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Montevideo, Uruguay

Stanley E.,Institute Investigaciones Biologicas Clemente Estable | Francescoli G.,Seccion Etologia | Toscano-Gadea C.A.,Institute Investigaciones Biologicas Clemente Estable
Journal of Arachnology | Year: 2016

In order to study how sexual selection takes place during mating, it is necessary to have a clear knowledge of the interactions that occur throughout mating and which morphological and behavioral traits are involved. Available information about harvestman reproductive biology is mainly restricted to anecdotal field observations, most of them lacking a detailed description and quantification of mating behavior. In this paper, we study the reproductive behavior of the gonyleptid Pachyloides thorellii Holmberg, 1878 (Pachylinae) and provide quantitative and descriptive information about its sexual behavior. We observed 15 matings, measured females and males, and analysed our behavioral data in the context of individuals' sizes. We observed conspicuous pre-copulatory, copulatory and post-copulatory courtship. We also found that females have several strategies to reject males' mating attempts. Like most gonyleptids, males and females of P. thorellii mate in face-to-face position; however, we observed that both male and female clasp their chelicerae mutually. This behavior has not previously been reported for the suborder Laniatores. The information obtained through this study establishes the basis for further studies on this species' reproductive biology and supports the suitability of this species as a model to explore the importance of male copulatory courtship for female choice and sperm use. Source


Tejera L.,Institute Ciencias Geologicas | Invernizzi C.,Seccion Etologia
Archivos de Zootecnia | Year: 2013

Honey production in Uruguay occurs mainly during spring and summer. However, on the East coast beekeepers can extend their production into autumn and winter. To analyze this situation we chose an apiary located at the mentioned area where population parameters were recorded during a year. Nectar and pollen loads samples were also analyzed to determine their botanical origin. Over the sampling period, the colonies had high population sizes. Eucalyptus spp. pollen was dominant in most nectar and pollen samples. Other relevant species were Baccharis spp. Trifolium repens, Acacia longifolia, Lotus sp. y Eryngium spp. Source


Chalkbrood disease is a mycosis of honey bee (Apis mellifera) larvae caused by the heterothallic fungus Ascophaera apis. In infected colonies it is often found that drone larvae are more affected than worker larvae and this difference is attributed to the higher probability of chilling of drone brood. Given the great differences found between worker and drone larvae, however, it would be expected to find differential physiological resistance to chalkbrood disease. Additionally, if hygienic behaviour of adult bees (uncapping of cells containing dead brood and its subsequent removal) is expressed differently in worker and drone cells, it may differentially affect the proportion of mummified larvae of each sex. The goal of this research was to determine how physiological resistance and hygienic behaviour affect chalkbrood incidence in worker and drone larvae. Firstly, the proportion of worker and drone larvae mummified after receiving food containing A. apis spores was determined. Then hygienic behaviour in relation to dead brood of both sexes was evaluated. It was found that drone larvae mummify and have fruiting bodies in a greater proportion than worker larvae and that hygienic behaviour is more efficient in relation to worker rather than drone cells. These results indicate that physiological susceptibility and hygienic behaviour are two factors that could explain satisfactorily the greater proportion of mummified drones found in diseased colonies. © IBRA 2012. Source


Antunez K.,Institute Investigaciones Biologicas Clemente Estable | Mendoza Y.,Instituto Nacional Of Investigacion Agropecuaria La Estanzuela | Santos E.,Seccion Etologia | Invernizzi C.,Seccion Etologia
Journal of Apicultural Research | Year: 2013

Nosema apis and Nosema ceranae are causative agents of Nosemosis in the honey bee Apis mellifera, although N. ceranae may cause a more virulent disease. Selection of colonies with high tolerance to N. ceranae could be important for reducing problems caused by this pathogen. The aim of the present work was to evaluate the existence of honey bee colonies with different degrees of N. ceranae infection and test if this difference could be related to the immune response or vitellogenin expression. Healthy honey bee colonies were relocated to a plantation of Eucalyptus grandis to favour natural infection of N. ceranae. Fifteen and thirty days after relocation, the proportion of infected bees and the number of N. ceranae spores per field were quantified. The colonies with higher and lower levels of infection (HL and LL, respectively) were selected. Newly emerged bees from both colonies were artificially infected with N. ceranae and seven days after infection the expression of immune related genes and vitellogenin was evaluated by real time PCR. No significant differences were observed in expression of abaecin, hymenoptaecin, defensin, glucose dehydrogenase or lysozyme mRNA levels between infected bees from HL and LL colonies or between control bees from both colonies. Vitellogenin expression was higher in bees from the LL colony than in bees from the HL colony, when infected or control bees were compared between them. This protein possesses pleiotropic effects and is a central element in the life-history of honey bees. For that reason, its differential expression could be associated with resistance to N. ceranae. © IBRA 2013. Source


Two different vocalization patterns for long-range (S-Type) vocal signals were detected in species of the genus Ctenomys. These patterns were described separately for C. pearsoni, C. mendocinus, and C. talarum. This paper gathers information about the vocalizations of other species, such as C. sociabilis, C. rionegrensis and C. torquatus. We confirm the existence of these patterns, identify which of those two patterns each species uses, and suggest some possible explanations about how these patterns could have originated. © SAREM, 2010. Source

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