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1. Endosymbiont-free ants: molecular biological evidence that neither Wolbachia, Cardinium or any other bacterial endosymbionts play a role in thelytokous parthenogenesis in the harvester ant species, Messor barbarus and M. capitatus (Hymenoptera: Formicidae)

Creator:
Martínez-Rodríguez, Paloma, Sarasa, Jonás, Peco, Gegona, Jauregui, Berta M., Rivera, Desiree, and Bella, Jose L.
Type:
article, články, model:article, and TEXT
Subject:
Zoologie, zoologie, entomologie, Wolbachia, Cardinium, Spiroplasma, endosymbionts, Formicidae, Messor, thelytokous parthenogenesis, 2, and 59
Language:
English
Description:
Thelytokous parthenogenesis is a type of sex determination in which females are produced from unfertilized eggs. Genetic and endosymbiont-induced forms of thelytoky have been described in the Hymenoptera. Our study has revealed that Wolbachia, Cardinium, Spiroplasma and other endosymbionts are probably absent in Iberian populations of harvester ants, Messor barbarus and Messor capitatus (Hymenoptera: Formicidae: Myrmicinae) and are thus not involved as factors in the sex determination of these two species. Our results lend weight to previous suggestions that bacterial parthenogenesis induction in Hymenoptera is probably limited to the reproductive systems of chalcidoid and cynipoid parasitoid wasps (Hymenoptera: Apocrita: Chalcidoidea and Cynipoidea, respectively)., Paloma Martínez-Rodríguez ... [et al.]., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2. Life-history of the parthenogenetic oonopid spider, Triaeris stenaspis (Araneae: Oonopidae)

Creator:
Korenko, Stanislav , Šmerda, Jakub , and Pekár, Stano
Type:
article, model:article, and TEXT
Subject:
Araneae, Oonopidae, Triaeris stenaspis, ontogeny, life cycle, development, fecundity, parthenogenesis, endosymbionts, Wolbachia, and Cardinium
Language:
English
Description:
Selected life-history traits of an oonopid spider, Triaeris stenaspis Simon, which has been introduced into greenhouses in Europe, were investigated. Spiders were reared in the laboratory under constant physical and dietary conditions, and followed from egg to death. The spiders passed through 3 juvenile instars, each lasting approximately a month. The adult stage lasted on average 6 months, which is 54% of the entire life cycle. The mortality in each juvenile instar was similar. Five morphological characters were recorded for each instar, which provided a reliable means of identifying the developmental stages. All spiders developed into females and although kept isolated they laid fertile eggs, which indicates thelytokous parthenogenesis. Eggs were always enclosed in a disc-shaped egg-sac, each containing 2 eggs. Total fecundity was on average 27 eggs and rate of laying eggs decreased with age. Fecundity was positively correlated with adult longevity. Fertility was rather low, approximately 59%. It was negatively correlated with fecundity but not related to longevity. Low fertility appears to be the only cost of parthenogenetic reproduction. There was considerable genotypic variation in all traits studied compared to that in sexually reproducing spiders. There were no apparent maternal effects on all the traits studied. Using molecular methods proved that parthenogenesis in T. stenaspis is not induced by the endosymbiotic bacteria, Wolbachia sp. or Cardinium sp.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public