The multidimensional nutritional niche of fungus-cultivar provisioning in free-ranging colonies of a neotropical leafcutter ant.

Foraging trails of leafcutter colonies are iconic scenes in the Neotropics, with ants collecting freshly cut plant fragments to provision a fungal food crop. We hypothesised that the fungus-cultivar's requirements for macronutrients and minerals govern the foraging niche breadth of Atta colombica leafcutter ants. Analyses of plant fragments carried by foragers showed how nutrients from fruits, flowers and leaves combine to maximise cultivar performance. While the most commonly foraged leaves delivered excess protein relative to the cultivar's needs, in vitro experiments showed that the minerals P, Al and Fe may expand the leafcutter foraging niche by enhancing the cultivar's tolerance to protein-biased substrates. A suite of other minerals reduces cultivar performance in ways that may render plant fragments with optimal macronutrient blends unsuitable for provisioning. Our approach highlights how the nutritional challenges of provisioning a mutualist can govern the multidimensional realised niche available to a generalist insect herbivore.

Obstructive jaundice induced by biliary ascariasis.

Ascaris lumbricoides is one of the most prevalent parasitic infections, especially in developing countries. Its presence can lead to a multitude of presentations, one of the rarer ones being obstructive jaundice due to migration of the worm in to the biliary tree. We describe a case of a man who presented as an emergency to the general surgeons complaining of abdominal pain, fever, jaundice and vomiting. Ultrasound was used and the diagnosis of biliary ascariasis was made. The patient underwent surgery consisting of a cholecystectomy, common bile duct exploration and T-tube choledochostomy. Our report highlights the varied aetiology of obstructive jaundice and the importance of including biliary ascariasis in the differential diagnosis of the jaundiced patient, especially from endemic areas.