SEXUAL COMPETITION FOR SPACE OF THE PARASITE 
XENOS PALLIDUS BRUES IN 
MALE POLISTES ANNULARIS (L.) 
(STREPSIPTERA, STYLOPIDAE, AND 
HYMENOPTERA, VESPIDAE)* 
By S. W. Dunkle 
Department of Entomology, University of Florida 
Gainesville, Florida 32611 
Introduction 
Xenos pallidus Brues is the only known stylopid parasite of 
Polistes annularis (L.) and is apparently restricted to this host 
(Bohart, 1941, and personal communication, 1979). X. pallidus 
within the host abdomen absorb nutrients directly from the blood. 
When mature the head and thorax is protruded between two of the 
wasp’s abdominal segments. The female remains a permanent larvi- 
form parasite while the male metamorphoses to pupa and adult. The 
male emerges and flies in quest of a female for his lifespan of a few 
hours. Eggs hatch within the body of the female and the larvae crawl 
from her brood chamber onto the surface of the host. Eventually they 
find and bore into larvae of P. annularis. Two or more generations of 
parasites develop per season and apparently overwinter as adult 
females in queen annularis. 
During the period 7 October-12 November 1979 I collected P. 
annularis on Newnan’s Lake, near Gainesville, Florida. The colonies 
collected contained a total of 13372 queens and 11542 males. The 
queens were used for venom extraction and are not included in the 
following discussion, but my subjective impression while sexing the 
wasps was that the males were more often parasitized. Between 17 
November and 23 November 1979, 1691 queen and 331 male annula¬ 
ris were collected at several other lakes near Gainesville. These 
queens were also used for venom extraction, and since only 3 of the 
males were parasitized by pallidus, only males from Newnan’s Lake 
are used in the analysis which follows. 
‘Florida Agricultural Experiment Station Journal Series, number 2267. 
Manuscript received by the editor April 3, 1980. 
327 
