Nectar Robbing and Pollination of Lantana camara (Verbenaceae)

Barrows, Edward M.

doi:10.2307/2989633

Cited by 91 publications

(70 citation statements)

References 10 publications

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“…Several hypotheses have been proposed to explain the occurrence of old-phase flower retention in other species. Barrows (1976) suggested that the presence of old-phase flowers in Lantana may discourage nectar thieves from perforating younger flowers. This is probably not the case in Phyla, since old-phase flowers occur adjacent to nectarcontaining flowers rather than encircling them as in Lantana.…”

Section: Resultsmentioning

confidence: 99%

FLORAL DISPLAY IN PHYLA INCISA : CONSEQUENCES FOR MALE AND FEMALE REPRODUCTIVE SUCCESS

1988

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Abstract. -The inflorescences of Phyla incisa consist of flowers in two phases: younger, nectarcontaining flowers that have yellow corolla throats and older, nectar-lacking flowers that have dark purple corolla throats. Observations of pollinator visitation patterns to both natural and manipulated inflorescences were made to determine the role ofeach flower phase in pollinator attraction. The effect of older-phase flowers on male and female reproductive success was determined by comparing stigmatic pollen loads and estimates of pollen removal from inflorescences having different numbers of these flowers.The pollinators of Phyla selected larger inflorescences more often than expected based upon the size distribution of inflorescences available to them. Both younger-and older-phase flowers contributed to the attraction of pollinators, but the latter were less effective in this function. The presence of older-phase flowers significantly increased the visitation rate to inflorescences and the amount of pollen removed but had little effect on pollen deposition on stigmas. The lack of correspondence between pollen deposition and pollinator-visitation rate was not due to stigma saturation, since stigma loads varied greatly. The data indicate that the deposition of pollen on stigmas in this species is a relatively stochastic process, whereas pollen removal from inflorescences occurs at a much more regular rate. Old-phase flower retention appears to contribute to reproductive success through increased pollen donation when pollinator activity is high and may also increase the probability of seed set when pollinators are rare.

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Section: Resultsmentioning

confidence: 99%

FLORAL DISPLAY IN PHYLA INCISA : CONSEQUENCES FOR MALE AND FEMALE REPRODUCTIVE SUCCESS

1988

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“…Além disso, a flor é dividida em duas regiões que "selecionam" os visitantes florais por tamanhos compatíveis com o diâmetro da primeira região e com o comprimento do tubo da corola da segunda região. Segundo Barrows (1976) e Schemske (1976, o comprimento do tubo da corola e a localização do néctar na base do tubo podem determinar o tipo de visitante capaz de explorar esse recurso.…”

Section: Discussionunclassified

Fenologia reprodutiva, biologia floral e polinização de Allamanda blanchetii, uma Apocynaceae endêmica da Caatinga

Araújo¹,

Quirino²,

Machado³

2011

Rev. bras. Bot.

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-(Reproductive phenology, floral biology and pollination of Allamanda blanchetii, an Apocynaceae endemic of the Caatinga). The reproductive phenology, floral biology, pollination mechanism and breeding system of Allamanda blanchetii A.DC. were studied in natural populations in the Almas Farm, Paraíba, Brazil. Allamanda blanchetii is a shrubby species, endemic of the Caatinga, flowering from February to July, with peak in March-April. The fruiting followed the flowering and continued until September. The tubular flowers are pink, their strong herkogamy preventing self pollination. The pollen grains are deposited in the upper side of the style head (non-receptive region), still in the pre anthesis phase (dehiscent anther), characterizing a secondary pollen presentation. The flowers produce an average of 36.6 µL of nectar, that is the only resource to the floral visitors. Allamanda blanchetii is self incompatible and the results suggest a late-acting self-incompatibility mechanism. The floral attributes are compatible with the melittophilous and psychophilous syndromes. In fact, the observed pollinators were the bee Eulaema nigrita Lepeletier, as main pollinator, and four species of butterflies, which act as secondary pollinators. The occurrence of strong herkogamy, secondary pollen presentation and self-incompatibility mechanism indicates high degree of specialization of pollination and breeding systems of A. blanchetii.Key words -herkogamy, secondary pollen presentation, self incompatibility RESUMO -(Fenologia reprodutiva, biologia floral e polinização de Allamanda blanchetii, uma Apocynaceae endêmica da Caatinga). A fenologia reprodutiva, a biologia floral, o mecanismo de polinização e o sistema reprodutivo de Allamanda blanchetii A.DC. foram analisados em populações naturais na Fazenda Almas, Paraíba, Brasil. Allamanda blanchetii é uma espécie arbustiva, endêmica da Caatinga, com floração de fevereiro a julho e pico nos meses de março e abril. A frutificação acompanhou a floração e estendeu-se até o mês de setembro. As flores são tubulares e de coloração rosa, cuja forte hercogamia evita a autopolinização. O pólen é depositado na parte superior da cabeça do estilete (região não receptiva), ainda na fase de botão em pré antese (anteras deiscentes), caracterizando a apresentação secundária de pólen. As flores produzem uma média de 36,6 µL de néctar, o qual é o único recurso para os visitantes florais. Allamanda blanchetii é auto-incompatível e os resultados sugerem mecanismo de incompatibilidade de ação tardia. Seus atributos florais estão relacionados com as síndromes de melitofilia e psicofilia e, de fato, os polinizadores registrados foram a abelha Eulaema nigrita Lepeletier como principal polinizador e quatro espécies de borboletas que atuam como polinizadores secundários. A ocorrência de forte hercogamia, apresentação secundária de pólen e mecanismo de auto-incompatibilidade indicam o elevado grau de especialização dos sistemas de polinização e reprodução de A. blanchetii.Palavras-chave -apresentaçã...

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“…In some plants, however, corollas are not abscised from flowers with the termination of reward production but are maintained with slight modification on the plant for an additional 1-7 days (see Gori [1983] for review). Several investigators have suggested that the retention of corollas on unrewarding flowers contributes to the floral display of the plant and increases its long-distance attractiveness to pollinators (Barrows, 1976(Barrows, , 1977Schemske, 1976Schemske, , 1980Faegri and van der Pijl, 1979;Gori, 1983;Casper and La Pine, 1984).…”

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confidence: 99%

FLORAL COLOR CHANGE IN LUPINUS ARGENTEUS (FABACEAE): WHY SHOULD PLANTS ADVERTISE THE LOCATION OF UNREWARDING FLOWERS TO POLLINATORS?

Gori

1989

Evolution

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Abstract. -I examined the adaptive significance of two floral traits in the perennial herb, Lupinus argenteus: 1) the retention of corollas on "spent" flowers, i.e., flowers containing inviable pollen, unreceptive stigmas, and negligible pollinator rewards and 2) a change in corolla color of retained "spent" flowers, which is restricted to a spot on the banner petal. At anthesis, this spot is yellow, and approximately four days later, it changes to purple. After the change, purple flowers remain on plants an additional 5-7 days before corolla abscission occurs; purple flowers were avoided by pollinators, presumably because they contained less pollen (rewards) than yellow ones. I experimentally tested the hypothesis that purple flowers contribute to the floral display of the plant by removing varying numbers of spent flowers and assessing the effect on pollination visitation. Pollinators preferentially approached and foraged on plants with greater numbers of flowers per inflorescence; they did not discriminate between yellow (rewarding) and purple (nonrewarding) flowers at interplant distances greater than 0.4 meters but would preferentially forage on plants with more total flowers, even if these individuals contained fewer rewarding flowers. Thus, spent flowers increased the overall attractiveness of plants to pollinators.In theory, color change may benefit plants in two ways. First, by directing pollinators to rewarding flowers, the change may increase pollinator foraging efficiency, with the result that pollinators visit more flowers before leaving plants (pollinator-tenure mechanism). Second, by directing pollinators to receptive flowers, the color change may prevent incoming pollen from being wasted on unreceptive stigmas and may prevent collection of inviable pollen (pollination-efficiency mechanism). I tested the pollinator-tenure mechanism experimentally by removing pollen from yellow flowers, thereby reducing the reliability of the color-reward signal. Pollinators visited fewer total flowers on experimental plants than on controls, resulting in reduced seed production in one year.

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Nectar Robbing and Pollination of Lantana camara (Verbenaceae)

Cited by 91 publications

References 10 publications

FLORAL DISPLAY IN PHYLA INCISA : CONSEQUENCES FOR MALE AND FEMALE REPRODUCTIVE SUCCESS

FLORAL DISPLAY IN PHYLA INCISA : CONSEQUENCES FOR MALE AND FEMALE REPRODUCTIVE SUCCESS

Fenologia reprodutiva, biologia floral e polinização de Allamanda blanchetii, uma Apocynaceae endêmica da Caatinga

FLORAL COLOR CHANGE IN LUPINUS ARGENTEUS (FABACEAE): WHY SHOULD PLANTS ADVERTISE THE LOCATION OF UNREWARDING FLOWERS TO POLLINATORS?

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