Aquatic Insects of Michigan

by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
University of Michigan

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Aquatic Hymenoptera (Parasitic Wasps) of Michigan - Identification

[under construction]

A number of parasitic wasps have come adapted for aquatic existence by attacking various life stages (principally eggs, larvae and/or pupae) of aquatic insect groups, especially those of Heteroptera and holometabolous orders (e.g., Lepidoptera, Coleoptera, etc.).

Information regarding the occurrence of aquatic Hymenoptera in Michigan is currently in preparation. Please email the author if you have records or information regarding this group in Michigan.

Below is a key to adult hymenoptera genera known to parasitize aquatic insects found in Michigan. Ecological information - and the key - is adapted from Bennett (2007), and will be updated with surveying of deposited collection material.


    a. Wing venation reduced

    b. Front wings usually with no enclosed cells, but, if present, with <5 enclosed cells
    c. Wings usually with long marginal fringe
    d. Hind wings veinless, or with one vein (enclosed cells absent)
    also: Rarely wingless
    1b a. Wing venation well-developed 9
    b. Front wings with >5 enclosed cells
    c. Without a long marginal fringe, at least on the anterior margins
    d. Hind wings with >2 veins, and at least one enclosed cell

    Hind femur enlarged and with a toothed or denticulate ventral margin

    2b Hind femur not enlarged, and without a toothed ventral margin 3
    3a(2b) Tarsi 3-segmented
    also: Parasites of insect eggs
    3b Tarsi 4- or 5-segmented 4
    4a(3b) Tarsi 4-segmented
    4b Tarsi 5-segmented 6
    5a(4a) a. Marginal vein short, terminating within the first third of the wing's length
    b. Stigmal vein absent
    c. Body not metallic
    also: Parasites of insect eggs
    5b a. Marginal vein long, extending beyond one-half the length of the wing Eulophidae
    b. Stigmal vein present
    c. Body with metallic reflections or highly colored
    Antennae inserted on the shelf at middle of face Diapriidae
    6b Antennae not arising from the shelf at middle of face 7

    Antennae with 2 distinctly smaller segments (anelli) between the pedicel and the first funicle segment

    also: Together the anelli thinner, and usually shorter, than the first funicle segment
    7b Antennae without 2 distinctly smaller segments between the pedicel and the first funicle segment 8
    8a(7b) a. Scutellum with 2 pits at the base, and an elevated pit ("cup") on the disk
    b. Forewing without a stigmal vein
    c. Abdomen compressed
    8b a. Scutellum without an elevated cup Scelionidae
    b. Forewing with a stigmal vein
    c. Abdomen depressed
    9a(1b) a. Hindwing with an anal lobe
    Pompilidae, Anoplius
    b. Trochanters 1-segmented
    c. Antennae with <15 segments and curled apically
    also: parasitizes Dolomedes (Araenea: Pisauridae) adult spiders
    9b a. Hindwing without an anal lobe 10
    b. Trochanters 2-segmented
    c. Antennae with > 15 segments

    Forewing with 2 recurrent veins (second recurrent vein is a crossvein in the apical lower half of the wing disk)

    10b Forewing with 1 recurrent vein (no crossvein in the apical lower half of the wing) Braconidae

Braconidae (Ichneumonoidea)

    Ademon - parasitizes ephydrids (Hydrellia) larvae-pupae
    Aphanta - parasitizes ephydrids (Hydrellia) pupae
    Asobara - parasitizes ephydrids (Parydra) larvae-pupae
    Bracon (=Microbracon) - parasitizes noctuids (Archanara) larvae
    Chaenusa - parasitizes ephydrids (Hydrellia) eggs-pupae
    Chorebidea - parasitizes ephydrids (Hydrellia) pupae
    Chorebidella - parasitizes ephydrids (Hydrellia) pupae
    Chorebus - parasitizes ephydrids (Hydrellia) pupae
    Dacnusa - parasitizes ephydrids (Hydrellia) pupae
    Opius - parasitizes ephydrids (Hydrellia) larvae-pupae
    Phaenocarpa - parasitizes sciomyzids (Antichaeta) pupae


    Trichopria - parasitizes ephydrid (Hydrellia), sciomyzid (Atrichomelina, Dictya, Elgiva, Sepedon ), and psephenid (Psephenus) pupae

Eulophidae (Chalcidoidea)

    Aprostocetus - hyperparasite in lestid (Lestes) eggs
    Mestocharis - parasitizes dytiscid (Dytiscus) eggs
    Psephenivorus - parasitizes psephenid (Psephenus) prepupae, pupae
    Tetrastichus - hyperparasite in, and parasite of, lestid (Lestes) eggs

      Tetrastichus coerulescens Ashmead

Fatigidae (Cynipoidea)

    Hexacola - parasitizes ephydrid (Parydra) larvae-pupae
    Kleidotoma - parasitizes ephydrid (Parydra, Scatella) larvae-pupae

      Kleidotoma parydrae

Ichneumonidae (Ichneumonoidea)

    Apsilops (=Neostricklandia, =Trichocryptus, =Trichestema) - parasitizes pyralids (Occidentalia, Chilo, Schoenobius, Nymphula) larvae - Michigan species: Apsilops bicolor (Cushman), Apsilops hirtifrons (Ashmead), Apsilops sericata (Viereck)
    Bathythrix (=Hemiteles) - parasitizes gyrinids (Gyrinus) larvae in pupal cases - Michigan species: Bathythrix triangularis (Cresson)
    Cremastus - parasitizes pyralids (Occidentalia, Chilo, Nymphula) larvae and pupae - Michigan species: Cremastus bilineatus Cushman, Cremastus incompletus (Provancher), Cremastus orbus Dreisbach - IN
    Medophron - parasitizes dytiscids (Agabus, Dytiscus) pupae
    Mesoleptus - parasitizes sciomyzids (Antichaeta) pupae - Michigan species: Mesoleptus declivus (Provancher), Mesoleptus incompletus Provancher
    Oecotelma (=Hemiteles) - parasitizes gyrinids (Gyrinus) larvae in pupal cases
    Phygadeuon - parasitizes sciomyzids (Antichaeta) pupae - MIchigan species: Phygadeuon aciculatus Provancher
    Pleurogyrus (=Hemiteles) - parasitizes gyrinids (Gyrinus) larvae in pupal cases
    Sulcarius - parasitizes limnephilids (Limnephilus) in larvae in cases
    Therascopus (=Eriplanus) - parasitizes gyrinids (Gyrinus) larvae in pupal cases

Mymaridae (Chalcidoidea)

    Caraphractus - parasitizes notonectid (Notonecta), gerrid (Gerris), calopterygid (Calopteryx), and dytiscid (Dytiscus, Agabus ) eggs

Pompilidae (Vespoidea)

    Anoplius - parasitizes Dolomedes (Araenea: Pisauridae) adult spiders

Pteromalidae (Chalcidoidea)

    Gyrinophagus - parasitizes gyrinid (Gyrinus, Dineutes) larvae in pupal cases
    Sisyridivora - parasitizes sisyrid (Climacia) larvae and pupae in cocoons

Scelionidae (Proctotrupoidea)

    Telenomus - parasitizes tabanid (Tabanus, Chyrsops) eggs
    Thoron - parasitizes nepid (Nepa, Ranatra) eggs
    Tiphodytes - parasitizes gerrid (Gerris, Trepobates, Limnoporus) eggs

Trichogrammatidae (Chalcidoidea)

    Hydrophylita - parasitizes coenagrionid (Ischnura) eggs
    Lathromera - parasitizes lestid (Lestes) eggs
    Paracentrobia - parasitizes lestid (Lestes) eggs
    Prestwichia - parasitizes nepid (Nepa, Ranatra ), dytiscid (Dytiscus) eggs
    Trichogramma - parasitizes water mite (Hydracarina), sialid (Sialis), corydalid (Corydalus), and sciomyzid (Sepedon, Elgiva,Tetanocera) eggs

Key to adults
(modified from Pinto 2006)

    1a a. Scutellum with at least 2 pair of setae (anterior pair may be very short), midlobe of mesoscutum usually with 2 or more pair of setae
    b. Eyes light to dark red in color
    also: Maxillary palp present; antennae with 4 postanellar segments, and; antennae without placoid sensilla (PLS) on surface; mesosomal dorsum sculptured, at least with obsolescent reticulae; fore wings very narrow, about 7x as long as wide, and densely setose
    1b a. Scutellum and midlobe of mesoscutum each with 1 pair of setae 2
    b. Eyes black in color
    2a(1b) a. Fore wing very narrow, 5-10x as long as wide
    b. Antenna with 2 funicular segments, both longer than wide
    c. Female club with two large spatulate sensilla
    2b a. Forewing considerably broader, considerably less than 5x as long as wide 3
    b. Antennae with funicle variable in structure, or entirely absent
    c. Female club without large spatulate sensilla
    also: Hind tibial spur short, apically pointed, at most slightly longer than the first tarsomere
    3a(2b) Antennae with only 1 elongate postanellar segment
    Trichogramma (Trichogramma) in part
    3b Antennae with more than 1 postanellar segment 4
    4a Antenna with a 2-segmented funicle and a 1-segmented club
    Trichogramma in part
    also: Fore wing with SV clearly diverging from the anterior margin and MV, never reduced to a small appendix; Fore wing disk noticeably setose, hind wing disk with two setal tracks (posterior track may be complete or partial), its anterior fringe considerably shorter than the posterior fringe; antenna with F2 not narrowed at apex, not bottle-shaped; Fore wing with RS1 track present behind the stigmal vein; premarginal vein (PM) with 2 setae
    4b Antenna with funicle present or not, but with a club distinctly 3-segmented 5
    also: maxillary palp 1-segmented
    5a(4b) Antennae with funicle absent
    also: Antennal club 5-segmented, club segment 1 width subequal to the maximum club width; female antennal club with a terminal process at the apex; fore wing with RS1 absent, discal setation moderately dense at most; male metasomal tergum VI (and often VII) with modified areas
    5b Antennae with funicle present 6
    6a(5b) Fore wing venation sinuate, greatest curvature distally where marginal vein (MV) gradually curves away from the anterior wing margin onto the stigmal vein (SV) Trichogramma (Vanlisus) in part
    6b Fore wing venation not sinuate, with the MV ending abruptly distally, not gradually curving onto the SV Paracentrobia
    also: Antennal club distinctly 3-segmented; 2 anelli present; Male sternum VIII modified into two narrow, strap-like appendages; anntenal funicular segments lacking PLS; sunicle distinctly narrower than the base of the club, funicular segment 1 about as wide as long, segment 2 transverse, distinctly broader than long; male genitalia with ADG incorporated into GC


    Bennett AMR. 2007. Aquatic hymenoptera, pp. 673-686 in Merritt RW, Cummins KW, Berg MB, An Introduction to the Aquatic Insects of North America, Fourth Edition. Kendall/Hunt Publishing Company, Dubuque, Iowa, USA.
    Pinto JD. 2006. A review of the New World genera of Trichogrammatidae (Hymenoptera). Journal of Hymenoptera Research 15(1): 38-163.

Page created: June 26, 2006; Last edited: October 25, 2007 (EB)