The Reproductive Biology of Two Species of Diplusodon Pohl (Lythraceae) from Serra do Cipó, Southeastern Brazil

Abstract

The reproductive biology of two shrub species of Diplusodon (Lythraceae), D. hirsutus and D. orbicularis, was studied. Their distribution is restricted, mainly associated with “campos rupestres”, a montane biome in SE Brazil. Both species proved to be self-compatible but because of herkogamy they are greatly dependent on visitors to effect pollination. The main pollinators are medium-sized bees. In experiments where pollinators were excluded or discouraged the percentage of abscised fruits was total or extremely high; most of these fruits dropped within the first two weeks after pollination in D. orbicularis and three weeks in D. hirsutus. The percentage of surviving fruits from control or manual pollination was higher in D. orbicularis (ca. 70 %) than in D. hirsutus (ca. 50 %). Seed set was very variable, with slightly lower means in D. hirsutus. Within each species the mean seed set was similar in self-, cross-pollinated fruits, and controls. In both species, the similarity between control and manual pollination fruit survival curves suggests that factors other than pollen limitation are the cause of abortion in the study area. The high rate of abscission, which was also observed in unmanipulated fruits, was attributed to resource limitation. In D. hirsutus this was caused by drought during seed development. In D. orbicularis it was enhanced by nutrient drain by shoot-galling flies. The lack of selective abortion of either selfed fruits or fruits with a small number of seeds may be a useful mechanism to overcome this detrimental effect which is felt later during fruit development.

Key words

Brazil - Diplusodon - Lythraceae - fruit abortion - pollination - rupestrian fields

References

• 01 Abrahamson,  W. G., and McCrea,  K. D.. (1986);  Nutrient and biomass allocation in Solidago altissima: effects of two stem gallmakers, fertilization, and ramet isolation.  Oecologia. 68 174-180
• 02 Alves,  R. J. V., and Kolbek,  J.. (1994);  Plant-species endemism in savanna vegetation on table mountains (campo rupestre) in Brazil.  Vegetatio. 113 125-139
• 03 Biere,  A., and Honders,  S. J.. (1996);  Impact of flowering phenology of Silene alba and S. dioica on susceptibility to fungal infection and seed predation.  Oikos. 77 467-480
• 04 Burd,  M.. (1998);  “Excess” flower production and selective fruit abortion: a model of potential benefits.  Ecology. 79 2123-2132
• 05 Cavalcanti,  T. B.. (1990);  Flora da Serra do Cipó, Minas Gerais: Lythraceae.  Bolm. Botânica, Univ. São Paulo. 12 67-93
• 06 Cavalcanti,  T. B.. (1995) Revisão de Diplusodon Pohl (Lythraceae). Brazil; Dissertation, University of São Paulo 505 pp
• 07 Cesarino,  F.,, Araújo,  J. E.,, and Zaidan,  L. B. P.. (1998);  Germinação de sementes e crescimento de plantas de Diplusodon virgatus Pohl, Lythraceae.  Acta bot. bras.. 12 349-356
• 08 Collevatti,  R. G.,, Amaral,  M. E.,, and Lopes,  F. S.. (1997);  Role of pollinators in seed set and a test of pollen limitation hypothesis in the tropical weed Triumfetta semitriloba (Tiliaceae).  Rev. Biol. Trop.. 45 1401-1407
• 09 Dafni,  A.. (1992) Pollination ecology. A practical approach. New York; Oxford University 250 pp
• 10 Faria,  G. M.. (1994) A fauna e a flora apícola de um ecossistema de campo rupestre, Serra do Cipó - MG, Brazil: composição, fenologia e suas interações. State University of São Paulo; Dissertation 239 pp
• 11 Fernandes,  G. W., and Price,  P. W.. (1991) Comparisons of tropical and temperate galling species richness: the roles of environmental harshness and plant nutrient status. Plant-animal interactions: evolutionary ecology in tropical and temperate regions. Price, P. W., Lewinsohn, T. M., Fernandes, G. W., and Benson, W. W., eds. New York; Wiley pp. 91-115
• 12 Fernandes,  G. W.,, Carneiro,  M. A. A.,, Lara,  A. C. F.,, Allain,  L. R.,, Andrade,  G. I.,, Julião,  G. R.,, Reis,  T. R.,, and Silva,  I. M.. (1996);  Galling insects on a neotropical species of Baccharis (Asteraceae).  Trop. Zool.. 9 315-332
• 13 Giulietti,  A. M., and Pirani,  J. R.. (1988) Patterns of geographic distribution of some plant species from the Espinhaço Range, Minas Gerais and Bahia, Brazil. Proceedings of a workshop on Neotropical distribution patterns. Heyer, W. R. and Vanzolini, P. E., eds. Rio de Janeiro; Academia Brasileira de Ciências pp. 39-69
• 14 Giulietti,  A. M.,, Menezes,  N. M.,, Pirani,  J. R.,, Meguro,  M.,, and Wanderley,  M. G. L.. (1987);  Flora da Serra do Cipó, Minas Gerais: Caracterização geral e lista de espécies.  Bolm. Botânica, Univ. São Paulo. 9 1-151
• 15 Gorchov,  D. L.. (1988);  Effects of pollen and resources on seed number and other fitness components in Amelanchier arborea (Rosaceae: Maloideae).  Amer. J. Bot.. 75 1275-1285
• 16 Graham,  S. A., and Kleiman,  R.. (1987);  Seed lipids of the Lythraceae.  Biochem. Syst. Ecol.. 15 433-439
• 17 Guitián,  J., and Navarro,  L.. (1996);  Allocation of reproductive resources within inflorescences of Petrocoptis grandiflora (Caryophyllaceae).  Can. J. Bot.. 74 1482-1486
• 18 Kudoh,  H., and Whigham,  D. F.. (1998);  The effect of petal size manipulation on pollinator/seed-predator mediated female reproductive success of Hibiscus moscheutos. .  Oecologia. 117 70-79
• 19 Levri,  M. A.. (1998);  The effect of timing of pollination on the mating system and fitness of Kalmia latifolia (Ericaceae).  Amer. J. Bot.. 85 1626-1630
• 20 Lindell,  T.. (1998);  Breeding systems and crossing experiments in Anemone patens and in the Anemone pulsatilla group (Ranunculaceae).  Nordic. J. Bot.. 18 549-561
• 21 Martin,  F. N.. (1959);  Staining and observing pollen tubes by means of fluorescence.  Stain Tech.. 34 125-128
• 22 Mendonça,  M. P., and Lins,  L. V. (org.). (2000) Lista vemelha das espécies ameaçadas de extinção da flora de Minas Gerais. Belo Horizonte; Fundação Biodiversitas e Fundação Zoo-Botânica de Belo Horizonte 157 pp
• 23 Møller,  A. P.. (1997);  Developmental selection against developmentally unstable offspring and sexual selection.  J. theor. Biol.. 185 415-422
• 24 Niesenbaum,  R. A.. (1996);  Linking herbivory and pollination: defoliation and selective fruit abortion in Lindera benzoin. .  Ecology. 77 2324-2331
• 25 Niesenbaum,  R. A.. (1999);  The effect of pollen load size and donor diversity on pollen performance, selective abortion, and progeny vigor in Mirabilis jalapa (Nyctaginaceae).  Amer. J. Bot.. 86 261-268
• 26 Nimer,  E.. (1989) Climatologia do Brasil. Rio de Janeiro; IBGE 421 pp
• 27 Pellmyr,  O.,, Massey,  L. K.,, Hamrick,  J. L.,, and Feist,  M. A.. (1997);  Genetic consequences of specialization: Yucca moth behaviour and self pollination in yuccas.  Oecologia. 109 273-278
• 28 Price,  P. W.,, Fernandes,  G. W.,, Lara,  A. C. F.,, Brawn,  J.,, Gerlinch,  D.,, Barrios,  H.,, Wright,  M.,, Ribeiro,  S. P.,, and Rothcliff,  N.. (1998);  Global patterns in local number of insect galling species.  J. Biogeogr.. 25 581-592
• 29 Queller,  D. C.. (1985);  Proximate and ultimate causes of low fruit production in Asclepias exaltata. .  Oikos. 44 373-381
• 30 Sacchi,  C. F.,, Price,  P. W.,, Craig,  T. P.,, and Itami,  J. K.. (1988);  Impact of shoot galler attack on sexual reproduction in the arroyo willow.  Ecology. 69 2021-2030
• 31 Souza,  A. L. T. de,, Fernandes,  G. W.,, Figueira,  J. E. C.,, and Tanaka,  M. O.. (1998);  Natural history of a gall-inducing weevil Collabismus clitellae (Coleoptera: Curculionidae) and some effects on its host plant Solanum lycocarpum (Solanaceae) in southeastern Brazil.  Ann. Entomol. Soc. Am.. 91 404-409
• 32 Traveset,  A.. (1995);  Spatiotemporal variation in pre-dispersal reproductive losses of a Mediterranean shrub, Euphorbia dendroides L..  Oecologia. 103 118-126
• 33 Zapata,  T. T., and Arroyo,  M. T. K.. (1978);  Plant reproductive ecology of a secondary deciduous tropical forest in Venezuela.  Biotropica. 10 221-230

Section Editor: G. Gottsberger