PROGRAMME

Wednesday, 13 September

Ecology symposium. Chairperson: James Cook

	Presenter	Title
8.30-9.00	Stuart West	Fighting in fig wasps: testing Hamilton's rule with interactions between relatives.
9.00-9.30	Ying-Ru Chen	Species interactions within the fig wasps community of  Ficus microcarpa L. in Taiwan.
9.30-10.00	Jaco Greeff	Ecological factors favouring dioecy in Ficus.
10.00-10.30	Jamie Moore	The female of the species is more deadly than the male: fig choice by the pollinator of a gynodioecious fig.
TEA
11.00-11.30	Ying-Ru Chen	Seasonal fluctuation of Ficus microcarpa L. and pollinators in Taiwan.
11.30-12.00	Emmanuelle Jousselin	Active pollination in the fig/pollinator mutualism: who decides which flowers are pollinated?
12.00-12.30	Allen Herre	Nature versus Nurture:  Factors influencing stability in the fig-wasp mutualism.

 

LUNCH 12.30-13.30

 

13.30 - 18.00 Field trip to Cape Point in the Cape Peninsula National Park.

18.00 Conference Dinner at Monkey Valley.

 

Thursday, 14 September

Workshop: Reproductive strategies and policing in a mutualism, ending with an informal braai in the afternoon.

ABSTRACTS

 

A classification of Ficus (Moraceae) under reconstruction

 

C.C. Berg

 

The Norwegian Arboretum/Botanical Institute, University of Bergen, 5259 Hjellestad, Norway, e-mail: Cornelis.Berg@bot.uib.no

 

The classification we have to deal with is the one proposed by Corner (1958, 1960, 1961, 1965). Neither botanists (Berg, 1989, 1998) nor entomologists (e.g., Ramirez, 1977) are quite satisfied with that classification. Although modern analytic methods will sooner or later contribute to a good 'natural' classification, but as a short term approach, re-evaluation of the use morphological characters can lead to a more satisfactory classification. The basis for this is to be an intimate knowledge of the genus down to the level of species (750 in total) worldwide. The extension of (my) studies from the African and the neotropical Ficus flora to the Malesian one created the opportunity to establish gradually that basis and a stage that a provisional revised classification can be presented. The major subdivisions (6) are the subgenera Urostigma (A), Pharmacosycea (B), Ficus (C), Synoecia (D), Sycidium (E), and Sycomorus (F), each subdivided into sections (19) and subsections (26) and numerous groups of related species (to be recognized as series?). These entities are related to morphological criteria, among which dioecy, heterostyly, bracts and bracteoles, glandular spots, and position of flowers and syconia. Moreover, the entities are related to Distribution patterns. These and morphological patterns suggest that there are three sets of subgenera: A + B, C + D, and E + F, which might represent three radiation events. The genera of pollinators can be largely related to subgenera, sections or subsections. A basic question in the evaluation (and evolution) of morphological traits of flowers and syconia is whether and to what extent they are functionally related to requirements and the evolution of the pollination system or physical and behavioral traits of the pollinators.  

 

A photographic review of some South-Central African figs, together with comment on Ficus natalensis Hochst. and Ficus thonningii, sensu lato.

 

John Burrows

 

Buffelskloof Nature Reserve, P. O. Box 710, Lydenberg, 1100, South Africa, e-mail: botart@intekom.co.za

 

A photographic review of those species of Ficus not found in the Flora of Southern Africa region and which are characteristic of the South-Central African subregion. Some mention will be made of two of the subcontinent's most problematic species complexes: Ficus natalensis Hochst and Ficus thonningii sensu lato, together with their associated fig wasps.

 

 

Species interactions within the fig wasp community of Ficus microcarpa L. in Taiwan

 

Ying-Ru Chen¹*, Lien-Siang Chou² and Wen-Jer Wu¹

 

¹Department of Entomology, Taiwan National University, Taiwan, e-mail: yrchen@ms10.url.com.tw

²Department of Zoology, Taiwan National University, Taiwan

 

Based on the observation of 35 trees from 1993-1998, although of a small size, figs of Ficus microcarpa L. are host to 19 species in 12 genera of non-pollinators, which oviposit by puncturing fig walls from outside. In order to investigate the relationships within this complicated community, we observed the data as follows: (1) Time sequence of oviposition, (2) Dissect D-phase figs from natural condition to record ovipositing floret types and offspring number of each species, (3) Using bagging experiments to control each factor. The results show that Philotrypesis emeryi, Philotrypesis okinavensis and Walkerella kurandensis came to oviposit before the pollinators, while Sycoscapter gajimaru, Sycoryctes moneres, Philotrypesis taiwanesis and Sycophila spp. oviposited after the pollinators. Some D-phase figs were found to include only Odontofroggatia spp., Walkerella kurandensis, Eufroggattisca okinavensis or Meselatus bicolor, four genera can stimulate figs to stay on trees and which do not depend on pollinators, this can prove that they are gallers. Analysis of D-phase figs revealed that pollinators occupied petiole florets, while sessile ones developed into seeds because of morphological division. A number of non-pollinators occupied sessile florets and affected seed production, but Philotrypesis spp., Sycoryctes meneres and Sycoscapter gajimaru with long ovipositors occupied petiole florets as did the pollinators. This result implies that the offspring of Sycoscapter gajimaru, Sycoryctes moneres, and Philotrypesis spp. may depend on pollinators, perhaps even eating them. Comparing the offspring numbers of pollinators between bagging experiments and natural data, we found that Sycoscapter gajimaru and Sycoryctes moneres indeed reduce the pollinators’ offspring number one to one, they are the parasitoids of pollinators. The data also showed that the influence of gallers’ numbers to pollinators’ are bigger than parasitoids do.

 

 

 

Seasonal fluctuation of Ficus microcarpa L. and pollinators in Taiwan

 

Ying-Ru Chen¹* and Lien-Siang Chou²

 

¹Department of Entomology, Taiwan National University, Taiwan, e-mail: yrchen@ms10.url.com.tw

²Department of Zoology, Taiwan National University, Taiwan

 

Time match between the fig crops and pollinators population is the most important problem in the phenological cooperation between figs and pollinators. In order to understand the matching situation, 35 Ficus microcarpa L. trees were investigated weekly in the campus of National Taiwan University in Taiwan during August 1992 to December 1998 for 6 years. The Research works included phenological investigation of Ficus microcarpa L. and population dynamics of pollinators. All crops were divided into 3 flowering seasons by 2 distinctly resting flowering periods annually in the field. One of the resting periods was from November to January and lasted for 1-2 months; the other from April to May was shorter. There were very few, even no figs during the period. The crops in Winter-Spring season were longer than that in Summer and Autumn seasons. On the other hand, Eupristina verticillata, the pollinators of Ficus microcarpa L., flies out from D-phase figs and has to enter the B-phase figs immediately because of their short lives. The relative population index of pollinators was estimated by pollinator's occupying rate (wing mark) and the number of pollinators in B-phase figs. The occupying rates of pollinators in each crop were low in Winter-Spring and Summer but high in Autumn. The number of pollinators in each fig varied from 1 to 6. The population dynamics of pollinators fluctuated greatly within a year. However, it was quite steady between years. The biological modeling that is simulated the situation in fields by computer infers that if 1 pollinator flies in the field, the population will establish immediately and climb to the maximum in 3 months. This implies high mortality rate and strong reproductive ability of pollinator population.

 

 

 

 

The phylogeny and evolution of fig-pollinating wasps - insights from a nuclear gene

 

James M. Cook*, V. Bull & Carlos Lopez Vaamonde 

 

Department of Biology, Imperial College, Silwood Park, Ascot SL5 7PY, UK, e-mail: j.cook@ic.ac.uk

 

There are many fascinating and unanswered questions concerning the evolution of fig-pollinating wasps (subfamily Agaoninae) and their interactions with fig plants (Ficus species). Several key questions require the availability of well-resolved and highly inclusive estimates of the phylogeny of figs and/or fig wasps at different taxonomic levels. These issues include the extent to which figs and their pollinators have cospeciated, and whether characters such as active pollination in wasps and dioecy in figs have arisen multiply and in correlation with other key traits. To address such issues we are developing a densely-sampled molecular phylogeny of the genera of fig wasps using 867 bp of the nuclear 28s rDNA D2+D3 expansion regions. Our current data set is the first to include members of all twenty fig wasp genera as well as several outgroups. In addition, most genera are represented by three or more species (a total of 66 pollinating fig wasp species). Our analyses support the monophyly of the Agaoninae, and also of nearly all of the genera within the Agaoninae. Our current best estimates of the generic phylogeny are used to address key issues in the evolution of fig-pollinating wasps and their host plants.

 

 

 

Ecological factors favouring dioecy in Ficus

 

Jaco M. Greeff*¹ and Stephen. G. Compton²

 

¹Department of Genetics, University of Pretoria, Pretoria, 0002, South Africa, e-mail: jgreeff@postino.up.ac.za

²Ecology and Evolution Group, School of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom, e-mail: pab6sgc@WEST-01.NOVELL.LEEDS.AC.UK

 

We developed a sex allocation model for Ficus that incorporates the trees’ mating group sizes and wasp sex ratio changes. Applying the model to paternity data, we find that the effective mating groups are in fact rather small and a substantial amount of brother-pollen competition can lead to significant female biased allocation in Ficus. A male or female tree can only be selectively favoured when it has twice the female fitness of a monoecious tree and hence the female bias will tend to stabilize monoecy. We further show that if parasitism of seeds and wasps is high enough, this two-fold threshold can be overcome if plants can protect all seeds from wasps (pollinators and parasites alike). This can lead to the establishment of females in the population, which in turn, select for monoecious trees to allocate more resources to their male function. This train of events can result in a population making the traverse from monoecy to dioecy.

 

 

 

Niche differentiation in a community of hemi-epiphytic figs (Ficus spp.). A paradox for tropical biodiversity?

 

Rhett Harrison¹*, Abang Abdul Hamid², James LaFrankie³, Hideyoshi Nagamasu⁴, Tohru Nakashizuka¹, Peter Palmiotto⁵, Lee Hua-Sen², Kenta Tanaka¹, Stephan Teo²

 

¹ Center for Ecological Research, Kyoto University, Kamitanakami Hirano-cho, Otsu 520-2113 Japan, e-mail: rhett@ecology.kyoto-u.ac.jp

² Forest Research Centre, Forest Department Sarawak, Jln. Detak Amar Kalong Ningkan, PO Box 31 26, 93762 Kuching Sarawak, Malaysia

³ CTFS Asia Program, Nanyang Technological University, 469 Bukit Timah Road, Singapore 1025 Singapore

⁴ The Kyoto University Museum, Kyoto University, Sakyo 606-01 Japan

⁵ Environmental Studies, Bowdoin College, Brunswick, Maine 04011 USA

Visit any tropical lowland forest and figs (Ficus spp.) almost always come out as one of the most species rich genera. In Lambir Hills National Park, Sarawak (40 20’ N, 1130 50’ E, 150 – 250 m above sea level) there are 80 species and varieties of figs, of which 28 species are hemi-epiphytes.  Just how do so many apparently ecologically similar species co-exist in a single habitat? Here we address this question in terms of the niche differentiation within a community of hemi-epiphytic figs. The following hypotheses were investigated; 1) species differ in the types of hosts they colonize, 2) species occupy different canopy strata/light environments, and 3) species segregate relative to soil type and/or slope.

                In 1998 a survey of hemi-epiphytic and climbing figs including a census of the 52 ha Long Term Ecological Dynamics Plot and 8 ha Canopy Biology Plot, in Lambir Hills N.P. was conducted. Data on species identification, size (DBH and canopy area), height and point of colonization, canopy illumination (CI) index, and host bark roughness were collected for all individuals. Host identifications and Distributions were obtained for individuals in the plots, and data on soil texture and slope angle for each 20x20 m quadrate of the 52ha plot were recorded in 1994. Host family was recorded separately for individuals outside the plots. The densities of figs are often very low preventing meaningful comparisons for most species. Species with nine or more individuals in the survey (11 species with 209 individuals) were compared quantitatively.

                Hemi-epiphytic figs colonized a total of 35 families of host tree but Dipterocarp hosts accounted for 40% of all colonization events. Considered together figs were significantly more likely than predicted, based on equal probability of occurrence, to colonize Dipterocarp hosts relative to non-Dipterocarp hosts. However, there were significant differences amongst species, and only three of the species occurred on Dipterocarps significantly more than expected. When rare species (n<9) were compared to common species no significant differences were detected in the proportion of Dipterocarp hosts colonized. Further comparisons between genera or light and heavy hardwoods were not possible

 

because of small sample sizes. There were highly significant differences in host DBH amongst species but no significant differences in bark roughness, with most species colonizing the full range of host bark types from smooth to deeply fissured. This suggests host size is the most important criteria. Fig species differed significantly in their height and position of colonization, CI index and mean maximum canopy area. Soil texture scores and slope angles also differed significantly amongst species. A cluster analysis followed by canonical discrimination analysis revealed four guilds amongst the common species, though at least one more could be recognized when rare species were included. Colonization position, especially trunk (low position) relative to branch crotches, height and the mean maximum canopy area were the most important variables.

                The existence of strong niche segregation in hemi-epiphytic figs (which does not correspond to phylogeny), however, is something of a paradox. Densities are so low (approximately 1 in 10 000 hosts) that there is clearly no competition, and unlikely to have been any over evolutionary time-scales either. Instead niche segregation would appear to have arisen from a Red Queen scenario, in which only certain combinations of characteristics are able to survive in the complex environment of the canopy.

 

 

"Cospeciation between figs and their wasps?" is the wrong question.

 

Edward Allen Herre¹*, Carlos A. Machado², Michelle Waycott¹, Vidya Athreya^1,4, Drude Molbo³ and John D. Nason⁴

 

¹Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Republic of Panama, e-mail: allenh@dosel.botany.ufl.edu & HERREA@GAMBOA.SI.EDU

²Department of Genetics, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, e-mail machado@waksman.rutgers.edu

³IE-ZEA, B.B., Université de Lausanne, 1015 Lausanne, Switzerland, e-mail   Drude.Molbo@ie-zea.unil.ch

⁴Department of Botany, Iowa State University, Ames, Iowa 50011, e-mail: john-nason@uiowa.edu (temporary email address)

 

This work presents evidence for and against strict sense cospeciation among figs and their wasps.  Accumulating evidence suggests that the idea that figs and wasps are cospeciating is minimally a gross oversimplification that obscures more interesting questions.

 

 

 

Nature versus Nurture:  Factors influencing stability in the fig-wasp mutualism

 

Edward Allen Herre ¹* and Stuart A. West²

 

¹Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Republic of Panama, e-mail: allenh@dosel.botany.ufl.edu & HERREA@GAMBOA.SI.EDU

²Institute of Cell, Animal & Population Biology, University of Edinburgh, UK, e-mail: Stu.West@ed.ac.uk

 

This work discusses the importance of pollinator wasp size within the context of several potentially competing hypotheses for the maintenance of the mutualism. Factors that influence wasps size and thereby indirectly the relative costs and benefits of the mutualism to each party are discussed.  The work then addresses factors that are likely to prevent various classes of non-pollinating species from undermining the system.

 

 

Fig odours to attract pollinating wasps: a taxonomic survey

 

Martine Hossaert-McKey¹*, Laure Grison², Alice Edwards² and R. Heath³

 

¹CEFE, CNRS, 1919 route de Mende, 34293 Montpellier Cedex 5, France, e-mail: hossaert@cefe.cnrs-mop.fr

²Chemistry Department, University of Brunei Darussalam, Bandar Seri Begawan, Brunei Darussalam

³USDA-ARS, Subtropical Horticulture RSCH Station, Miami, Fl 33158, USA

 

When receptive, figs produce odours that attract the specific pollinating wasp. The odour seems to be a sufficiently efficient message to ensure not only specificity but also attraction of flying insects, landing on receptive fig and triggering the wasp’s fig entering behaviour. Hence, receptive fig odour plays a central role in the functioning of the mutualism and in ensuring the coexistence of numerous fig species within the same habitat. Sometimes, however, some illegitimate wasps are also attracted to a receptive fig showing possible leakage points in the system. Nothing is known about the variation of receptive fig odour within and among Ficus taxonomic groups. Do related figs have similar odours? Do pollinator errors occur between figs producing similar odours? We present here the first set of results on a survey of receptive fig odours, comparing odours within and among Ficus sections.

 

 

Active pollination in the fig/pollinator mutualism: who decides which flowers are pollinated?

 

Emmanuelle Jousselin* and Finn Kjellberg

 

CEFE-CNRS, 1919 route de Mende, 34293 Montpellier Cedex 5, France, e-mail: jousselin@cefe.cnrs-mop.fr

 

Among plant pollinator relationships, the ones involving pollinating seed parasites may lead to extreme coevolution between partners. One of the most impressive product of this coevolution is active pollination, i.e. behavioural and anatomic traits aimed at pollinating purposely. It has evolved in at least three mutualisms: the Yucca/ Yucca moth, the senita cactus/ senita moth and the Ficus/ agaonid associations. Ficus species are pollinated either passively or actively. It has been suggested that active pollination allows the wasps to pollinate the ovaries in which they lay an egg thus inducing the development of the fig embryo and ensuring better larval nutrition. We tested this hypothesis by establishing on flowers of 6 different species of figs, including monoecious species and male and female figs of dioecious species, which flowers received an egg and/or pollen. We show that: 1) in passively pollinated figs, pollen is dispersed haphazardly within the fig, 2) in actively pollinated male figs (i.e. figs producing only wasps and pollen), pollinators do deposit pollen on the flowers in which they lay their eggs, 3) in actively pollinated monoecious and female figs (i.e. figs which are selected to produce seeds) pollinators do not have control over which flowers are fertilised because, stigmas are too densely packed. Their close physical contact can even result in lateral growth of pollen tubes. This probably increases fig seed production. Thus, over such a specialised trait as active pollination, there seems to be a conflict of interest between partners of the mutualism. This conflict may explain why active pollination has been repeatedly lost in the fig-agaonid mutualism.

 

 

Fig traits, wasp traits, Ficus taxonomy, wasp taxonomy, phylogenies, and variation in the biology of the interaction: does it make sense?

 

Finn Kjellberg¹* and Jean-Yves Rasplus²

 

¹ CNRS-CEFE, 1919 route de Mende, 34293 Montpellier Cédex 5, France, email kjellberg@cefe.cnrs-mop.fr

² INRA, Centre de biologie et de gestion des populations, 488 rue de la Croix Lavit, 34090 Montpellier, France, email rasplus@ensam.inra.fr

 

This contribution was suggested by C.C. Berg in an Email: “ The characters that distinguishes Ficus from other Moraceae are (largely) linked to the pollination system. I have been wondering to what extent characters that distinguish major or lesser groups of species can be related to pollination or pollinator groups, characters like the position of the staminate flowers - disperse or ostiolar, the internal bristles, the shape of the stigmas, enclosure of stamens in a tubular perianth surrounded by bracteoles (in subg. Sycomorus), etc. [...]. My knowledge about the pollinators is too poor to come with suggestions”. We could ask similar questions for the pollinating wasps. We will try to summarise the information we have gathered on fig and wasp traits, on their taxonomy and on their biology, asking what are the emerging patterns? In some cases, trait similitude has to be explained by convergent biology (coevolved adaptive syndromes), while in other cases common ancestry is the answer (good phylogenetic markers). It appears that just by looking at a preserved fig and its associated wasp(s) floating in alcohol, much of their story can be told.

 

 

 

Fruit characteristics and factors affecting fruit removal in a Panamanian community of strangler figs

 

Carmi Korine ^1,2, Elisabeth K. V. Kalko^1,3, Edward Allen Herre ¹*

 

¹Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Republic of Panama, e-mail  allenh@dosel.botany.ufl.edu & HERREA@GAMBOA.SI.EDU

²Mitrani Department of Desert Ecology, Blaustein Institute for Desert Research Midreshet Ben-Gurion, 84990, Israel

³Department of Experimental Ecology (Bio III), University of Ulm, Albert-Einstein Allee 11, 89069 Ulm, Germany

 

We describe fruiting characteristics for 12 species in a community of strangler figs (Moraceae: Urostigma) studied in Panama. We quantify diurnal and nocturnal removal rates and proportions of fruits removed, and relate them to the activities of the main dispersers of the figs: bats and birds. These results combined with previous studies show that there are clear differences between fig species with fruit that ripen red and those with fruit that remain green(ish). In the red-fruited species, the fruit are small, ripen asynchronously over relatively long periods, produce little scent, and are mainly taken during the day by birds. In contrast, in the green(ish)-fruited species, the fruits are larger, span a range of sizes, ripen relatively synchronously, produce very distinctive aromas, and are mainly taken at night by bats. This dichotomy in fruiting characteristics suggests coadaptive links between groups of dispersers and different species within the genus Ficus. All fig species produce a range of fruit crop sizes (10-155 fuits/m² canopy area) of which a high proportion were removed by seed dispersers (>80%). Removal rates (fruit removed per day) were positively correlated with crop size, suggesting that trees with large crop size attract more frugivores. Removal rates of green-fruited figs were significantly lower and persistence and abortion of ripe fruit were significant higher around full moon, apparently due to the reduced activity of bats. We further estimate the number of bats that are sustained by a tree fruit crop and account for the observed fruit removal. We then discuss the evidence for coadaptation between different groups of figs and their seed dispersers, Finally, we consider the conservation implications for figs as keystone resources in tropical forests.

 

Combined nuclear and mitochondrial phylogenies of Australasian pollinating and non-pollinating fig wasps: an emerging pattern of parallel cladogenesis?

 

Carlos Lopez Vaamonde¹*, Jean Yves Rasplus², George D. Weiblen³, and James M. Cook¹

 

¹Department of Biology & NERC Centre for Population Biology, Imperial College, Silwood Park, Ascot, Berkshire SL5 7PY, UK, e-mail: c.lopez-vaamonde@ic.ac.uk; j.cook@ic.ac.uk.

²Laboratoire de Modelisation et de Biologie Evolutive, 488 Rue de Croix Lavit, 34090 Montpellier, France, e-mail: rasplus@ensam.inra.fr.

³Department of Zoology, 203 Natural Science Building, Michigan State University, East Lansing, MI 48824 USA, e-mail: gweiblen@pilot.msu.edu

 

Figs (Ficus spp.) and their pollinating wasps form an obligate mutualism. This has long been considered a classic case of coevolution and cospeciation but these ideas have not been tested explicitly, due to the lack of robust phylogenies. Figs are also exploited by several clades of non-pollinating wasps, which are parasites of the mutualism, and whose patterns of speciation have received little attention. We use data from three DNA fragments (2 nuclear and one mitochondrial) to estimate the phylogenies of 20 species of Pleistodontes pollinating wasps and 15 species of Sycoscapter non-pollinating wasps that are associated with Ficus species in the sub-generic section Malvanthera (endemic to Australasia). A single, well-resolved, best estimate of Sycoscapter phylogeny is obtained, and three alternative topologies representing estimates of Pleistodontes phylogeny. We then use a maximum cospeciation analysis of the 15 Pleistodontes / Sycoscapter species pairs to show that the level of cospeciation is significantly greater than expected by chance, but that the congruence of the respective phylogenies is also significantly less than perfect. The level of cospeciation estimated ranges from 50 to 64% and depends on the topology and model of character evolution used. A significant fraction of speciation events in the two genera appear to be correlated but other processes such as host-switching, duplication and extinction must also play a substantial role. Surprisingly, genetic distances between Sycoscapter species are greater than between their associated Pleistodontes species, suggesting that the Sycoscapter species are older than the corresponding Pleistodontes species or, more likely, have experienced a higher rate of molecular evolution. In contrast, we note that morphological differentiation between Sycoscapter species is far lower than between the corresponding Pleistodontes species.

 

 

Phylogenetic relationships, historical biogeography, and character evolution of fig pollinating wasps

 

Carlos A. Machado¹, Emmanuelle Jousselin², Stephen G. Compton³, and Edward Allen Herre⁴*

 

¹Department of Genetics, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, e-mail machado@waksman.rutgers.edu

²CEFE-CNRS, 1919 route de Mende, 34293 Montpellier Cedex 5, France, e-mail jousselin@cefe.cnrs-mop.fr

³Ecology and Evolution Group, School of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom, e-mail: pab6sgc@WEST-01.NOVELL.LEEDS.AC.UK

⁴Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Republic of Panama, e-mail  allenh@dosel.botany.ufl.edu & HERREA@GAMBOA.SI.EDU

 

This work presents the phylogenetic relationships and times of divergence among the pollinator wasp genera and relates them to their current biogeographical Distributions.  The fig-wasp mutualism appears to have originated roughly 90 million years before present in the supercontinent of Gondwana. The work further discusses the implications of character evolution in the wasps with respect to their phylogenetic relationships.

 

 

There is more to the picture than meets the eye: genetic markers reveal multiple sympatric pollinator species in several Ficus species!

 

Drude Molbo¹*, Edward Allen Herre², Carlos A. Machado³ & L. Keller¹

 

¹IE-ZEA, B.B., Université de Lausanne, 1015 Lausanne, Switzerland, e-mail: Drude.Molbo@ie-zea.unil.ch

 ²Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Republic of Panama, e-mail: allenh@dosel.botany.ufl.edu & HERREA@GAMBOA.SI.EDU

³Department of Genetics, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, e-mail machado@waksman.rutgers.edu

 

Whether concerning taxonomy, mutualism, sex ratios or conservation, almost every study of fig wasps is based on the premise that each species of fig has ONE single species specific pollinator. In order to study sex ratios and population genetics in pollinators of Panamanian strangler figs, we developed a series of microsatellite genetic markers. Unexpectedly, we found that the "single pollinator species" routinely consists of more than one genetically distinct wasp species co-occurring sympatrically on single host fig species to the point of co-founding individual fruits. This presence of cryptic species within the same host fig has a number of important ecological and evolutionary implications.

 

 

The female of the species is more deadly than the male: fig choice by the pollinator of a gynodioecious fig.

 

Jamie C. Moore*, Stephen G. Compton, M.J. Hatcher & A. Dunn

 

Ecology and Evolution Research Group, School of Biology, University of Leeds, UK, e-mail: bgyjcm@leeds.ac.uk

 

The identification of areas of conflict between participants (and their costs) is an integral part of the study of mutualism.  An interesting example is seen in the relationship between gynodioecious figs (Ficus spp., Moraceae) and their fig wasp pollinators (Agaonidae: Chalcidoidea).  In such species, wasps (which use fig flowers as oviposition sites) are unable to oviposit in female figs, and hence are under selection to avoid them.  However, given the obligate nature of the relationship, the evolution of wasp discriminatory abilities could lead to the breakdown of fig reproduction, and ultimately to extinction.  In this paper, we investigate fig choice by Liporrhopalum tentacularis, pollinator of the gynodioecious Ficus montana.  Using greenhouse sampling experiments and specific choice trials, we demonstrate that L. tentacularis does not discriminate between the fig sexes either in conditions analogous to the field or when presented with both simultaneously.  Also, wasps showed no preference for figs of certain diameters, or for figs located in certain directions from the site of wasp eclosure.  Instead, the primary factor determining fig choice during the greenhouse experiments was the height of the fig from the base of the plant, with wasps preferring figs close to the base.  Whilst this preference may be not be due to fig height per se, instead being a function of the distance of the fig from the site of wasp release, it also accounted for between plant differences in wasp entry rates.  We go on to compare results with previous work on wasp fig choice and dispersal behaviour, and, in light of the ecology of the two species, discuss possible reasons for differences between the L.tentacularis-F. montana mutualism and other studied relationships.

 

 

Abstract not received in time.

 

David Nash

 

Department of Population Biology, Zoological Institute, University of Copenhagen, Universitetsparken 15, Dk-2100, Copenhagen East, Denmark, e-mail: DRNash@spam.zi.ku.dk

 

 

Pollen flow and genetic structure in a population of Ficus burtt-davyi

 

John Nason¹*, Steve Compton², and Sally Ross²

 

¹Department of Botany, Iowa State University, Ames, Iowa 50011, e-mail: john-nason@uiowa.edu (temporary email address)

²Ecology and Evolution Group, School of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom, e-mail: pab6sgc@WEST-01.NOVELL.LEEDS.AC.UK

 

Rates of pollen immigration and spatial genetic structure were examined for a South African population of Ficus burtt-davyi (Moraceae). This species is primarily found as a strangling hemiepiphyte, however, in the southern portion of its range where this study was conducted it also grows on exposed rocky substrates. The study population (BOTS) was located in the Settler Botanical Garden in Grahamstown and consisted of more than 120 reproductively mature trees isolated from the nearest conspecific population by more than 1 km. Paternity analyses using allozyme markers indicate 100% pollen immigration into the BOTS population for the fruit crops examined. Although the majority of trees in the BOTS population represent unique multilocus allozyme genotypes, there is a significant excess of identical genotypes across trees with replicated genotypes exhibiting significant positive spatial clustering. These analyses of spatial and genetic structuring are interpreted to indicate extensive clonal spread with the ramets of individual genets located up to 60 m apart. Patterns of pollen immigration and clonal structure are interpreted with respect observed patterns of flowering phenology. These findings have important implications for the persistence of fig wasp populations.

 

 

 

Do dioecious figs regulate their internal temperature? The case of the Mediterrranean F. carica and the Bornean F. condesa and F. aurata

Sandra Patiño¹*, Laure Grison², Alice A. Edwards³, Martine Hossaert-Mckey² and John Grace¹

 

1. Institute of Ecology and Resource Management, The University of Edinburgh, Mayfield Rd. Edinburgh EH9 3JU, Scotland, e-mail spatino@srv0.bio.ed.ac.uk & jgrace@srv0.bio.ed.ac.uk

2. Centre National de la Recherche Scientifique-CEFE, 1919 route de mende, 34293 Montpellier cedex 5, France, e-mail hossaert@cefe.cnrs-mop.fr & grison@cefe.cnrs-mop.fr

3. Chemistry Department, Universiti Brunei Darussalam, Jln. Tungku Link, Bandar Seri Begawan BE 1410, Brunei Darussalam, e-mail aedwards@fos.ubd.edu.bn

 

It is known that at least 11 neotropical monoecious species of figs regulate temperature by transpiration (evaporative cooling) and thus maintain suitable low internal tissue temperatures for the development of the pollinator wasps.  Temperature increases of a few degrees above ambient is enough to induce mass mortality in the wasps.

We study the temperature regime of two tropical dioecious species from Brunei, F. condensa and F. aurata and the Mediterranean species F. carica.  We calculated the transpiration rates of female and male receptive and visited (by pollinators) figs using data of internal fig temperatures and microclimate parameters.  We extract the volatile compounds emitted by receptive figs under different controlled temperatures and test them for pollinator attraction.

We discuss the significance of our results in relation to the ecology and reproductive biology of the tropical dioecious figs F. aurata and F. condensa in comparison with the mediterranean species F. carica.

 

 

Five ways to be a fig and get dispersed in a Bornean lowland rain forest.

 

Mike Shanahan

 

Ecology &Evolution Group, School of Biology, University of Leeds, Leeds, LS2 9JT,England, e-mail:mikeshanahan@yahoo.com and

Institute of Biodiversity & Environmental Conservation, UNIMAS, 93400 Kota Samarahan, Sarawak, Malaysia

 

Figs, the fruit of Ficus species (Moraceae) exhibit great diversity in the manner in which they are packaged and presented. This diversity is reflected in the fact that figs are eaten by virtually all tropical frugivores, many of which act as seed dispersers.  However, the figs of a given Ficus species are not equally suitable for all frugivores in a given area. Rather, potential dispersers are partitioned by guilds of Ficus species with similar fruiting ecology. In this paper, using data from Borneo, I describe five ways in which sympatric Ficus species attract subsets of the frugivore community and consider the determinants and implications of this dispersal guild structure.

 

 

Colonisation of a biologically-purged oceanic volcano and an emergent island by figs (Ficus spp.; Moraceae) and their associated animals.

 

Mike Shanahan^1,2*, Rhett Harrison³, Ruby Yamuna⁴, Ian W. B. Thornton⁵

 

¹Ecology &Evolution Group, School of Biology, University of Leeds, Leeds, LS2 9JT,England, e-mail:mikeshanahan@yahoo.com

²Institute of Biodiversity & Environmental Conservation, UNIMAS, 93400 Kota Samarahan, Sarawak, Malaysia

³Center for Ecological Research, Kyoto University, Kamitanakami Hiranocho, Otsu, Shiga, 520-2113, Japan, e-mail: rhett@ecology.kyoto-u.ac.jp

⁴Herbarium, Biology Department, University of Papua New Guinea, Port Moresby, Papua New Guinea

⁵School of Zoology, La Trobe University, Bundoora, Victoria, Australia 3083

 

Long Island, a volcanic island 50 km from Papua New Guinea, erupted catastrophically in the mid-1600s with the probable extirpation of all life there.  The island was surveyed over 15 days in 1999 for figs (Ficus spp; Moraceae) and their vertebrate dispersers and pollinating wasps (Hymenoptera; Agaonidae).  At least 31 Ficus species have colonised Long Island since the eruption.  Evidence of pollinator wasp colonisation was found for all 16 fig species observed fruiting. Twenty-six bird and nine mammal species occurring on Long Island are identified as potential seed dispersers.  Of these, it is the fruit bats and pigeons that are likely to have been instrumental in the island's early colonisation with subsequent spread being facilitated by these frugivores as well as a number of passerine birds, and an introduced cuscus. Comparisons of fruit characters and frugivore attraction between fig species reveal two broad Ficus dispersal guilds.  Members of the first guild produce relatively large, green fruits in the lower strata of the forest and attract fruit bats. The second guild included species attracting attract both birds and fruit bats with generally smaller, red fruit produced throughout the forest's vertical structure. Eight Ficus species have colonised Motmot, a 31 year-old emergent island in the volcano's crater lake.  However, only one frugivore species was recorded alive on the island.  Fig seeds are likely to have arrived during rare over-flights or roosting visits by frugivores or in the bodies of prey brought to Motmot by raptors. We found no evidence of pollinator presence on Motmot. Most figs on Motmot remain immature and the only individuals observed fruiting had not been pollinated. Once the figs on Motmot start to fruit regularly we can expect a rapid increase in the numbers of fleshy-fruited plant species colonising the island.

 

Adaptation for Ficus erecta var. beecheyana and its pollinator in subtropical forest at Hue-Sun Forest Station, Taiwan

 

Hsy-Yu Tzeng*, Chern-Hsiung Ou, Fu-Yuan Lu and Li-Jung Tseng

 

Fushan Station, Taiwan Forestry Research Institute. Post box 132, Ilan 260, Taiwan, ROC.

 

This study was carried out from October 1995 to February 1997, and we investigated phenology and pollination of 30 mature trees of the gynodioecious fig Ficus erecta var. beecheyana in subtropical forest at Hue-Sun Forest Station, Taiwan. The reproductive phenology demonstrated considerable sexual specialization. Male trees bore a main spring crop from February to April prior to the peak of rainfall, and a few of inter-phase syconia to maintain the pollinator population of Blastophaga nipponica. Female trees produced with the peak of male-phase figs as before as 2 to 3 weeks. The phenomena responded to the life span of female-phase figs as 2 to 3 weeks, if the pollinator did not pollinate or lay eggs during the female phase. For the frailly, tiny, short-lived pollinators, the phenology of the important phase of male and female-phase syconia avoid two heavy rainfall period.  The male figs contributed to maintain and raise the survival of the special-species pollinator, and the female figs were adapted to the fluctuation of climate that might have a good seed germination and seedling  establishment. With the phenomenon of phenology and pollination of F. erecta var. beecheyana and its pollinators, them were adapted and might have a good relationship of mutualism at Hue-Sun Forest Station, Taiwan.

 

 

Population structure and dynamics of Ficus sycomorus L., along the Sabie River, Kruger National Park, South Africa.

 

Kathy van der Velde*, K.H Rogers and E.T.F. Witkowski

 

Department of Animal, Plant and Environmental Sciences, University of the Witwatersrand, P.O. WITS, 2050, South Africa, e-mail nooks@gecko.biol.wits.ac.za

 

Ficus sycomorus L., commonly known as the sycamore fig, is an important component of riparian ecosystems. Over the last ten years (prior to 1999) there has been no visible evidence of fig recruitment in the Kruger National Park (KNP). Size and age structures were used to assess the population structure and dynamics of the sycamore figs, along 40km of the Sabie River, within the KNP. These approaches were considered in the context of physical and biological disturbances. A population structure dominated by large and medium sized individuals and devoid of small plants was found, indicating that the establishment of individuals in the smaller size classes is not occurring at present. Germination occurred in abundance, however germinant survival was reduced through herbivore activities (94% of seedlings found in protected areas). The age-structure of the population was determined by the use of aerial photographic records and allometric relationships. Recruitment into the larger size classes has declined steadily in the last 40 years, coinciding with the exponential increase in elephant population size. Water availability, flooding regime and  geomorphology of the Sabie River were also found to influence the establishment and persistence of individuals. Fewer individuals were found on active (29) and ephemeral (185) sites, relative to seasonal (275) sites, as individuals on the active and ephemeral sites are subjected to harsher flooding and drought conditions, respectively.  The mixed bedrock/ alluvial system of the Sabie River was also found to influence the survival of individuals, as the majority of drought induced sycamore fig deaths occurred on anastomosing channels, which are bedrock controlled. This study shows that Ficus sycomorus populations can be described as episodic recruiters, and we predict that large recruitment events coincide with major flooding events.

 

Fig wasp species richness and host association: a current assessment.

 

Simon van Noort

 

Division of Life Sciences, South African Museum, PO Box 61, Cape Town, 8000, South Africa, e-mail: svannoort@samuseum.ac.za

 

World species richness of pollinating fig wasps (Agaoninae) and two groups of non-pollinating fig wasps (Sycoecinae and Otitesellinae) is estimated based on extrapolations from known fig wasp - host fig tree associations and host Ficus (Moraceae) species richness. Current taxonomic revisions of the Sycoecinae and Otitesellinae have allowed for a contemporary appraisal of correlations between fig wasp genera and host fig tree sections and subsections.

                A detailed comparative assessment of Ficus and fig wasp species richness in an east African and southern African savanna is presented. A typical savanna fig tree and fig wasp species richness is protected within Mkomazi Game Reserve (Tanzania), although Ficus bubu, a species assumed to be rare or overlooked, is locally abundant in the reserve and has a high associated fig wasp species richness. Eighty-eight species of fig wasp have been recorded from the reserve of which around three-quarters are undescribed. This is about half of the fig wasp species expected to be reared from the nine recorded fig tree species in Mkomazi, which represent 23% of Tanzania's fig tree diversity. An assessment of local species richness in South Africa was achieved by demarcating a comparative region (in size and habitat) to that of Mkomazi Game Reserve. This region was centred around Mkuze Game Reserve in the Kwazulu/Natal Province. Twelve Ficus species have been recorded within this demarcated area, including five of the species recorded in Mkomazi. Ninety fig wasp species have been reared from seven of these host species. Based on collections from elsewhere in southern Africa, the remaining five fig tree species should produce at least a further 27 fig wasp species. This is a comparable species richness to that recorded in Mkomazi. However, it is probable that further fig tree species will be recorded from Mkomazi, and because of general host-specificity this will elevate fig wasp species richness beyond comparable sites in southern Africa.

 

Coevolution in dioecious fig pollination: insights from phylogeny

 

George D. Weiblen

 

Department of Zoology, 203 Natural Sciences Building, Michigan State University, East Lansing, Michigan 48824, USA, e-mail: gweiblen@pilot.msu.edu

 

The evolution of mutualistic interactions between the dioecious figs (Ficus subgenus Ficus, Moraceae) and their pollinating wasps (Hymenoptera: Agaonidae) was examined with comparative methods.  Fig species are either monoecious or gynodioecious depending on the arrangement of unisexual flowers within the specialized inflorescence but the gynodioecious species are functionally dioecious due to interactions with pollinating seed predators in the subfamily Agaoninae.  Phylogenetic relationships of the functionally dioecious figs based on the internal transcribed spacer region of nuclear ribosomal DNA (nrDNA) and morphology were compared with a phylogeny of the associated pollinators inferred from mitochondrial DNA (mtDNA) sequences and morphology to test hypotheses of cospeciation and coadaptation.  Parallel phylogenies and correlated branch lengths based on fig nrDNA and pollinator mtDNA were consistent with cospeciation, although at least one highly supported case of phylogenetic incongruence was suggestive of ancestral host switching. Parsimony reconstruction of ancestral fig breeding systems indicated that the evolution of functional dioecy was accompanied by a relative reduction in pollinator ovipositor length and that reversals to monoecy in functionally dioecious lineages were associated with shifts to longer ovipositors in ancestral pollinators. Correlated changes in fig style lengths and pollinator ovipositors further suggest a role for coadaptation in the regulation of resource conflicts between these obligate mutualists.

 

 

Fighting in fig wasps: testing Hamilton's rule with interactions between relatives

 

Stuart A. West¹*, Martyn G. Murray¹, Carlos A. Machado², Edward Allen Herre³ & Ashleigh S. Griffin¹

 

¹Institute of Cell, Animal & Population Biology, University of Edinburgh, UK, e-mail: Stu.West@ed.ac.uk

²Department of Genetics, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, e-mail: machado@waksman.rutgers.edu

³Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Republic of Panama, e-mail: allenh@dosel.botany.ufl.edu & HERREA@GAMBOA.SI.EDU

 

When should wingless male fig wasps indulge in lethal combat over the females in their fruit? We: (a) examine what recent social evolution theory predicts; (b) test these predictions with comparative data.

 

POSTER:

Establishment of fig and fig wasp populations on the Krakatau islands; consequences of mutualism for the recolonization of disturbed habitats.

 

Monika Zavodna^1,2*, Paul Arens², Peter van Dijk¹, Ben Vosman², Jos van Damme¹

 

¹Netherlands Institute of Ecology, Centre for Terrestrial Ecology (NIOO-CTO), Boterhoeksestraat 22, P.O. Box 40, 6666 ZG Heteren, The Netherlands

²Plant Research International, Droevendaalsesteeg 1, P.O. Box 16, 6700 AA Wageningen, The Netherlands; e-mail: m.zavodna@plant.wag-ur.nl

 

The genus Ficus is one of the most diverse genera of flowering plants. There are over 700 described species divided among four recognized subgenera. Fig trees produce all year round abundant fruits and therefore provide a permanent food supply for many animals, which may act as seed dispersers. Thus, fig species are considered as keystone species for the functioning of many tropical ecosystems as well as for restoration of biodiversity of disturbed habitats in the tropics. Fig fruit and seed production however, are completely dependent on pollination by minute wasps (Agaonidae, Chalcidoidea). This is a mutualistic relationship, since the wasps depend on the fig trees for the completion of their life cycle. Moreover, different fig species have their own specific pollinating wasp species. This mutualism is expected to have important consequences for the maintenance and establishment of viable fig populations in disturbed and fragmented habitats. To investigate these effects, population genetic studies are conducted in two Ficus species (F. montana and F. septica) and their wasps, which have colonized the Krakatau islands after the sterilizing eruption of 1883. The sterilization, the isolation by sea and the archipelago configuration make the Krakatau islands an ideal natural experiment to study colonization and gene flow processes. Therefore codominant highly-polymorphic microsatellite markers are being developed for all four species and will be used to answer the following questions:

How does colonization affect the levels of genetic variation in wasp and fig populations? What is the relative contribution of the local pollinator pool versus the immigrant pollinator pool in recently founded small populations? How are sex-ratio’s in wasps correlated to inbreeding levels?

 

 

 

LIST OF DELEGATES

 

Berg,  (Kees) Cornelius C.  The Norwegian Arboretum/Botanical Institute, University of Bergen, 5259 Hjellestad, Norway, e-mail: Cornelis.Berg@bot.uib.no

 

Burrows, John. Buffelskloof Nature Reserve, P. O. Box 710, Lydenberg, 1100, South Africa, e-mail: botart@intekom.co.za

 

Burrows, Sandie. Buffelskloof Nature Reserve, P. O. Box 710, Lydenberg, 1100, South Africa, e-mail: botart@intekom.co.za

 

Chen, Ying-Ru. Department of Entomology, Taiwan National University, Taiwan, e-mail: yrchen@ms10.url.com.tw

 

Cook James M. Department of Biology, Imperial College, Silwood Park, Ascot SL5 7PY, UK, e-mail: j.cook@ic.ac.uk

 

Greeff, Jaco M. Department of Genetics, University of Pretoria, Pretoria, 0002, South Africa, e-mail: jgreeff@postino.up.ac.za

 

Harrison, Rhett. Center for Ecological Research, Kyoto University, Kamitanakami Hirano-cho, Otsu 520-2113 Japan, e-mail: rhett@ecology.kyoto-u.ac.jp

 

Herre, E. Allen. Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Republic of Panama, e-mail: allenh@dosel.botany.ufl.edu & HERREA@GAMBOA.SI.EDU

 

Hossaert-McKey, Martine. CEFE, CNRS, 1919 route de Mende, 34293 Montpellier Cedex 5, France, e-mail: hossaert@cefe.cnrs-mop.fr

 

Jousselin, Emmanuelle. CEFE-CNRS, 1919 route de Mende, 34293 Montpellier Cedex 5, France, e-mail: jousselin@cefe.cnrs-mop.fr

 

Kjellberg, Finn. CNRS-CEFE, 1919 route de Mende, 34293 Montpellier Cédex 5, France, email kjellberg@cefe.cnrs-mop.fr

 

Lopez Vaamonde, Carlos. Department of Biology & NERC Centre for Population Biology, Imperial College, Silwood Park, Ascot, Berkshire SL5 7PY, UK, e-mail: c.lopez-vaamonde@ic.ac.uk

 

Molbo, Drude. IE-ZEA, B.B., Université de Lausanne, 1015 Lausanne, Switzerland, e-mail: Drude.Molbo@ie-zea.unil.ch

 

Moore, Jamie C. Ecology and Evolution Research Group, School of Biology, University of Leeds, UK, e-mail: bgyjcm@leeds.ac.uk

 

Nash, David. Department of Population Biology, Zoological Institute, University of Copenhagen, Universitetsparken 15, Dk-2100, Copenhagen East, Denmark, e-mail: DRNash@spam.zi.ku.dk

 

Nason, John D. Department of Botany, Iowa State University, Ames, Iowa 50011, e-mail: john-nason@uiowa.edu (temporary email address)

 

Patiño, Sandra. Institute of Ecology and Resource Management, The University of Edinburgh, Mayfield Rd. Edinburgh EH9 3JU, Scotland, e-mail spatino@srv0.bio.ed.ac.uk

 

Shanahan, Mike. Ecology &Evolution Group, School of Biology, University of Leeds, Leeds, LS2 9JT,England, e-mail:mikeshanahan@yahoo.com

 

Sonibare, Mubo A.  Botany and Microbiology Department, University of Ibadan, Nigeria, e-mail: library@kdl.ui.edu.ng

 

Tzeng, Hsy-Yu.  Fushan Station, Taiwan Forestry Research Institute. Post box 132, Ilan 260, Taiwan, ROC

 

van der Velde, Kathy. Department of Animal, Plant and Environmental Sciences, University of the Witwatersrand, P.O. WITS, 2050, South Africa, e-mail nooks@gecko.biol.wits.ac.za

 

van Noort, Simon. Division of Life Sciences, South African Museum, PO Box 61, Cape Town, 8000, South Africa, e-mail: svannoort@samuseum.ac.za

 

Weiblen, George D. Department of Zoology, 203 Natural Sciences Building, Michigan State University, East Lansing, Michigan 48824, USA, e-mail: gweiblen@pilot.msu.edu

 

West, Stuart A. Institute of Cell, Animal & Population Biology, University of Edinburgh, UK, e-mail: Stu.West@ed.ac.uk

 

Zavodna, Monika. Plant Research International, Droevendaalsesteeg 1, P.O. Box 16, 6700 AA Wageningen, The Netherlands,  e-mail: m.zavodna@plant.wag-ur.nl