The Biotic Environment

accumulated by cucumber beetles. In Lepidoptera the chemicals are accumulated by the 697

caterpillar stage and are transferred at metamorphosis to the adult. Further, in some species the female endows her eggs with the toxin so that they, too, are protected (Blum and Hilker, 2002). Most insect species that sequester toxins from their host plant are aposematically (brightly and distinctly) colored, a feature commonly indicative of a distasteful organism and one that makes them stand out against the background of their host plant. On sampling such insects, a would-be vertebrate predator discovers their unpalatability and quickly learns to avoid insects having a particular color pattern. Remarkably, a few insect predators have evolved tolerance to the plant-produced toxins stored by their insect prey and are, themselves, unpalatable to predators further up the food chain (Eisner et al., 1997). The fourth advantage to be gained by tolerance to these plant products is protection against pathogenic microorganisms. For example, cardiac glycosides in the hemolymph of the large milkweed bug, Oncopeltus fasciatus, have a strong antibacterial effect. Also, cucurbitacins sequestered by the adult female cucumber beetle, Diabrotica undecimpunctata howardi, provide antifungal protection for her eggs and offspring (Tallamy et al., 1998).

The channeling of energy into production of toxic or repellent substances is the most often used method by which plants may obtain protection, though others are known. A few plants expend this "energy of protection" on formation of structures that prevent or deter feeding, or even harm would-be feeders. For example, passion flowers (Passiflora adenopoda) have minute hooked hairs that grip the integument of caterpillars attempting to feed on them. The hairs both impede movement and tear the integument as the caterpillars struggle to free themselves so that the insects die from starvation and/or desiccation (Gilbert, 1971). Leguminous plants have evolved a variety of physical (as well as chemical) mechanisms to protect their seeds from Bruchidae (pea and bean weevils). These include production of gum as a larva penetrates the seed pod so that the insect is drowned or its movements hindered, production of a flaky pod surface that is shed, carrying the weevil's eggs with it, as the pod breaks open to expose its seeds, and production of pods that open explosively so that seeds are immediately dispersed and, therefore, not available to females that oviposit directly on seeds (Center and Johnson, 1974).

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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