A large proportion of the Hymenoptera are beneficial to man in that they are either parasitic on other animals or, as in the case of bees, assist in the pollination of flowers. A small group of genera are, however, purely vegetable feeders and the larval stages feed either on or in plant material.
The family Eurytomidae has one large genus Harmolita in which nearly all the numerous species are plant feeders. The genus Eurytoma are parasitoids on the larvae of Harmolita sp. (their near relatives) and when these die, they continue the rest of their developmental period feeding on the sap of the plants which surround them.
The pods of various leguminous trees are hosts to a number of phytophagus Hymenoptera. The genus Bruchophagus, with few exceptions, feed in the seeds of Acacia and related trees. The fact that these pods are also liable to be infested with bruchids has led in a number of instances to Bruchophagus being labelled as bruchid parasites (whereas of course they are plant feeders). The name Bruchophagus was given to this genus by Ashmead because of the supposed association with the Bruchidae.
The majority of the phytophagus Hymenoptera associated with the pods of legumes are connected with species having small seeds such as Crotolaria and some Vigna sp. The Acacia species are not very prone to attack and this may be because the pods are difficult to enter or the larvae are not able to metabolise the secondary compounds sometimes contained in these seeds. From the little biological knowledge available for this group it may be assumed that attack takes place in the early stages of pod development. Although these insects feed in the same environment as the bruchidae, the incidence of attack is considerably lower and therefore of lesser importance.
Without detailed observations on these insects it will be very difficult to distinguish between the damage caused by them or other indiscriminate feeders.
