Bandwidth is one of the canonical NP-complete problems [17]. It is NP-hard to approximate within any constant, even on trees [22]. Gupta gave a randomized approximation algorithm [8] for bandwidth on trees, which has an approximation ratio of O(log n). This algorithm has the best currently known approximation ratio on trees. Gupta showed that his algorithm has an approximation ratio of O(log n)...

– The black and red medium-sized parasitoid wasp Bassus brooksi Sharkey n. sp. (Braconidae) is described from wild-caught specimens from dry forest habitats ranging from northern Mexico to the northwestern Costa Rican coastal plain, and from specimens reared from the Area de Conservacion Guanacaste, Costa Rica. The wasp larvae develop in the caterpillars of a relatively unrelated array of at le...

• Certain plant species hyperaccumulate selenium (Se) up to 0.6% of their dry weight. It is not known whether Se hyperaccumulation offers the plants any advantage. In this study the hypothesis was tested that Se can protect plants from invertebrate herbivory or fungal infection. • Indian mustard ( Brassica juncea ) plants grown with or without Se were subjected to herbivory by caterpillars ( Pi...

The cellular arm of the insect immune response is mediated by the activity of hemocytes. While hemocytes have been well-characterized morphologically and functionally in model insects, few studies have characterized the hemocytes of non-model insects. Further, the role of ontogeny in mediating immune response is not well understood in non-model invertebrate systems. The goals of the current stu...

1. Plants are frequently under attack by multiple insect herbivores, which may interact indirectly through herbivore-induced changes in the plant's phenotype. The identity, order, and timing of herbivore arrivals may influence the outcome of interactions between two herbivores. How these aspects affect, in turn, subsequently arriving herbivores that feed on double herbivore-induced plants has n...

Caterpillars have long been used as models for studying animal defence. Their impressive armour, including flamboyant warning colours, poisonous spines, irritating sprays, and mimicry of plant parts, snakes and bird droppings, has been extensively documented. But research has mainly focused on visual and chemical displays. Here we show that some caterpillars also exhibit sonic displays. During ...

Nutritional regulation is a powerful mechanism used by generalist feeders to obtain the balance of nutrients they require from nutritionally diverse, perhaps unbalanced, foods. We examined nutritional regulation in a species with a narrow individual diet breadth: the forest tent caterpillar, Malacosoma disstria. Fourth instar caterpillars were provided with artificial foods consisting of differ...

The very species-rich tropical moth genus Eois Hübner (Lepidoptera: Geometridae) is a promising model group for studying host plant specialization and adaptive radiation. While most Eois species are assumed to be specialized herbivores on Piper L. species, records on other plant taxa such as Peperomia Ruiz & Pavón (Piperaceae) are still relatively scarce. Moreover, little is known about life hi...

1. Because predation risk typically alters how prey forage for food, interactions between predation risk and food availability are commonly found. Less is known about how host plant quality and predation risk interact to affect prey behaviour and physiology. 2. Using the caterpillar, Manduca sexta , and its predator, Podisus maculiventris , the effects of predation risk and host plant quality o...

Temperature and crowding are key environmental factors mediating the transmission and epizooty of infectious disease in ectotherm animals. The host physiology may be altered in a temperature-dependent manner and thus affects the pathogen development and course of diseases within an individual and host population, or the transmission rates (or infectivity) of pathogens shift linearly with the ho...