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700 or late in the season, when temperatures may not be much above freezing, must provide a large enough reward to make foraging profitable at these temperatures. An alternative to production of large amounts of nectar by individual flowers is for plants that bloom at lower temperatures to grow in high density and flower synchronously (Heinrich and Raven, 1972).

Beyond a certain distance between plants, however, the amount of nectar that an insect requires to collect at each plant (in order to remain "interested" in that species) exceeds the maximum amount that the plant is able to produce. Thus, the plant must adopt a different strategy. Among orchids, for example, about one half of the species produce no nectar, but rely on other methods to attract insects, especially deception by mimicry. The flowers may resemble (1) other nectar-producing flowers, (2) female insects so that males are attracted and attempt pseudocopulation, (3) hosts of insect parasitoids, or (4) insects that are subsequently attacked by other territorial insects. These somewhat risky methods of attracting insects are offset by the evolution of highly specific pollen receptors (so that only pollen from the correct species is acquired) and a high degree of seed set for each pollination (Price, 1997).

It is important for both plants and insects that insects visit members of the same plant species. The chances of this occurring are greatly increased (1) when the plant species has a restricted period of bloom, in terms of both season and/or time of day; (2) where members of a species grow in aggregations, though this is counterbalanced by a restriction of gene flow if pollinators work within a particular plant population; and (3) when the flowers are easily recognized by an insect which learns to associate a given plant species with food. Recognition is achieved as a result of flower morphology (and related to this is accessibility of the nectar and pollen), color, and scent. The advantage to an insect species when its members can recognize particular flowers is that, through natural selection, the species will become more efficient at gathering and utilizing the food produced by those flowers.

The degree of influence that these variables exert is manifest as a spectrum of intimacy between plants and their insect pollinators. At one end of the spectrum, the plant-insect relationship is non-specific; that is, a variety of insect species serve as pollinators for a variety of plants. Neither insects nor flowers are especially modified structurally or physiologically. At the opposite extreme, the relationship is such that a plant species is pollinated by a single insect species. Structural features of the pollinator precisely complement flower morphology; the plant's blooming period is synchronized with the life history and diurnal activity of the insect; and, where present, nectar is produced in exactly the right quantity and quality to satisfy the insect's requirements.

Harvester ants (those that use seeds as food) are important seed dispersers, resulting from accidental loss of the seeds as they transport them back to the nest or by failure to use the seeds before they germinate. This activity partially compensates for the damage caused to the plant by the ants' seed predation. This mutualistic relationship has been taken to a new level of sophistication by myrmecochorous plants, which produce attractive appendages (elaiosomes) on their seeds and chemicals to induce the ants to transport the seeds without damaging them (Figure 23.4). The elaiosomes are rich in nutrients and form the food of the ants, while the seed itself is discarded. Though examples of myrmecochory are known worldwide, it seems to be a phenomenon ofhabitats that are nutrient-poor (especially those deficient in phosphorus and potassium), notably the dry schlerophyll regions of Australia and South Africa where more than 90% of the 3100 known species of myrmecochorous plants are found. It has been speculated that plants in these habitats use myrmecochory because energetically it is far less expensive than the production of the larger fruits preferred by vertebrates (Beattie, 1985; Holldobler and Wilson, 1990).

FIGURE 23.4. Workers of Formica podzolica from the northern United States gathering violet (Viola nuttallii) seeds. Note the elaiosomes that will later be eaten by colony members. [From A. J. Beattie. 1985, The Evolutionary Theory of Ant-Plant Mutualisms. By permission of Cambridge University Press.]

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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