The Impact On Fig-fig Wasp Mutualism Of Galls Distribution Of Differcnt Fig Wasps Inside Fig Syconia

It has long been a fascinating question for researchers that non-pollinators parasite the fig-wasp mutualism for a long time without any benefits to support. The coexistence mechanism has not been clearly elucidated by now. The utilization mode of galls inside syconia by fig wasps were studied to learn if there is any use to the long time stability of fig-wasp mutualism. The reproductive strategies of two species of Philotrypesis parasite on Ficus hispida were studied. We also compared the resource allocation difference of monoecious Ficus racemosa and dioecious Ficus auriculata. The results are as follows.1 Reproductive characters of two Philotrypesis species on Ficus hispida.P. pilosa oviposite when fig syconia at female-flora phase, it can last two days for them to lay eggs. And Philotrypesis sp. lay eggs when syconia at the inter-flora phase, the oviposite time can last one week. When ovipositing, there usually many wasps gathered on the same syconium. As to P. pilosa, about 20 wasps oviposite simultaneity at most. The per oviposite time for each P. pilosa is 3.97min(S.D.=2.98min, n=32). It is even more for Philotrypesis sp. to oviposite simultaneity, there are about 80 wasps we have ever seen. The oviposite time is 12.75min(S.D.=9.1min, n=30).The offspring number of each P. pilosa is 7.8±9.3, and that for Philotrypesis sp. is 6.5±7.2. The amount of offspring of each P. pilosa and Philotrypesis sp. are not significantly different (Mann-Whitney U test: Z=﹣0.434, P = 0.664). According to the introduction experiment, 52.6% of P. pilosa and 66.7%of Philotrypesis sp. only have daughters, so they must oviposite together to have enough sons to copulate.Both P. pilosa and Philotrypesis sp. prefer to live in the gall ovaries near fig wall, there are only a few of them live in the ovaries near fig lumen.2 Comparison of style length of female florets and their fate in monoecious Ficus racemosa and dioecious Ficus auriculata.At female-flora phase, the style length of F. racemosa is single-apex distributed , while the style length of F. auriculata is bimodal distributed. In syconia of F. racemosa, the average style length is shorter than the ovipositor length of fig pollinating wasps. But refer to F. auriculata, the style length in male syconia is shorter than the pollinator'ovipositor, the style length in female syconia is longer than the pollinators'ovipositor.At post-flora phase of syconia, the galls induced by fig wasps and seeds occupy different interspace in syconia of F. racemosa. Most seeds grow near the fig wall while the galls induced by fig wasps inclined to project into fig cavity. In F. auriculata, the development of fig wasps and seeds are departed into male syconia and female syconia respectively.3 Distribution patterns of galls introduced by different fig wasps in syconium of different Ficus species.In syconia of the Ficus we studied , the galls induced by different fig wasps distribute in different interspace. The distribution patterns of different wasps are as follows. The galls induced by fig pollinating wasps usually occupy the intermediate and inner layers, the galls usually have relatively long pedicels. The galls induced by non-pollinators which are gall-makers have similar distribution pattern as pollinators, but the galls they made are more corpulent, the pedicels are more longer. It is usually easy to recognize. The other non-pollintors'distribution are quite the opposite. The galls they occupied usually have short pedicels, and most of them live near fig wall.Different wasps make different sizes of gall ovaries. Of non-pollinators, gall makers usually induce the biggest gall ovaries. Gall ovaries induced by other non-pollinators have similar sizes as those caused by their hosts.