Bumblebees acquire alternative puzzle-box solutions via social learning.

The astonishing behavioural repertoires of social insects have been thought largely innate, but these insects have repeatedly demonstrated remarkable capacities for both individual and social learning. Using the bumblebee Bombus terrestris as a model, we developed a two-option puzzle box task and used open diffusion paradigms to observe the transmission of novel, nonnatural foraging behaviours through populations. Box-opening behaviour spread through colonies seeded with a demonstrator trained to perform 1 of the 2 possible behavioural variants, and the observers acquired the demonstrated variant. This preference persisted among observers even when the alternative technique was discovered. In control diffusion experiments that lacked a demonstrator, some bees spontaneously opened the puzzle boxes but were significantly less proficient than those that learned in the presence of a demonstrator. This suggested that social learning was crucial to proper acquisition of box opening. Additional open diffusion experiments where 2 behavioural variants were initially present in similar proportions ended with a single variant becoming dominant, due to stochastic processes. We discuss whether these results, which replicate those found in primates and birds, might indicate a capacity for culture in bumblebees.

Foraging Bumblebees Selectively Attend to Other Types of Bees Based on Their Reward-Predictive Value.

Using social information can be an efficient strategy for learning in a new environment while reducing the risks associated with trial-and-error learning. Whereas social information from conspecifics has long been assumed to be preferentially attended by animals, heterospecifics can also provide relevant information. Because different species may vary in their informative value, using heterospecific social information indiscriminately can be ineffective and even detrimental. Here, we evaluated how selective use of social information might arise at a proximate level in bumblebees (Bombus terrestris) as a result of experience with demonstrators differing in their visual appearance and in their informative value as reward predictors. Bumblebees were first trained to discriminate rewarding from unrewarding flowers based on which type of "heterospecific" (one of two differently painted model bees) was next to each flower. Subsequently, these bumblebees were exposed to a novel foraging context with two live painted bees. In this novel context, observer bumblebees showed significantly more social information-seeking behavior towards the type of bees that had predicted reward during training. Bumblebees were not attracted by paint-marked small wooden balls (moved via magnets) or paint-marked non-pollinating heterospecifics (woodlice; Porcellio laevis) in the novel context, indicating that bees did not simply respond to conditioned color cues nor to irrelevant social cues, but rather had a "search image" of what previously constituted a valuable, versus invaluable, information provider. The behavior of our bumblebees suggests that their use of social information is governed by learning, is selective, and extends beyond conspecifics.

Primary melanoma of the adrenal gland: a case report and review of the literature.

BACKGROUND: Primary melanoma of the adrenal gland is exceptionally rare as demonstrated by the few cases reported in the medical literature, and it has a high fatality rate. We present the case of a patient with two relapses and survival to date. CASE REPORT: We describe the case of a 58-year-old Caucasian woman who consulted her doctor with symptoms of asthenia, anorexia and weight loss. A mass was palpated in her abdomen at the height of the left hypochondrium. A computed tomographic scan revealed a retroperitoneal mass measuring 10 cm × 15 cm originating in the left adrenal gland. A left nephroadrenalectomy and splenectomy were performed. Histopathologically, the retroperitoneal mass corresponded to a melanoma, and no primary melanoma was found in any other location. The patient was treated with interferon-α-2b. Three years after her diagnosis the patient presented with a retroperitoneal relapse of the mass measuring 7.2 cm, which was removed. Five years after the first relapse a new retroperitoneal relapse mass was diagnosed, which was also removed. Since then the patient has been healthy and free from illness. CONCLUSION: Histological and immunohistochemical studies, together with the criteria described by Ainsworth et al. and Carstens et al., allowed us to diagnose primary melanoma of the adrenal gland.