170 research outputs found
Les Scelionidae de l'Archipel des Açores (Hymenoptera).
IX Expedição Científica do Departamento de Biologia - Terceira 1994.Distribution géographique de l’èspece Telenomus sp. Plusieurs espéces, appartenant à trois families, ont été capturé aux Açores
Contribution to the study of the egg parasitic Hymenoptera of the Azores Islands.
3rd International Symposium "Trichogramma and other egg parasitoids", San Antonio (Texas, USA), September 23-27, 1990.During the summer of 1989, several Hymenoptera egg and non egg parasitoids were captured in the island of Sao Miguel, Azores. The non egg parasitoids belong to the Ichneumonoidea, Cynipoidea, Ceraphronoidea, Proctotrupoidea (Diapriidae and Plastygasteridae) and Chalcidoidea (Aphelinidae and Eulophidae). The egg
parasites are Proctotrupoidea (Scelionidae) and Chalcidoidea (Mymaridae and Trichogrammatidae). These last ones belong to the genera: Gryon, Telenomus, Ooctonus, Anaphes and Trichogramma. They are the first egg parasitoids to be recorded from the Azores. The Trichogramma is T. cordubensis, only known from Spain and North Africa
Response to Selection for a High or a Low Sex Ratio in Wolbachia-infected Lines of Trichogramma cordubensis Subjected to High Temperature
Trichogramma cordubensis is an
egg parasitoid completely infected by endosymbiotic bacteria belonging to the Wolbachia genus and inducing the thelytokous mode of reproduction. Previous results showed that the thelytoky persistence at
high temperature is genetically variable. Experimental selection was performed to confirm these results
and to determine the possibilities of adaptation to the environment assuming cyclic bisexual reproduction. No selection was efficient and the genetic variability of the sex ratio at high temperature is probably lower than previously assumed. This reduces the adaptive possibilities in the studied Trichogramma
species.Установлено, что Trichogramma cordubensis - яйцевой паразит, характеризующийся наличием эндосимбионтных бактерий Wolbachia и телитокическим способом размножения. Отмечено, что устойчивость к высокой температуре у телитокических видов генетически варьирует. Проведена экспериментальная селекция линий с высоким и низким половым индексом для определения возможных адаптаций к условиям окружающей среды, вызывающим двуполый способ размножения. Установлено, что селекция выбранных линий была не эффективной. Генетически обусловленная изменчивость полового индекса при высокой температуре оказалась ниже, чем предполагалось. Отмечено, что это уменьшает адаптивные возможности T. cordubensis
Preliminary inventory of Hymenopteran egg parasitoids from Morocco
Le but de ce travail était de dresser la liste des parasitoïdes oophages du Maroc. Ceux-ci appartiennent à 18 espèces incluses dans quatre familles de Chalcidoidea et à 27 espèces, dont six espèces de Telenomus non décrites, incluses dans deux familles de Proctotrupoidea. Cette liste est accompagnée d’informations (qui sont nouvelles ou issues des travaux de divers auteurs) portant sur la morphologie, quelquefois sur des enzymes étudiées par électrophorèse, sur la distribution et sur la biologie de ces espèces, dont 9 sont nouvelles pour le Maroc. La plupart des espèces vivent aussi en Eurasie ou en Europe (74%) ou dans une zone géographique encore plus large (10%). Toutefois, 13% des espèces semblent endémiques au Maroc. Parmi les espèces non endémiques seules 3% vivent en Afrique. L’inventaire des parasitoïdes oophages marocains est encore très incomplet: il nécessite donc d’autres récoltes qui pourront révéler de nouveaux moyens de lutte biologique
Comparison of Wolbachia Bacterial Density in Females of Four Thelythokous Strains of Trichogramma cordubensis and T. evanescens (Hymenoptera, Trichogrammatidae)
The endosymbionts of the genus Wolbachia
infect numerous arthropods and nematods, and often cause different effects on the reproduction of
these hosts. The endosymbiotic bacteria Wolbachia induces the thelytokous mode of reproduction in
the egg parasitoids of the genus Trichogramma. The Dot-blot technique was performed to compare the
symbiont Wolbachia density using the wsp gene of Wolbachia and the 18S gene of Trichogramma. It was
established that Wolbachia density is not different in two host species, Trichogramma cordubensis Vargas
et Cabello and T. evanescens Haliday.Эндосимбиотические бактерии рода Wolbachia заражают различных артропод и нематод, оказывая различный эффект на их репродуктивные особенности. Бактерии рода Wolbachia вызывают телитокию у яйцеедов рода Trichogramma. Использована техника Dot-blot для сравнения плотности симбионта Wolbachia, с помощью выделения гена wsp у симбионта Wolbachia и гена 18S у Trichogramma. Экспериментально установлено, что плотность Wolbachia у двух видов, Trichogramma cordubensis Vargas et Cabello и T. evanescens Haliday, одинаковая
Heritable symbionts in a world of varying temperature
Heritable microbes represent an important component of the biology, ecology and evolution of many plants, animals and fungi, acting as both parasites and partners. In this review, we examine how heritable symbiont–host interactions may alter host thermal tolerance, and how the dynamics of these interactions may more generally be altered by thermal environment. Obligate symbionts, those required by their host, are considered to represent a thermally sensitive weak point for their host, associated with accumulation of deleterious mutations. As such, these symbionts may represent an important determinant of host thermal envelope and spatial distribution. We then examine the varied relationship between thermal environment and the frequency of facultative symbionts that provide ecologically contingent benefits or act as parasites. We note that some facultative symbionts directly alter host thermotolerance. We outline how thermal environment will alter the benefits/costs of infection more widely, and additionally modulate vertical transmission efficiency. Multiple patterns are observed, with symbionts being cold sensitive in some species and heat sensitive in others, with varying and non-coincident thresholds at which phenotype and transmission are ablated. Nevertheless, it is clear that studies aiming to predict ecological and evolutionary dynamics of symbiont–host interactions need to examine the interaction across a range of thermal environments. Finally, we discuss the importance of thermal sensitivity in predicting the success/failure of symbionts to spread into novel species following natural/engineered introduction
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