We study the maximum differential coloring problem, where the vertices of an n-vertex graph must be labeled with distinct numbers ranging from 1 to n, so that the minimum absolute difference between two labels of any two adjacent vertices is maximized. As the problem is NP-hard for general graphs [16], we consider planar graphs and subclasses thereof. We prove that the maximum differential colo...

In recent years, large amounts of pesticides are used to achieve record harvests (for example, DDT has been used in Mexico for more than 50 years) [1], [2]). DDT is forbidden in the U.S., Canada and Europe because causes cancer. To reduce the pesticide amount it is necessary to locate precisely the distribution of insects and caterpillars. This task is very important not only for crops but also...

The mechanisms underlying responses of invertebrates to forest edges remain poorly understood. Here, we use an experimental approach to investigate the predation rates on butterflies in two neotropical forest fragments. Neither distance from forest edge nor degree of forest openness affected predation rates on artificial caterpillars. The mean predation rate of artificial caterpillars on Barro ...

A broadcast on a graph G is a function f : V → {0, 1, 2, . . . }. The broadcast number of G is the minimum value of ∑ v∈V f(v) among all broadcasts f for which each vertex of G is within distance f(v) from some vertex v with f(v) ≥ 1. The broadcast number is bounded above by the radius and the domination number of G. We consider a class of trees that contains the caterpillars and characterize t...

BACKGROUND Recent studies have demonstrated the utility of DNA barcoding in the discovery of overlooked species and in the connection of immature and adult stages. In this study, we use DNA barcoding to examine diversity patterns in 121 species of Nymphalidae from the Yucatan Peninsula in Mexico. Our results suggest the presence of cryptic species in 8 of these 121 taxa. As well, the reference ...

Photo 1: A colony of Hylesia caterpillars lying dormant at the base a guava tree in Trinidad. They aggregate tightly to avoid detection by predators. also possess urticating hairs deter predator attacks. Photograph credit: Graham L. White. 2: Every evening, journey tight procession up trunk (left) and along branches (right) feed on leaves canopy, then return again dawn. If one individual stops,...

this study examines the assumption that plant resistance to herbivory has fitness costs. to assess costs, i used the standard method of determining whether there is a significant negative genetic correlation between the resistance character and damage in the presence of herbivory and with fitness in the absence of herbivory. seeds of five plants from four genotypes of arabidopsis thaliana were ...

Peroxides are formed in the midgut fluids of caterpillars when ingested tannins and other phenolic compounds oxidize. If these peroxides broke down in the presence of redox-active metal ions, they would form damaging free radicals (Fenton-type reactions). Elemental iron is present in relatively large amounts in leaves and artificial diets, but little is known about its concentration and redox s...

We demonstrate the advantage of using a many-sorted resolution calculus by a mechanical solution of a challenge problem. This problem known as "Schubert's Steamroller" had been unsolved by automated theorem provers until now. Our solution clearly demonstrates the power of a many-sorted resolution calculus. The proposed method is applicable to all resolution-based inference systems. 1, SCHUBERT'...

Virtually all studies of plant-herbivore-natural enemy interactions focus on plant quality as the major constraint on development and survival. However, for many gregarious feeding insect herbivores that feed on small or ephemeral plants, the quantity of resources is much more limiting, yet this area has received virtually no attention. Here, in both lab and semi-field experiments using tents c...