Ambient air temperature does not predict body size of foragers in bumble bees (Bombus impatiens)

Bumble bees are important pollinators of crops and other plants. However, many aspects of their basic biology remain relatively unexplored. For example, one important and unusual natural history feature in bumble bees is the massive size variation seen between workers of the same nest. This size polymorphism may be an adaptation for division of labor, colony economics, or be nonadaptive. It was also suggested that perhaps this variation allows for niche specialization in workers foraging at different temperatures: larger bees might be better suited to forage at cooler temperatures and smaller bees might be better suited to forage at warmer temperatures. This we tested here using a large, enclosed growth chamber, where we were able to regulate the ambient temperature.We found no significant effect of ambient or nest temperature on the average size of bees flying to and foraging from a suspended feeder. Instead, bees of all sizes successfully flew and foraged between 16C and 36C. Thus, large bees foraged even at very hot temperatures, which we thought might cause overheating. Size variation therefore could not be explained in terms of niche specialization for foragers at different temperature

Discrimination Training with Multimodal Stimuli Changes Activity in the Mushroom Body of the Hawkmoth Manduca sexta

The mushroom bodies of the insect brain play an important role in olfactory processing, associative learning and memory. The mushroom bodies show odor-specific spatial patterns of activity and are also influenced by visual stimuli.Functional imaging was used to investigate changes in the in vivo responses of the mushroom body of the hawkmoth Manduca sexta during multimodal discrimination training. A visual and an odour stimulus were presented either together or individually. Initially, mushroom body activation patterns were identical to the odour stimulus and the multimodal stimulus. After training, however, the mushroom body response to the rewarded multimodal stimulus was significantly lower than the response to the unrewarded unimodal odour stimulus, indicating that the coding of the stimuli had changed as a result of training. The opposite pattern was seen when only the unimodal odour stimulus was rewarded. In this case, the mushroom body was more strongly activated by the multimodal stimuli after training. When no stimuli were rewarded, the mushroom body activity decreased for both the multimodal and unimodal odour stimuli. There was no measurable response to the unimodal visual stimulus in any of the experiments. These results can be explained using a connectionist model where the mushroom body is assumed to be excited by olfactory stimulus components, and suppressed by multimodal configurations.Discrimination training with multimodal stimuli consisting of visual and odour cues leads to stimulus specific changes in the in vivo responses of the mushroom body of the hawkmoth

Location, location, location: larvae position inside the nest is correlated with adult body size in worker bumble bees (Bombus impatiens)

Social insects display task-related division of labour. In some species, division of labour is related to differences in body size, and worker caste members display morphological adaptations suited for particular tasks. Bumble-bee workers (Bombus spp.) can vary in mass by eight- to tenfold within a single colony, which previous work has linked to division of labour. However, little is known about the proximate mechanism behind the production of this wide range of size variation within the worker caste. Here, we quantify the larval feeding in Bombus impatiens in different nest zones of increasing distance from the centre. There was a significant difference in the number of feedings per larva across zones, with a significant decrease in feeding rates as one moved outwards from the centre of the nest. Likewise, the diameter of the pupae in the peripheral zones was significantly smaller than that of pupae in the centre. Therefore, we conclude that the differential feeding of larvae within a nest, which leads to the size variation within the worker caste, is based on the location of brood clumps. Our work is consistent with the hypothesis that some larvae are 'forgotten', providing a possible first mechanism for the creation of size polymorphism in B. impatiens

Natural history and imaging in men with high genetic risk for developing prostate cancer

Prostate cancer is the most common malignancy and the second leading cause of cancer related deaths in the United States. Established risk factors for prostate cancer incidence include older age, African-American race, and positive family history. Prostate cancer has substantial inherited predisposition and certain genetic variants are associated with increased risk of disease. Screening and imaging should target high-risk populations based on their genetic predisposition

Percent lipid is associated with body size but not task in the bumble bee Bombus impatiens

In some group-living organisms, labor is divided among individuals. This allocation to particular tasks is frequently stable and predicted by individual physiology. Social insects are excellent model organisms in which to investigate the interplay between physiology and individual behavior, as division of labor is an important feature within colonies, and individual physiology varies among the highly related individuals of the colony. Previous studies have investigated what factors are important in determining how likely an individual is, compared to nestmates, to perform certain tasks. One such task is foraging. Corpulence (i.e., percent lipid) has been shown to determine foraging propensity in honey bees and ants, with leaner individuals being more likely to be foragers. Is this a general trend across all social insects? Here we report data analyzing the individual physiology, specifically the percent lipid, of worker bumble bees (Bombus impatiens) from whom we also analyze behavioral task data. Bumble bees are also unusual among the social bees in that workers may vary widely in size. Surprisingly we find that, unlike other social insects, percent lipid is not associated with task propensity. Rather, body size closely predicts individual relative lipid stores, with smaller worker bees being allometrically fatter than larger worker bee

PSA progression compared to radiographic or clinical progression in metastatic castration-resistant prostate cancer patients treated with enzalutamide

Abstract only 105 Background: Enzalutamideis ahighly effective treatment in patients with metastatic castration resistant prostate cancer (mCRPC). Although Prostate Cancer Working Group Guidelines (PCWG) recommend continuing treatment until radiographic progression of disease (rPD) or clinical progression (cPD), many patients discontinue therapy for rising PSA alone. Methods: We conducted an open label, randomized phase 2 clinical trial in mCRPC patients (on testosterone suppression therapy) previously untreated with docetaxel, abiraterone, or enzalutamide, comparing enzalutamide alone or in combination with PROSTVAC, a therapeutic cancer vaccine designed to induce an anti-tumor immune response. The study discontinued accrual after a planned interim analysis indicated no difference in progression between the two arms. Patients were followed beyond PSA progression (first of three confirmed PSA rises, evaluated monthly) until rPD per PCWG (scans done every 3 months per protocol). Results: A total of 57 patients were enrolled with a median follow up time of 55.4 months. Of those, 47 (82%) patients were Caucasian and seven (12%) patients were African American. The median age of patients on enrollment was 67.2 years. 49/57 (86%) patients had PSA progression and the median time to first PSA rise for all 57 patients combined was 6.4 months (95% CI: 3.7-11.0 months) after starting enzalutamide. 38/57 (67%) patients experienced progressive disease (majority with rPD and 1/38 (3%) with cPD), with the median time to progression for all 57 patients of 23.3 months (95% CI: 16.1-27.8 months). Conclusions: Consistent with PCWG recommendations, these data suggest that a rising PSA may not be a warning of near-term clinically significant disease progression in mCRPC patients given the nearly 17-month difference between the first rise in PSA and ultimate rPD or cPD seen in this analysis. These data highlight the need to continue to educate patients and providers on PCWG criteria for progression, which were also used in original trials that led to the FDA approval of enzalutamide, so as not to substantially limit the potential efficacy of mCRPC therapies such as enzalutamide. Clinical trial information: NCT01867333