Flowers, beetle-pollinated

Gottsberger G. (1989) Beetle pollination and flowering rhythm of Annona spp. (Annonaceae) in Brazil. Plant System, and Evol. 16, 165-187. 

Many flowering plants attract insect pollinators by releasing odorant molecules that mimic an insect s natural food sources or potential egg-laying sites. Plants pollinated by flies or beetles that normally feed on or lay their eggs in dung or carrion sometimes use foulsmelling compounds to attract these insects. 

The pheromones can also be used to enhance a beneficial activity of the beetles. Nitidulids are primary pollinators of custard apple (Annona) flowers, but poor pollination has often been a problem (Gazit et al., 1982 Nagel et al., 1989). A new concept was to place pheromone lures in Annona trees to increase beetle density and enhance pollination, and Pena et al. (1999) found that pollination and fruit set were significantly improved when the pheromones were employed. 

Control Cover seedlings or plants with floating row co er. and hand-pollinate covered squash family plants pile deep straw mulch around plants to discourage beetles from moving between plants apply parasitic nematodes to soil to control larvae spray with pyrethrin when adults are seen feeding on pollen in flowers. 

This is accomplished using the alternative oxidase system (Box D in Fig. 18-6). The lotus flower maintains a temperature of 30-35°C, while the ambient temperature may vary from 10-30°C. While the volatilization of insect attractants may be the primary role for thermogenesis in plants, the warm flowers may also offer an important reward to insect pollinators. Beetles and bees require thoracic temperatures above 30°C to initiate flight and, therefore. 

Camphor and <7-limonene are allomones in that the trees which produce them are protected from insect attack by their presence. For instance, Arthur Birch, one of the great terpene chemists of the twentieth century, reported finding d-limonene in the latex exuded by trees of the species Araucaria bidwilli.1 2 These trees are protected from termite attack because the d-limonene they produce is an alarm pheromone for termites that live in the same area. Similarly, antifeedants could be considered to be allomones since the signal generator, the plant, receives the benefit of not being eaten. Myrcene is a kairomone, in that it is produced by the ponderosa pine and its presence attracts the females of the bark beetle, Dendroctonous brevicomis. Geraniol is found in the scent of many flowers such as the rose. Its presence attracts insects to the flower and it can be classified as a synomone since the attracted insect finds nectar and the plant obtains a pollinator. 

Nearly 200000 animal species play roles in poflinating the 250 000 species of wild flowering plants on our planet [12]. Among them, about 1500 species of vertebrates such as birds (e.g. hummingbirds) and mammals (e.g. bats, lemurs) serve as pollinators [12]. However, the main pollinators are insects they include bees, wasps, moths, butterflies, beetles and so on. Bees are the most efficient and the only dependable pollinators, because they visit flowers methodically to collect nectar and pollen and do not destroy the flower or the plant in the process. 

Flower scent is extremely variable between plant species, but often monoterpenes are the dominating group of compounds in floral odor bouquet. Flowers of one plant species can emit more than 100 scent compounds. Linalool, (3-ocimene and p-myrcene are monoterpenes that have been most-oft reported from flowers. Proportion of monoterpenes of the total scent is variable depending on the age of flowers and the part of the flower analyzed, but their proportion in many cases exceeds 50% of the total flower emission. The ratio of different compounds in flower scent affects the composition of pollinating insect communities. Wasps, flies, beetles and butterflies have a different odor preference in addition to preferences of visible flower colors. Specialized pollinator species use the combination of visual and olfactometric cues of flowers to detect their specific host species. 

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