Significant reproductive skew in the facultatively polygynous ant Pheidole pallidula

Reproductive skew - the extent to which reproduction is unevenly shared between individuals in a social group - varies greatly between and within animal species. In this study, we investigated how queens share parentage in polygynous (multiple queen) colonies of the Mediterranean ant Pheidole pallidula. We used highly polymorphic microsatellites markers to determine parentage of gynes (new queens), males and workers in P. pallidula field colonies. The comparison of the genotypes of young and adult workers revealed a very low queen turnover (less than 2%). The first main finding of the study of reproductive skew in these colonies was that there was a significant departure from equal contribution of queens to gyne, male and worker production. Reproductive skew was greater for male production than for queen and worker production. There was no relationship between the magnitude of the reproductive skew and the number of reproductive queens per colony, their relatedness and the overall colony productivity, some of the factors predicted to influence the extent of reproductive skew. Finally, our study revealed for the first time a trade-off in the relative contribution of nestmate queens to gyne and worker production. The queens contributing more to gyne production contributed significantly less to worker production.

Metastatic bone disease

The skeleton is the first and most common site of distant relapse in breast and prostate carcinomas. Tumor bone disease is responsible for a considerable morbidity, which also makes major demands on resources for healthcare provision. Increased bone resorption in tumor bone disease appears to be essentially mediated by the ostoclasts, explaining why bisphosphonates have been successfully used for the treatment of malignant ostolysis. Hypercalcemia occurs in 10-20% of the patients with advanced cancer, and the uncoupling between bone resorption and bone formation is easily demonstrated by the measurement of bone markers. The differential diagnosis between tumor-induced hypercalcemia and primary hyperparathyroidism is most often easy when using intact parathyroid hormone (PTH) assays; moreover, parathyroid hormone-related protein (PTHrP) determination can be useful in selected cases. The diagnosis of bone metastases is often easy when the patient is symptomatic. The diagnostic usefulness of bone markers is limited, and the available data indicate that bone markers are so far unsuitable for an early diagnosis of neoplastic skeletal involvement on an individual basis. However, by combining bone-specific alkaline phosphatase (BALP) or modern bone resorption markers with specific tumor markers, such as PSA or CA15.3, the diagnostic sensitivity of bone markers can be improved. Their degree of elevation correlates with the tumor burden and has been shown to be an independent prognostic factor for several tumors. On the other hand, biochemical markers of bone turnover have the unique potential to simplify and improve the monitoring of metastatic bone disease, which remains a continuous challenge for the oncologist. Peptide-bound cross-links could be quite useful to discriminate between patients progressing early on treatment from those with longer disease control. Also, the diagnostic efficiency of a 50% increase in these markers could identify imminent progression. © 2006 Elsevier Inc. All rights reserved.