Some Factors Influencing the Predation of Polistes Wasps on the Tobacco Hornworm
Some Factors Influencing the Predation of Polistes Wasps on the Tobacco Hornworm
复制标题
影响马蜂捕食烟草天蛾的一些因素
DOI：
10.1093/jee/50.6.778
复制
发表时间：
1957
影响因子：
2.2
通讯作者：
F. R. Lawson
中科院分区：
文献类型：
--
作者：
R. L. Rabb;F. R. Lawson
The following is substantially the authors' summary. Investigations of several factors influencing the effectiveness ofPolistes exclamans exclamansVier. andP. fuscatus fuscatus(F.) in the natural control ofProtoparce sexta[Manduca sexta](Joh.) on tobacco were made near Clayton, North Carolina, in 1956. The seasonal variations in the abundance of theProtoparcelarvae and those of other free-feeding species were reflected in the samples of prey taken from the wasps returning to their nests.Plathypena scabra(F.), although absent from prey samples in June, was one of the most numerous species taken in July and August; it decreased sharply after this, when three large fields of soyabeans, on which it had been feeding, were ploughed under.Within a distance of 800 ft. from tobacco, the percentage ofProtoparcein the prey ofPolistes exclamanswas inversely proportional to the distance from tobacco; the same relation was not clearly demonstrated forP. fuscatus, which is slightly larger and apparently flies a greater distance thanP. exclamans, but the recovery of marked wasps released in a tobacco field showed an inverse relation between distance and the numbers of both species. Most of theProtoparcelarvae carried to the nests were in the third or fourth instars, but the wasps killed many smaller larvae without removing them. They inspected but usually did not kill fifth-instar larvae.Polisteshad little effect in reducing damage to tobacco byHeliothis virescens(F.) andH. zea(Boddie), which feed within the protection of terminal buds during their period of greatest economic importance, but caused large reductions in populations ofProtoparce. Predators, chieflyPolistesspp., killed 68 per cent. of the latter in an experimental area, but, along with other natural enemies, failed to reduce the population below the economic level. This failure is not considered representative, however, because of the abnormally highProtoparcepopulation and the paucity of natural nesting sites forPolistesnear the tobacco. In addition, the abundance of alternative prey, particularlyPlathypenaon neighbouring soyabeans, undoubtedly reduced the attack onProtoparce.
