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HYMENOPTERA, Serphidae (= Proctotrupidae) (Proctotrupoidea) --  <Images> & <Juveniles>

 

Please refer also to the following link for details on this group:

 

Serphidae = Link 1

 

These are either solitary or gregarious parasitoids of the larvae of Coleoptera (Staphylinidae, Carabidae, Coccinellidae and Elateridae).  Some species are also known from Diptera.  Serphus ater Nees was reared from the centipede, Lithobius sp.  The value of serphids in biological control is suspect because of their attack on predaceous beetles; however, they are usually so scarce in collections, that not much attention has been focused on them as biocontrol agents.

 

Biology & Behavior

 

The life history of Phaenoserphus viator Hal., a gregarious internal parasitoid of carabid larvae in Europe, was studied by Eastham (1929).  He presumed a single annual generation on Pterostichus niger Schall., and adults appear during August and September in the field.  Larval development is slow during the periods that the host is feeding and hibernating, and 1st instar larvae persist until the host larva nears pupation in spring or early summer.  Rapid parasitoid growth then ensues, and the host body contents are rather thoroughly consumed.  After feeding, the larvae (30 or more) emerge from the body in an orderly manner.  Just prior to breaking through the integument, they are all oriented longitudinally, with heads directed caudad.  Individual ruptures in the integument are made in transverse rows of 3-4, always ventrally and intersegmentally.  About 3/4ths of the parasitoid body is extruded from the wound, and the caudal portion remains within it to serve to hold the prepupa and pupa in position.  Immediately after emergence, the last larval molt occurs, but no cocoon is formed.  The external prepupal stage is 7-10 days and the pupal stage lasts ca. 2 weeks (Clausen 1940/1962).

 

Phaenoserphus viator, a parasitoid of the larvae of Carabus in Europe, was studied by Raynaud (1935).  Behavior is similar to P. viator, except that winter was thought to be passed in the egg stage.

 

Paracodrus apterogynus Hal. is parasitic on the larva of Agriotes.  Its development is similar to Phaenoserphus, and emergence habit is identical, although if the number is not excessive only two individuals emerge from each intersegmental area (Zolk 1924).  A single host gives rise to 14-52 parasitoids, and gravid females may contain as many as 170 eggs.

 

Exallonyx philonthiphagus Williams is a solitary internal parasitoid of mature larvae of Philonthus turbidus Erich. in Hawaii.  Fully fed larvae emerge from the host body through an aperture in the 5th or 6th abdominal segment ventrally (Williams 1932).  The pupa lies with its venter to that of the host, and the head is pointed forward.  In female pupae, only the tip of the abdomen remains within the host body, while in males the head and thorax only are external (Clausen 1940/1962).

 

In Japan observations have been made on an unnamed species which was solitary on Scymnus larvae (Clausen 1940/1962).  Oviposition took place in 1st and early 2nd instar larvae and was accomplished by bringing the abdomen forward beneath the body and inserting it by a rapid thrust, somewhat ventrally, in the host's mid abdominal region.  Larval development was rapid, and feeding was completed at the time the host larva attached itself to the leaf or bark in preparation for pupation.  Then the parasitoid larva lay with its head at the caudal end of the body.  The host body contents were not entirely consumed, and feeding was apparently only on the fluid or semi fluid contents.  Emergence from the host was not by cutting the integument, but in a manner as follows:  The head of the mature larva was pressed against the skin ventrally near the caudal end of the body.  Then, by rhythmic pulsations over several hours, it was forced outward slowly until a break occurred.  When most of the body was free, the last larval exuviae was cast and the pupa then lay venter to venter with the host and with the tip of the abdomen curved ventrally, enveloped in the last larval exuviae, but still embedded in the host body.  It required ca. 12 hrs for complete emergence and another 36 hrs before pupation, the entire cycle being completed in ca. 20 days (Clausen 1940/1962). 

 

Clausen (1940) noted that it appears that there is considerable uniformity in the manner of larval development, emergence from the host body and the peculiar position assumed by the pupa beneath the host.

 

For detailed descriptions of immature stages of Serphidae, please see Clausen (1940/1962).

 

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References:   Please refer to  <biology.ref.htm>, [Additional references may be found at:  MELVYL Library]

 

Brues, C. T.  1939.  Serphidae in Baltic Amber, With the description of a new living species.  Proc. Amer. Acad. Arts & Sci. 58:  344-

 

Fan, J., & J. He. 2003.  Hymenoptera: Serphidae.  In:  Fauna of Insects in Fujian Province of China. Ed. Haung, B. K.  Vol. 7: 716-723.

 

Kieffer, J. J.  2009.  Serphidae (= Proctotrupidae) et Calliceratidae (= Ceraphronidae).  Bibliolife, Sept. 2009.

 

Ulrich, W.  2004.  Soil-living parasitic Hymenoptera: comparison between a forest and an open landscape habitat.  Pedobiologia 48(1):  59-69.