Pollen Carriers of Cocos Nucifera L. (Palmae) in Costa Rica and Ecuador
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Rev. Biol Trop., 34(2): 297-301, 1986 Pollen carriers of Cocos nucife ra L. (Palmae) in Costa Rica and Ecuador (Neo tropical region) Ingemar Hedstrom Department of Zoology, Section of Entomology, Uppsala University, Box 561, S-751 22 Uppsala,Sweden. Present address: Escuela de Biología, Univer�idad de Costa Rica, Costa Rica. (Received: November 17, 1986) Abstract: Potcntial pollinating insects of the coconut palm, Cocos nucifera L. (Palmae), were identified in Cahuita National Park, Barbilla Biological Reserve, Pacuarito de Siquirres, Guácimo and Bribrí, Province of Limón, and in Turrúcares and La Garita, Province of A laj u ela , Costa Rica. Observationswere also conducted in Guayaquil and Cerecita, Province of Guayas, Ecuador. The most common poDen carnerin Costa Rica was Trigona si/vestriana Vachal, followed by T. testacea Klug, T. fu/viven tris Guérin, T. frontalis Friese, T. tataira Smith, T. corvina Cockerell, Melipona fa sciata Latreille, all stingless meliponid bees, and the honeybee Apis me/lifera L. In Ecuador ,A. mellife ra was observed visiting both staminate and pistillate flowers of C. nucifera. Obscrvations on interference competition betwecn sorne of the species of Trigona from Costa Rica are also prescnted. The coconut palm, Cocos nucifera L. (PaI was planted in January 1983 and set its first mae) has a pantropical distribution, and it is inflorescense in JuIy 1986, e.g. 3 1/2 years later currently believed to have originated in the (Hedstrom, unpubl.). Pacific isIands (Purseglove, 1972). Cruezo and The dimorphic flowers of e nucifera (Fig. Harries (1984) pointed out that coconuts that 1), which is a monoecious plant, are adapted to germinated during voyages of the Spanish both wind and insect pollination (Heywood, explorers, or remained unconsumed, were 1978), although the latter seems to be the usually planted on any shore they visited. The general rule. Sholdt and Mitchell (1967), who data of introduction of e nucife ra into studied coconut pollination in Hawaii, concluded America is unknown, and it may well have been that Apis mellifera L. was the main pollinator, long prior to the arrival of the Europeans but also wind pollination occured to a certain (Standley and Steyermark, 1958). In Costa Ri extent. Sauer (1983) reported that Apis indica ca, the coconut palm is found in all lowland Fabr. has been observed visiting the flowers of habitats (V andermeer, 1983) and occasionally e nucifera in tropical Asia. at higher altitudes as well. Although e nucife ra To my knowledge no data has been published is believed to be an introduced palm in the on insects visiting e nucifera in the Neotropical Neotropics, it has been very well adapted and region. This was confirmed by the specialist normally yields abundant crops. It has a Andrew Henderson (personal communication, nonseasonal life cycle and sets fruits year round. 1985) at the New York Botanical Carden. The flowering of e nucifera begins normally at Hence the objetive of this study was to present 6-10 years of age and proceeds at the rate of a check-list on sorne pollen carriers of e nuci about one inflorescence a month (Vendermeer, fe ra in the Neotropics. 1983). One individual, which was planted by the author in Guayaquil, Ecuador, in December Study sites andmethods 1977 , produced its first inflorescence in February 1986, e.g. 8 years later. On the other In Costa Rica, the observations were carried hand, in Barbilla National Park, Costa Rica, the out on November 11, 1984 (between 8 :00- only observed individual of e nucife ra , which 11 :00 hours), on January 9-10, 1985 (8 :00- is a so called "small Malaysian coconut tree", 9:30 and 13:00-16:00 hours), respectively, and 297 ? 298 REVISTA DE BIOLOGIA TROPICAL Fig. 2. The study sitc in Cahuita National Par k 01" Costa Rica. hours), and on July 27, 1986 (10:15-12:30 Fig. 1. The dimorphic flowers of Cocus nucife ra. hours), respectively. These seven sites have -A: Inmature pistillate flower. -B: Newly opened sta been ascribed by Holdridge (Tosi, 1969) tu minate flowers. Cahuita National Park, Costa Rica, June 1985. the ecological zones of tropical moist forest (Cahuita, Bribrí, Guácimo), tropical wet on June 15, 1985 (15:00-16:00 hours), along forest (Barbilla), premontane wet forest (Pacua the Caribbean beach at Cahuita National Park rito), and premontane moist forest (La Garita, (Fig. 2), by sitting perched at the hight of the Turrúcares. inflorescences of C. nucife ra . The same method Close observations of the behaviour of was utilized in Guayaquil and Cerecita, visiting insects on the flowers of C. nucife ra at Province of Guayas, on the Pacific lowlands, on all study sites were carried out in order to respectively November 11, 1986 (15 :00-16:00) determine their efficiency in transferring and November 12, 1986 (10:30-11 :00 hours). pollen between individuals of the palm Field observations and collection of species. foraging insects on C. nucife ra were also Visiting insects on the flowersof C. nucifera conducted in Pacuarito (30 m), Guácimo (100 were collected with a net or by the quick use of m), Bribrí (30 m) and River Dantas (200 m), at a killing bottle with one hand kept behind the the upper, northern border of Barbilla Biological flowers to prevent escape. Flower visitors were Reserve, Province of Umón, and in La Garita killed and the presence of pollen grains (700 m) and in Turrúcares (680 m), Province attached to their body was investigated. On of Alajuela, Costa Rica, one June 15, 1985 August 20-:f5, 1985 , in Turrúcares, Costa Rica, (8 :30-9 :30 hours), on January 12, 1985 (5 :30 individual f�male flowers (n = 20) of C. nucife and 18:00 hours), on July 24, 1986 (15 :00- ra were bagged between 17:00-D7 :00 hours 16:00 hours), on July 20, 1986 (7 :00-18:30 during the receptive period, in order to hinder hours), on January 19, 1985 (16:00-17:00 insects active at night to pollinate the flowers. HEDSTROM: Pollen carriers of Co cos 299 Fig. 4. Interference competition between two indivi duals of Trigona fulviventris facing off in the air. Pacuarito de Siquirres, Costa Rica, June 1985. that approached that particular inflorescence of e nucife ra landed directly on the newly opened pistillate flowers in order to extract nectar. 83% (n = 18) of these be es carried light-yellow coloured pollen grains of e nuci fera in their corbicula, obviously from previously visited staminate flowers of the same species. After visiting the pistillate flowers of the inflorescence, 33% of the bees were observed visiting the staminate flowers on the Fig. 3. Trigona fulviventris (Apidae) feeding on poLlen from anthers of the male flower of Cocus nucife ra. same inflorescence. By now the bees had beco Pacuarito de Siquirres, Costa Rica, June 1985. me rather "sticky" from the nectar attached to all parts of their bodies. RESULTS In Guácimo, both staminate and pistillate At the study sites in Cahuita National Park flowers of e nucife ra were visited by T. testa the most common ponen vector on both cea and T. corvina (Table 1). In Pacuarito and staminate (male) and pistillate (female) flowers La Garita, T. fu /viven tris and T. corvina, re of e nucifera was the comparatively large spectively, were the only observed visiting spe· and dark coloured species of Trigona silvestria cies on e nucife ra. Observed T silvestriana on na Vachal, followed by the smaller and pistillate flowers in Turrúcares carried heavy somewhat lighter coloured species T. fu /viven loads of pollen of e mucife ra packed in the tris Guérin (Fig. 3), T. testacea Klug, T. fr onta corbiculae. Pollen carriers on flowers of e mu lis Friese and T. tataira Smith, all stingless cife ra in Cahuita National Park, Barbilla Bio meliponid bees (Hymenoptera ; Apidae). logical Reserve and Guácimo, Costa Rica were Specimens of Melipona fa sciata Latreille and active all day from early sunrise till sunset. Apis me/life ra Linneus, both members of the Unidentified species of Vespidae (Hymenop same insect fa mily (Apidae), were also observed tera), Lepidoptera, Coleoptera (Cetoniinae) and on the flowers of e nucife ra in the same study Diptera were occasionally observed visiting site, but in low numbers. both staminate and pistillate flowers of e In Ecuador, large numbers of A. mellifera, nucife ra, but few or no pollen grains at al!, were together with unidentified species of Vespidae fo und attached to the body of these non-a pis (Hymenoptera) and Diptera, were observed species. visiting both staminate and pistillate flowers Of the pistillate flowers of e nucife ra , in both study areas. bagged at night , 20 % (n = 20) developed fr uits. A most interesting observation was made at What 1 interpreted as intraspecific interfer the study site in Guácimo, Costa Rica. One of ence competition between individuals of T. the inflorescences in that are a had both fu lviventri�. was observed in Pacuarito de Siqui staminate and pistillate flowers. All observed rres and Cahuita National Park . The aggressive potential pollen vectors of T. corvina (n = 18) bees faced off in the air and rose together up to 300 REVISTA DE BIOLOGIA TROPICAL TABLE I Visiting bees on unisexual flowers of Cocos nucifera L. in Cahuita Na tional Pa rk, Barbilla Biological Reserve, Pacuarito de Siqui"es, Bribrí, Guácimo, Turrúcares and La Garita, Costa Rica, November 1984, January and June 1985, and July 1986 Observation sites (C) (B) (Br) (G) (LA) (P) (T) Apidae Trigona (Trigona} silvestrüzna Vachal x x x le T. (Partamona) testacea Klug x x x x T. (Plebeüz)fr ontalis Friese x T.