Ehrlich and Raven's postulate that rapid diversification follows innovation in plant defense has often been invoked a posteriori for lineages of unusual diversity chemical distinctiveness. The can be more rigorously tested by defining novel class using and/or anatomical criteria, independent taxonomic lineage. If multiple have evolved the new type, then according to they should consistently diverse than their sister groups (of equal age, definition) when latter retain primitive defensive...

Many mandibulate insects that feed on milkweeds, or other latex-producing plants, cut leaf veins before feeding distal to the cuts. Vein cutting blocks latex flow intended sites and can be viewed as an insect counteradaptation plant's defensive secretion. Experimental vein severance renders milkweed leaves edible generalist herbivores do not show vein-cutting behaviors ordinarily ignore milkweeds in nature.

To determine if the arrangement of secretory canals in leaves affects foraging by folivorous insects, we examined behaviors 33 species found on diverse canal—bearing plants. Insect were categorized into three principal classes: vein cutting, trenching, and neither behavior. Canal architectures ascertained damaging with standardized tests measuring response Our observations document a precise correspondence between herbivore behavior canal morphology. Vein—cutting insects occur plants...

To test if secretory canals limit the host ranges of polyphagous moth larvae, we measured growth Trichoplusia ni (cabbage looper) and Spodoptera ornithogalli (yellow—striped armyworm) on plants in nine families, including species with without canals. Larvae were reared to final instar excised leaves plant, weighed, then enclosed field either detached depressurized or intact undamaged After 24 h, larvae reweighed examined for evidence trenching. For comparison, additional generalist...

Aphids and other insects alighting on lettuce inflorescences, Lactuca sativa L., often rupture latex canals causing exudation. I sought to determine how frequently aphids become trapped in exudate, release latex, parts compare their propensity for trapping insects. For the last objective, compared survivorship reproduction of whiteflies leaves, flower stalks (pedicels), bracts, buds black seeded Simpson lettuce. The two most abundant planted near Beltsville, MD, were Uroleucon pseudambrosiae...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolyene pheromone components from an arctiid moth (Utetheisa ornatrix): characterization and synthesisSubhash C. Jain, David E. Dussourd, William Conner, Thomas Eisner, Angel Guerrero, Jerrold MeinwaldCite this: J. Org. Chem. 1983, 48, 13, 2266–2270Publication Date (Print):July 1, 1983Publication History Published online1 May 2002Published inissue 1 July...

According to the escalation–radiation model of co-evolution, insect herbivores that acquire ability circumvent a plant defence enter new adaptive zone and increase in species. How herbivore counter-adaptations defences might lead speciation is poorly understood. Studies nymphalid butterflies suggest evolution broadened host range may be critical step. This paper examines if leaf-feeding insects capable deactivating defensive canals with canal cutting often have broad ranges. A total 94...

In North America, notodontid caterpillars feed almost exclusively on hardwood trees. One notable exception, Theroa zethus feeds instead herbaceous plants in the Euphorbiaceae protected by laticifers. These elongate canals follow leaf veins and contain latex under pressure; rupture causes immediate release of sticky poisonous exudate. T. larvae deactivate defense poinsettia other euphorbs applying acid from their ventral eversible gland, thereby creating furrows veins. The secretion softens...

Unlike most notodontids, Theroa zethus larvae feed on plants that emit copious latex when damaged. To determine how the overcome this defense, we filmed final instars poinsettia, Euphorbia pulcherrima, then simulated their behaviors and tested individually combined affect exudation. Larvae initially scraped stem, petiole, or midrib with mandibles, secreted acid from ventral eversible gland (VEG) onto abraded surface. Scraping facilitated penetration by disrupting waxy cuticle. As softened...

After feeding on a tree leaf, caterpillars in ten families sever the petiole and allow remaining leaf fragment to fall ground. Previous researchers proposed that thereby reduced bird predation by eliminating visual evidence of feeding. In this study, 26 species five were filmed clipping leaves. Caterpillar behavior did not conform cue hypothesis. Some clipped midribs petioles repeatedly even though single clip would suffice reduce cues for birds. Every caterpillar rubbed its spinneret (which...