Experimental studies on the life-cycle ofRaillietiella gigliolii(Pentastomida: Cephalobaenida) in the South American worm-lizardAmphisbaena alba: a unique interaction involving two insects

Parasitology ◽  
1985 ◽  
Vol 91 (3) ◽  
pp. 471-481 ◽  
Author(s):  
Judith M. Winch ◽  
J. Riley
Keyword(s):  
Life Cycle ◽  
Experimental Studies ◽  
South American ◽  
Atta Cephalotes ◽  
The South ◽  
Rhinoceros Beetle ◽  
Trophic Links ◽  
High Prevalence ◽  
Leaf Cutting ◽  
Refuse Dumps

SUMMARYRaillietiella giglioliiis a cephalobaenid pentastomid which inhabits the lungs of the South American worm-lizardAmphisbaena alba. The host is a facultative inquiline of nests of the leaf-cutting antAtta cephaloteswhere it feeds occasionally (and possibly by accident) on ants but more often on beetles and their larvae which are themselves inquilines of ant nests. Ants store exhausted leaf-substrate in special underground chambers which serve as refuse dumps and it is here that larvae of the three-horned rhinoceros beetleCoetosis bilobafeed: these larvae are also known to be prey items ofA. alba. From observations of captive colonies ofAtta, we have demonstrated that pentastomid-egg contaminated faeces ofA. alba, introduced into the colony, are rapidly cut up and thrown onto the refuse dump, where, under natural circumstances they will be eaten byCoelosis. These larvae have an unusual and highly specialized gut physiology and parasite eggs will develop to an infective stage within the haemocoel in 70–96 days. Cockroaches are refractory to infection. Ants are the vital link in transmission since they literally deliver eggs to theCoelosislarvae. The strong trophic links which exist between the various components of the life-cycle offset a low fecundity of 100 eggs/female parasite/day but nonetheless maintain a high prevalence (86%) of infection.

The role of the vascular endothelium in arenavirus haemorrhagic fevers

2009 ◽  
Vol 102 (12) ◽  
pp. 1024-1029 ◽  
Author(s):  
Stefan Kunz
Keyword(s):  
Vascular Endothelium ◽  
Cell Function ◽  
Experimental Studies ◽  
Lassa Fever ◽  
Vascular Involvement ◽  
Lassa Virus ◽  
South American ◽  
The South ◽  
Endothelial Cell Function

SummaryViral haemorrhagic fevers (VHF) caused by arenaviruses are among the most devastating emerging human diseases.The most important pathogen among the arenaviruses is Lassa virus (LASV), the causative agent of Lassa fever that is endemic to West Africa. On the South American continent, the New World arenavirus Junin virus (JUNV), Machupo (MACV), Guanarito (GTOV), and Sabia virus (SABV) have emerged as causative agents of severe VHFs. Clinical and experimental studies on arenavirus VHF have revealed a crucial role of the endothelium in their pathogenesis. However, in contrast to other VHFs, haemorrhages are not a salient feature of Lassa fever and fatal cases do not show overt destruction of vascular tissue.The functional alteration of the vascular endothelium that precede shock and death in fatal Lassa fever may be due to more subtle direct or indirect effects of the virus on endothelial cells. Haemorrhagic disease manifestations and vascular involvement are more pronounced in the VHF caused by the South American haemorrhagic fever viruses. Recent studies on JUNV revealed perturbation of specific endothelial cell function, including expression of cell adhesion molecules, coagulation factors, and vasoactive mediators as a consequence of productive viral infection.These studies provided first possible links to some of the vascular abnormalities observed in patients; however, their relevance in vivo remains to be investigated.

Description of a new Amblystira (Hemiptera: Heteroptera: Tingidae) from Argentina with a key to the South American species of the genus

Zootaxa ◽  
2010 ◽  
Vol 2675 (1) ◽  
pp. 65 ◽  
Author(s):  
SARA I. MONTEMAYOR
Keyword(s):  
Life Cycle ◽  
South America ◽  
Manihot Esculenta ◽  
New World ◽  
South American ◽  
The South ◽  
South American Species ◽  
Manihot Esculenta Crantz ◽  
Important Crop

Amblystira Stål is a new world American genus comprising nineteen species, most of them distributed in Central and South America. Nine species have been recorded from South America, and only Amblystira silvicola Drake is known from Argentina (Drake & Ruhoff, 1965). Members of the genus are dark, the cephalic spines are generally absent or poorly developed, the hood is absent, the paranota are scarcely developed or absent as well as the lateral pronotal carinae, the discoidal area is short not reaching the middle of the hemelytra, and the costal area is slender. The only member of the genus that has been recorded as a pest is Amblystira machalana Van Duzee, commonly known as “black lacebug”, which feeds on cassava, Manihot esculenta Crantz, an important crop of South America. Arias & Belloti (2003) studied the life cycle, behavior, and damage caused by A. machalana on M. esculenta. (Guilbert, 2005) described the fifth instar of Amblystira peltogyne Drake & Hambleton.

scholarly journals Occurrence of Leaf-Cutting and Grass-Cutting Ants of the Genus Atta (Hymenoptera: Formicidae) in Geographic Regions of Brazil

Sociobiology ◽  
2020 ◽  
Vol 67 (4) ◽  
pp. 514
Author(s):  
Luiz Carlos Forti ◽  
Jael Santos Rando ◽  
Roberto Da Silva Camargo ◽  
Aldenise Alves Moreira ◽  
Maria Aparecida Castellani ◽  
...  
Keyword(s):  
Southern Region ◽  
Atta Cephalotes ◽  
The South ◽  
Atta Sexdens ◽  
Atta Laevigata ◽  
Leaf Cutting ◽  
Geographic Regions ◽  
Atta Opaciceps ◽  
Southeastern Region ◽  
Comprehensive Study

Leaf-cutting ants are widely distributed in Brazil, particularly species of the genus Atta. We therefore described the occurrence of leaf-cutting and grass-cutting ant species of the genus Atta. Five routes comprising some of the main highways in the South, Southeast, Center-West, and North of Brazil were sampled, in addition to ants received from other 82 municipalities, composing 300 municipalities sampled. This is the first comprehensive study of Atta in Brazil. The following species were found: A. laevigata, A. capiguara, A. sexdens rubropilosa, A. sexdens piriventris, A. sexdens sexdens and A. cephalotes. Atta laevigata and A. capiguara were the species present in the largest number of the Brazilian municipalities sampled. Atta laevigata assumed the position of species of greatest occurrence in the Brazilian territory. Atta sexdens piriventris was only recorded in the southern region of Brazil. Atta bisphaerica presented lower expansion than A. capiguara. Atta cephalotes and Atta opaciceps are species of very restricted occurrence. Southeastern region was characterized by the occurrence of A. capiguara and A. laevigata. Atta laevigata exhibited a generalized pattern of occurrence in the Center-West and North. Our study contributes to a better understanding of the so far unknown occurrence of leaf-cutting and grass-cutting ants within Brazil.

scholarly journals The Life Cycle of the South American Monsoon System

2008 ◽  
Vol 21 (23) ◽  
pp. 6227-6246 ◽  
Author(s):  
Adma Raia ◽  
Iracema Fonsecade Albuquerque Cavalcanti
Keyword(s):  
Life Cycle ◽  
Zonal Wind ◽  
Late Onset ◽  
Low Frequency ◽  
Monsoon Onset ◽  
South American ◽  
The South ◽  
South American Monsoon ◽  
Monsoon System ◽  
South American Monsoon System

Abstract The South American monsoon system (SAMS) life cycle plays an important role in the distribution and duration of the rainy season mainly over southwestern Amazonia, and the central west and southeast Brazil regions, affecting the economy through impacts on the agriculture and hydrology sectors. In this study a new criterion is applied to identify the monsoon onset and demise that was not used before in the SAMS region. This criterion is based on the atmospheric humidity flux over an area recognized as the monsoon core because of zonal wind reversal and changes in humidity from the transition seasons to summer and winter. Areas in Brazil that have a monsoon regime are identified, and several features associated with the life cycle are discussed. The climatological onset and demise are identified as the end of October and the end of March, respectively, and an interannual variability is found in the times of onset/demise. The main observed features in the two phases are discussed, such as the role of the South Atlantic subtropical high displacement, the northwestern moisture flux east of Andes and from the Atlantic Ocean, the zonal wind intensity and direction over central South America, the vertical motion over the continent, and the expansion/reduction of the Bolivian high circulation with associated high-level divergence. The frontal systems contribute to the pressure decrease, wind direction changes, and soil moisture increase previous to the onset. Low-frequency troughs with intraseasonal variability establish conditions favorable to the monsoon onset, and low-frequency ridges are related to late onset.

Cnidochloa: A New Genus of Grasses from Brazil (Poaceae: Panicoideae: Paniceae)

2020 ◽  
Vol 105 (2) ◽  
pp. 183-194
Author(s):  
Fernando O. Zuloaga ◽  
Sandra S. Aliscioni ◽  
M. Amalia Scataglini
Keyword(s):  
New Genus ◽  
Phylogenetic Position ◽  
South American ◽  
The South ◽  
South American Species ◽  
Molecular Characters

Generic boundaries of the South American species Panicum longipedicellatum Swallen are explored and compared with allied genera of the tribe Paniceae. On the basis of morphological, anatomical, and molecular characters a new genus, Cnidochloa Zuloaga, is proposed. The phylogenetic position of the new genus within the Paniceae is evaluated.

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