REPRODUCTION AND DISPERSAL 



86i 



length that the insects are unable to lay their eggs in the right spot (fig. 1188). But 

 in the staminate figs, known as caprifigs, there are short-styled rudiments of 

 pistillate flowers (often called gall flowers, fig. 1189), in which eggs may be placed 

 properly, later hatching into wasps. Some stimulus exerted by the insect causes 

 the ovary primordia to develop into seedless galls. After a time the males hatch, 

 eating their way out 

 of the galls in which 

 they developed and 

 into the galls occu- 

 pied by developing 

 females ; copulation is 

 followed by the death 

 of the males within 

 the caprifig. The fe- 

 males thereupon 

 escape (fig. 11 90), 

 crawling over the 

 staminate flowers of 

 the caprifig and be- 

 coming dusted with 

 pollen; those that 

 chance to visit figs 

 incidentally pollinate 

 the stigmas therein, 

 but have no progeny, 

 while those that go 

 to caprifigs have prog- 

 eny, but are of no 

 service in pollination. 



One of the strangest features of a process strange throughout is that the pistil- 

 late flowers mature two months before the staminate flowers; however, by the time 

 the latter are mature, another crop of synconia has developed with stigmas ready for 

 pollination, so that stigmas of a given generation are pollinated from inflorescences 

 of the preceding generation. In southern Italy there are three such crops of figs 

 and caprifigs each year (viz., in April, June, and August), and three corresponding 

 generations of wasps. This symbiosis between Picus and Blastophaga has been 

 denominated mutualism, but surely it is a somewhat destructive form of mutualism, 

 where death without progeny comes to such a large proportion of the symbionts on 

 each side, namely, to the female insects that enter the figs and to the pistillate flowers 

 of the caprifigs. 



Centuries before the process of pollination was discovered, the ancients cultivated 

 the commercially valueless caprifigs, and placed branches with maturing synconia 

 on fertile fig trees ; this process, known as caprification, makes it easy for the female 

 wasps (which fly weakly, though possessing wings) upon emergence from the capri- 

 figs to enter and pollinate the figs. Caprification and pollination are quite unneces- 

 sary for reproduction commercially, since figs always are propagated from cuttings. 

 Caprification is not always necessary, even for the production of commercial figs. 



'1189 1187 n 118 

 Figs. 1186-1190. — Pollination of the fig {Ficus Carica): 

 1 1 86, a synconium cut longitudinally, showing gall flowers pro- 

 duced by the fig wasp {Blastophaga grossorum) ; near the mouth 

 of the cavity is a female fig wasp, which has escaped from one 

 of the galls; 1187, a similar synconium with seed-producing 

 pistillate flowers; near the mouth of the cavity are two female 

 fig wasps, one of which has already crept inside; 11 88, a long- 

 styled seed-producing flower; 1189, a short-styled gall flower; 

 iigo, a fig wasp escaping from a gall flower. — From Kerner. 



