discovery-dominance trade-offs, and ant diversity and spatial segregation suggested that competition only plays a secondary role in structuring assemblages in arboreal habitats. Despite L. humile and S. richteri were ecologically co-dominant, their hegemony was lower in the reserve than in their introduced range likely due to biotic resistance. The other invasive ants (Wasmannia auropunctata, Brachymyrmex patagonicus, and Nylanderia fulva) were not dominant. It is possible that their establishment, persistence, and high prevalence in anthropic habitats in native and introduced populations to be attributed to their better physiologic adaptations to disturbed habitats rather than to their superior competitive abilities.Fil: Calcaterra, Luis Alberto. Fundación para el Estudio de Especies Invasivas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sonia, Cabrera. Fundación para el Estudio de Especies Invasivas; ArgentinaFil: Briano, Juan. Fundación para el Estudio de Especies Invasivas; Argentin

Ecological dominance of the red imported fire ant, Solenopsis invicta, in its native range

© 2008 Springer. Part of Springer Science+Business MediaDespite the widespread impacts invasive species can have in introduced populations, little is known about competitive mechanisms and dominance hierarchies between invaders and similar taxa in their native range. This study examines interactions between the red imported fire ant, Solenopsis invicta, and other above-ground foraging ants in two habitats in northeastern Argentina. A combination of pitfall traps and baits was used to characterize the ant communities, their dominance relationships, and to evaluate the effect of phorid flies on the interactions. Twenty-eight ant species coexisted with S. invicta in a gallery forest gap, whereas only ten coexisted with S. invicta in a xerophytic forest grassland. S. invicta was the most numerically dominant species in the richest and complex habitat (gallery forest); however it performed better as discoverer and dominator in the simpler habitat. S. invicta was active during day and night. In spite of its poor capacity to discover resources, S. invicta showed the highest ecological dominance and the second-best behavioral dominance after Camponotus blandus. S. invicta won 78% of the interactions with other ants, mostly against its most frequent competitor, Pheidole cf. obscurithorax, dominating baits via mass recruitment and chemical aggression. P. cf. obscurithorax was the best food discoverer. S. invicta won 80% of the scarce interactions with Linepithema humile. Crematogaster quadriformis was one of the fastest foragers and the only ant that won an equal number of contests against S. invicta. The low presence of phorid flies affected the foraging rate of S. invicta, but not the outcome of interspecific interactions. This study revealed that the red imported fire ant ecologically dominated other terrestrial ants in its native range; however, other species were able to be numerically dominant or co-dominant in its presenceLuis A. Calcaterra, Juan. P. Livore, Alicia Delgado and Juan A. Brian