In the graph packing problem we are given several graphs and have to map them into a single host graph G such that each edge of G is used at most once. Much research has been devoted to the packing of trees, especially to the case where the host graph must be planar. More formally, the problem is: Given any two trees T1 and T2 on n vertices, we want a simple planar graph G on n vertices such th...

We describe seven new species of Spathidexia (Diptera: Tachinidae) reared from Area de Conservación Guanacaste (ACG), northwestern Costa Rica. All were reared from -various species of ACG caterpillars during an ongoing inventory of caterpillars, their food plants and their parasitoids. By coupling morphology, photographic documentation, life history and molecular data, we provide a clear and co...

The forest tent caterpillar,Malacosoma disstriaHübner (Lepidoptera: Lasiocampidae), is distributed throughout North American hardwood forests. Although considered polyphagous, regional populations tend to use only a few host species for oviposition, suggesting that M. disstria is more oligophagous than commonly thought. We tested this premise using larvae from Manitoba, Canada; Michigan; and Lo...

A linear arrangement is a mapping π from the n vertices of graph G to distinct consecutive integers. Linear arrangements can be represented by drawing along horizontal line and edges as semicircles above said line. In this setting, length an edge defined absolute value difference between positions its two in arrangement, cost sum all lengths. Here we study variants Maximum Arrangement problem (...

Positive species interactions have the potential to strongly influence the structure and dynamics of ecological communities, yet surprisingly few studies have documented their general importance. We tested the hypothesis that the mutualistic association between fire ants and aphids enhances the impact of fire ants on the herbivorous and predaceous arthropod community of cotton. We found that th...

Predators have played a significant role in the evolution of herbivorous insects, and we can observe a wide variety of larval defense mechanisms in nature, especially among members of the Lepidoptera. Slug caterpillars (Limacodidae) are known for their unusual morphologies, including various types of protuberances and stinging spines on their dorsal surfaces, which suggest that their evolution ...

Caterpillars have an impressive array of defenses to avoid being eaten. For example, they may blend in extremely well with their background (Cott 1940; Edmunds 1974, 1990), they may mimic potential predators of their own predators (Nentwig 1985; Pough 1988), they may construct shelters (Fitzgerald 1980; Fitzgerald and Willer 1983; Damman 1987), and they may be unpalatable due to urticating hair...