Description & Statistics
This subfamilly is one of the largest groups in the Sphecidae, although there are only 9 identified genera. The subfamily has also been given family status at times. Members are solitary, predatory wasps, each genus with a unique prey preferences. Mature females dig tunnels in the ground to nest.
As with all other sphecoid wasps, the larvae are carnivorous, and females seek prey on which to lays their eggs. They provision the nest cells with paralyzed, living prey that the larvae feed on
The notorious "bee wolf," Philanthus triangulum F. (= apivorus Latr.) is of special concern to bee keepers in some parts of Europe. An extended account of this insect in relation to honeybees was presented by Fabre (1891). Female Philanthus kills the adult bee by stinging it in the throat, after which she begins an extensive malaxation of the throat by means of which the honey in the crop is forced up to the mouth, where it is consumed. Alternate malaxation and feeding may continue for more than an hour. Then the prey is dragged to the burrow, which extends 1 m or more into the soil and ends in a group of cells, in one of which the bee is placed. The egg is then laid ventrally on the thorax. Clausen (1940) mentioned that it is believed that the larvae are not able to mature on bees which have not been deprived of honey. A much larger number of bees is killed than can be used for stocking the nest.
An extended account of the status of this pest in certain honey-producing sections of Germany is given by Thiem (1935). In one area nearly 2-million bees, representing 48 hives, were destroyed in one season. The following season, boys who had been employed for that purpose killed 31,000 Philanthus adults. However, ca. 1/2 million emerged later anyway. The factory and mine dumps of brown coal and salt waste in these areas seemed to provide exceptionally favorable conditions for the development of the wasp. The only practical control appeared to be elimination of these favored breeding sites. Sometimes covering the areas with soil and inducing grass to grow accomplished this. Other measures involved individual treatment of the wasp burrows in the more sandy areas.
P. gibbosus Fab. kills its prey, adult Halictidae, at the time of capture, and considerable putrefaction occurs before larval feeding is complete (Reinhard 1924). The burrows may be several meters in length, comprising a number of cells. From 8-16 bees are placed in each cell, and the egg is laid on the last of the series to be brought in, usually a small prey. Great specialization is shown in the attack of Aphilanthops frigidus Smith on ants of the genus Formica (Wheeler 1913). Only queen ants are attacked, and capture occurs only during the nuptial flight. The wasp responds only to the visual stimulus of the winged individuals and ignores those lacking wings. After stinging the queen, the wings are cut off and the body dragged into the burrow. The egg is laid on an isolated ant which has been cut into two parts, and others are taken from storage and fed to the larva as it grows. Because flights of any single ant species occur only during a short period, the wasp preys on a series of species during the season (Clausen 1940/1962).
Species of the subfamily Philanthinae burrow in the soil, where they excavate a series of cells and store them with adult prey. The dominant genus Philanthus is known to prey on various Hymenoptera, in particular Apoidea.
This group was considered as a subfamily of Philanthidae in the Apoidea by Finnamore & Michener (1993). They are known from all regions except Australasia. They are numerous around flowers, and their prey generally includes adult Apiformes in several families (including Apis mellifera L.). This gave rise to the common name "bee-wolf.” There were more than 152 species known by 2000.
Krombein (1981) keyed the species of Philanthidae of Sri Lanka and Bohart & Grissell (1975) keyed the Nearctic genera and species of Philanthidae
Bohart, R.M. & A. S. Menke. 1976. Sphecid Wasps of the World: a Generic Revision. University of California Press, Berkeley, California.
Menke, A.S. 1967. Odontosphex Arnold, a genus of the Philanthinae, with a key to the tribes and genera of the subfamily (Hymenoptera; Sphecidae). Pan-Pacific Entomologist 43: 141-148.