532 



THE COMMUNITY 



hibernal (June, July, and early August). In 

 this area there are two peaks of flowering: 

 a prevernal peak in August, and an aestival- 

 serotinal peak from December to March. 



types of communities. Only then can the 

 data be surveyed as a whole and a global 

 view of seasonal periodicity be placed on a 

 sound statistical basis. 



PREDOM I NANTS 



«'-U£ JA1 (CYANOCITTA CRISTMA") 



PEROMYSCUS LEUCOPUS NOVEBORACE NSI S (FISCHER) 



iCIURUS NIGER RUFIVENTER (GEOFFROY) 



CARYCHIUM EVIGUUM (SAY) 

 DICYPHUS GRACILENTUS PARSH 

 ERYTHRONEURA OBLIQUA SAY 



/CRNAL SOCIETY 



I EPrlRIX FUSCULA CROT. 



;; GLYPriNA SPURIA LEG. 



3 GONGYLIDIELLUM PALLIDUM EM. 



} PARASITUS SP. 



T PHRUROLITHUS FALUSTRIS BKS. 



SEASONALS 

 ESTIVAL SOCIETY 

 MANGORA GIBBEROSA HT2, 

 PSEUDOGRIPHONEURA CREVECOEURI COO 

 SAPROMYZOSOMA PHILADELPHICA MA C O 



SEROTINAL SOCIETY 



BRACHYPTERUS URTICAE (FABl 

 DIAPHEROMERA FEMORATA (SAY) 

 MANGORA GIBBEROSA HTZ 

 PARASITUS SP 



AUTUMNAi SOCiET^i 

 PHYLLOTRETA SINUATA STEPH. 

 PHYTONOMUS NIGRIROSTPIS ^43. 

 XYSTlCUS -P 



H lEMAL SOCIETY 



i EPITRIX FUSCULA CROT. 



:: JUNCO (JUNCO HYEMALIS) 



.•• TREE SPARROW (SPIZELLA MONTICOLA) 



• TELEPHANUS VELOX HALD 



Fig. 179. Seasonal periodicity in numbers of animals in a red oak-elm-sugar maple forest 

 community in central Illinois. (After Smith.) 



Roughly six months after each flowering 

 period there is a fruiting period. 



Such a seasonal picture is related to many 

 complex, interacting climatic and local in- 

 fluences. We are greatly in need of many 

 seasonal studies in all parts of the world, at 

 various altitudes, and in many different 



Turning to an example in the north 

 temperate region, the contrasts are notable. 

 Smith (1928) studied the seasonal suc- 

 cession in several types of communities 

 in central Illinois, and found that sea- 

 sonal rhythms could be detected by the 

 annual recurrence of groups of species in 



