Sexual Competition For Space of the Parasite Xenos Pallidus Brues in Male Polistes Annularis (L.) (Strepsiptera, Stylopidae, and Hymenoptera, Vespidae)

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 larviform 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 maleannularis 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.