Fragmentation Effects on Diversity of Wasp Community and Its Impact on Fig／Fig Wasp Interaction in Ficus racemosa L.

Abstract: Habitat fragmentation usually results in alteration of species composition or biological communities. However, little is known about the effect of habitat fragmentation on the fig/fig wasp system. In this study, we compared the structure of a fig wasp community and the interaction between figs and fig wasps of Ficus racemosa L. in a primary forest, a locally fragmented forest and a highly fragmented forest. Our results show that, in the highly fragmented forest, the proportion of pollinator wasps is lower and the proportion of non-pollinator wasps is higher compared with the primary forest and locally fragmented forest. The proportion of fruits without pollinator wasps in mature fruits is also greatly increased in the highly fragmented forest. The proportion of galls in all female flowers increases in the highly fragmented forest, whereas the proportion of viable seeds does not change considerably. The disruption of groups of fig trees results in a decrease in pollinator wasps and even might result in the extinction of pollinator wasps in some extreme cases, which may transform the reciprocal interaction between figs and fig wasps into a parasite/host system. Such an effect may lead to the local extinction of this keystone plant resource of rain forests in the process of evolution, and thereby, may change the structure and function of the tropical rain forest.

N:P stoichiometry in Ficus racemosa and its mutualistic pollinator

Aims Nitrogen(N)and phosphorus(P)are limiting nutrients to life across a variety of ecosystems.N:P stoichiometry,concerning the balance of these two elements,has recently received great attention.However,little is known about the nature of N:P stoichiometry in obligate mutualism.Methods N:P stoichiometry of Ficus racemosa and its pollinating wasp Ceratosolen fusciceps,an example of coevolving obligate mutualism,was investigated,and the N:P stoichiometric traits of male versus female wasps were compared.Important Findings Nutrient concentrations in C.fusciceps were much higher than in its host.N enrichment in fig wasp was evidently stronger than phosphorus.N concentrations of male fig wasps were significantly higher than those of females,while P concentrations of female fig wasps were remarkably higher than those ofmale ones.Therefore,N:P ratios inmale fig wasps were significantly greater than in female fig wasps.N:P ratio in fig-pollinating wasp displayed linear functions to fig N contents,suggesting that N limitation in fig wasps may dominate the nutritional relationship between fig pollinator and its host.Fig wasp population size had significant influences on N concentrations in host fig and female wasp per se.Driven by the nutritional stress of pollinating and parasite insects,fig fruit preferred increasing its diameter first but not nutrient richness.Values forNand P contents of fig pollinators showed seasonal differenceswith greater N:P ratios in dry season than in rainy season.The observations suggest that tropical climate change would result in more severe N limitation to fig-pollinating wasp and may further influence the stability of fig–fig wasp mutualism.

Reversible Antifertility Activity of Hydroalcoholic Extract of Ficus Racemosa L. in Male Mice

Objective To evaluate male antifertility activity of hydroalcoholic extract of Ficus racemosa bark. Methods Swiss male mice were orally administered hydroalcoholic extract of Ficus racemosa bark （50 mg/kg for 30 d and 100 mg/kg body weight for next 30 d）, and the effect of the treatment on body weight, reproductive organs weight, sperm, biochemical profile （sialic acid in epididymis and fructose in seminal vesicle）, fertility and vaginal contraceptive efficacy was investigated. Recovery studies were also performed. Results Extract reduced fertility to 70% within 60 d. Suppression of cauda epididymis sperm count, motility, viability and abnormal morphology was observed. Marked reduction was noted in the weight of reproductive organs and the level of sialic acid in epididymis and fructose in seminal vesicle. Vaginal application of bark extract exhibited 80% vaginal contraceptive efficacy. After cessation of plant extract treatment, the altered parameters recovered after 60 d. Conclusion Clinical assessment of male antifertility agents should include acceptability, safety and efficacy during and after the treatment. The above results revealed the potential, reversible male antifertility effect of hydroalcoholic extract F. racemosa bark.

Seasonal Changes in the Trade-off Among Fig-supported Wasps and Viable Seeds in Figs and Their Evolutionary Implications

Abstract: What the real trade-off is among fig-supported wasps and the viable seeds of figs is heatedly debated in the studies of fig/fig wasp mutualism. In the present study, we collected wasp offspring (galls) and the viable seeds of premature fruits, and determined the foundress number in receptive fruits and all the types of wasps supported by Ficus racemosa L. during both the rainy and dry seasons in Xishuangbanna, China. The data show that the galls were positively correlated with viable seeds (n= 32; r= 0.74; P < 0.001) when the proportion of vacant female flowers (PVFF) was high, in April (68.0%), and were negatively correlated with viable seeds (n= 48; r=?0.59; P < 0.05) when PVFF were limited (PVFF = 42.6%) during a colder month (January). The mean foundress number per fruit during the colder months is significantly lower than during the warmer months (F5, 603= 27.9; P < 0.001) and pollinator wasps can live longer during the colder months. During the colder months, the proportions of non-pollinators and wasp offspring are higher than those found during other months, whereas the proportion of viable seeds is not different compared with that of other months. Non-pollinator wasps tend to oviposit the female flowers that have been oviposited by pollinator wasps. The non-pollinators only negatively affect pollinator wasps and there is no obvious negative effect of non-pollinator wasps on viable seeds, so ovipositing by non-pollinator wasps will not result in the extinction of the figs during the process of evolution. The results of the present study indicate that figs can allow less foundresses to be in fruit cavities when PVFF are limited, which provides supporting evidence for the previous assumption that the plants have developed a mechanism to maintain a stable system because of the conflicts between the parties involved.