The Floral and Pollination Biology of Lauraceae in Taiwan

• Main Authors: Yi-Bin Fan, 范義彬
• Other Authors: 楊平世
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/31653178734342800399

博士 === 國立臺灣大學 === 昆蟲學研究所 === 94 === The family Lauraceae contains the most dominant species in Taiwan’s natural hardwood forest and is considered one of the most important families in Taiwan. This study was focused on the florescence and pollinating biology of four widely distributed species of Laurel family, Cinamomum camphora (Linn.) Presl., Machilus thunbergii Sieb et Zucc, Litsea cubeba (Lour.) Pers. and Litsea acuminata (Blume) Kurata, in Taiwan’s broadleaf forests and the co-evolution relationship between those plants and related insects. Cinamomum camphora (Linn.) Presl. is characterized by inflorescence cryme and hermaphroditism. The average flower size, longevity and average number of pollen grains were 5.52±0.58mm, 6.45±1.41 days and 3170.7 grains respectively. The blooming season was from March to April and flowers and stamens are open no matter day and night when blooming. Totally 65 insect species of 23 families of 5 orders were observed. Their taxonomic composition were: Diptera (11 families, 33 species), Lepidoptera (5 families, 15 species), Coleoptera (5 families, 11 species), Hemiptera (2 families, 3 species) and Hymenoptera (3 families, 3 species). Insect visitors to the blossoms were the potential pollinators and flies are the most important ones. Natural fruit-set rate was 1.23±2.89﹪. Machilus thunbergii Sieb et Zucc is characterized by inflorescence cryme and hermaphroditism. The size of flower, longevity of individual flower and the average number of pollen grains is 10.32±0.73 mm, 4.24± 1.08 days and 9273.6 grains respectively. The blooming season is in the spring from February to March, flowers and stamens will close after opening, and insects visit the blossoms day and night, especially during 09:00~15:00. There were totally 34 species insects of 21 families from 5 orders were recorded to visit flowers of M. thunbergii. Their taxonomic composition were: Diptera (11 families, 22 species), Lepidoptera (3 families, 3 species), Coleoptera(1 families, 1 species), and Dermaptera (1 families, 1 species). Insect visitors were the potential pollinators and honeybees (Apis spp.) and flies were the most important ones. Natural fruit-set rate was 5.98±11.11﹪. Litsea cubeba (Lour.) Pers. is characterized by inflorescence umbel and dioecism. Blooming season is from February to March. Male inflorescence diameter was 9.20±0.82 mm and small flower diameter was 3.73±0.77mm; the longevity of individual flower were 13.04±4.52 days and the number of pollen grains was 7786.8. While size of female inflorescence diameter, small flower diameter and longevity of individual flower were 8.11±0.85 mm, 2.28±0.35 mm and 15.68±4.90 days respectively. Flower and stamens are open all the day when blooming. Their insect visitors include 108 species of 36 families from 4 orders. Their taxonomic composition were: Coleoptera (16 families, 39 species), Lepidoptera (6 families, 33 species), Diptera (7 families, 24 species) and Hymenoptera (6 families, 12 species). 77 species of 33 families from 4 orders have been observed visiting male flowers of L. cubeba. They were: Coleoptera (16 families, 36 species), Lepidoptera (5 families, 16 species), Diptera (6 families, 15 species) and Hymenoptera (5 families, 10 species). There were 44 species of 16 families from 4 orders visited the female flowers of L. cubeba. They were: Lepidoptera (5 families, 17 species), Coleoptera (4 families, 12 species), Diptera (4 families, 12 species) and Hymenoptera (3 families, 3 species). The major pollinating insects flying between male and female flowers include Cantharidae and Chrysomelidae (Coleoptera), Syrphidae (Diptera), Noctuidae and Geometridae (Lepidoptera). Natural fruit-set rate was 29.76±19.90﹪. In addition, honeybees (Apis spp.) have been verified not visiting flowers of C. camphora and female flowers of L. cubeba and L. acuminata. Therefore they are pollen robbers rather than pollinators. Litsea acuminata (Blume) Kurata is characterized by inflorescence umbel and dioecism. It will bloom in June and July. The average size of male and female inflorescence diameter is 9.86±1.24 mm and 6.92±0.82 mm respectively. It has 14130 grains of pollen in average. Flowers and stamens are also open in both daytime and nighttime when blooming. Their insect visitors include 66 species of 29 families from 4 orders. Their taxonomic composition were: Lepidoptera (11 families, 25 species), Diptera (8 families, 16 species) , Hymenoptera (5 families, 14 species) and Coleoptera (5 families, 11 species). There were 59 species of 33 families from 4 orders visited male flowers of L. acuminata. They were: Lepidoptera (11 families, 25 species), Diptera (6 families, 13 species). Hymenoptera (4 families, 11 species) and Coleoptera (5 families, 10 species). There were 16 species of 9 families from 4 orders visited the female flowers of L. acuminata. They were: Lepidoptera (3 families, 3 species), Coleoptera (1 families, 1 species) and Diptera (3 families, 5 species). There were 8 species of 6 families from 3 orders visiting both male and female flowers, major pollinating insects were: Lepidoptera (2 families, 3 species), Hymenoptera (2 families, 3 species) and Diptera (1 families, 2 species). Natural fruit-set rate was 29.76±19.90﹪. In conclusion, the reproduction of L. cubeba and L. acuminata （dioecism） is much more successful than C. camphora and M. thunbergii’s（hermaphroditism） in the fruit-set even though the pollination mode of L. cubeba and L. acuminata （dioecism） is simplier than C. camphora and M. thunbergii’s（hermaphroditism）.